On-demand activatable peroxidase-mimicking enzymatic polymer nanocomposite films.

Nanozymes continue to attract considerable attention to minimise the dependence on expensive enzymes in bioassays, particularly in medical diagnostics. While there has been considerable effort directed towards developing different nanozymes, there has been limited progress in fabricating composite materials based on such nanozymes. One of the biggest gaps in the field is the control, tuneability, and on-demand catalytic response. Herein, a nanocomposite nanozymatic film that enables precise tuning of catalytic activity through stretching is demonstrated. In a systematic study, we developed poly(styrene-stat-n-butyl acrylate)/iron oxide-embedded porous silica nanoparticle (FeSiNP) nanocomposite films with controlled, highly tuneable, and on-demand activatable peroxidase-like activity. The polymer/FeSiNP nanocomposite was designed to undergo film formation at ambient temperature yielding a highly flexible and stretchable film, responsible for enabling precise control over the peroxidase-like activity. The fabricated nanocomposite films exhibited a prolonged FeSiNP dose-dependent catalytic response. Interestingly, the optimised composite films with 10 wt% FeSiNP exhibited a drastic change in the enzymatic activity upon stretching, which provides the nanocomposite films with an on-demand performance activation characteristic. This is the first report showing control over the nanozyme activity using a nanocomposite film, which is expected to pave the way for further research in the field leading to the development of system-embedded activatable sensors for diagnostic, food spoilage, and environmental applications.