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Low aspect ratio micropores for single‐particle and single‐cell analysis
Author(s) -
Goyal Gaurav,
Mulero Rafael,
Ali Jamel,
Darvish Armin,
Kim Min Jun
Publication year - 2015
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201400570
Subject(s) - microparticle , materials science , particle (ecology) , nanotechnology , drop (telecommunication) , particle size , resolution (logic) , microporous material , chemical engineering , biophysics , chemistry , composite material , telecommunications , oceanography , artificial intelligence , computer science , engineering , biology , geology
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.