1
|
Su Y, Zhou L. Review of single-molecule immunoassays: Non-chip and on-chip Assays. Anal Chim Acta 2024; 1322:342885. [PMID: 39182983 DOI: 10.1016/j.aca.2024.342885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 06/17/2024] [Accepted: 06/17/2024] [Indexed: 08/27/2024]
Abstract
Enhancing the sensitivity of immunoassays is an important requirement in the field of immunology, especially in light of rapid developments in genetic testing, making the detection of low-abundance protein biomarkers crucial. Therefore, innovations in highly sensitive immunoassays are imperative. This demand has led to the emergence of single-molecule immunoassays (SMIs), driving advancements in early diagnostic techniques, and ushering in a new era of immunoassays. This review begins by tracing the development of immunoassays and offers a detailed discussion of SMI technology across two distinct pathways: non-chip (SMI without microfluidic chips) and on-chip (SMI with microfluidic chips). Furthermore, we evaluated and compared these methods using two pathways. In addition, this review discusses the significance of SMI techniques in the diagnosis of various diseases and their current applications in laboratory and clinical settings. The progress of SMI in commercial applications and suggestions for innovative directions are also summarized. Despite the considerable potential of SMI, these technologies face challenges in practical application, particularly in developing countries and economically disadvantaged regions. The final section of this review addresses the challenges and prospects of these technologies.
Collapse
Affiliation(s)
- Yan Su
- State Key Laboratory of Biochemical Engineering, PLA Key Laboratory of Biopharmaceutical Production & Formulation Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China; Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, 100190, China
| | - Lei Zhou
- State Key Laboratory of Biochemical Engineering, PLA Key Laboratory of Biopharmaceutical Production & Formulation Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China; Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, 100190, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Innovation Academy for Green Manufacture Institute, Chinese Academy of Sciences, Beijing, 100190, China; Biosafety Research Center Yangtze River Delta in Zhangjiagang, Suzhou, 215611, China.
| |
Collapse
|
2
|
Lyu W, Cheng X, Yu Z, Dong R, Sheng Z, Zhang T, Yin X, Shen F. Early-stage diagnosis of ovarian cancer via digital immunoassay on a SlipChip. Talanta 2024; 280:126782. [PMID: 39216422 DOI: 10.1016/j.talanta.2024.126782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 08/20/2024] [Accepted: 08/24/2024] [Indexed: 09/04/2024]
Abstract
Ovarian cancer (OC) is one of the three major gynecologic malignancies and has the highest mortality rate because of the late diagnosis. Liquid biopsy based on serum protein biomarkers has demonstrated great potential for early diagnosis but remains limited by the analysis performance of conventional immunoassay technologies, such as chemiluminescence, and biomarkers, such as CA125. To address this challenge and achieve accurate early-stage diagnosis of OC, we developed a digital immunoassay on a SlipChip (DiSC) for quantitative analysis of a potential serum protein biomarker, Spondin-1 (SPON1). The DiSC system achieved a limit of detection (LoD) of 23 fg/μL for digital quantification of SPON1. The DiSC system was utilized to quantify the serum level of SPON1 in 357 clinical serum samples, including 63 from patients with benign ovarian tumors and 294 from patients with malignant ovarian cancer, ranging from stages I to IV. SPON1 concentrations were significantly different in samples from patients with malignant ovarian cancer. Notably, significantly different SPON1 levels were observed in early stages (I and II), in lymph node-negative cases (N0), and before metastasis (M0), suggesting that SPON1 could serve as a sensitive diagnostic biomarker for early-stage OC. The differential diagnostic model based on SPON1 levels quantified using DiSC demonstrated an area under the curve (AUC) of 0.8187 for early-stage OC, a significant improvement over CA-125 (AUC = 0.6967). For OC of all stages, the AUC was 0.8225, which could be further increased to 0.8750 when combined with CA-125. This showcases the potential of SPON1 as a novel biomarker for sensitive early-stage diagnosis of ovarian cancer and the capability of the DiSC system in discovering low-abundance biomarkers for disease diagnosis.
Collapse
Affiliation(s)
- Weiyuan Lyu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xinrui Cheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Ziqing Yu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Ruirui Dong
- Affiliated Women's Hospital of Jiangnan University, Jiangnan University, Wuxi, 214002, China
| | - Zheyi Sheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Ting Zhang
- Affiliated Women's Hospital of Jiangnan University, Jiangnan University, Wuxi, 214002, China
| | - Xia Yin
- State Key Laboratory for Oncogenes and Related Genes, Shanghai Key Laboratory of Gynecologic Oncology, Department of Obstetrics and Gynecology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China.
| | - Feng Shen
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China.
| |
Collapse
|
3
|
Xie Y, Chen Z, Cai D, Huang D, Huang E, Yang X, Zhang T, Wen H, Wang Y, Zhao M, Liu D, Xu B. Rapid Detection of Uropathogens Using an Integrated Multiplex Digital Nucleic Acid Detection Assay Powered by a Digital-to-Droplet Microfluidic Device. Anal Chem 2024. [PMID: 39018349 DOI: 10.1021/acs.analchem.4c02578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/19/2024]
Abstract
The digital nucleic acid detection assay features the capability of absolute quantitation without the need for calibration, thereby facilitating the rapid identification of pathogens. Although several integrated digital nucleic acid detection techniques have been developed, there are still constraints in terms of automation and analysis throughput. To tackle these challenges, this study presents a digital-to-droplet microfluidic device comprising a digital microfluidics (DMF) module at the bottom and a droplet microfluidics module at the top. Following sample introduction, the extraction of nucleic acid and the dispensation of nucleic acid elution for mixing with the multiple amplification reagents are carried out in the DMF module. Subsequently, the reaction droplets are transported to the sample inlet of the droplet microfluidic module via a liquid outlet, and then droplet generation in four parallel units within the droplet microfluidics module is actuated by negative pressure generated by a syringe vacuum. The digital-to-droplet microfluidic device was employed to execute an integrated multiplex digital droplet nucleic acid detection assay (imDDNA) incorporating loop-mediated isothermal amplification (LAMP). This assay was specifically designed to enable simultaneous detection of four uropathogens, namely, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterococcus faecalis. The entire process of the imDDNA is completed within 75 min, with a detection range spanning 5 orders of magnitude (9.43 × 10-2.86 × 104 copies μL-1). The imDDNA was employed for the detection of batched clinical specimens, showing a consistency of 91.1% when compared with that of the conventional method. The imDDNA exhibits simplicity in operation and accuracy in quantification, thus offering potential advantages in achieving rapid pathogen detection.
Collapse
Affiliation(s)
- Yang Xie
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
| | - Zhenhua Chen
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Guangdong Engineering Technology Research Center of Microfluidic Chip Medical Diagnosis, Guangzhou 510180, China
| | - Dongyang Cai
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Guangdong Engineering Technology Research Center of Microfluidic Chip Medical Diagnosis, Guangzhou 510180, China
| | - Dezhi Huang
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
| | - Enqi Huang
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
| | - Xiao Yang
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Guangdong Engineering Technology Research Center of Microfluidic Chip Medical Diagnosis, Guangzhou 510180, China
| | - Ting Zhang
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Guangdong Engineering Technology Research Center of Microfluidic Chip Medical Diagnosis, Guangzhou 510180, China
| | - Hongting Wen
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
| | - Yu Wang
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510005, China
| | - Meng Zhao
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510005, China
| | - Dayu Liu
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Guangdong Engineering Technology Research Center of Microfluidic Chip Medical Diagnosis, Guangzhou 510180, China
| | - Banglao Xu
- Department of Laboratory Medicine, the Second Affiliated Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China
- Guangdong Engineering Technology Research Center of Microfluidic Chip Medical Diagnosis, Guangzhou 510180, China
| |
Collapse
|
4
|
Yang Y, Vagin SI, Rieger B, Destgeer G. Fabrication of Crescent Shaped Microparticles for Particle Templated Droplet Formation. Macromol Rapid Commun 2024; 45:e2300721. [PMID: 38615246 DOI: 10.1002/marc.202300721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 04/08/2024] [Indexed: 04/15/2024]
Abstract
Crescent-shaped hydrogel microparticles are shown to template uniform volume aqueous droplets upon simple mixing with aqueous and oil media for various bioassays. This emerging "lab on a particle" technique requires hydrogel particles with tunable material properties and dimensions. The crescent shape of the particles is attained by aqueous two-phase separation of polymers followed by photopolymerization of the curable precursor. In this work, the phase separation of poly(ethylene glycol) diacrylate (PEGDA, Mw 700) and dextran (Mw 40 000) for tunable manufacturing of crescent-shaped particles is investigated. The particles' morphology is precisely tuned by following a phase diagram, varying the UV intensity, and adjusting the flow rates of various streams. The fabricated particles with variable dimensions encapsulate uniform aqueous droplets upon mixing with an oil phase. The particles are fluorescently labeled with red and blue emitting dyes at variable concentrations to produce six color-coded particles. The blue fluorescent dye shows a moderate response to the pH change. The fluorescently labeled particles are able to tolerate an extremely acidic solution (pH 1) but disintegrate within an extremely basic solution (pH 14). The particle-templated droplets are able to effectively retain the disintegrating particle and the fluorescent signal at pH 14.
Collapse
Affiliation(s)
- Yimin Yang
- Control and Manipulation of Microscale Living Objects, Department of Electrical Engineering, TUM School of Computation, Information and Technology, TranslaTUM - Center for Translational Cancer Research, Technical University of Munich, Einsteinstraße 25, 81675, Munich, Germany
| | - Sergei I Vagin
- WACKER-Chair of Macromolecular Chemistry, Department of Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Bernhard Rieger
- WACKER-Chair of Macromolecular Chemistry, Department of Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Ghulam Destgeer
- Control and Manipulation of Microscale Living Objects, Department of Electrical Engineering, TUM School of Computation, Information and Technology, TranslaTUM - Center for Translational Cancer Research, Technical University of Munich, Einsteinstraße 25, 81675, Munich, Germany
| |
Collapse
|
5
|
Dou X, Zhang Z, Li C, Du Y, Tian F. A novel nanoparticle-based fluorescent sandwich immunoassay for specific detection of Salmonella Typhimurium. Int J Food Microbiol 2024; 413:110593. [PMID: 38308876 DOI: 10.1016/j.ijfoodmicro.2024.110593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/16/2024] [Accepted: 01/19/2024] [Indexed: 02/05/2024]
Abstract
The diseases caused by foodborne pathogens have a serious impact on human health and social stability. Conventional detection methods can involve long assay times and complex pretreatment steps, making them unsuitable for rapid, large-scale analysis of food samples. We constructed a novel nano-fluorescence sandwich immunosorbent immunoassay (nano-FSIA) to rapidly detect Salmonella Typhimurium in food, based on strong covalent binding between streptavidin and biotin. We used antibodies coupled to large particle-size fluorescent microspheres as fluorescent probes for direct quantitative analysis of S. typhimurium in milk. The optimized parameters were determined, and specificity and sensitivity were validated in phosphate-buffered saline (PBS) and milk. The results demonstrated a wide dynamic detection range for S. typhimurium (103-108 colony forming units [CFU]/mL), with the limit of detection in PBS and milk at 234 and 346 CFU/mL, respectively. The results of nano-FSIA were consistent with those of plate counts and enzyme-linked immunosorbent assays, providing an effective and promising single-bacterium counting method for the rapid detection of Salmonella.
