Enzymatic degradation of bacterial cellulose derived carbon nanofibers (BC-CNF) by myeloperoxidase (MPO): Performance evaluation for biosensing

Abstract

Myeloperoxidase (MPO) is a promising biomarker for early warning of incidence of cardiovascular diseases (CVDs). Among various sensing mechanisms for detection and quantification of MPO, enzymatic degradation of carbon nanoparticles (CNPs) in presence of MPO has unique advantages such as visual change in optical contrast of sample without requiring additional probe chemicals or reagents. While the degradation of various forms of CNPs (including carbon nanotubes and graphene oxide) due to MPO has been reported in literature, the degradation is typically very slow, resulting in response times on the order of multiple hours, and thus presents a significant limitation for CVD diagnosis. Besides, the extent of degradation is highly sensitive to substrate uniformity, necessitating complicated synthesis processes to obtain pristine CNPs. In this work, we have characterized the enzymatic degradation of bacterial cellulose derived carbon nanofibers (BC-CNF) due to MPO in vitro and explored the feasibility of realizing a BC-CNF colorimetric biosensor for measuring MPO activity. The degradation of BC-CNFs is thoroughly characterized using SEM, TEM, Raman and UV–Vis spectroscopy. We report that carboxylic group functionalized BC-CNFs demonstrate noticeable change in optical contrast due to degradation with clinically relevant concentrations of MPO in approximately 1h, and hold great promise for realizing low-cost biosensors for MPO.