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Kong TF, Shen X, Sim MY, Yong J, Ng TK, Chong TW, Marcos. Urine osmolality assessment through the integration of urea hydrolysis and impedance measurement. LAB ON A CHIP 2024; 24:3728-3737. [PMID: 38953748 DOI: 10.1039/d4lc00114a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
We present the development and validation of an impedance-based urine osmometer for accurate and portable measurement of urine osmolality. The urine osmolality of a urine sample can be estimated by determining the concentrations of the conductive solutes and urea, which make up approximately 94% of the urine composition. Our method utilizes impedance measurements to determine the conductive solutes and urea after hydrolysis with urease enzyme. We built an impedance model using sodium chloride (NaCl) and urea at various known concentrations. In this work, we validated the accuracy of the impedance-based urine osmometer by developing a proof-of-concept first prototype and an integrated urine dipstick second prototype, where both prototypes exhibit an average accuracy of 95.5 ± 2.4% and 89.9 ± 9.1%, respectively in comparison to a clinical freezing point osmometer in the hospital laboratory. While the integrated dipstick design exhibited a slightly lower accuracy than the first prototype, it eliminated the need for pre-mixing or manual pipetting. Impedance calibration curves for conductive and non-conductive solutes consistently yielded results for NaCl but underscored challenges in achieving uniform urease enzyme coating on the dipstick. We also investigated the impact of storing urine at room temperature for 24 hours, demonstrating negligible differences in osmolality values. Overall, our impedance-based urine osmometer presents a promising tool for point-of-care urine osmolality measurements, addressing the demand for a portable, accurate, and user-friendly device with potential applications in clinical and home settings.
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Affiliation(s)
- Tian Fook Kong
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
| | - Xinhui Shen
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
| | - Mei Yi Sim
- Department of Urology, Singapore General Hospital, 20 College Road, Singapore, 169856, Singapore.
| | - Jin Yong
- Department of Urology, Singapore General Hospital, 20 College Road, Singapore, 169856, Singapore.
| | - Tze Kiat Ng
- Department of Urology, Singapore General Hospital, 20 College Road, Singapore, 169856, Singapore.
| | - Tsung Wen Chong
- Department of Urology, Singapore General Hospital, 20 College Road, Singapore, 169856, Singapore.
| | - Marcos
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
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2
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Jayan H, Yin L, Xue S, Zou X, Guo Z. Raman spectroscopy-based microfluidic platforms: A promising tool for detection of foodborne pathogens in food products. Food Res Int 2024; 180:114052. [PMID: 38395567 DOI: 10.1016/j.foodres.2024.114052] [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: 11/24/2023] [Revised: 01/15/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024]
Abstract
Rapid and sensitive detection of foodborne pathogens in food products is paramount for ensuring food safety and public health. In the ongoing effort to tackle this issue, detection methods are continually researched and upgraded to achieve rapidity, sensitivity, portability, and cost-effectiveness. This review addresses the critical need for improved technique by focusing on Raman spectroscopy-based microfluidic platforms, which have shown potential in revolutionizing the field of foodborne pathogen analysis offering point-of-care diagnosis and multiplex detection. The key problem lies in the persistent threat of compromised food quality and public health due to inadequate pathogen detection. The review elucidates the various trapping strategies employed in a microfluidic platform, including optical trapping, electrical trapping, mechanical trapping, and acoustic trapping for the capture of microbial cells. Subsequently, the review delves into the key aspects of the application of microbial detection in food products, highlighting recent advances and challenges in the field. The integrated technique allows point-of-care application assessment, which is an attractive quality for in-line and real-time detection of foodborne pathogens. However, the application of the technique in food products is limited and requires further research to combat the complexity of the food matrix, reduced costs of production, and ensure real-time use for diverse pathogens. Ultimately, this review aims to propel advancements in microbial detection, thus promoting enhanced food safety through state-of-the-art technologies.
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Affiliation(s)
- Heera Jayan
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; International Joint Research Laboratory of Intelligent Agriculture and Agri-products Processing, Jiangsu University, Zhenjiang 212013, China
| | - Limei Yin
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Shanshan Xue
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Xiaobo Zou
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; International Joint Research Laboratory of Intelligent Agriculture and Agri-products Processing, Jiangsu University, Zhenjiang 212013, China
| | - Zhiming Guo
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; China Light Industry Key Laboratory of Food Intelligent Detection & Processing, Jiangsu University, Zhenjiang 212013, China.