Collapse
Affiliation(s)
- Xuechen Dou
- Systems Engineering Institute, Academy of Military Sciences, People's Liberation Army, Tianjin 30161, China
| | - Zhiwei Zhang
- Systems Engineering Institute, Academy of Military Sciences, People's Liberation Army, Tianjin 30161, China
| | - Chao Li
- Systems Engineering Institute, Academy of Military Sciences, People's Liberation Army, Tianjin 30161, China; National Bio-Protection Engineering Center, Tianjin 300161, China
| | - Yaohua Du
- Systems Engineering Institute, Academy of Military Sciences, People's Liberation Army, Tianjin 30161, China; National Bio-Protection Engineering Center, Tianjin 300161, China.
| | - Feng Tian
- Systems Engineering Institute, Academy of Military Sciences, People's Liberation Army, Tianjin 30161, China.
| |
Collapse
|
6
|
Dramé-Maigné A, Espada R, McCallum G, Sieskind R, Gines G, Rondelez Y. In Vitro Enzyme Self-Selection Using Molecular Programs. ACS Synth Biol 2024; 13:474-484. [PMID: 38206581 DOI: 10.1021/acssynbio.3c00385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Directed evolution provides a powerful route for in vitro enzyme engineering. State-of-the-art techniques functionally screen up to millions of enzyme variants using high throughput microfluidic sorters, whose operation remains technically challenging. Alternatively, in vitro self-selection methods, analogous to in vivo complementation strategies, open the way to even higher throughputs, but have been demonstrated only for a few specific activities. Here, we leverage synthetic molecular networks to generalize in vitro compartmentalized self-selection processes. We introduce a programmable circuit architecture that can link an arbitrary target enzymatic activity to the replication of its encoding gene. Microencapsulation of a bacterial expression library with this autonomous selection circuit results in the single-step and screening-free enrichment of genetic sequences coding for programmed enzymatic phenotypes. We demonstrate the potential of this approach for the nicking enzyme Nt.BstNBI (NBI). We applied autonomous selection conditions to enrich for thermostability or catalytic efficiency, manipulating up to 107 microcompartments and 5 × 105 variants at once. Full gene reads of the libraries using nanopore sequencing revealed detailed mutational activity landscapes, suggesting a key role of electrostatic interactions with DNA in the enzyme's turnover. The most beneficial mutations, identified after a single round of self-selection, provided variants with, respectively, 20 times and 3 °C increased activity and thermostability. Based on a modular molecular programming architecture, this approach does not require complex instrumentation and can be repurposed for other enzymes, including those that are not related to DNA chemistry.
Collapse
Affiliation(s)
- Adèle Dramé-Maigné
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
| | - Rocío Espada
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
| | - Giselle McCallum
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
| | - Rémi Sieskind
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
| | - Guillaume Gines
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
| | - Yannick Rondelez
- Gulliver UMR CNRS 7083, ESPCI Paris, Université PSL, 75005 Paris, France
| |
Collapse
|
7
|
Zhang Q, Chai W, Pan X, Gai H. Amplification-Free Digital Immunoassay down to the Attomolar Level by Synergistic Sedimentation of Brownian Motion Suppression and Dehydration Transfer. Anal Chem 2024. [PMID: 38329294 DOI: 10.1021/acs.analchem.3c05066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Amplification-free digital immunoassays (DIAs) typically utilize optical nanoparticles to enhance single immunocomplex molecule detection. The efficiency and uniformity of transferring the nanoparticles from a bulk solution to a solid surface determine the limit of detection (LOD) and the accuracy of DIAs. Previous methods suffer from issues like low efficiency, nonuniform distribution, and particle aggregation. Here, we present a novel technique named synergistic sedimentation of Brownian motion suppression and dehydration transfer (SynSed) for nanoparticles using water-soluble polymers. The efficiency of transferring quantum dots (QDs) was increased from 10.7 to 91.4%, and the variation in QD distribution was restricted to 8.8%. By incorporating SynSed into DIAs, we achieved a remarkable reduction in the LOD (down to 3.9 aM) for carcinoembryonic antigen and expanded the dynamic range to cover 3 orders of magnitude in concentration, ranging from 0.01 to 10 fM. DIAs enhanced with SynSed possess ultrahigh sensitivity, advanced accuracy, and specificity, offering a great premise in early disease diagnostics, risk stratification, and treatment response monitoring.
Collapse
Affiliation(s)
- Qingquan Zhang
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China
| | - Wenwen Chai
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China
| | - Xiaoyan Pan
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Hongwei Gai
- School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China
| |
Collapse
|
8
|
Zangi R. Breakdown of Langmuir Adsorption Isotherm in Small Closed Systems. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38315174 PMCID: PMC10883037 DOI: 10.1021/acs.langmuir.3c03894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
For more than a century, monolayer adsorptions in which adsorbate molecules and adsorbing sites behave ideally have been successfully described by Langmuir's adsorption isotherm. For example, the amount of adsorbed material, as a function of concentration of the material which is not adsorbed, obeys Langmuir's equation. In this paper, we argue that this relation is valid only for macroscopic systems. However, when particle numbers of adsorbate molecules and/or adsorbing sites are small, Langmuir's model fails to describe the chemical equilibrium of the system. This is because the kinetics of forming, or the probability of observing, occupied sites arises from two-body interactions, and as such, ought to include cross-correlations between particle numbers of the adsorbate and adsorbing sites. The effect of these correlations, as reflected by deviations in predicting composition when correlations are ignored, increases with decreasing particle numbers and becomes substantial when only few adsorbate molecules, or adsorbing sites, are present in the system. In addition, any change that augments the fraction of occupied sites at equilibrium (e.g., smaller volume, lower temperature, or stronger adsorption energy) further increases the discrepancy between observed properties of small systems and those predicted by Langmuir's theory. In contrast, for large systems, these cross-correlations become negligible, and therefore when expressing properties involving two-body processes, it is possible to consider independently the concentration of each component. By applying statistical mechanics concepts, we derive a general expression of the equilibrium constant for adsorption. It is also demonstrated that in ensembles in which total numbers of particles are fixed, the magnitudes of fluctuations in particle numbers alone can predict the average chemical composition of the system. Moreover, an alternative adsorption equation, predicting the average fraction of occupied sites from the value of the equilibrium constant, is proposed. All derived relations were tested against results obtained by Monte Carlo simulations.
Collapse
Affiliation(s)
- Ronen Zangi
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Spain
- Department of Organic Chemistry I, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 48009 Bilbao, Spain
| |
Collapse
|
9
|
Cantwell C, McGrath JS, Smith CA, Whyte G. Image-Based Feedback of Multi-Component Microdroplets for Ultra-Monodispersed Library Preparation. MICROMACHINES 2023; 15:27. [PMID: 38258146 PMCID: PMC10820162 DOI: 10.3390/mi15010027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/14/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024]
Abstract
Using devices with microfluidic channels can allow for precise control over liquids flowing through them. Merging flows of immiscible liquids can create emulsions with highly monodispersed microdroplets within a carrier liquid, which are ideal for miniaturised reaction vessels which can be generated with a high throughput of tens of thousands of droplets per second. Control of the size and composition of these droplets is generally performed by controlling the pumping system pushing the liquids into the device; however, this is an indirect manipulation and inadequate if absolute precision is required in the size or composition of the droplets. In this work, we extend the previous development of image-based closed-loop feedback control over microdroplet generation to allow for the control of not only the size of droplets but also the composition by merging two aqueous flows. The feedback allows direct control over the desired parameters of volume and ratio of the two components over a wide range of ratios and outperforms current techniques in terms of monodispersity in volume and composition. This technique is ideal for situations where precise control over droplets is critical, or where a library of droplets of different concentrations but the same volume is required.
Collapse
Affiliation(s)
- Christy Cantwell
- Institute of Biochemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - John S. McGrath
- Institute of Biochemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh EH14 4AS, UK
- Sphere Fluidics Limited, Granta Centre, Granta Park, Great Abington, Cambridge CB21 6AL, UK
| | - Clive A. Smith
- Sphere Fluidics Limited, Granta Centre, Granta Park, Great Abington, Cambridge CB21 6AL, UK
| | - Graeme Whyte
- Institute of Biochemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh EH14 4AS, UK
| |
Collapse
|
10
|
Zhang J, Wu J, Wang G, He L, Zheng Z, Wu M, Zhang Y. Extracellular Vesicles: Techniques and Biomedical Applications Related to Single Vesicle Analysis. ACS NANO 2023; 17:17668-17698. [PMID: 37695614 DOI: 10.1021/acsnano.3c03172] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Extracellular vesicles (EVs) are extensively dispersed lipid bilayer membrane vesicles involved in the delivery and transportation of molecular payloads to certain cell types to facilitate intercellular interactions. Their significant roles in physiological and pathological processes make EVs outstanding biomarkers for disease diagnosis and treatment monitoring as well as ideal candidates for drug delivery. Nevertheless, differences in the biogenesis processes among EV subpopulations have led to a diversity of biophysical characteristics and molecular cargos. Additionally, the prevalent heterogeneity of EVs has been found to substantially hamper the sensitivity and accuracy of disease diagnosis and therapeutic monitoring, thus impeding the advancement of clinical applications. In recent years, the evolution of single EV (SEV) analysis has enabled an in-depth comprehension of the physical properties, molecular composition, and biological roles of EVs at the individual vesicle level. This review examines the sample acquisition tactics prior to SEV analysis, i.e., EV isolation techniques, and outlines the current state-of-the-art label-free and label-based technologies for SEV identification. Furthermore, the challenges and prospects of biomedical applications based on SEV analysis are systematically discussed.
Collapse
Affiliation(s)
- Jie Zhang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Jiacheng Wu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Guanzhao Wang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Luxuan He
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Ziwei Zheng
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| | - Minhao Wu
- Department of Immunology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, P. R. China
| | - Yuanqing Zhang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, P. R. China
| |
Collapse
|
11
|
Ueno H, Sano M, Hara M, Noji H. Digital Cascade Assays for ADP- or ATP-Producing Enzymes Using a Femtoliter Reactor Array Device. ACS Sens 2023; 8:3400-3407. [PMID: 37590841 PMCID: PMC10521141 DOI: 10.1021/acssensors.3c00587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 07/31/2023] [Indexed: 08/19/2023]
Abstract
Digital enzyme assays are emerging biosensing methods for highly sensitive quantitative analysis of biomolecules with single-molecule detection sensitivity. However, current digital enzyme assays require a fluorogenic substrate for detection, which limits the applicability of this method to certain enzymes. ATPases and kinases are representative enzymes for which fluorogenic substrates are not available; however, these enzymes form large domains and play a central role in biology. In this study, we implemented a fluorogenic cascade reaction in a femtoliter reactor array device to develop a digital bioassay platform for ATPases and kinases. The digital cascade assay enabled quantitative measurement of the single-molecule activity of F1-ATPase, the catalytic portion of ATP synthase. We also demonstrated a digital assay for human choline kinase α. Furthermore, we developed a digital cascade assay for ATP-synthesizing enzymes and demonstrated a digital assay for pyruvate kinase. These results show the high versatility of this assay platform. Thus, the digital cascade assay has great potential for the highly sensitive detection and accurate characterization of various ADP- and ATP-producing enzymes, such as kinases, which may serve as disease biomarkers.
