Differential sensing, commonly called array-based sensing is an alternative technique to specific sensing where a set of cross-reactive sensor elements can discriminate wide range of analytes simultaneously. In this work, we have used cationic two-dimensional MoS2 as receptor elements for recognition of bio-analytes. Seven different receptors were fabricated through functionalization with thiol ligands where the non-thiol terminal was design to facilitate possible bio-molecular interactions. A biocompatible and anionic, Green fluorescent protein (GFP) was considered as signal transducers which can bind to cationic MoS2 followed by a depression in fluorescence intensity. The incoming analytes can bind to the cationic MoS2 followed by displacement of GFP from its surface because of enhancement in fluorescence intensity. The intensity differences before and after addition of analytes were used for creating canonical pattern. The sensor array successfully discriminated 15 different proteins at 50 nM with detection limit of 1 nM. The system was also suitable to detect 10 different proteins in fetal bovine serum medium which indicates the array has potential to be used in biological complex media. The optimized sensor array also effectively discriminated different bacteria in urine media. Bacteria having different types and amounts of drug resistivity were separately patterned in the canonical score plot. Along with bacterial cell discrimination, the array was successfully employed for the discrimination of lysates of different drug resistant bacteria. The mechanism of sensing was investigated through optical and electrodynamic studies which indicates involvement of van der waals force plays a major role in discrimination. In future, dual mode sensing of the bacterial sample can provide an accurate and rapid detection of pathogens.

Differential sensing of proteins and bacteria by using cationic two-dimensional MoS2 sensor array

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.