title: Label-Free Detection of Single Living Bacteria via Electrochemical Collision Event.
abstract: We detected single living bacterial cells on ultramicroelectrode (UME) using a single-particle collision method and optical microscopic methods. The number of collision events involving the bacterial cells indicated in current-time (i-t) curves corresponds to the number of bacterial cells (i.e., Escherichia coli) on the UME surface, as observed visually. Simulations were performed to determine the theoretical current response (75 pA) and frequency (0.47 pM(-1) s(-1)) of single Escherichia coli collisions. The experimental current response (83 pA) and frequency (0.26 pM(-1) s(-1)) were on the same order of magnitude as the theoretical values. This single-particle collision approach facilitates detecting living bacteria and determining their concentration in solution and could be widely applied to studying other bacteria and biomolecules.
authors.affiliation: Korea Advanced Institute of Science and Technology, Department of Chemistry, Daejeon, 34141, South Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Sookmyung Women's University, Department of Chemistry, Seoul, 04310, South Korea.
authors.forename: Byung-Kwon
authors.initials: BK
authors.lastname: Kim
authors.affiliation: University of Maryland, Fischell Department of Bioengineering, College Park, MD 20742, USA.
authors.forename: Mijeong
authors.initials: M
authors.lastname: Kang
authors.affiliation: Chonbuk National University, Department of Chemistry Education and Institute of Fusion Science, Jeonju 54896, South Korea.
authors.forename: Jun Hui
authors.initials: JH
authors.lastname: Park
mesh_terms: D058491:Bacterial Load / Q000379:methods*; D055664:Electrochemical Techniques / Q000379:methods*; D004926:Escherichia coli / Q000302:isolation & purification*; D008853:Microscopy / Q000379:methods*