Microbial Nanobionics: Application of Nanobiosensors in Microbial Growth and Diagnostics

Abstract

Microbial nanobiosensors (NBSs) contain immobilized microorganisms and a chain of transduction and are generally used for a single biochemical process. There are two classes of microbial NBSs that use the same principle for measuring the activity of metabolism in the presence of the analyte. The NBSs using immobilized microorganisms from which the products resulting from metabolism are measured are known as microbial NBSs. NBSs that measure the electrical activity of the metabolism of microorganisms when consuming a “biofuel” are generally known as bioelectrochemical cells or biofuel cells. The advantages of microbial NBSs are lower sensitivity to inhibition and contamination of the substrate; higher tolerance to pH and temperature variations; higher lifetime compared to the enzymatic ones; cheap; high variability, because they are able to adapt better to environmental conditions; cofactor independence; physiological response to toxic compounds; and ease of preparation due to the easy cultivation of microorganisms. The disadvantages of NBSs are as follows: they have a longer response time than enzymatic electrodes; and reusing them in a new measurement requires a longer time. Photomicrobial NBSs are based on the optical phenomena manifested by microorganisms in metabolic processes: photoluminescence, chemiluminescence, electroluminescence, polarization, absorbance, etc.