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 dual-functionality 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 biosilica-embedded materials or systems with antimicrobial activity required in the biomedical field.