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3
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Deivasigamani R, Mohd Maidin NN, Abdul Nasir NS, Abdulhameed A, Ahmad Kayani AB, Mohamed MA, Buyong MR. A correlation of conductivity medium and bioparticle viability on dielectrophoresis-based biomedical applications. Electrophoresis 2023; 44:573-620. [PMID: 36604943 DOI: 10.1002/elps.202200203] [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: 08/12/2022] [Revised: 11/28/2022] [Accepted: 12/26/2022] [Indexed: 01/07/2023]
Abstract
Dielectrophoresis (DEP) bioparticle research has progressed from micro to nano levels. It has proven to be a promising and powerful cell manipulation method with an accurate, quick, inexpensive, and label-free technique for therapeutic purposes. DEP, an electrokinetic phenomenon, induces particle movement as a result of polarization effects in a nonuniform electrical field. This review focuses on current research in the biomedical field that demonstrates a practical approach to DEP in terms of cell separation, trapping, discrimination, and enrichment under the influence of the conductive medium in correlation with bioparticle viability. The current review aims to provide readers with an in-depth knowledge of the fundamental theory and principles of the DEP technique, which is influenced by conductive medium and to identify and demonstrate the biomedical application areas. The high conductivity of physiological fluids presents obstacles and opportunities, followed by bioparticle viability in an electric field elaborated in detail. Finally, the drawbacks of DEP-based systems and the outlook for the future are addressed. This article will aid in advancing technology by bridging the gap between bioscience and engineering. We hope the insights presented in this review will improve cell suspension medium and promote DEP-viable bioparticle manipulation for health-care diagnostics and therapeutics.
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Affiliation(s)
- Revathy Deivasigamani
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, Malaysia
| | - Nur Nasyifa Mohd Maidin
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, Malaysia
| | - Nur Shahira Abdul Nasir
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, Malaysia
| | | | - Aminuddin Bin Ahmad Kayani
- Functional Materials and Microsystems Research Group and the Micro Nano Research Facility, RMIT University, Melbourne, Australia.,ARC Research Hub for Connected Sensors for Health, RMIT University, Melbourne, Australia
| | - Mohd Ambri Mohamed
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, Malaysia
| | - Muhamad Ramdzan Buyong
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, Malaysia
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4
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Recent advances of integrated microfluidic systems for fungal and bacterial analysis. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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5
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Anbumani S, da Silva AM, Alaferdov A, Puydinger dos Santos MV, Carvalho IGB, de Souza e Silva M, Moshkalev S, Carvalho HF, de Souza AA, Cotta MA. Physiochemically Distinct Surface Properties of SU-8 Polymer Modulate Bacterial Cell-Surface Holdfast and Colonization. ACS APPLIED BIO MATERIALS 2022; 5:4903-4912. [PMID: 36162102 PMCID: PMC9580523 DOI: 10.1021/acsabm.2c00632] [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: 07/16/2022] [Accepted: 09/13/2022] [Indexed: 11/28/2022]
Abstract
SU-8 polymer is an excellent platform for diverse applications due to its high aspect ratio of micro/nanostructure fabrication and exceptional physicochemical and biocompatible properties. Although SU-8 polymer has often been investigated for various biological applications, how its surface properties influence the interaction of bacterial cells with the substrate and its colonization is poorly understood. In this work, we tailor SU-8 nanoscale surface properties to investigate single-cell motility, adhesion, and successive colonization of phytopathogenic bacteria, Xylella fastidiosa. Different surface properties of SU-8 thin films have been prepared using photolithography processing and oxygen plasma treatment. A more significant density of carboxyl groups in hydrophilic plasma-treated SU-8 surfaces promotes faster cell motility in the earlier growth stage. The hydrophobic nature of pristine SU-8 surfaces shows no trackable bacterial motility and 5-10 times more single cells adhered to the surface than its plasma-treated counterpart. In addition, plasma-treated SU-8 samples suppressed bacterial adhesion, with surfaces showing less than 5% coverage. These results not only showcase that SU-8 surface properties can impact the spatiotemporal bacterial behavior but also provide insights into pathogens' prominent ability to evolve and adapt to different surface properties.
