Self-assembly and photocatalytic activity of branched silicatein/silintaphin filaments decorated with silicatein-synthesized TiO2 nanoparticles

Abstract

The fundamental mechanisms of biomineralization and their translation into innovative synthetic approaches have yielded promising perspectives for the fabrication of biomimetic and bioinspired organic-inorganic hybrid materials. In siliceous sponges, the enzyme silicatein catalyzes the polycondensation of molecular precursors to nano-structured SiO2 that is deposited on self-assembled filaments consisting of the two silicatein isoforms (silicatein-α and -β) and the scaffold protein silintaphin-1. Due to its broad substrate specificity silicatein is also able to convert in vitro various other precursors to non-biogenic materials (e.g., hydrolysis of titanium bis(ammonium lactato)-dihydroxide [TiBALDH] and subsequent polycondensation to titania [TiO2]). In the present approach, silicatein was bioengineered to carry a protein tag (Arg-tag) that confers binding affinity to TiO2. Then, by combining Arg-tagged silicatein-α with silicatein-β and silintaphin-1, self-assembled branched hybrid protein microfilaments were fabricated. Upon subsequent incubation with TiBALDH the filaments were decorated with TiO2 and assayed for photocatalytic activity through photodegradation of the dye methylene blue. This is the first approach that considers concomitant application of two silicatein isoforms for the synthesis of bioinspired organic-inorganic hybrid materials. It is also the first time that the biocatalytic activity of the enzymes has been combined with both the structure-providing properties of silintaphin-1 and a TiO2 affinity protein tag to fabricate self-assembled branched protein filaments as template for a silicatein-synthesized TiO2 photocatalyst. The TiO2-decorated filaments might be explored as a practical alternative to approaches where biotemplates have to be laboriously isolated from their original biological source prior to TiO2 immobilization.

Core shell‐structured NiFe2O4@TiO2 nanoparticle‐anchored reduced graphene oxide for rapid degradation of rhodamine B

“…Therefore, nano-structured TiO 2 (nanoparticles, nanorods, nanotubes, nanowires, etc.) [12][13][14][15] has received considerable attention in the correlated investigations. Because of the complicated separating procedures, pure nano-structured TiO 2 application was restricted.…”

Biological Route to Fabricate Silica on Cellulose Using Immobilized Silicatein Fused with a Carbohydrate-Binding Module

“…The self-assembly of proteins is an interesting property that is integral to the formation of highly ordered protein architectures. Previous studies examined the self-assembly of silicateins that leads to a structure-guiding property when mixing specified ratios of silicateins such as silicatein-α and silicatein-β to form nanosilica structures and filaments. , Those studies confirmed that the self-assembled silicatein can also catalyze silica polymerization. However, the recombinant silicateins show an aggregation property, which results in the formation of randomly arranged aggregates to form precipitates.…”

Review on Recent Developments in Bioinspired-Materials for Sustainable Energy and Environmental Applications

“…The peptide nanostructures act as scaffold which permit energy transfer and show absorption ability in ultraviolet region, by enhancing their capacity they were used for dye sensitized solar cells [243]. Titanium dioxide can be merged with aggregated protein fibers to produce a template for titanium dioxide photocatalyst [224]. Wang et al fabricated copper phosphate nanosheets in flower shape in which titanium dioxide nanoparticles were integrated over the flower petals which act as photocatalyst for solar light harvesting device [244].…”