Collapse
Affiliation(s)
| | - Mio Sano
- Department of Applied Chemistry,
Graduate School of Engineering, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Digital Bioanalysis Laboratory, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Mayu Hara
- Department of Applied Chemistry,
Graduate School of Engineering, The University
of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Digital Bioanalysis Laboratory, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | | |
Collapse
|
12
|
Wu Y, Fu Y, Guo J, Guo J. Single-molecule immunoassay technology: Recent advances. Talanta 2023; 265:124903. [PMID: 37418954 DOI: 10.1016/j.talanta.2023.124903] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/09/2023]
Abstract
Detecting diseases at the molecular level aids in early diagnosis and treatment. However, traditional immunological detection techniques, such as enzyme-linked immunosorbent assay (ELISA) and chemiluminescence, have detection sensitivities between 10-16 and 10-12 mol/L, which are inadequate for early diagnosis. Single-molecule immunoassays can reach detection sensitivities of 10-18 mol/L and can detect biomarkers that are difficult to measure using conventional detection techniques. It can confine molecules to be detected in a small spatial area and provide absolute counting of the detected signal, offering the advantage of high efficiency and accuracy. Herein, we demonstrate the principles and equipment of two single-molecule immunoassay techniques and discuss their applications. It is shown that the detection sensitivity can be improved by 2-3 orders of magnitude compared to common chemiluminescence or ELISA assays. The microarray-based single-molecule immunoassay technique can test 66 samples in 1 h, which is more efficient than conventional immunological detection techniques. In contrast, microdroplet-based single-molecule immunoassay techniques can generate 107 droplets in 10 min, which is more than 100 times faster than a single droplet generator. By comparing the two single-molecule immunoassay techniques, we highlight our personal perspectives on the current limitations of point-of-care applications and future development trends.
Collapse
Affiliation(s)
- Yi Wu
- University of Electronic Science and Technology of China, Chengdu, China
| | - Yusheng Fu
- University of Electronic Science and Technology of China, Chengdu, China
| | - Jiuchuan Guo
- University of Electronic Science and Technology of China, Chengdu, China.
| | - Jinhong Guo
- School of Sensing Science and Engineering, Shanghai Jiao Tong University, Shanghai, China; The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, #1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, China.
| |
Collapse
|
13
|
Lai YK, Kao YT, Hess JF, Calabrese S, von Stetten F, Paust N. Interfacing centrifugal microfluidics with linear-oriented 8-tube strips and multichannel pipettes for increased throughput of digital assays. LAB ON A CHIP 2023; 23:2623-2632. [PMID: 37158238 DOI: 10.1039/d3lc00339f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present a centrifugal microfluidic cartridge for the eight-fold parallel generation of monodisperse water-in-oil droplets using standard laboratory equipment. The key element is interfacing centrifugal microfluidics with its design based on polar coordinates to the linear structures of standard high-throughput laboratory automation. Centrifugal step emulsification is used to simultaneously generate droplets from eight samples directly into standard 200 μl PCR 8-tube strips. To ensure minimal manual liquid handling, the design of the inlets allows the user to load the samples and the oil via a standard multichannel pipette. Simulation-based design of the cartridge ensures that the performance is consistent in each droplet generation unit despite the varying radial positions that originate from the interface to the linear oriented PCR 8-tube strip and from the integration of linear oriented inlet holes for the multichannel pipettes. Within 10 minutes, sample volumes of 50 μl per droplet generation unit are emulsified at a fixed rotation speed of 960 rpm into 1.47 × 105 monodisperse droplets with a mean diameter of 86 μm. The overall coefficient of variation (CV) of the droplet diameter was below 4%. Feasibility is demonstrated by an exemplary digital droplet polymerase chain reaction (ddPCR) assay which showed high linearity (R2 ≥ 0.999) across all of the eight tubes of the strip.
Collapse
Affiliation(s)
- Yu-Kai Lai
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Yu-Ting Kao
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Jacob Friedrich Hess
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Silvia Calabrese
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
| | - Felix von Stetten
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Nils Paust
- Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| |
Collapse
|
14
|
Zhang J, Wiener AD, Meyer RE, Kan CW, Rissin DM, Kolluru B, George C, Tobos CI, Shan D, Duffy DC. Improving the Accuracy, Robustness, and Dynamic Range of Digital Bead Assays. Anal Chem 2023. [PMID: 37229528 DOI: 10.1021/acs.analchem.3c00918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report methods that improve the quantification of digital bead assays (DBA)─such as the digital enzyme-linked immunosorbent assay (ELISA)─that have found widespread use for high sensitivity measurement of proteins in clinical research and diagnostics. In digital ELISA, proteins are captured on beads, labeled with enzymes, individual beads are interrogated for activity from one or more enzymes, and the average number of enzymes per bead (AEB) is determined based on Poisson statistics. The widespread use of digital ELISA has revealed limitations to the original approaches to quantification that can lead to inaccurate AEB. Here, we have addressed the inaccuracy in AEB due to deviations from Poisson distribution in a digital ELISA for Aβ-40 by changing the AEB calculation from a fixed threshold between digital counting and average normalized intensity to a smooth, continuous combination of digital counting and intensity. We addressed issues with determining the average product fluorescence intensity from single enzymes on beads by allowing outlier, high intensity arrays to be removed from average intensities, and by permitting the use of a wider range of arrays. These approaches improved the accuracy of a digital ELISA for tau protein that was affected by aggregated detection antibodies. We increased the dynamic range of a digital ELISA for IL-17A from AEB ∼25 to ∼130 by combining long and short exposure images at the product emission wavelength to create virtual images. The methods reported will significantly improve the accuracy and robustness of DBA based on imaging─such as single molecule arrays (Simoa)─and flow detection.
Collapse
Affiliation(s)
- Jianli Zhang
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Alexander D Wiener
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Raymond E Meyer
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Cheuk W Kan
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - David M Rissin
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Bharathi Kolluru
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Christopher George
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Carmen I Tobos
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - Dandan Shan
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| | - David C Duffy
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, Massachusetts 01821, United States
| |
Collapse
|
15
|
Zhang J, Wu J, Chen C, He G, Liu W, Xu S, Gu H, Wang Y, Xu H. A micro-chamber free digital bio-detection for multiplexed and ultrasensitive immunoassay based on encoded magnetic microbeads and tyramide signal amplification strategy. Talanta 2023; 262:124685. [PMID: 37220690 DOI: 10.1016/j.talanta.2023.124685] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/25/2023]
Abstract
Digital bio-detection has become one of the most appealing methods in recent years due to its excellent performance with ultra-sensitivity in detection of low-abundance targets. Traditional digital bio-detection needs the utilization of micro-chambers for physical isolation of targets, while the recently developed beads-based micro-chamber free one is attracting extensive attention, although there exist the disadvantages of overlaps between positive ("1") and negative ("0") signals as well as the decreased detection sensitivity in multiplexed mode. Here we propose a feasible and robust micro-chamber free digital bio-detection for multiplexed and ultrasensitive immunoassay based on encoded magnetic microbeads (EMMs) and tyramide signal amplification (TSA) strategy. An EMMs-based multiplexed platform is constructed by using a fluorescent encoding method, then a puissant signal amplification of positive events in TSA procedure is achieved via systematical revelation of key factors influences. For proof of concept, a three-plexed tumor markers detection is performed to evaluate our established platform. The detection sensitivity is comparable to the corresponding single-plexed assays and is also approximately 30-15,000 times improvement compared to the conventional suspension chip. Therefore, this multiplexed micro-chamber free digital bio-detection paves a promising way to be an ultrasensitive and powerful tool for clinical diagnosis.
Collapse
Affiliation(s)
- Jiayu Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jiancong Wu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Cang Chen
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Guoqing He
- Hangzhou Joinstar Biotechnology Co., Ltd., Hangzhou, 310000, China
| | - Wei Liu
- Hangzhou Joinstar Biotechnology Co., Ltd., Hangzhou, 310000, China
| | - Sitong Xu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Hongchen Gu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Yao Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
| | - Hong Xu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
| |
Collapse
|
16
|
Gantz M, Neun S, Medcalf EJ, van Vliet LD, Hollfelder F. Ultrahigh-Throughput Enzyme Engineering and Discovery in In Vitro Compartments. Chem Rev 2023; 123:5571-5611. [PMID: 37126602 PMCID: PMC10176489 DOI: 10.1021/acs.chemrev.2c00910] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Novel and improved biocatalysts are increasingly sourced from libraries via experimental screening. The success of such campaigns is crucially dependent on the number of candidates tested. Water-in-oil emulsion droplets can replace the classical test tube, to provide in vitro compartments as an alternative screening format, containing genotype and phenotype and enabling a readout of function. The scale-down to micrometer droplet diameters and picoliter volumes brings about a >107-fold volume reduction compared to 96-well-plate screening. Droplets made in automated microfluidic devices can be integrated into modular workflows to set up multistep screening protocols involving various detection modes to sort >107 variants a day with kHz frequencies. The repertoire of assays available for droplet screening covers all seven enzyme commission (EC) number classes, setting the stage for widespread use of droplet microfluidics in everyday biochemical experiments. We review the practicalities of adapting droplet screening for enzyme discovery and for detailed kinetic characterization. These new ways of working will not just accelerate discovery experiments currently limited by screening capacity but profoundly change the paradigms we can probe. By interfacing the results of ultrahigh-throughput droplet screening with next-generation sequencing and deep learning, strategies for directed evolution can be implemented, examined, and evaluated.
Collapse
Affiliation(s)
- Maximilian Gantz
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K
| | - Stefanie Neun
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K
| | - Elliot J Medcalf
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K
| | - Liisa D van Vliet
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K
| |
Collapse
|
17
|
Baranova AA, Alferova VA, Korshun VA, Tyurin AP. Modern Trends in Natural Antibiotic Discovery. Life (Basel) 2023; 13:life13051073. [PMID: 37240718 DOI: 10.3390/life13051073] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/10/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
Natural scaffolds remain an important basis for drug development. Therefore, approaches to natural bioactive compound discovery attract significant attention. In this account, we summarize modern and emerging trends in the screening and identification of natural antibiotics. The methods are divided into three large groups: approaches based on microbiology, chemistry, and molecular biology. The scientific potential of the methods is illustrated with the most prominent and recent results.