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Affiliation(s)
- Silambarasan Anbumani
- Institute
of Physics “Gleb Wataghin”, University of Campinas, Campinas, SP 13083-859, Brazil
| | - Aldeliane M. da Silva
- Institute
of Physics “Gleb Wataghin”, University of Campinas, Campinas, SP 13083-859, Brazil
| | - Andrei Alaferdov
- Center
for Semiconductor Components and Nanotechnologies, University of Campinas, Campinas, SP 13083-870, Brazil
| | | | - Isis G. B. Carvalho
- Citrus
Center APTA “Sylvio Moreira” Agronomic Institute of
Campinas, Cordeirópolis, SP 13490-970, Brazil
| | - Mariana de Souza e Silva
- Citrus
Center APTA “Sylvio Moreira” Agronomic Institute of
Campinas, Cordeirópolis, SP 13490-970, Brazil
| | - Stanislav Moshkalev
- Center
for Semiconductor Components and Nanotechnologies, University of Campinas, Campinas, SP 13083-870, Brazil
| | - Hernandes F. Carvalho
- Department
of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas, SP 13083-862, Brazil
| | - Alessandra A. de Souza
- Citrus
Center APTA “Sylvio Moreira” Agronomic Institute of
Campinas, Cordeirópolis, SP 13490-970, Brazil
| | - Monica A. Cotta
- Institute
of Physics “Gleb Wataghin”, University of Campinas, Campinas, SP 13083-859, Brazil
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Shen X, Teo TW, Kong TF. A Technique for Rapid Bacterial-Density Enumeration through Membrane Filtration and Differential Pressure Measurements. MICROMACHINES 2022; 13:mi13081198. [PMID: 36014121 PMCID: PMC9415702 DOI: 10.3390/mi13081198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 02/01/2023]
Abstract
In this article, we present a microfluidic technique for the rapid enumeration of bacterial density with a syringe filter to trap bacteria and the quantification of the bacterial density through pressure difference measurement across the membrane. First, we established the baseline differential pressure and hydraulic resistance for a filtration membrane by fully wetting the filter with DI water. Subsequently, when bacteria were infused and trapped at the pores of the membrane, the differential pressure and hydraulic resistance also increased. We characterized the infusion time required for the bacterial sample to achieve a normalized hydraulic resistance of 1.5. An equivalent electric-circuit model and calibration data sets from parametric studies were used to determine the general form of a calibration curve for the prediction of the bacterial density of a bacterial sample. As a proof of concept, we demonstrated through blind tests with Escherichia coli that the device is capable of determining the bacterial density of a sample ranging from 7.3 × 106 to 2.2 × 108 CFU/mL with mean and median accuracies of 87.21% and 91.33%, respectively. The sample-to-result time is 19 min for a sample with lower detection threshold, while for higher-bacterial-density samples the measurement time is further shortened to merely 8 min.
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Affiliation(s)
- Xinhui Shen
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Ting Wei Teo
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Tian Fook Kong
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
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7
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Experimental Verification of Dielectric Models with a Capacitive Wheatstone Bridge Biosensor for Living Cells: E. coli. SENSORS 2022; 22:s22072441. [PMID: 35408055 PMCID: PMC9002767 DOI: 10.3390/s22072441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/14/2022] [Accepted: 03/19/2022] [Indexed: 12/10/2022]
Abstract
Detection of bioparticles is of great importance in electrophoresis, identification of biomass sources, food and water safety, and other areas. It requires a proper model to describe bioparticles' electromagnetic characteristics. A numerical study of Escherichia coli bacteria during their functional activity was carried out by using two different geometrical models for the cells that considered the bacteria as layered ellipsoids and layered spheres. It was concluded that during cell duplication, the change in the dielectric permittivity of the cell is high enough to be measured at radio frequencies of the order of 50 kHz. An experimental setup based on the capacitive Wheatstone bridge was designed to measure relative changes in permittivity during cell division. In this way, the theoretical model was validated by measuring the dielectric permittivity changes in a cell culture of Escherichia coli ATTC 8739 from WDCM 00012 Vitroids. The spheroidal model was confirmed to be more accurate.
