In-site encapsulating gold “nanowires” into hemin-coupled protein scaffolds through biomimetic assembly towards the nanocomposites with strong catalysis, electrocatalysis, and fluorescence properties

Abstract

An efficient and green biomimetic assembly protocol was developed for the fabrication of multifunctional nanocomposites by mimicking the configuration of natural protein enzymes. Bovine serum albumin (BSA) as the protein model was first split to produce the disassembled BSA (dBSA) of linear polymer and then coupled with catalytic Hemin (Hem). The yielded dBSA-Hem scaffolds were utilized to in-site encapsulate gold nanoclusters (AuNCs) through biominerization, yielding the dBSA-Hem-AuNCs. It was discovered that the nanocomposites could display the well-defined composition and spheric morphology. In particular, they could exhibit unexpectedly strong catalysis, electrocatalysis, and fluorescence properties, in which the biominerized AuNCs would act as fluorescence sources and “nanowires” for promoting the electron-transfer of the catalytic nanocomposites. Colorimetric investigations show that the developed enzyme mimics could present peroxidase-like catalysis activities comparable to natural horseradish peroxidase. In addition, they could facilitate the direct electrocatalysis for H₂O₂ at concentrations as low as 0.40 μM. Moreover, strong red fluorescence of AuNCs in nanocomposites could be expected for the fluorimetric analysis of H₂O₂ with linear concentrations ranging from 50 nM to 100 μM. Such a biomimetic assembly route may open a new door toward the preparation of diverse nanocomposites with multifunctional catalysis and fluorescence, thus promising extensive applications of catalysis and detection in the chemical, environmental, and biomedical fields.