Collapse
Affiliation(s)
- Anna A Baranova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Gause Institute of New Antibiotics, Bolshaya Pirogovskaya 11, 119021 Moscow, Russia
| | - Vera A Alferova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Gause Institute of New Antibiotics, Bolshaya Pirogovskaya 11, 119021 Moscow, Russia
| | - Vladimir A Korshun
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Anton P Tyurin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| |
Collapse
|
18
|
Abstract
This paper reviews methods for detecting proteins based on molecular digitization, i.e., the isolation and detection of single protein molecules or singulated ensembles of protein molecules. The single molecule resolution of these methods has resulted in significant improvements in the sensitivity of immunoassays beyond what was possible using traditional "analog" methods: the sensitivity of some digital immunoassays approach those of methods for measuring nucleic acids, such as the polymerase chain reaction (PCR). The greater sensitivity of digital protein detection has resulted in immuno-diagnostics with high potential societal impact, e.g., the early diagnosis and therapeutic intervention of Alzheimer's Disease. In this review, we will first provide the motivation for developing digital protein detection methods given the limitations in the sensitivity of analog methods. We will describe the paradigm shift catalyzed by single molecule detection, and will describe in detail one digital approach - which we call digital bead assays (DBA) - based on the capture and labeling of proteins on beads, identifying "on" and "off" beads, and quantification using Poisson statistics. DBA based on the single molecule array (Simoa) technology have sensitivities down to attomolar concentrations, equating to ∼10 proteins in a 200 μL sample. We will describe the concept behind DBA, the different single molecule labels used, the ways of analyzing beads (imaging of arrays and flow), the binding reagents and substrates used, and integration of these technologies into fully automated and miniaturized systems. We provide an overview of emerging approaches to digital protein detection, including those based on digital detection of nucleic acids labels, single nanoparticle detection, measurements using nanopores, and methods that exploit the kinetics of single molecule binding. We outline the initial impact of digital protein detection on clinical measurements, highlighting the importance of customized assay development and translational clinical research. We highlight the use of DBA in the measurement of neurological protein biomarkers in blood, and how these higher sensitivity methods are changing the diagnosis and treatment of neurological diseases. We conclude by summarizing the status of digital protein detection and suggest how the lab-on-a-chip community might drive future innovations in this field.
Collapse
Affiliation(s)
- David C Duffy
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, MA 01821, USA.
| |
Collapse
|
19
|
Fan W, Dong Y, Ren W, Liu C. Single microentity analysis-based ultrasensitive bioassays: Recent advances, applications, and perspectives. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.117035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
|
20
|
Zhou X, Zheng B. Surface modification for improving immunoassay sensitivity. LAB ON A CHIP 2023; 23:1151-1168. [PMID: 36636910 DOI: 10.1039/d2lc00811d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Immunoassays are widely performed in many fields such as biomarker discovery, proteomics, drug development, and clinical diagnosis. There is a growing need for high sensitivity of immunoassays to detect low abundance analytes. As a result, great effort has been made to improve the quality of surfaces, on which the immunoassay is performed. In this review article, we summarize the recent progress in surface modification strategies for improving the sensitivity of immunoassays. The surface modification strategies can be categorized into two groups: antifouling coatings to reduce background noise and nanostructured surfaces to amplify the signals. The first part of the review summarizes the common antifouling coating techniques to prevent nonspecific binding and reduce background noise. The techniques include hydrophilic polymer based self-assembled monomers, polymer brushes, and surface attached hydrogels, and omniphobicity based perfluorinated surfaces. In the second part, some common nanostructured surfaces to amplify the specific detection signals are introduced, including nanoparticle functionalized surfaces, two dimensional (2D) nanoarrays, and 2D nanomaterial coatings. The third part discusses the surface modification techniques for digital immunoassays. In the end, the challenges and the future perspectives of the surface modification techniques for immunoassays are presented.
Collapse
Affiliation(s)
- Xiaohu Zhou
- Institute for Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China.
| | - Bo Zheng
- Institute for Cell Analysis, Shenzhen Bay Laboratory, Shenzhen 518132, China.
| |
Collapse
|
21
|
Krainer G, Saar KL, Arter WE, Welsh TJ, Czekalska MA, Jacquat RPB, Peter Q, Traberg WC, Pujari A, Jayaram AK, Challa P, Taylor CG, van der Linden LM, Franzmann T, Owens RM, Alberti S, Klenerman D, Knowles TPJ. Direct digital sensing of protein biomarkers in solution. Nat Commun 2023; 14:653. [PMID: 36746944 PMCID: PMC9902533 DOI: 10.1038/s41467-023-35792-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 01/03/2023] [Indexed: 02/08/2023] Open
Abstract
The detection of proteins is of central importance to biomolecular analysis and diagnostics. Typical immunosensing assays rely on surface-capture of target molecules, but this constraint can limit specificity, sensitivity, and the ability to obtain information beyond simple concentration measurements. Here we present a surface-free, single-molecule microfluidic sensing platform for direct digital protein biomarker detection in solution, termed digital immunosensor assay (DigitISA). DigitISA is based on microchip electrophoretic separation combined with single-molecule detection and enables absolute number/concentration quantification of proteins in a single, solution-phase step. Applying DigitISA to a range of targets including amyloid aggregates, exosomes, and biomolecular condensates, we demonstrate that the assay provides information beyond stoichiometric interactions, and enables characterization of immunochemistry, binding affinity, and protein biomarker abundance. Taken together, our results suggest a experimental paradigm for the sensing of protein biomarkers, which enables analyses of targets that are challenging to address using conventional immunosensing approaches.
Collapse
Affiliation(s)
- Georg Krainer
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Kadi L Saar
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - William E Arter
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Timothy J Welsh
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Magdalena A Czekalska
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.,Fluidic Analytics Limited, Unit A The Paddocks Business Centre, Cherry Hinton Road, Cambridge, CB1 8DH, UK
| | - Raphaël P B Jacquat
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Quentin Peter
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Walther C Traberg
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Arvind Pujari
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.,Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Akhila K Jayaram
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Pavankumar Challa
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Christopher G Taylor
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Lize-Mari van der Linden
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany
| | - Titus Franzmann
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany
| | - Roisin M Owens
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, CB3 0AS, UK
| | - Simon Alberti
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47/49, Dresden, Germany
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Tuomas P J Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. .,Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Ave, Cambridge, CB3 0HE, UK.
| |
Collapse
|
22
|
Minagawa Y, Nakata S, Date M, Ii Y, Noji H. On-Chip Enrichment System for Digital Bioassay Based on Aqueous Two-Phase System. ACS NANO 2023; 17:212-220. [PMID: 36579744 PMCID: PMC9835982 DOI: 10.1021/acsnano.2c06007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
We developed an on-chip enrichment method based on an aqueous two-phase system of dextran/polyethylene glycol mix, DEX/PEG ATPS, for digital bioassay. Accordingly, we prepared an array device of femtoliter reactors that displays millions of uniformly shaped DEX-rich droplets under a PEG-rich medium. The DEX-rich droplets effectively enriched DNA molecules from the PEG-rich medium. To quantify the enrichment power of the system, we performed a digital bioassay of alkaline phosphatase (ALP). Upon genetically tagging ALP molecules with the DEX-binding domain (DBD) derived from dextransucrase, the ALP molecules were enriched 59-fold in the DEX droplets in comparison to that in a conventional digital bioassay. Subsequently, we performed a Cas13-based digital SARS-CoV-2 RNA detection assay to evaluate the performance of this system for a more practical assay. In this assay, the target RNA molecules bound to the DBD-tagged Cas13 molecules were effectively enriched in the DEX droplets. Consequently, an enrichment factor of 31 was achieved. Enrichment experiments for nonlabeled proteins were also performed to test the expandability of this technique. The model protein, nontagged β-galactosidase, was enriched in DEX droplets containing DBD-tagged antibody, with an enrichment factor of over 100. Thus, this system enabled effective on-chip enrichment of target molecules to enhance the detection sensitivity of digital bioassays without using external instruments or an external power source, which would be applicable for on-site bioassays or portable diagnostic tests.
Collapse
Affiliation(s)
- Yoshihiro Minagawa
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8656, Japan
| | - Shoki Nakata
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8656, Japan
| | - Motoki Date
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8656, Japan
| | - Yutaro Ii
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8656, Japan
| | - Hiroyuki Noji
- Department
of Applied Chemistry, The University of
Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8656, Japan
| |
Collapse
|
23
|
Jiang Z, Shi H, Tang X, Qin J. Recent advances in droplet microfluidics for single-cell analysis. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.116932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
24
|
Fan W, Ren W, Liu C. Advances in optical counting and imaging of micro/nano single-entity reactors for biomolecular analysis. Anal Bioanal Chem 2023; 415:97-117. [PMID: 36322160 PMCID: PMC9628437 DOI: 10.1007/s00216-022-04395-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 10/14/2022] [Accepted: 10/19/2022] [Indexed: 11/07/2022]
Abstract
Ultrasensitive detection of biomarkers is of paramount importance in various fields. Superior to the conventional ensemble measurement-based assays, single-entity assays, especially single-entity detection-based digital assays, not only can reach ultrahigh sensitivity, but also possess the potential to examine the heterogeneities among the individual target molecules within a population. In this review, we summarized the current biomolecular analysis methods that based on optical counting and imaging of the micro/nano-sized single entities that act as the individual reactors (e.g., micro-/nanoparticles, microemulsions, and microwells). We categorize the corresponding techniques as analog and digital single-entity assays and provide detailed information such as the design principles, the analytical performance, and their implementation in biomarker analysis in this work. We have also set critical comments on each technique from these aspects. At last, we reflect on the advantages and limitations of the optical single-entity counting and imaging methods for biomolecular assay and highlight future opportunities in this field.
Collapse
Affiliation(s)
- Wenjiao Fan
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, 710119 Shaanxi Province People’s Republic of China ,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Xi’an, 710119 Shaanxi Province People’s Republic of China ,School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an, 710119 Shaanxi Province People’s Republic of China
| | - Wei Ren
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, 710119 Shaanxi Province People’s Republic of China ,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Xi’an, 710119 Shaanxi Province People’s Republic of China ,School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an, 710119 Shaanxi Province People’s Republic of China
| | - Chenghui Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, 710119 Shaanxi Province People’s Republic of China ,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, Xi’an, 710119 Shaanxi Province People’s Republic of China ,School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an, 710119 Shaanxi Province People’s Republic of China
| |
Collapse
|
25
|
Liu W, Chen D, Pian H, Su F, Wang H, Zhang P, Li Z. One-by-one single-molecule counting method for digital quantification of SARS-CoV-2 RNA. NANO TODAY 2022; 47:101664. [PMID: 36340244 PMCID: PMC9618441 DOI: 10.1016/j.nantod.2022.101664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/11/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Digital counting individual nucleic acid molecule is of great significance for fundamental biological research and accurate diagnosis of genetic diseases, which is hard to achieve with existing single-molecule detection technologies. Herein, we report a novel one-by-one single-molecule counting method for digital quantification of SARS-Cov-2 RNA. This method uses one fluorescent micromotor functionalized with peptide nucleic acids (PNAs) to specially capture one target RNA molecule. The RNA-micromotors can be propelled by the electric field to target district and accurately counted. Moreover, the method can also clearly discriminate one-base mutation in the target RNAs, indicating the great potential for clinical diagnostics and virus traceability survey.
Collapse
Affiliation(s)
- Weiliang Liu
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Desheng Chen
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Hongru Pian
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Fengxia Su
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Hui Wang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Pengbo Zhang
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Zhengping Li
- Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, PR China
| |
Collapse
|
26
|
Beck S, Shin D, Kim SJ, Hedde PN, Zhao W. Digital Protein Detection in Bulk Solutions. ACS OMEGA 2022; 7:37714-37723. [PMID: 36312374 PMCID: PMC9608401 DOI: 10.1021/acsomega.2c04666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Quick and accurate molecular diagnostics in protein detection can greatly benefit medicine in disease diagnosis and lead to positive patient outcomes. However, specialized equipment used in clinical laboratories often comes with trade-offs between operation and function serving a single role for very specific needs. For example, to achieve high analytical sensitivity and specificity, instruments such as high-performance liquid chromatography and/or liquid chromatography-mass spectrometry use a complex instrument design and require thorough training of the users. On the other hand, simple tests such as protein detection in urinary tract infection using dip-stick assays provide very quick results but suffer from poor analytical sensitivity. Here, we present an application study for the 3D particle counter technology, which is based on optical confocal detection in order to scan large sample volumes (0.5-3 mL) in glass cuvettes, that aims to close the gap between analytical sensitivity and turnover assay time and simplify protein detection by adopting bead-based immunoassays. Combining the 3D particle counter technology with bead-based immunoassays, a subpicomolar limit of detection-ranging from 119 to 346 fM-was achieved within 3.5-hour assay time for recombinant mouse interleukin 6 detection. As an alternative instrument to a flow cytometer, the 3D particle counter takes advantages of bead-based immunoassays and provides unique accessibility and flexibility for users.
