Optical glucose sensors based on chitosan-capped ZnS-doped Mn nanomaterials

Abstract

The primary goal of glucose sensing at the point of care is to identify glucose concentrations within the diabetes range. However, lower glucose levels also pose a severe health risk. In this paper, we propose quick, simple, and reliable glucose sensors based on the absorption and photoluminescence spectra of chitosan-capped ZnS-doped Mn nanomaterials in the range of 0.125 to 0.636 mM glucose, corresponding to 2.3 mg/dL to 11.4 mg/dL. The detection limit was 0.125 mM (or 2.3 mg/dL), much lower than the hypoglycemia level of 70 mg/dL (or 3.9 mM).

Chitosan-capped ZnS-doped Mn nanomaterials retain their optical properties while improving sensor stability. This study reports for the first time how the sensors’ efficacy was affected by chitosan content from 0.75 to 1.5 wt.%. The results showed that 1 wt.% chitosan-capped ZnS-doped Mn is the most sensitive, selective, and stable material. We also tested the biosensor with glucose in phosphate-buffered saline. In the same range of 0.125 to 0.636 mM, the chitosan-coated ZnS-doped Mn sensors exhibited better sensitivity than in a working water environment.