Irene Sinn - Academia.edu (original) (raw)

Papers by Irene Sinn

The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and enc... more The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multi-drug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue towards addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension's viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 minutes; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 minutes. We thus demonstrated a label-free, micro-viscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains.

The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and enc... more The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multi-drug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue towards addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension's viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 minutes; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 minutes. We thus demonstrated a label-free, micro-viscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains.

The rapid identification and characterization of bacterial pathogens is an important goal for poi... more The rapid identification and characterization of bacterial pathogens is an important goal for point-of-care diagnostics. Droplet-based lab-on-a-chip systems decrease analysis time and allow for higher levels of throughput because each droplet acts as an isolated reaction chamber. We demonstrate an asynchronous magnetic bead rotation (AMBR) droplet system for single cell and colony growth studies. By monitoring a magnetic bead’s asynchronous frequency response to a rotating magnetic field, the continuous growth and division of individual bacterium and the growth of a small bacterial colony can be observed. The sensitivity of the combined AMBR droplet microfluidics system reduces minimum inhibitory concentration (MIC) measurement time from days to minutes. This technology provides a single cell, as well as a colony analysis platform, that can be used for rapid, high-throughput characterization of individual bacteria or bacterial colonies.

Electrochimica Acta, 2013

ABSTRACT A key characteristic in the theory of the induced charge electrokinetic flow is the vort... more ABSTRACT A key characteristic in the theory of the induced charge electrokinetic flow is the vortices generated by the interaction of the applied electric field with the induced dipolar electric double layers around an electrically conducting surface. The vortices can significantly influence the electrokinetic motion of a particle with an electrically conducting surface. This paper provides the visual evidence of the vortices in the induced charge electrokinetic flow in a “DC field” around a metal surface that is “not an active electrode”. According to authors’ knowledge, this is the first experimental proof of induced-charge electrokinetic phenomena for DC electric field while all the literatures employed the AC field as the acting force during the experiments. Moreover, former studies had mostly reported the vortices around active electrode, used as a conducting surface. Current paper reports the induced vortices around a non-electrode conducting surface. In addition, the experimental results of this paper show that the measured velocity of the electrokinetic motion of particles with a metal hemisphere in a microchannel is much higher than that of the non-conducting polymer particles of the same size under the electric field. These experimental data agree well with the theoretical prediction.

Biosensors with increasingly high sensitivity are crucial for probing small scale properties. The... more Biosensors with increasingly high sensitivity are crucial for probing small scale properties. The asynchronous magnetic bead rotation (AMBR) sensor is an emerging sensor platform, based on magnetically actuated rotation. Here the frequency dependence of the AMBR sensor's sensitivity is investigated. An asynchronous rotation frequency of 145 Hz is achieved. This increased frequency will allow for a calculated detection limit of as little as a 59 nm change in bead diameter, which is a dramatic improvement over previous AMBR sensors and further enables physical and biomedical applications.

The field of microfluidics has exploded in the past decade, particularly in the area of chemical ... more The field of microfluidics has exploded in the past decade, particularly in the area of chemical and biochemical analysis systems. Borrowing technology from the solid-state electronics industry and the production of microprocessor chips, researchers working with glass, silicon, and polymer substrates have fabricated macroscale laboratory components in miniaturized formats. These devices pump nanoliter volumes of liquid through micrometer-scale channels and perform complex chemical reactions and separations. The detection of reaction products is typically done fluorescently with off-chip optical components, and the analysis time from start to finish can be significantly shorter than that of conventional techniques. In this review we describe these microfluidic analysis systems, from the original continuous flow systems relying on electroosmotic pumping for liquid motion to the large diversity of microarray chips currently in use to the newer droplet-based devices and segmented flow systems. Although not currently widespread, microfluidic systems have the potential to become ubiquitous. 325 Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Click here for quick links to Annual Reviews content online, including: • Other articles in this volume • Top cited articles • Top downloaded articles • Our comprehensive search Further ANNUAL REVIEWS 326 Livak-Dahl · Sinn · Burns Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. 328 Livak-Dahl · Sinn · Burns Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. P = P capillary , 6. 330 Livak-Dahl · Sinn · Burns Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only.

