Low aspect ratio micropores for single-particle and single-cell analysis.
This paper describes microparticle and bacterial translocation studies using low aspect ratio solid-state micropores. Micropores, 5 μm in diameter, were fabricated in 200 nm thick free-standing silicon nitride membranes, resulting in pores with an extremely low aspect ratio, nominally 0.04. For microparticle translocation experiments, sulfonated polystyrene microparticles and magnetic microbeads in size range of 1-4 μm were used. Using the microparticle translocation characteristics, we find that particle translocations result in a change only in the pore's geometrical resistance while the access resistance remains constant. Furthermore, we demonstrate the ability of our micropore to probe high-resolution shape information of translocating analytes using concatenated magnetic microspheres. Distinct current drop peaks were observed for each microsphere of the multibead architecture. For bacterial translocation experiments, nonflagellated Escherichia coli (strain HCB 5) and wild type flagellated Salmonella typhimurium (strain SJW1103) were used. Distinct current signatures for the two bacteria were obtained and this difference in translocation behavior was attributed to different surface protein distributions on the bacteria. Our findings may help in developing low aspect ratio pores for high-resolution microparticle characterization and single-cell analysis.
School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA.
Gaurav
G
Goyal
Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, USA.
Rafael
R
Mulero
Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, USA.
Jamel
J
Ali
School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA.
Armin
A
Darvish
School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA.|Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA, USA.
Min Jun
MJ
Kim
D018988:Bacterial Translocation; D004867:Equipment Design; D004926:Escherichia coli / Q000502:physiology; D008567:Membranes, Artificial; D008863:Microspheres; D010316:Particle Size; D016062:Porosity; D012486:Salmonella typhimurium / Q000502:physiology; D017655:Silicon Compounds; D059010:Single-Cell Analysis / Q000295:instrumentation* / Q000379:methods*
D008567:Membranes, Artificial; D017655:Silicon Compounds; C032734:silicon nitride
Low aspect micropores; Resistive pulse sensing; Single-cell analysis