Label-Free Detection of Single Living Bacteria via Electrochemical Collision Event

Ji Young Lee; Byung-Kwon Kim; Mijeong Kang; Jun Hui Park

doi:10.1038/srep30022

Label-Free Detection of Single Living Bacteria via Electrochemical Collision Event

Sci Rep. 2016 Jul 20:6:30022. doi: 10.1038/srep30022.

Authors

Ji Young Lee¹, Byung-Kwon Kim², Mijeong Kang³, Jun Hui Park⁴

Affiliations

¹ Korea Advanced Institute of Science and Technology, Department of Chemistry, Daejeon, 34141, South Korea.
² Sookmyung Women's University, Department of Chemistry, Seoul, 04310, South Korea.
³ University of Maryland, Fischell Department of Bioengineering, College Park, MD 20742, USA.
⁴ Chonbuk National University, Department of Chemistry Education and Institute of Fusion Science, Jeonju 54896, South Korea.

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacterial Load / methods*
Electrochemical Techniques / methods*
Escherichia coli / isolation & purification*
Microscopy / methods*