Lab on a Chip, 2011

Inappropriate antibiotic use is a major factor contributing to the emergence and spread of antimi... more Inappropriate antibiotic use is a major factor contributing to the emergence and spread of antimicrobial resistance. The long turnaround time (over 24 hours) required for clinical antimicrobial susceptibility testing (AST) often results in patients being prescribed empiric therapies, which may be inadequate, inappropriate, or overly broad-spectrum. A reduction in the AST time may enable more appropriate therapies to be prescribed earlier. Here we report on a new diagnostic asynchronous magnetic bead rotation (AMBR) biosensor droplet microfluidic platform that enables single cell and small cell population growth measurements for applications aimed at rapid AST. We demonstrate the ability to rapidly measure bacterial growth, susceptibility, and the minimum inhibitory concentration (MIC) of a small uropathogenic Escherichia coli population that was confined in microfluidic droplets and exposed to concentrations above and below the MIC of gentamicin. Growth was observed below the MIC, and no growth was observed above the MIC. A 52% change in the sensor signal (i.e. rotational period) was observed within 15 minutes, thus allowing AST measurements to be performed potentially within minutes.

Journal of Vascular and Interventional Radiology, 2011

To develop an ex-vivo arterial perfusion model to evaluate vascular responses to bare metal stent... more To develop an ex-vivo arterial perfusion model to evaluate vascular responses to bare metal stents (BMS) and drug-eluting stents (DES) in porcine carotid arteries.

Cardiovascular Revascularization Medicine, 2011

Purpose: The objective of this study was to investigate potential differences in vascular respons... more Purpose: The objective of this study was to investigate potential differences in vascular response to stenting of coronary arteries with bare metal (BMS) and drug-eluting (DES) stents in juvenile vs. mature swine. Methods and materials: Twenty-one mature (N3 years) and 22 juvenile (6-9 months) Yucatan swine were implanted with 3×12-mm XIENCE V DES and ML VISION BMS in coronary arteries. After 7 and 28 days, vessels were analyzed using light microscopy (n=5-7) and confocal and scanning electron microscopy (n=5-10). Messenger RNA expression levels of inflammatory and endothelial gene markers were tested from stented tissue at 7 and 28 days (n=3). A 2 × 2 analysis of variance followed by t tests compared treatment and/or age effects. Results: No age differences in neointimal area and percentage stenosis were measured. Juvenile swine exhibited increased fibrin scores compared to mature swine (2.6±0.5 vs. 2.2±0.5, Pb.05) at 7 days, with no age-related difference at 28 days. At 7 days, significant increases in para-strut inflammation (Pb.01) and in VCAM-1, ICAM-1, CD40 and MCP-1 gene expression (Pb.05) were observed in mature swine, but differences were largely resolved by 28 days. DES exhibited less endothelial coverage than BMS at 7 days, but this difference was abrogated by 28 days, with no difference between age groups. Conclusions: Our results indicate that mature swine exhibited an increased foreign body response compared to mature swine at 7 and 28 days following stenting that may indicate marginal delays in resolution of foreign body response in aged populations. These differences are unlikely to affect methodologies for preclinical stent safety evaluations.

