Microalgae-derived peptide with dual-functionalities of silica deposition and antimicrobial activity for biosilica-based biomaterial design

Peptides are relatively small macromolecules, and their functionalities are usefully combined with organic or inorganic materials to design highly-efficient biomedical devices. Marine organisms are potential resources to identify a novel peptide with such functionalities, which can be employed to improve both of the inorganic and organic properties, essential for biomaterial design. This study reported and characterized a newly-found peptide, TO, derived from marine diatom, Thalassiosira oceanica. The peptide exhibited extraordinary dual functions: silica deposition and antimicrobial activity. It has not yet been reported that a peptide had both silica synthesis ability and antibacterial activity. When the peptide was incorporated into polyurethane (PU) foam, this dualfunctionality was employed, and each function varied by peptide and silica precursor concentrations. In particular, the PU form (PU@mTO@SiO2) with silica deposited by modified TO (mTO) showed increased water capacity by 200%. Antimicrobial activities of PU@mTO@SiO2 and control PU@SiO2 (made w/o peptide) were evaluated against E. coli, P. aeruginosa, S. aureus, and B. subtilis. PU@mTO@SiO2 exhibited significant antibacterial activity toward the tested bacteria. The TO or mTO peptide will facilitate the designing of novel biosilicaembedded materials or systems with antimicrobial activity required in the biomedical field.