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Gerlt MS, Ruppen P, Leuthner M, Panke S, Dual J. Acoustofluidic medium exchange for preparation of electrocompetent bacteria using channel wall trapping. LAB ON A CHIP 2021; 21:4487-4497. [PMID: 34668506 PMCID: PMC8577197 DOI: 10.1039/d1lc00406a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 10/13/2021] [Indexed: 06/02/2023]
Abstract
Comprehensive integration of process steps into a miniaturised version of synthetic biology workflows remains a crucial task in automating the design of biosystems. However, each of these process steps has specific demands with respect to the environmental conditions, including in particular the composition of the surrounding fluid, which makes integration cumbersome. As a case in point, transformation, i.e. reprogramming of bacteria by delivering exogenous genetic material (such as DNA) into the cytoplasm, is a key process in molecular engineering and modern biotechnology in general. Transformation is often performed by electroporation, i.e. creating pores in the membrane using electric shocks in a low conductivity environment. However, cell preparation for electroporation can be cumbersome as it requires the exchange of growth medium (high-conductivity) for low-conductivity medium, typically performed via multiple time-intensive centrifugation steps. To simplify and miniaturise this step, we developed an acoustofluidic device capable of trapping the bacterium Escherichia coli non-invasively for subsequent exchange of medium, which is challenging in acoustofluidic devices due to detrimental acoustic streaming effects. With an improved etching process, we were able to produce a thin wall between two microfluidic channels, which, upon excitation, can generate streaming fields that complement the acoustic radiation force and therefore can be utilised for trapping of bacteria. Our novel design robustly traps Escherichia coli at a flow rate of 10 μL min-1 and has a cell recovery performance of 47 ± 3% after washing the trapped cells. To verify that the performance of the medium exchange device is sufficient, we tested the electrocompetence of the recovered cells in a standard transformation procedure and found a transformation efficiency of 8 × 105 CFU per μg of plasmid DNA. Our device is a low-volume alternative to centrifugation-based methods and opens the door for miniaturisation of a plethora of microbiological and molecular engineering protocols.
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Affiliation(s)
- M S Gerlt
- Mechanics and Experimental Dynamics, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - P Ruppen
- Bioprocess Laboratory, Department of Biosystems Science and Engineering, Swiss Federal Institute of Technology (ETH Zurich), Mattenstrasse 26, CH-4058 Basel, Switzerland.
- NCCR Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, CH-4058 Basel, Switzerland
| | - M Leuthner
- Mechanics and Experimental Dynamics, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
| | - S Panke
- Bioprocess Laboratory, Department of Biosystems Science and Engineering, Swiss Federal Institute of Technology (ETH Zurich), Mattenstrasse 26, CH-4058 Basel, Switzerland.
- NCCR Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, CH-4058 Basel, Switzerland
| | - J Dual
- Mechanics and Experimental Dynamics, Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
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Kong TF, Tan PY, Tay BZ, Shen X, Marcos. Bacteria and cancer cell pearl chain under dielectrophoresis. Electrophoresis 2021; 42:1070-1078. [PMID: 33442876 DOI: 10.1002/elps.202000277] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 12/14/2020] [Accepted: 01/05/2021] [Indexed: 11/10/2022]
Abstract
In this work, we aim to observe and study the physics of bacteria and cancer cells pearl chain formation under dielectrophoresis (DEP). Experimentally, we visualized the formation of Bacillus subtilis bacterial pearl chain and human breast cancer cell (MCF-7) chain under positive and negative dielectrophoretic force, respectively. Through a simple simulation with creeping flow, AC/DC electric fields, and particle tracing modules in COMSOL, we examined the mechanism by which bacteria self-organize into a pearl chain across the gap between two electrodes via DEP. Our simulation results reveal that the region of greatest positive DEP force shifts from the electrode edge to the leading edge of the pearl chain, thus guiding the trajectories of free-flowing particles toward the leading edge via positive DEP. Our findings additionally highlight the mechanism why the free-flowing particles are more likely to join the existing pearl chain rather than starting a new pearl chain. This phenomenon is primarily due to the increase in magnitude of electric field gradient, and hence DEP force exerted, with the shortening gap between the pearl chain leading edge and the adjacent electrode. The findings shed light on the observed behavior of preferential pearl chain formation across electrode gaps.
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Affiliation(s)
- Tian Fook Kong
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Pei Yen Tan
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Benjamin Zikai Tay
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.,Interdisciplinary Graduate Programme, NTU Institute for Health Technologies (HealthTech NTU), Nanyang Technological University, Singapore
| | - Xinhui Shen
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Marcos
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
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