Interrogating biomineralization one amino acid at a time: amplification of mutational effects in protein-aided titania morphogenesis through reaction-diffusion control

• Published in: Chemical communications (Cambridge, England) England), 2021-05, Vol.57 (39), p.483-486
• Main Authors: Pushpavanam, Karthik, Hellner, Brittney, Baneyx, François
• Format: Article
• Language: English
• Subjects: Amino acids; Catalytic activity; Crystallography; Fluxes; Hydrogels; Inorganic materials; Metal oxides; Morphology; Nanoparticles; Needles; Photocatalysis; Precursors; Proteins; Reaction time
• ISSN: 1359-7345; 1364-548X
• DOI: 10.1039/d1cc01521d

To emulate the control that biomineralizing organisms exert over reactant transport, we construct a countercurrent reaction-diffusion chamber in which an agarose hydrogel regulates the fluxes of inorganic precursor and precipitating solid-binding protein. We show that the morphology of the bioprecipitated titania can be changed from monolithic to interconnected particle networks and dispersed nanoparticles either by decreasing reaction time or by increasing agarose weight percentage at constant precursor and protein concentrations. More strikingly, protein variants with one or two substitutions in their metal oxide-binding domain yield unique peripheral morphologies (needles, threads, plates, and peapods) with distinct crystallography and photocatalytic activity. Our results suggest that diffusional control can magnify otherwise subtle mutational effects in biomineralizing proteins and provide a path for the green synthesis of morphologically and functionally diverse inorganic materials. A reaction-diffusion biomineralization chamber operated with solid-binding proteins produces unique titania morphologies and magnifies the otherwise subtle effects of single or double mutations in the protein's materials-binding segment.