Collapse
Affiliation(s)
- Sungjun Beck
- Department
of Biological Chemistry, University of California,
Irvine, Irvine, California 92697, United States
| | - Donghae Shin
- Department
of Biological Chemistry, University of California,
Irvine, Irvine, California 92697, United States
| | - Sun Jin Kim
- Department
of Pharmaceutical Sciences, University of
California, Irvine, Irvine, California 92697, United States
| | - Per Niklas Hedde
- Department
of Pharmaceutical Sciences, University of
California, Irvine, Irvine, California 92697, United States
- Laboratory
for Fluorescence Dynamics, University of
California, Irvine, Irvine, California 92697, United States
- Beckman
Laser Institute & Medical Clinic, University
of California, Irvine, Irvine, California 92697, United States
| | - Weian Zhao
- Department
of Biological Chemistry, University of California,
Irvine, Irvine, California 92697, United States
- Department
of Pharmaceutical Sciences, University of
California, Irvine, Irvine, California 92697, United States
- Institute
for Immunology, University of California,
Irvine, Irvine, California 92697, United States
- Sue and Bill
Gross Stem Cell Research Center, University
of California, Irvine, Irvine, California 92697, United States
- Chao
Family Comprehensive Cancer Center, University
of California, Irvine, Irvine, California 92697, United States
- Edwards
Life Sciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, California 92697, United States
- Department
of Biomedical Engineering, University of
California, Irvine, Irvine, California 92697, United States
| |
Collapse
|
27
|
Breukers J, Op de Beeck H, Rutten I, López Fernández M, Eyckerman S, Lammertyn J. Highly flexible and accurate serial picoinjection in droplets by combined pressure and flow rate control. LAB ON A CHIP 2022; 22:3475-3488. [PMID: 35943442 DOI: 10.1039/d2lc00368f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Picoinjection is a robust method for reagent addition into microfluidic droplets and has enabled the implementation of numerous multistep droplet assays. Although serial picoinjectors allow to screen many conditions in one run by injecting different combinations of reagents, their use is limited because it is complex to accurately control each injector independently. Here, we present a novel method for flexible, individual picoinjector control that allows to inject a predefined range of volumes by controlling the flow rate of the injector as well as turning off injection by setting the equilibrium pressure, which resulted in a stable interface of the injector liquid with the main microfluidic channel. Robust setting of the equilibrium pressure of an injector was achieved by applying accurate (R2 > 0.94) linear models between the injector and oil pressure in real-time. To illustrate the flexibility of this method, we performed several proof-of-concepts using 1, 2 or 3 picoinjectors loaded with fluorescent dyes. We successfully demonstrated picoinjection approaches using time-invariant settings, in which an injector setting was applied for prolonged times, and time-variant picoinjection, in which the injector settings were continuously varied in order to sweep the injected volumes, both resulting in monodisperse (CV < 3.4%) droplet libraries with different but reproducible fluorescent intensities. To illustrate the potential of the technology for fast compound concentration screenings, we studied the effect of a concentration range of a detergent on single-cell lysis. We anticipate that this robust and versatile methodology will make the serial picoinjection technology more accessible to researchers, allowing its wide implementation in numerous life science applications.
Collapse
Affiliation(s)
- Jolien Breukers
- Department of Biosystems, Biosensors Group, KU Leuven, Leuven 3001, Belgium.
| | - Hannah Op de Beeck
- Department of Biosystems, Biosensors Group, KU Leuven, Leuven 3001, Belgium.
| | - Iene Rutten
- Department of Biosystems, Biosensors Group, KU Leuven, Leuven 3001, Belgium.
| | - Montserrat López Fernández
- Confo Therapeutics, Technologiepark-Zwijnaarde 30, Ghent 9052, Belgium
- Center for Medical Biotechnology, VIB-Ghent University, Technologiepark-Zwijnaarde 75, Ghent 9052, Belgium
- Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, Ghent 9052, Belgium
| | - Sven Eyckerman
- Center for Medical Biotechnology, VIB-Ghent University, Technologiepark-Zwijnaarde 75, Ghent 9052, Belgium
- Department of Biomolecular Medicine, Ghent University, Technologiepark-Zwijnaarde 75, Ghent 9052, Belgium
| | - Jeroen Lammertyn
- Department of Biosystems, Biosensors Group, KU Leuven, Leuven 3001, Belgium.
| |
Collapse
|
28
|
Ogo A, Okayama S, Nakatani M, Hashimoto M. CO 2-Laser-Micromachined, Polymer Microchannels with a Degassed PDMS slab for the Automatic Production of Monodispersed Water-in-Oil Droplets. MICROMACHINES 2022; 13:1389. [PMID: 36144013 PMCID: PMC9502940 DOI: 10.3390/mi13091389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/17/2022] [Accepted: 08/23/2022] [Indexed: 06/16/2023]
Abstract
In our recent study, we fabricated a pump/tube-connection-free microchip comprising top and bottom polydimethylsiloxane (PDMS) slabs to produce monodispersed water-in-oil droplets in a fully automated, fluid-manipulation fashion. All microstructures required for droplet production were directly patterned on the surfaces of the two PDMS slabs through CO2-laser micromachining, facilitating the fast fabrication of the droplet-production microchips. In the current extension study, we replaced the bottom PDMS slab, which served as a microfluidic layer in the microchip, with a poly(methyl methacrylate) (PMMA) slab. This modification was based on our idea that the bottom PDMS slab does not contribute to the automatic fluid manipulation and that replacing the bottom PDMS slab with a more affordable and accessible, ready-to-use polymer slab, such as a PMMA, would further facilitate the rapid and low-cost fabrication of the connection-free microchips. Using a new PMMA/PDMS microchip, we produced water-in-oil droplets with high degree of size-uniformity (a coefficient of variation for droplet diameters of <5%) without a decrease in the droplet production rate (~270 droplets/s) as compared with that achieved via the previous PDMS/PDMS microchip (~220 droplets/s).
Collapse
|
29
|
Morales RTT, Ko J. Future of Digital Assays to Resolve Clinical Heterogeneity of Single Extracellular Vesicles. ACS NANO 2022; 16:11619-11645. [PMID: 35904433 PMCID: PMC10174080 DOI: 10.1021/acsnano.2c04337] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Extracellular vesicles (EVs) are complex lipid membrane vehicles with variable expressions of molecular cargo, composed of diverse subpopulations that participate in the intercellular signaling of biological responses in disease. EV-based liquid biopsies demonstrate invaluable clinical potential for overhauling current practices of disease management. Yet, EV heterogeneity is a major needle-in-a-haystack challenge to translate their use into clinical practice. In this review, existing digital assays will be discussed to analyze EVs at a single vesicle resolution, and future opportunities to optimize the throughput, multiplexing, and sensitivity of current digital EV assays will be highlighted. Furthermore, this review will outline the challenges and opportunities that impact the clinical translation of single EV technologies for disease diagnostics and treatment monitoring.
Collapse
Affiliation(s)
- Renee-Tyler T Morales
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jina Ko
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| |
Collapse
|
30
|
Noji H, Minagawa Y, Ueno H. Enzyme-based digital bioassay technology - key strategies and future perspectives. LAB ON A CHIP 2022; 22:3092-3109. [PMID: 35861036 DOI: 10.1039/d2lc00223j] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Digital bioassays based on single-molecule enzyme reactions represent a new class of bioanalytical methods that enable the highly sensitive detection of biomolecules in a quantitative manner. Since the first reports of these methods in the 2000s, there has been significant growth in this new bioanalytical strategy. The principal strategy of this method is to compartmentalize target molecules in micron-sized reactors at the single-molecule level and count the number of microreactors showing positive signals originating from the target molecule. A representative application of digital bioassay is the digital enzyme-linked immunosorbent assay (ELISA). Owing to their versatility, various types of digital ELISAs have been actively developed. In addition, some disease markers and viruses possess catalytic activity, and digital bioassays for such enzymes and viruses have, thus, been developed. Currently, with the emergence of new microreactor technologies, the targets of this methodology are expanding from simple enzymes to more complex systems, such as membrane transporters and cell-free gene expression. In addition, multiplex or multiparametric digital bioassays have been developed to assess precisely the heterogeneities in sample molecules/systems that are obscured by ensemble measurements. In this review, we first introduce the basic concepts of digital bioassays and introduce a range of digital bioassays. Finally, we discuss the perspectives of new classes of digital bioassays and emerging fields based on digital bioassay technology.
Collapse
Affiliation(s)
- Hiroyuki Noji
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
| | - Yoshihiro Minagawa
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
| | - Hiroshi Ueno
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
| |
Collapse
|
31
|
Leyva–Pérez A, Bilanin C, Bacic M, Greco R. Acid and base water coexists in a micro–structured ionic liquid and catalyzes organic reactions in one–pot. ChemCatChem 2022. [DOI: 10.1002/cctc.202200557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Antonio Leyva–Pérez
- CSIC Instituto de Tecnologia Quimica Avda. de los Naranjos S/N 46022 Valencia SPAIN
| | - Cristina Bilanin
- Instituto de Tecnologia Quimica Instituto de Tecnologia Quimica SPAIN
| | - Matea Bacic
- Instituto de Tecnologia Quimica Instituto de Tecnologia Quimica SPAIN
| | - Rossella Greco
- Instituto de Tecnologia Quimica Instituto de Tecnologia Quimica SPAIN
| |
Collapse
|
32
|
Chen ZP, Yang P, Yang ZZ, Chai YQ, Yuan R, Zhuo Y, Liang WB. One-Step Digital Droplet Auto-Catalytic Nucleic Acid Amplification with High-Throughput Fluorescence Imaging and Droplet Tracking Computation. Anal Chem 2022; 94:9166-9175. [PMID: 35708271 DOI: 10.1021/acs.analchem.2c01754] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Digital droplet technology has emerged as a powerful new tool for biomarker analysis. Temperature cycling, enzymes, and off-chip processes are, nevertheless, always required. Herein, we constructed a digital droplet auto-catalytic hairpin assembly (ddaCHA) microfluidic system to achieve digital quantification of single-molecule microRNA (miRNA). The designed continuous chip integrates droplet generation, incubation, and fluorescence imaging on the chip, avoiding the requirement for extra droplet re-collection and heating operations. Clearly, the digital readout was obtained by partitioning miRNA into many individual pL-sized small droplets in which the target molecule is either present ("positive") or absent ("negative"). Importantly, the suggested enzyme-free auto-catalytic hairpin assembly (aCHA) in droplets successfully mitigated the effects of the external environment and thermal cycling on droplets, and its reaction rate is significantly superior to that of traditional CHA. We got excellent sensitivity with a linear correlation from 1 pM to 10 nM and a detection limit of 0.34 pM in the fluorescence spectrum section, as well as high selectivity to other miRNAs. Furthermore, the minimum target concentration could be reduced to 10 fM based on the high-throughput tracking computation of fluorescent droplets with a self-developed Python script, and the fluorescence intensity distribution agreed well with the theoretical value, demonstrating that it is feasible to detect miRNA efficiently and accurately, which has great potential applications in clinical diagnostics and biochemical research.