Biosensors and Bioelectronics, 2011

Continuous growth of individual bacteria has been previously studied by direct observation using ... more Continuous growth of individual bacteria has been previously studied by direct observation using optical imaging. However, optical microscopy studies are inherently diffraction limited and limited in the number of individual cells that can be continuously monitored. Here we report on the use of the asynchronous magnetic bead rotation (AMBR) sensor, which is not diffraction limited. The AMBR sensor allows for the measurement of nanoscale growth dynamics of individual bacterial cells, over multiple generations. This torque-based magnetic bead sensor monitors variations in drag caused by the attachment and growth of a single bacterial cell. In this manner, we observed the growth and division of individual Escherichia coli, with 80-nm sensitivity to the cell length. Over the life cycle of a cell, we observed up to a 300% increase in the rotational period of the biosensor due to increased cell volume. In addition, we observed single bacterial cell growth response to antibiotics. This work demonstrates the non-microscopy limited AMBR biosensor for monitoring individual cell growth dynamics, including cell elongation, generation time, lag time, and division, as well as their sensitivity to antibiotics.

Applied Physics Letters, 2011

Magnetic particles serve as an important tool for a variety of biomedical applications but often ... more Magnetic particles serve as an important tool for a variety of biomedical applications but often lack uniformity in their magnetic responsiveness. For quantitative analysis studies, magnetic particles should ideally be monodisperse and possess uniform magnetic properties. Here we fabricate magnetically uniform Janus particles with tunable magnetic properties using a spin-coating and thermal evaporation method. The resulting 2 m ferromagnetic particles exhibited a 4% magnetic response variability, and the 10 m ferromagnetic particles exhibited a 1% size variability and an 8% magnetic response variability. Furthermore, by reducing the film thickness, the particle behavior was tuned from ferromagnetic to superparamagnetic.

Analytical Chemistry, 2012

The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and enc... more The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multidrug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue toward addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension's viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 min; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 min. We thus demonstrated a labelfree, microviscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains.

The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and enc... more The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multi-drug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue towards addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension's viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 minutes; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 minutes. We thus demonstrated a label-free, micro-viscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains.

The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and enc... more The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multi-drug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue towards addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension's viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 minutes; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 minutes. We thus demonstrated a label-free, micro-viscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains.

The rapid identification and characterization of bacterial pathogens is an important goal for poi... more The rapid identification and characterization of bacterial pathogens is an important goal for point-of-care diagnostics. Droplet-based lab-on-a-chip systems decrease analysis time and allow for higher levels of throughput because each droplet acts as an isolated reaction chamber. We demonstrate an asynchronous magnetic bead rotation (AMBR) droplet system for single cell and colony growth studies. By monitoring a magnetic bead’s asynchronous frequency response to a rotating magnetic field, the continuous growth and division of individual bacterium and the growth of a small bacterial colony can be observed. The sensitivity of the combined AMBR droplet microfluidics system reduces minimum inhibitory concentration (MIC) measurement time from days to minutes. This technology provides a single cell, as well as a colony analysis platform, that can be used for rapid, high-throughput characterization of individual bacteria or bacterial colonies.

Electrochimica Acta, 2013

ABSTRACT A key characteristic in the theory of the induced charge electrokinetic flow is the vort... more ABSTRACT A key characteristic in the theory of the induced charge electrokinetic flow is the vortices generated by the interaction of the applied electric field with the induced dipolar electric double layers around an electrically conducting surface. The vortices can significantly influence the electrokinetic motion of a particle with an electrically conducting surface. This paper provides the visual evidence of the vortices in the induced charge electrokinetic flow in a “DC field” around a metal surface that is “not an active electrode”. According to authors’ knowledge, this is the first experimental proof of induced-charge electrokinetic phenomena for DC electric field while all the literatures employed the AC field as the acting force during the experiments. Moreover, former studies had mostly reported the vortices around active electrode, used as a conducting surface. Current paper reports the induced vortices around a non-electrode conducting surface. In addition, the experimental results of this paper show that the measured velocity of the electrokinetic motion of particles with a metal hemisphere in a microchannel is much higher than that of the non-conducting polymer particles of the same size under the electric field. These experimental data agree well with the theoretical prediction.

