Bioinspired H-bond cross-linking of nanostructured gelatine by inorganic goethite α-FeOOH

Abstract

This paper reports the effect of goethite nanowire filler on hydrogen (H) linking in gelatine. Nanostructured gelatine that would otherwise be soluble becomes insoluble in water at room temperature if goethite nanowire filler is added. The experimental results reveal a significant increase in the gel fraction of the composite with 6 vol% α-iron (III) oxide-hydroxide (α-FeOOH) additive, reaching over 73% after being kept in water, compared with that of pristine gelatine, with a mere 13% gel fraction. In the presented composite, the solubility of gelatine can also be controlled by visible light, as absorption in the narrow-band-gap α-iron (III) oxide-hydroxide results in local heating of nanowires. The illuminated 6 vol% α-iron (III) oxide-hydroxide/gelatine composite shows a gel fraction of 13.4%, while the control sample kept in the dark exhibits a high gel fraction value of 73.8%. The observed remotely switchable disintegration of gelatine by visible light presents a feature that can be used in designing temporary tissue engineering and drug delivery substrates.