Collapse
Affiliation(s)
- Zhao-Peng Chen
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Peng Yang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Ze-Zhou Yang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Ya-Qin Chai
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Ruo Yuan
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Ying Zhuo
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| | - Wen-Bin Liang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China
| |
Collapse
|
33
|
Leirs K, Dal Dosso F, Perez-Ruiz E, Decrop D, Cops R, Huff J, Hayden M, Collier N, Yu KXZ, Brown S, Lammertyn J. Bridging the Gap between Digital Assays and Point-of-Care Testing: Automated, Low Cost, and Ultrasensitive Detection of Thyroid Stimulating Hormone. Anal Chem 2022; 94:8919-8927. [PMID: 35687534 DOI: 10.1021/acs.analchem.2c00480] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Medical diagnostics is moving toward disease-related target detection at very low concentrations because of the (1) quest for early-stage diagnosis, at a point where only limited target amounts are present, (2) trend toward minimally invasive sample extraction, yielding samples containing low concentrations of target, and (3) need for straightforward sample collection, usually resulting in limited volume collected. Hence, diagnostic tools allowing ultrasensitive target detection at the point-of-care (POC) are crucial for simplified and timely diagnosis of many illnesses. Therefore, we developed an innovative, fully integrated, semi-automated, and economically viable platform based on (1) digital microfluidics (DMF), enabling automated manipulation and analysis of very low sample volumes and (2) low-cost disposable DMF chips with microwell arrays, fabricated via roll-to-roll processes and allowing digital target counting. Thyroid stimulating hormone detection was chosen as a relevant application to show the potential of the system. The assay buffer was selected using design of experiments, and the assay was optimized in terms of reagent concentration and incubation time toward maximum sensitivity. The hydrophobic-in-hydrophobic microwells showed an unparalleled seeding efficiency of 97.6% ± 0.6%. A calculated LOD of 0.0013 μIU/mL was obtained, showing the great potential of the platform, especially taking into account the very low sample volume analyzed (1.1 μL). Although validation (in biological matrix) and industrialization (full automation) steps still need to be taken, it is clear that the combination of DMF, low-cost DMF chips, and digital analyte counting in microwell arrays enables the implementation of ultrasensitive and reliable target detection at the POC.
Collapse
Affiliation(s)
- Karen Leirs
- Department of Biosystems - Biosensors group, KU Leuven, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium
| | - Francesco Dal Dosso
- Department of Biosystems - Biosensors group, KU Leuven, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium
| | - Elena Perez-Ruiz
- Department of Biosystems - Biosensors group, KU Leuven, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium
| | - Deborah Decrop
- Department of Biosystems - Biosensors group, KU Leuven, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium
| | - Ruben Cops
- Department of Biosystems - Biosensors group, KU Leuven, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium
| | - Jeffrey Huff
- Diagnostics Division Dept. 0NTA, Bldg. CP-1, Abbott Laboratories, 100 Abbott Park Rd., Abbott Park, Illinois 60064-6093, United States
| | - Mark Hayden
- Diagnostics Division Dept. 0NTA, Bldg. CP-1, Abbott Laboratories, 100 Abbott Park Rd., Abbott Park, Illinois 60064-6093, United States
| | | | - Karen X Z Yu
- Sagentia, Harston Mill, Harston, Cambridge CB227GG, UK
| | - Stephen Brown
- Sagentia, Harston Mill, Harston, Cambridge CB227GG, UK
| | - Jeroen Lammertyn
- Department of Biosystems - Biosensors group, KU Leuven, Willem de Croylaan 42, box 2428, 3001 Leuven, Belgium
| |
Collapse
|
34
|
Zhang Y, Zhao Y, Cole T, Zheng J, Bayinqiaoge, Guo J, Tang SY. Microfluidic flow cytometry for blood-based biomarker analysis. Analyst 2022; 147:2895-2917. [PMID: 35611964 DOI: 10.1039/d2an00283c] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Flow cytometry has proven its capability for rapid and quantitative analysis of individual cells and the separation of targeted biological samples from others. The emerging microfluidics technology makes it possible to develop portable microfluidic diagnostic devices for point-of-care testing (POCT) applications. Microfluidic flow cytometry (MFCM), where flow cytometry and microfluidics are combined to achieve similar or even superior functionalities on microfluidic chips, provides a powerful single-cell characterisation and sorting tool for various biological samples. In recent years, researchers have made great progress in the development of the MFCM including focusing, detecting, and sorting subsystems, and its unique capabilities have been demonstrated in various biological applications. Moreover, liquid biopsy using blood can provide various physiological and pathological information. Thus, biomarkers from blood are regarded as meaningful circulating transporters of signal molecules or particles and have great potential to be used as non (or minimally)-invasive diagnostic tools. In this review, we summarise the recent progress of the key subsystems for MFCM and its achievements in blood-based biomarker analysis. Finally, foresight is offered to highlight the research challenges faced by MFCM in expanding into blood-based POCT applications, potentially yielding commercialisation opportunities.
Collapse
Affiliation(s)
- Yuxin Zhang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Ying Zhao
- National Chengdu Centre of Safety Evaluation of Drugs, West China Hospital of Sichuan University, Chengdu, China
| | - Tim Cole
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Jiahao Zheng
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Bayinqiaoge
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Jinhong Guo
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, #1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, China.
| | - Shi-Yang Tang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| |
Collapse
|
35
|
Yaginuma H, Ohtake K, Akamatsu T, Noji H, Tabata KV. A microreactor sealing method using adhesive tape for digital bioassays. LAB ON A CHIP 2022; 22:2001-2010. [PMID: 35481587 DOI: 10.1039/d2lc00065b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Digital assays using microreactors fabricated on solid substrates are useful for carrying out sensitive assays of infectious diseases and other biological tests. However, sealing of the microchambers using fluid oil is difficult for non-experts, and thus hinders the widespread use of digital microreactor assays. Here, we propose the physical isolation of tiny reactors with adhesive tape (PITAT) using simple, commercially available pressure-sensitive adhesive (PSA) tape as a separator of the microreactors. We confirmed that PSA tape can effectively seal the microreactors and prevent molecules from diffusing out. By testing several types of adhesive tape, we found that rubber-based adhesives are the most suitable for this purpose. In addition, we demonstrated that single-molecule enzyme assays can be successfully performed inside microreactors sealed with PSA tape. The results obtained using PITAT are quantitatively comparable to conventional oil sealing, although it is quick and cost-effective. Finally, we demonstrated that single-particle virus counting of the influenza virus can be achieved using PITAT. Collectively, our results suggest that PITAT may be suitable for use in the design of sensitive tests for infectious diseases at the point of care, where no sophisticated equipment or machines are available.
Collapse
Affiliation(s)
- Hideyuki Yaginuma
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Kuniko Ohtake
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Takako Akamatsu
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Hiroyuki Noji
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Kazuhito V Tabata
- Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
- Sothis Technologies, Tokyo, Japan
| |
Collapse
|
36
|
Arrabito G, Gulli D, Alfano C, Pignataro B. "Writing biochips": high-resolution droplet-to-droplet manufacturing of analytical platforms. Analyst 2022; 147:1294-1312. [PMID: 35275148 DOI: 10.1039/d1an02295d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The development of high-resolution molecular printing allows the engineering of analytical platforms enabling applications at the interface between chemistry and biology, i.e. in biosensing, electronics, single-cell biology, and point-of-care diagnostics. Their successful implementation stems from the combination of large area printing at resolutions from sub-100 nm up to macroscale, whilst controlling the composition and volume of the ink, and reconfiguring the deposition features in due course. Similar to handwriting pens, the engineering of continuous writing systems tackles the issue of the tedious ink replenishment between different printing steps. To this aim, this review article provides an unprecedented analysis of the latest continuous printing methods for bioanalytical chemistry, focusing on ink deposition systems based on specific sets of technologies that have been developed to this aim, namely nanofountain probes, microcantilever spotting, capillary-based polymer pens and continuous 3D printing. Each approach will be discussed revealing the most important applications in the fields of biosensors, lab-on-chips and diagnostics.
Collapse
Affiliation(s)
- Giuseppe Arrabito
- Department of Physics and Chemistry (DiFC) Emilio Segrè, University of Palermo, Building 17, V.le delle Scienze, Palermo 90128, Italy.
| | - Daniele Gulli
- Department of Physics and Chemistry (DiFC) Emilio Segrè, University of Palermo, Building 17, V.le delle Scienze, Palermo 90128, Italy.
| | - Caterina Alfano
- Structural Biology and Biophysics Unit, Fondazione Ri.MED, Palermo 90133, Italy
| | - Bruno Pignataro
- Department of Physics and Chemistry (DiFC) Emilio Segrè, University of Palermo, Building 17, V.le delle Scienze, Palermo 90128, Italy.
| |
Collapse
|
37
|
Kim K, Song S, Sung J. Non‐steady‐state enzyme reaction dynamics. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kyungwoo Kim
- Department of Chemistry and Institute of Innovative Functional Imaging Chung‐Ang University Seoul South Korea
| | - Sanggeun Song
- Department of Chemistry and Institute of Innovative Functional Imaging Chung‐Ang University Seoul South Korea
| | - Jaeyoung Sung
- Department of Chemistry and Institute of Innovative Functional Imaging Chung‐Ang University Seoul South Korea
| |
Collapse
|
38
|
Peri SSS, Raza MU, Sabnani MK, Ghaffari S, Gimlin S, Wawro DD, Lee JS, Kim MJ, Weidanz J, Alexandrakis G. Self-Induced Back-Action Actuated Nanopore Electrophoresis (SANE) Sensor for Label-Free Detection of Cancer Immunotherapy-Relevant Antibody-Ligand Interactions. Methods Mol Biol 2022; 2394:343-376. [PMID: 35094337 PMCID: PMC9207820 DOI: 10.1007/978-1-0716-1811-0_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We fabricated a novel single molecule nanosensor by integrating a solid-state nanopore and a double nanohole nanoaperture. The nanosensor employs Self-Induced Back-Action (SIBA) for optical trapping and enables SIBA-Actuated Nanopore Electrophoresis (SANE) for concurrent acquisition of bimodal optical and electrical signatures of molecular interactions. This work describes how to fabricate and use the SANE sensor to quantify antibody-ligand interactions. We describe how to analyze the bimodal optical-electrical data to improve upon the discrimination of antibody and ligand versus bound complex compared to electrical measurements alone. Example results for specific interaction detection are described for T-cell receptor-like antibodies (TCRmAbs) engineered to target peptide-presenting Major Histocompatibility Complex (pMHC) ligands, representing a model of target ligands presented on the surface of cancer cells. We also describe how to analyze the bimodal optical-electrical data to discriminate between specific and non-specific interactions between antibodies and ligands. Example results for non-specific interactions are shown for cancer-irrelevant TCRmAbs targeting the same pMHCs, as a control. These example results demonstrate the utility of the SANE sensor as a potential screening tool for ligand targets in cancer immunotherapy, though we believe that its potential uses are much broader.
