Upconversion Fluorescence Silk Mateirals

As a typical class of soft materials,Bombyx mori silk fibroin(SF)has exhibited promising properties in biomedical applications due to excellent biocompatibility,remarkable mechanical strength and controllable biodegradability.To functionalize SF materials with some additional properties will provide us with vast opportunities in fabricating SF devices of next generation.To achieve this goal,a generic strategy of soft materials meso-functionalization is put forward.Lanthanide(Ln)-doped upconversion nanoparticles(UCNPs)were firstly proposed to functionalize silk fibroin at mesoscopic scale to acquire scaffolds with upconversion fluorescent emission.The surfaces of UCNPs were-modified by SiO2 or PEG,whose the hydroxyl groups(-OH)can interact with the carbonyl groups(C=O)in SF materials.The addition of UCNPs would lead to the secondary sturcure transition of scaffolds from β-sheet to random coils.However as-prepared scaffolds almost maintained the original properties of silk fibroin,exhibited promising mechanical properties and compatibility.The scientific significance is to obtain soft materials with the intrinsic bio-imaging function,and this will lead to the imaging and sensing of bio-scaffold in real time and non-invasive manner in detection strategy.In addition to that,we designed a composite silk fibroin film which take the advantage of intrinsic upconversion fluorescence of functionalized SF materials upon near infrared and typical light-driven reversible photoisomerization properties of dithienylethene derivatives.The composite film could realize initial data storage upon UV and be edited upon near-infrared laser.This may shed light on the fabrication offlexible and bio-compatible optical storage device based on the original properties of silk fibroin.