Hybrid cellulose nanocrystal/magnetite glucose biosensors. (1st November 2020) - Tracey, Chantal T.
Graphical abstract: Highlights: Green synthesis of colloidally stable cellulose nanocrystal/magnetite nanoparticle hybrid sol and thin films. Cellulose nanocrystals acting as a biocompatible supporting material for catalytically active magnetite nanoparticles. Biomimetic peroxidase-like activity of magnetite nanoparticles. Dermal and oral blood glucose monitoring. Abstract: There exists a high demand for simple and affordable blood glucose monitoring methods. For this purpose, new generations of biosensors are being developed for possible in vivo or dermal use. We present (non)sulphated cellulose nanocrystal/magnetite thin films to act as dermal and oral glucose biosensors. The biocompatible (N-CNC)-Fe3 O4 and (S-CNC)-Fe3 O4 hybrid systems exhibit peroxidase-like activity, indicated by an almost instant color change when in the presence of glucose and ABTS. Both types of biosensors detect glucose concentrations as low as 5 mM (which corresponds to the level of glucose in biological fluids), with (S-CNC)-Fe3 O4 being 1.5 - 2 times as sensitive as (N-CNC)-Fe3 O4 . Hybrid catalytic activity is more pronounced at room temperature and in acidic environments. The hybrids can therefore be used to determine glucose levels by using sweat and saliva – non-blood bodily secretions which tend to be slightly to moderately acidic and have relatively low glucose levels.