Biosensors with increasingly high sensitivity are crucial for probing small scale properties. The... more Biosensors with increasingly high sensitivity are crucial for probing small scale properties. The asynchronous magnetic bead rotation (AMBR) sensor is an emerging sensor platform, based on magnetically actuated rotation. Here the frequency dependence of the AMBR sensor's sensitivity is investigated. An asynchronous rotation frequency of 145 Hz is achieved. This increased frequency will allow for a calculated detection limit of as little as a 59 nm change in bead diameter, which is a dramatic improvement over previous AMBR sensors and further enables physical and biomedical applications.

The field of microfluidics has exploded in the past decade, particularly in the area of chemical ... more The field of microfluidics has exploded in the past decade, particularly in the area of chemical and biochemical analysis systems. Borrowing technology from the solid-state electronics industry and the production of microprocessor chips, researchers working with glass, silicon, and polymer substrates have fabricated macroscale laboratory components in miniaturized formats. These devices pump nanoliter volumes of liquid through micrometer-scale channels and perform complex chemical reactions and separations. The detection of reaction products is typically done fluorescently with off-chip optical components, and the analysis time from start to finish can be significantly shorter than that of conventional techniques. In this review we describe these microfluidic analysis systems, from the original continuous flow systems relying on electroosmotic pumping for liquid motion to the large diversity of microarray chips currently in use to the newer droplet-based devices and segmented flow systems. Although not currently widespread, microfluidic systems have the potential to become ubiquitous. 325 Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Click here for quick links to Annual Reviews content online, including: • Other articles in this volume • Top cited articles • Top downloaded articles • Our comprehensive search Further ANNUAL REVIEWS 326 Livak-Dahl · Sinn · Burns Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. 328 Livak-Dahl · Sinn · Burns Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. P = P capillary , 6. 330 Livak-Dahl · Sinn · Burns Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only. Annu. Rev. Chem. Biomol. Eng. 2011.2:325-353. Downloaded from www.annualreviews.org by Mr. Eric Livak-Dahl on 06/21/11. For personal use only.

Lab on a Chip, 2011

Inappropriate antibiotic use is a major factor contributing to the emergence and spread of antimi... more Inappropriate antibiotic use is a major factor contributing to the emergence and spread of antimicrobial resistance. The long turnaround time (over 24 hours) required for clinical antimicrobial susceptibility testing (AST) often results in patients being prescribed empiric therapies, which may be inadequate, inappropriate, or overly broad-spectrum. A reduction in the AST time may enable more appropriate therapies to be prescribed earlier. Here we report on a new diagnostic asynchronous magnetic bead rotation (AMBR) biosensor droplet microfluidic platform that enables single cell and small cell population growth measurements for applications aimed at rapid AST. We demonstrate the ability to rapidly measure bacterial growth, susceptibility, and the minimum inhibitory concentration (MIC) of a small uropathogenic Escherichia coli population that was confined in microfluidic droplets and exposed to concentrations above and below the MIC of gentamicin. Growth was observed below the MIC, and no growth was observed above the MIC. A 52% change in the sensor signal (i.e. rotational period) was observed within 15 minutes, thus allowing AST measurements to be performed potentially within minutes.

Journal of Vascular and Interventional Radiology, 2011

To develop an ex-vivo arterial perfusion model to evaluate vascular responses to bare metal stent... more To develop an ex-vivo arterial perfusion model to evaluate vascular responses to bare metal stents (BMS) and drug-eluting stents (DES) in porcine carotid arteries.