Collapse
Affiliation(s)
| | - Muhammad Usman Raza
- Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX, USA
| | - Manoj K Sabnani
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Soroush Ghaffari
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | | | - Debra D Wawro
- Resonant Sensors Incorporated (RSI), Arlington, TX, USA
| | - Jung Soo Lee
- Department of Mechanical Engineering, Southern Methodist University, Dallas, TX, USA
| | - Min Jun Kim
- Department of Mechanical Engineering, Southern Methodist University, Dallas, TX, USA
| | - Jon Weidanz
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA
| | - George Alexandrakis
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA.
| |
Collapse
|
39
|
Siedlik MJ, Issadore D. Pico-washing: simultaneous liquid addition and removal for continuous-flow washing of microdroplets. MICROSYSTEMS & NANOENGINEERING 2022; 8:46. [PMID: 35498338 PMCID: PMC9050730 DOI: 10.1038/s41378-022-00381-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/02/2022] [Accepted: 03/07/2022] [Indexed: 05/19/2023]
Abstract
Droplet microfluidics is based on a toolbox of several established unit operations, including droplet generation, incubation, mixing, pico-injection, and sorting. In the last two decades, the development of droplet microfluidic systems, which incorporate these multiple unit operations into a workflow, has demonstrated unique capabilities in fields ranging from single-cell transcriptomic analyses to materials optimization. One unit operation that is sorely underdeveloped in droplet microfluidics is washing, exchange of the fluid in a droplet with a different fluid. Here, we demonstrate what we name the "pico-washer," a unit operation capable of simultaneously adding fluid to and removing fluid from droplets in flow while requiring only a small footprint on a microfluidic chip. We describe the fabrication strategy, device architecture, and process parameters required for stable operation of this technology, which is capable of operating with kHz droplet throughput. Furthermore, we provide an image processing workflow to characterize the washing process with microsecond and micrometer resolution. Finally, we demonstrate the potential for integrated droplet workflows by arranging two of these unit operations in series with a droplet generator, describe a design rule for stable operation of the pico-washer when integrated into a system, and validate this design rule experimentally. We anticipate that this technology will contribute to continued development of the droplet microfluidics toolbox and the realization of novel droplet-based, multistep biological and chemical assays.
Collapse
Affiliation(s)
- Michael J. Siedlik
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 United States
| | - David Issadore
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 United States
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA 19104 United States
| |
Collapse
|
40
|
Molloy A, Harrison J, McGrath JS, Owen Z, Smith C, Liu X, Li X, Cox JAG. Microfluidics as a Novel Technique for Tuberculosis: From Diagnostics to Drug Discovery. Microorganisms 2021; 9:microorganisms9112330. [PMID: 34835455 PMCID: PMC8618277 DOI: 10.3390/microorganisms9112330] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 12/29/2022] Open
Abstract
Tuberculosis (TB) remains a global healthcare crisis, with an estimated 5.8 million new cases and 1.5 million deaths in 2020. TB is caused by infection with the major human pathogen Mycobacterium tuberculosis, which is difficult to rapidly diagnose and treat. There is an urgent need for new methods of diagnosis, sufficient in vitro models that capably mimic all physiological conditions of the infection, and high-throughput drug screening platforms. Microfluidic-based techniques provide single-cell analysis which reduces experimental time and the cost of reagents, and have been extremely useful for gaining insight into monitoring microorganisms. This review outlines the field of microfluidics and discusses the use of this novel technique so far in M. tuberculosis diagnostics, research methods, and drug discovery platforms. The practices of microfluidics have promising future applications for diagnosing and treating TB.
Collapse
Affiliation(s)
- Antonia Molloy
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
| | - James Harrison
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
| | - John S. McGrath
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Zachary Owen
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Clive Smith
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Xin Liu
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Xin Li
- Sphere Fluidics Limited, The McClintock Building, Suite 7, Granta Park, Great Abington, Cambridge CB21 6GP, UK; (J.S.M.); (Z.O.); (C.S.); (X.L.); (X.L.)
| | - Jonathan A. G. Cox
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK; (A.M.); (J.H.)
- Correspondence: ; Tel.: +44-121-204-5011
| |
Collapse
|
41
|
Zhang L, Fan W, Jia D, Feng Q, Ren W, Liu C. Microchamber-Free Digital Flow Cytometric Analysis of T4 Polynucleotide Kinase Phosphatase Based on Single-Enzyme-to-Single-Bead Space-Confined Reaction. Anal Chem 2021; 93:14828-14836. [PMID: 34713697 DOI: 10.1021/acs.analchem.1c03724] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Digital bioassays have attracted extensive attention in biomedical applications due to their ultrahigh sensitivity. However, traditional digital bioassays require numerous microchambers such as droplets or microwells, which restricts their application scope. Herein, we propose a microchamber-free flow cytometric method for the digital quantification of T4 polynucleotide kinase phosphatase (T4 PNKP) based on an unprecedented phenomenon that each T4 PNKP molecule-catalyzed reaction can be spatially self-confined on a single microbead, which ultimately enables the one-target-to-one-fluorescence-positive microbead digital signal transduction. The digital signal-readout mode can clearly detect T4 PNKP concentrations as low as 1.28 × 10-10 U/μL, making it most sensitive method to date. Significantly, T4 PNKP can be specifically distinguished from other phosphatases and nucleases in complex samples by digitally counting the fluorescence-positive microbeads, which cannot be realized by traditional bulk measurement-based methods. Taking advantage of the novel space-confined enzymatic feature of T4 PNKP, this digital mechanism can use T4 PNKP as the enzyme label to fabricate digital sensing systems toward various biomolecules such as digital enzyme-linked immunosorbent assay (ELISA). Therefore, this work not only enlarges the toolbox for high-sensitivity biomolecule detection but also opens new gates to fabricate next-generation digital assays.
Collapse
Affiliation(s)
- Lijun Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China
| | - Wenjiao Fan
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China
| | - Dailu Jia
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China
| | - Qinya Feng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China
| | - Wei Ren
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China
| | - Chenghui Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education; Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province; School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China
| |
Collapse
|
42
|
Wang Y, Shah V, Lu A, Pachler E, Cheng B, Di Carlo D. Counting of enzymatically amplified affinity reactions in hydrogel particle-templated drops. LAB ON A CHIP 2021; 21:3438-3448. [PMID: 34378611 PMCID: PMC11288628 DOI: 10.1039/d1lc00344e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Counting of numerous compartmentalized enzymatic reactions underlies quantitative and high sensitivity immunodiagnostic assays. However, digital enzyme-linked immunosorbent assays (ELISA) require specialized instruments which have slowed adoption in research and clinical labs. We present a lab-on-a-particle solution to digital counting of thousands of single enzymatic reactions. Hydrogel particles are used to bind enzymes and template the formation of droplets that compartmentalize reactions with simple pipetting steps. These hydrogel particles can be made at a high throughput, stored, and used during the assay to create ∼500 000 compartments within 2 minutes. These particles can also be dried and rehydrated with sample, amplifying the sensitivity of the assay by driving affinity interactions on the hydrogel surface. We demonstrate digital counting of β-galactosidase enzyme at a femtomolar detection limit with a dynamic range of 3 orders of magnitude using standard benchtop equipment and experiment techniques. This approach can faciliate the development of digital ELISAs with reduced need for specialized microfluidic devices, instruments, or imaging systems.
Collapse
Affiliation(s)
- Yilian Wang
- Department of Bioengineering, University of California, Los Angeles, CA, USA.
| | - Vishwesh Shah
- Department of Bioengineering, University of California, Los Angeles, CA, USA.
| | - Angela Lu
- Department of Bioengineering, University of California, Los Angeles, CA, USA.
| | - Ella Pachler
- Department of Bioengineering, University of California, Los Angeles, CA, USA.
| | - Brian Cheng
- Department of Bioengineering, University of California, Los Angeles, CA, USA.
| | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles, CA, USA.
- Department of Mechanical and Aerospace Engineering, California NanoSystems Institute, Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA, USA
| |
Collapse
|
43
|
Escobar A, Chiu P, Qu J, Zhang Y, Xu CQ. Integrated Microfluidic-Based Platforms for On-Site Detection and Quantification of Infectious Pathogens: Towards On-Site Medical Translation of SARS-CoV-2 Diagnostic Platforms. MICROMACHINES 2021; 12:1079. [PMID: 34577722 PMCID: PMC8470930 DOI: 10.3390/mi12091079] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/26/2021] [Accepted: 08/30/2021] [Indexed: 12/18/2022]
Abstract
The rapid detection and quantification of infectious pathogens is an essential component to the control of potentially lethal outbreaks among human populations worldwide. Several of these highly infectious pathogens, such as Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have been cemented in human history as causing epidemics or pandemics due to their lethality and contagiousness. SARS-CoV-2 is an example of these highly infectious pathogens that have recently become one of the leading causes of globally reported deaths, creating one of the worst economic downturns and health crises in the last century. As a result, the necessity for highly accurate and increasingly rapid on-site diagnostic platforms for highly infectious pathogens, such as SARS-CoV-2, has grown dramatically over the last two years. Current conventional non-microfluidic diagnostic techniques have limitations in their effectiveness as on-site devices due to their large turnaround times, operational costs and the need for laboratory equipment. In this review, we first present criteria, both novel and previously determined, as a foundation for the development of effective and viable on-site microfluidic diagnostic platforms for several notable pathogens, including SARS-CoV-2. This list of criteria includes standards that were set out by the WHO, as well as our own "seven pillars" for effective microfluidic integration. We then evaluate the use of microfluidic integration to improve upon currently, and previously, existing platforms for the detection of infectious pathogens. Finally, we discuss a stage-wise means to translate our findings into a fundamental framework towards the development of more effective on-site SARS-CoV-2 microfluidic-integrated platforms that may facilitate future pandemic diagnostic and research endeavors. Through microfluidic integration, many limitations in currently existing infectious pathogen diagnostic platforms can be eliminated or improved upon.
Collapse
Affiliation(s)
- Andres Escobar
- School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada; (A.E.); (J.Q.); (Y.Z.)
| | - Phyllis Chiu
- Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada;
| | - Jianxi Qu
- School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada; (A.E.); (J.Q.); (Y.Z.)
| | - Yushan Zhang
- School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada; (A.E.); (J.Q.); (Y.Z.)
| | - Chang-qing Xu
- School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada; (A.E.); (J.Q.); (Y.Z.)
- Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4L8, Canada;
| |
Collapse
|
44
|
Mou L, Hong H, Xu X, Xia Y, Jiang X. Digital Hybridization Human Papillomavirus Assay with Attomolar Sensitivity without Amplification. ACS NANO 2021; 15:13077-13084. [PMID: 34324808 DOI: 10.1021/acsnano.1c02311] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Detection of nucleic acid without amplification can avoid problems associated with thermal cycling such as labor-intensiveness and aerosol pollution. Here we develop a droplet-based digital microfluidic hybridization assay for nucleic acid detection with attomolar sensitivity. This assay provides a clinically useful sensitivity for detecting human papillomavirus (HPV) without amplification. The sensitivity is accomplished using femtoliter-sized droplet microfluidics for concentrating enzyme-catalyzed fluorescent products into a detectable signal and magnetic beads for accelerating reaction time. Meanwhile, using magnetic beads and droplet microfluidic chips, we can improve the sampling efficiency over conventional methods. We characterized the sensitivity, selectivity, detection range, stability, and accuracy of our assay. Our assay is 50-fold more sensitive than the traditional hybrid capture assay. The assay without amplification avoids problems of complex handling procedures and aerosol pollution. The direct and sensitive detection of nucleic acid using a droplet microfluidic system provides an early disease diagnosis tool.
Collapse
Affiliation(s)
- Lei Mou
- Department of Clinical Laboratory, Third Affiliated Hospital of Guangzhou Medical University, No. 63 Duobao Road, Liwan District, Guangzhou, Guangdong 510150, P. R. China
- Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088, Xueyuan Road, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Honghai Hong
- Department of Clinical Laboratory, Third Affiliated Hospital of Guangzhou Medical University, No. 63 Duobao Road, Liwan District, Guangzhou, Guangdong 510150, P. R. China
| | - Xiaojian Xu
- Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088, Xueyuan Road, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Yong Xia
- Department of Clinical Laboratory, Third Affiliated Hospital of Guangzhou Medical University, No. 63 Duobao Road, Liwan District, Guangzhou, Guangdong 510150, P. R. China
| | - Xingyu Jiang
- Department of Clinical Laboratory, Third Affiliated Hospital of Guangzhou Medical University, No. 63 Duobao Road, Liwan District, Guangzhou, Guangdong 510150, P. R. China
- Department of Biomedical Engineering, Southern University of Science and Technology, No. 1088, Xueyuan Road, Xili, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| |
Collapse
|
45
|
Louey A, Hernández D, Pébay A, Daniszewski M. Automation of Organoid Cultures: Current Protocols and Applications. SLAS DISCOVERY 2021; 26:1138-1147. [PMID: 34167363 DOI: 10.1177/24725552211024547] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
GRAPHICAL ABSTRACT [Formula: see text].
Collapse
Affiliation(s)
- Alexandra Louey
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
| | - Damián Hernández
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
| | - Alice Pébay
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia.,Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
| | - Maciej Daniszewski
- Department of Anatomy and Physiology, The University of Melbourne, Parkville, Victoria, Australia
| |
Collapse
|
46
|
Bouzetos E, Ganar KA, Mastrobattista E, Deshpande S, van der Oost J. (R)evolution-on-a-chip. Trends Biotechnol 2021; 40:60-76. [PMID: 34049723 DOI: 10.1016/j.tibtech.2021.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 01/17/2023]
Abstract
Billions of years of Darwinian evolution has led to the emergence of highly sophisticated and diverse life forms on Earth. Inspired by natural evolution, similar principles have been adopted in laboratory evolution for the fast optimization of genes and proteins for specific applications. In this review, we highlight state-of-the-art laboratory evolution strategies for protein engineering, with a special emphasis on in vitro strategies. We further describe how recent progress in microfluidic technology has allowed the generation and manipulation of artificial compartments for high-throughput laboratory evolution experiments. Expectations for the future are high: we foresee a revolution on-a-chip.
Collapse
Affiliation(s)
- Evgenios Bouzetos
- Laboratory of Microbiology, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands
| | - Ketan Ashok Ganar
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands
| | - Enrico Mastrobattista
- Pharmaceutics Division, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Siddharth Deshpande
- Laboratory of Physical Chemistry and Soft Matter, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands.
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research, 6708, WE, Wageningen, The Netherlands.
| |
Collapse
|
47
|
Zhu Y, Li J, Lin X, Huang X, Hoffmann MR. Single-Cell Phenotypic Analysis and Digital Molecular Detection Linkable by a Hydrogel Bead-Based Platform. ACS APPLIED BIO MATERIALS 2021; 4:2664-2674. [PMID: 33763633 PMCID: PMC7976597 DOI: 10.1021/acsabm.0c01615] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/01/2021] [Indexed: 11/29/2022]
Abstract
Cell heterogeneity, such as antibiotic heteroresistance and cancer cell heterogeneity, has been increasingly observed. To probe the underlying molecular mechanisms in the dynamically changing heterogeneous cells, a high throughput platform is urgently needed to establish single cell genotype-phenotype correlations. Herein, we report a platform combining single-cell viability phenotypic analysis with digital molecular detection for bacterial cells. The platform utilizes polyethylene glycol hydrogel that cross-links through a thiol-Michael addition, which is biocompatible, fast, and spontaneous. To generate uniform nanoliter-sized hydrogel beads (Gelbeads), we developed a convenient and disposable device made of needles and microcentrifuge tubes. Gelbead-based single cell viability and molecular detection assays were established. Enhanced thermal stability and uncompromised efficiency were achieved for digital polymerase chain reaction (PCR) and digital loop-mediated isothermal amplification (LAMP) within the Gelbeads. Reagent exchange for in situ PCR following viability phenotypic analyses was demonstrated. The combined analyses may address the genotypic differences between cellular subpopulations exhibiting distinct phenotypes. The platform promises unique perspectives in mechanism elucidation of environment-evolution interaction that may be extended to other cell types for medical research.
Collapse
Affiliation(s)
- Yanzhe Zhu
- Linde+Robinson Laboratories, California Institute of Technology, Pasadena, California 91125, United States
| | - Jing Li
- Linde+Robinson Laboratories, California Institute of Technology, Pasadena, California 91125, United States
| | - Xingyu Lin
- Linde+Robinson Laboratories, California Institute of Technology, Pasadena, California 91125, United States
| | - Xiao Huang
- Linde+Robinson Laboratories, California Institute of Technology, Pasadena, California 91125, United States
| | - Michael R Hoffmann
- Linde+Robinson Laboratories, California Institute of Technology, Pasadena, California 91125, United States
| |
Collapse
|
48
|
Photooxidation-induced fluorescence amplification system for an ultra-sensitive enzyme-linked immunosorbent assay (ELISA). Sci Rep 2021; 11:5831. [PMID: 33712666 PMCID: PMC7954804 DOI: 10.1038/s41598-021-85107-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/21/2021] [Indexed: 12/11/2022] Open
Abstract
This report suggests a method of enhancing the sensitivity of chemifluorescence-based ELISA, using photooxidation-induced fluorescence amplification (PIFA). The PIFA utilized autocatalytic photooxidation of the chemifluorescent substrate, 10-acetyl 3,7-dihydroxyphenoxazine (ADHP, Amplex Red) to amplify the fluorescent product resorufin, initially oxidized by horse radish peroxidase (HRP). As the amplification rate is proportional to the initial level of resorufin, the level of antigen labeled by HRP is quantified by analyzing the profile of fluorescence intensity. The normalized profile was interpolated into an autocatalysis model, and the rate of increase at half-maximum time was quantified by the use of an amplification index (AI). The lower limit of detection, for resorufin or HRP, was less than one-tenth that of the plate reader. It requires only slight modification of the fluorescence reader and is fully compatible with conventional or commercial ELISA. When it is applied to a commercial ELISA kit for the detection of amyloid beta, it is verified that the PIFA assay enhanced the detection sensitivity by more than a factor of 10 and was compatible with a conventional 96-well ELISA assay kit. We anticipate this PIFA assay to be used in research for the detection of low levels of proteins and for the early diagnosis of various diseases with rare protein biomarkers, at ultra-low (pg/mL) concentrations.
Collapse
|
49
|
Zhao S, Zhang Z, Hu F, Wu J, Peng N. Massive droplet generation for digital PCR via a smart step emulsification chip integrated in a reaction tube. Analyst 2021; 146:1559-1568. [PMID: 33533355 DOI: 10.1039/d0an01841d] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Step emulsification (SE) devices coupled with parallel generation nozzles are widely used in the production of large-scale monodisperse droplets, especially for droplet-based digital polymerase chain reaction (ddPCR) analysis. Although current ddPCR systems based on the SE method can provide a fully enclosed ddPCR scheme, high demands on chip fabrication and system control will increase testing costs and reduce its flexibility in ddPCR analysis. In this study, a compact SE device, integrating a smart SE chip into a reaction tube, was developed to prepare large-scale water-in-fluorinated-oil droplets for ddPCR analysis. The SE chip contained dozens of droplet-generation nozzles. By adjusting the nozzle height of the SE chip, monodisperse droplets in a picolitre to nanolitre vloume could be prepared at a production rate of tens to hundreds of microlitres per minute. Subsequently, we utilized such an integrated SE device to prepare monodisperse droplets for ddPCR experiments. The volume of PCR reagent and the number of droplets could be flexibly adjusted according to the requirements of the ddPCR analysis. The quantitative results showed that emulsions prepared by the SE device could achieve ddPCR detection with high accuracy, good repeatability, and an adaptive dynamic range, which also demonstrated the robustness and reliability of such devices in the droplet preparation. Thus, this compact SE device provides an inexpensive, flexible, and simplified droplet preparation method for digital PCR quantitative analysis.
Collapse
Affiliation(s)
- Shuhao Zhao
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China.
| | | | | | | | | |
Collapse
|
50
|
Li D, Cao Y, Huang B, Han M, Wu X, Sun Q, Zheng C, Zhao L, Ma C, Jin H, Wang X, Liu Y, Zhang Y. Active Femtoliter Droplet Generation in Microfluidics by Confined Interface Vibration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1297-1305. [PMID: 33428403 DOI: 10.1021/acs.langmuir.0c03368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The precise and effective generation of micron-sized droplets is one of the most common and important issues for droplet-based microfluidics. Active droplet generation makes use of additional energy input in promoting interfacial instabilities for droplet generation. Here, we report a new technique for the active generation of femtoliter droplets in microfluidic systems using confined interfacial vibration (CIV). The CIV is formed at the orifice of a traditional inkjet nozzle first by pushing the liquid out and then pulling it back. Droplets are pinched off during the withdrawal process, and this is different from the current active droplet generation techniques, which only monodirectionally push the liquid out. Droplets with radius ranging from ca. 1 to 28 μm can be actively generated by CIV at an orifice with radius 30 μm, distinguishing from conventional active generation techniques in which the droplets are always comparable or slightly bigger than the orifice. Experimental results showed that the droplet volume can be customized by controlling the intensity of the CIV. The inherent digital nature of the inkjet technique enables easy and precise regulating of the droplet volume, making it seamlessly compatible with the digital microfluidic systems.
Collapse
Affiliation(s)
- Dege Li
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Yi Cao
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Bingfang Huang
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Molong Han
- Centre of Micro-photonics, Swinburne University of Technology, Melbourne 3122, Australia
| | - Xinlei Wu
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Qiang Sun
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Chao Zheng
- Department of Chemical and Process Engineering, University of Surrey, Guildford GU2 7XH, U.K
| | - Lilong Zhao
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Chi Ma
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Hui Jin
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Xiaolong Wang
- Dongying Science and Technology Bureau, Dongying 257000, China
| | - Yonghong Liu
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Yanzhen Zhang
- College of Mechanical and Electronic Engineering, China University of Petroleum (East China), Qingdao 266580, China
- Centre of Micro-photonics, Swinburne University of Technology, Melbourne 3122, Australia
| |
Collapse
|