Since the onset of the HIV epidemic,assessing CD4+T-cells has become a routine procedure for evaluating immune deficiency,with flow cytometry established as the gold standard.Over time,various strategies and platforms...Since the onset of the HIV epidemic,assessing CD4+T-cells has become a routine procedure for evaluating immune deficiency,with flow cytometry established as the gold standard.Over time,various strategies and platforms have been introduced to improve CD4+cell enumeration,aiming to enhance the performance of diagnostic devices and bring the service closer to patients.These advancements are particularly critical for low-resource settings and point-of-care applications,where the excellent performance of flow cytometry is hindered by its unsuitability in such environments.This work presents an innovative electrochemical microfluidic device that,with further development,could be applied for HIV management in low resource settings.The setup integrates an electrochemical sensor within a PDMS microfluidic structure,allowing for on-chip electrode functionalization and cell detection.Using electrochemical impedance spectroscopy,the biosensor demonstrates a linear detection range from 1.25×105 to 2×106 cells/mL,with a detection limit of 1.41×105 cells/mL for CD4+cells isolated from blood samples,aligning with clinical ranges for both healthy and HIV+patients.The biosensor shows specificity towards CD4+cells with negligible response to monocytes,neutrophils,and bovine serum albumin.Its integration with a microfluidic chip for sensor fabrication and cell detection,compact size,minimal manual handling,ease of fabrication,electrochemical detection capability,and potential for multiplexing together with the detection range make the device particularly advantageous for use in low-resource settings,standing out among other devices described in the literature.This study also investigates the integration of a microfluidic Dean Flow Fractionation(DFF)chip for cell separation.展开更多
Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations,such as bodily fluids,water,or wastewater.Nonetheless,very few practical impleme...Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations,such as bodily fluids,water,or wastewater.Nonetheless,very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice,and even fewer have been integrated with other microanalytical steps.Existing approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall assay.In this paper,we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent approaches.In this way,we reduce the need for additional chemical reagents to zero while enabling device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB technology.We apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution in the vicinity of planar electrodes using electrochemical acid generation through redox-active self-assembled monolayers.The presented device comprises a printed circuit board with an array of gold electrodes that were functionalized with 4-aminothiophenol;this formed a self-assembled monolayer that was electropolymerized to improve its electrochemical reversibility.Protein preconcentration was performed in two configurations.The first was open and needed the use of a holder to suspend a well of fluid above the electrodes;the second used microfluidic channels to enclose small volumes of fluid.Reported here are the resulting data for protein preconcentration in both these forms,with a quantitative concentration factor shown for the open form and qualitative proof shown for the microfluidic.展开更多
基金funding from Santander postgraduate mobility awards and Department of Electronic&Electrical Engineering,University of BathR.S.was funded through UK Engineering and Physical Sciences Research Council grant number EP/V040189/1.
文摘Since the onset of the HIV epidemic,assessing CD4+T-cells has become a routine procedure for evaluating immune deficiency,with flow cytometry established as the gold standard.Over time,various strategies and platforms have been introduced to improve CD4+cell enumeration,aiming to enhance the performance of diagnostic devices and bring the service closer to patients.These advancements are particularly critical for low-resource settings and point-of-care applications,where the excellent performance of flow cytometry is hindered by its unsuitability in such environments.This work presents an innovative electrochemical microfluidic device that,with further development,could be applied for HIV management in low resource settings.The setup integrates an electrochemical sensor within a PDMS microfluidic structure,allowing for on-chip electrode functionalization and cell detection.Using electrochemical impedance spectroscopy,the biosensor demonstrates a linear detection range from 1.25×105 to 2×106 cells/mL,with a detection limit of 1.41×105 cells/mL for CD4+cells isolated from blood samples,aligning with clinical ranges for both healthy and HIV+patients.The biosensor shows specificity towards CD4+cells with negligible response to monocytes,neutrophils,and bovine serum albumin.Its integration with a microfluidic chip for sensor fabrication and cell detection,compact size,minimal manual handling,ease of fabrication,electrochemical detection capability,and potential for multiplexing together with the detection range make the device particularly advantageous for use in low-resource settings,standing out among other devices described in the literature.This study also investigates the integration of a microfluidic Dean Flow Fractionation(DFF)chip for cell separation.
文摘Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations,such as bodily fluids,water,or wastewater.Nonetheless,very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice,and even fewer have been integrated with other microanalytical steps.Existing approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall assay.In this paper,we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent approaches.In this way,we reduce the need for additional chemical reagents to zero while enabling device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB technology.We apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution in the vicinity of planar electrodes using electrochemical acid generation through redox-active self-assembled monolayers.The presented device comprises a printed circuit board with an array of gold electrodes that were functionalized with 4-aminothiophenol;this formed a self-assembled monolayer that was electropolymerized to improve its electrochemical reversibility.Protein preconcentration was performed in two configurations.The first was open and needed the use of a holder to suspend a well of fluid above the electrodes;the second used microfluidic channels to enclose small volumes of fluid.Reported here are the resulting data for protein preconcentration in both these forms,with a quantitative concentration factor shown for the open form and qualitative proof shown for the microfluidic.
