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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.
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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
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Xu Z, Liu X, Zong C, Zhang Q, Gai H. Homogeneous immunoassay utilizing fluorescence resonance energy transfer from quantum dots to tyramide dyes deposited on full immunocomplexes. Analyst 2023; 148:4877-4884. [PMID: 37642356 DOI: 10.1039/d3an01174g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
There is an urgent need for homogeneous immunoassays that offer sufficient sensitivity for routine clinical practice. In this study, we have developed a highly sensitive, fluorescence resonance energy transfer (FRET)-based homogeneous immunoassay. Unlike previous FRET-based homogeneous immunoassays, where acceptors were attached to antibody molecules located far from the donor, we employed acceptors to label the entire sandwich-structured immunocomplex, including two antibodies and one antigen. As a result, the FRET signal was amplified by a factor of 10, owing to the reduced distance between the donor and acceptors. We validated our method by quantifying carcinoembryonic antigen (CEA) and α-fetoprotein (AFP) in PBS buffer and blank plasma. The limits of detection (LOD) for CEA and AFP in both PBS buffer and blank plasma were comparable, reaching sub-femtomolar levels. Furthermore, we successfully quantified CEA and AFP in three human plasma samples, thereby confirming the reliability of our method for clinical applications.
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Affiliation(s)
- Zihan Xu
- School of Chemistry and Materials Science, Jiangsu Normal University, Shanghai Road 101, Xuzhou, Jiangsu, China.
| | - Xiaojun Liu
- School of Chemistry and Materials Science, Jiangsu Normal University, Shanghai Road 101, Xuzhou, Jiangsu, China.
| | - Chenghua Zong
- School of Chemistry and Materials Science, Jiangsu Normal University, Shanghai Road 101, Xuzhou, Jiangsu, China.
| | - Qingquan Zhang
- School of Chemistry and Materials Science, Jiangsu Normal University, Shanghai Road 101, Xuzhou, Jiangsu, China.
| | - Hongwei Gai
- School of Chemistry and Materials Science, Jiangsu Normal University, Shanghai Road 101, Xuzhou, Jiangsu, China.
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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.
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Affiliation(s)
- David C Duffy
- Quanterix Corporation, 900 Middlesex Turnpike, Billerica, MA 01821, USA.
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Gao Y, Zhou D, Xu Q, Li J, Luo W, Yang J, Pan Y, Huang T, Wang Y, He B, Song Y, Wang Y. Metal-Organic Framework-Mediated Bioorthogonal Reaction to Immobilize Bacteria for Ultrasensitive Fluorescence Counting Immunoassays. ACS APPLIED MATERIALS & INTERFACES 2023; 15:5010-5018. [PMID: 36681942 DOI: 10.1021/acsami.2c21350] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ultrasensitive quantification of protein biomarkers has significant implications in disease diagnosis. Herein, we report a fluorescent bacteria counting immunoassay (FBCIA) strategy for protein biomarker detection based on a cascade signal conversion and amplification strategy including the copper metal-organic framework (Cu-MOF)-mediated Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) for fluorescent bacteria immobilization that converted the concentration of target protein to countable bacterial number and the further self-proliferation of bacteria to amplify the detectable bacterial number. The developed low-background and enzyme-free cascade methodology achieved highly sensitive detection of carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA) with detection limits down to 0.8 pg/mL and 64.5 fg/mL, respectively. On top of that, we also developed a smartphone device for visualizing individual bacteria and point-of-care counting of the resulting bacteria for the detection of clinical samples. The good consistency between FBCIA and clinical enzyme-linked immunosorbent assay (ELISA) validated the high reliability and promising potential of our developed platform in clinical applications.
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Affiliation(s)
- Yanfeng Gao
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Dongtao Zhou
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Qin Xu
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Jingjing Li
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
- Department of Laboratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Wen Luo
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Jingjing Yang
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Yongchun Pan
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Ting Huang
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Yanping Wang
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Bangshun He
- Department of Laboratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China
| | - Yujun Song
- College of Engineering and Applied Sciences, State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Yuzhen Wang
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergistic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
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Yuan H, Chen P, Wan C, Li Y, Liu BF. Merging microfluidics with luminescence immunoassays for urgent point-of-care diagnostics of COVID-19. Trends Analyt Chem 2022; 157:116814. [PMID: 36373139 PMCID: PMC9637550 DOI: 10.1016/j.trac.2022.116814] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/29/2022] [Accepted: 10/30/2022] [Indexed: 11/09/2022]
Abstract
The Coronavirus disease 2019 (COVID-19) outbreak has urged the establishment of a global-wide rapid diagnostic system. Current widely-used tests for COVID-19 include nucleic acid assays, immunoassays, and radiological imaging. Immunoassays play an irreplaceable role in rapidly diagnosing COVID-19 and monitoring the patients for the assessment of their severity, risks of the immune storm, and prediction of treatment outcomes. Despite of the enormous needs for immunoassays, the widespread use of traditional immunoassay platforms is still limited by high cost and low automation, which are currently not suitable for point-of-care tests (POCTs). Microfluidic chips with the features of low consumption, high throughput, and integration, provide the potential to enable immunoassays for POCTs, especially in remote areas. Meanwhile, luminescence detection can be merged with immunoassays on microfluidic platforms for their good performance in quantification, sensitivity, and specificity. This review introduces both homogenous and heterogenous luminescence immunoassays with various microfluidic platforms. We also summarize the strengths and weaknesses of the categorized methods, highlighting their recent typical progress. Additionally, different microfluidic platforms are described for comparison. The latest advances in combining luminescence immunoassays with microfluidic platforms for POCTs of COVID-19 are further explained with antigens, antibodies, and related cytokines. Finally, challenges and future perspectives were discussed.
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Affiliation(s)
- Huijuan Yuan
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Peng Chen
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chao Wan
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yiwei Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Bi-Feng Liu
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
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