LPMG sensor based on TMF period coating PDMS for detecting Cyt c

Cytochrome c (Cyt c) levels are important indicators for detecting diseases such as liver failure, myocardial infarction, and cancer, holding significant research value in the field of disease monitoring. In this paper, a long-period microfiber grating (LPMG) sensor for detecting Cyt c was proposed, which is composed of a tapered microfiber (TMF) and a grating structure formed by periodically coating polydimethylsiloxane (PDMS). Cyt c absorbs energy under laser irradiation and converts it into heat, causing a change in the surrounding environment temperature, thereby modulating the LPMG structure and resulting in a shift in the LPMG transmission spectrum wavelength. Experimental results demonstrate that the proposed sensor exhibits good linearity in the range of Cyt c concentrations from 0-1000 μM, with a sensitivity of -0.041 nm/μM and a detection limit of 0.488 μM. The proposed sensor is easy to operate, with high sensitivity and a low detection limit, enabling online monitoring of Cyt c over a wide linear range. It represents an ideal means for detecting Cyt c and holds broad prospects for application in disease detection.