Sensitive voltammetric sensor for fast detection of mycolic acids present in mycobacteria

Abstract

The present work describes a fast, simple, and economic method for electroanalytical detection of mycolic acids (MA) present in the cell envelope of Mycobacterium, Corynebacterium, Nocardia, and Rhodococcus. MA are pre-concentrated on a glassy carbon electrode modified with a poly-L-lysine film, resulting in a well-defined reduction wave at -0.73 V (vs. Ag/AgCl) and being the base for detection and quantification of bacteria, like Mycobacterium smegmatis, used as model in this work. The method was optimized and analytical curves were constructed for Mycobacterium smegmatis by using square wave voltammetry. The method offers a detection limit of 5.9 e 10 colony forming units (CFU) mL-1, and the reproducibility for 10 measurements at 1.4 e 102 CFU mL-1 showed a standard deviation of 1.8%. The method was successfully applied for detection of MA in water samples as indirect measure of the presence of Mycobacteria. © 2013 by ESG.