Cardiovascular Revascularization Medicine, 2011

Purpose: The objective of this study was to investigate potential differences in vascular respons... more Purpose: The objective of this study was to investigate potential differences in vascular response to stenting of coronary arteries with bare metal (BMS) and drug-eluting (DES) stents in juvenile vs. mature swine. Methods and materials: Twenty-one mature (N3 years) and 22 juvenile (6-9 months) Yucatan swine were implanted with 3×12-mm XIENCE V DES and ML VISION BMS in coronary arteries. After 7 and 28 days, vessels were analyzed using light microscopy (n=5-7) and confocal and scanning electron microscopy (n=5-10). Messenger RNA expression levels of inflammatory and endothelial gene markers were tested from stented tissue at 7 and 28 days (n=3). A 2 × 2 analysis of variance followed by t tests compared treatment and/or age effects. Results: No age differences in neointimal area and percentage stenosis were measured. Juvenile swine exhibited increased fibrin scores compared to mature swine (2.6±0.5 vs. 2.2±0.5, Pb.05) at 7 days, with no age-related difference at 28 days. At 7 days, significant increases in para-strut inflammation (Pb.01) and in VCAM-1, ICAM-1, CD40 and MCP-1 gene expression (Pb.05) were observed in mature swine, but differences were largely resolved by 28 days. DES exhibited less endothelial coverage than BMS at 7 days, but this difference was abrogated by 28 days, with no difference between age groups. Conclusions: Our results indicate that mature swine exhibited an increased foreign body response compared to mature swine at 7 and 28 days following stenting that may indicate marginal delays in resolution of foreign body response in aged populations. These differences are unlikely to affect methodologies for preclinical stent safety evaluations.

Biosensors and Bioelectronics, 2011

Continuous growth of individual bacteria has been previously studied by direct observation using ... more Continuous growth of individual bacteria has been previously studied by direct observation using optical imaging. However, optical microscopy studies are inherently diffraction limited and limited in the number of individual cells that can be continuously monitored. Here we report on the use of the asynchronous magnetic bead rotation (AMBR) sensor, which is not diffraction limited. The AMBR sensor allows for the measurement of nanoscale growth dynamics of individual bacterial cells, over multiple generations. This torque-based magnetic bead sensor monitors variations in drag caused by the attachment and growth of a single bacterial cell. In this manner, we observed the growth and division of individual Escherichia coli, with 80-nm sensitivity to the cell length. Over the life cycle of a cell, we observed up to a 300% increase in the rotational period of the biosensor due to increased cell volume. In addition, we observed single bacterial cell growth response to antibiotics. This work demonstrates the non-microscopy limited AMBR biosensor for monitoring individual cell growth dynamics, including cell elongation, generation time, lag time, and division, as well as their sensitivity to antibiotics.

Applied Physics Letters, 2011

Magnetic particles serve as an important tool for a variety of biomedical applications but often ... more Magnetic particles serve as an important tool for a variety of biomedical applications but often lack uniformity in their magnetic responsiveness. For quantitative analysis studies, magnetic particles should ideally be monodisperse and possess uniform magnetic properties. Here we fabricate magnetically uniform Janus particles with tunable magnetic properties using a spin-coating and thermal evaporation method. The resulting 2 m ferromagnetic particles exhibited a 4% magnetic response variability, and the 10 m ferromagnetic particles exhibited a 1% size variability and an 8% magnetic response variability. Furthermore, by reducing the film thickness, the particle behavior was tuned from ferromagnetic to superparamagnetic.

Analytical Chemistry, 2012

The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and enc... more The long turnaround time in antimicrobial susceptibility testing (AST) endangers patients and encourages the administration of wide spectrum antibiotics, thus resulting in alarming increases of multidrug resistant pathogens. A method for faster detection of bacterial proliferation presents one avenue toward addressing this global concern. We report on a label-free asynchronous magnetic bead rotation (AMBR) based viscometry method that rapidly detects bacterial growth and determines drug sensitivity by measuring changes in the suspension's viscosity. With this platform, we observed the growth of a uropathogenic Escherichia coli isolate, with an initial concentration of 50 cells per drop, within 20 min; in addition, we determined the gentamicin minimum inhibitory concentration (MIC) of the E. coli isolate within 100 min. We thus demonstrated a labelfree, microviscometer platform that can measure bacterial growth and drug susceptibility more rapidly, with lower initial bacterial counts than existing commercial systems, and potentially with any microbial strains.