Gold nanocluster decorated fibrous substrate for photo-modulated cellular growth

Abstract

Three-dimensional substrates with nanostructures have drawn attention in biological fields, especially in cell cultures. A photothermal effect is introduced into the substrate to realize remote regulation of cellar behaviours, which is highly desirable. Herein, we report a photofunctional fibrous substrate by decorating photothermal gold nanoclusters to modulate cell growth. Through programmable annealing, the ultra-small Au NCs were well integrated into the filamentous aggregates of gellan gum. Benefiting from the metal coordination interactions in biomolecules, a fibrous substrate that consists of gold nanoclusters, filamentous aggregates of gellan gum and bioactive whey protein were obtained via ionic crosslinks. The incorporated gold nanoclusters tightened the arrangement of the fibrous structures and increased the rigidity of the substrate. The enhanced local mechanical property was found to promote cell adhesion. Meanwhile, the photothermal properties of gold nanoclusters permitted whey protein release from the substrate by light in an on-demand way. The released whey protein significantly induced cell proliferation. Therefore, photo-modulated cellular growth was achieved on the gold nanocluster decorated fibrous substrate. Coupling optical gold nanoclusters in a three-dimensional substrate can facilely introduce light responsiveness, which will broaden their biomedical applications.