Fabrication And Application Of Multifunctional Hybrid Materials Based On Bovine Serum Albumin Protein-gold Nanoclusters

Proteins are composed of 20 natural amino acids,with complex spatial structures,and participate in a variety of chemical reactions.At present,the study of protein assembly has become a hot topic,such as the co-assembly between proteins,between proteins and metal ions,and between proteins and organic molecules.Gold nanoclusters（AuNCs）contain unique physical and chemical properties and photoelectric effects due to their special size,dielectric limiting effect,quantum size effect and macroscopic quantum tunneling effect.In terms of application,AuNCs contain several advantages compared with other fluorescent materials.For example,certain organic fluorescent small molecules contain good luminescence performance but poor photobleaching-resistant property,fluorescent quantum dots are complex synthesis-demanding and exhibit high toxicity,while AuNCs contain low toxicity,good biocompatibility and optical stability.Nowadays,as a new fluorescent reagent AuNCs have attracted great attention in the field of biological imaging,however the monochromaticity of Au NC imaging has become a drawback.In order to overcome this weakpoint,we proposed here for the first time a new and simple method to prepare a new type of protein-gold cluster multifunctional hybrid materials.Firstly,thiocyanin T（ThT）was co-assembled with bovine serum albumin（BSA）conjugated gold clusters where BSA was served as the skeleton.Taking advantage of the binding force between ThT and denatured BSA,two-color fluorescent nanoparticles called BSA-AuNCs@ThT were synthesized.These new materials has the advantages of simple synthesis procedure,low cost,green and environmentally friendly,good biocompatibility,and strong fluorescence properties,which makes them a good choice for wider applications.Next,we coated polyethyleneimine（PEI）with high cationic properties on the BSA-AuNCs@ThT materials to prepare the multifunctional hybrid nanomaterials with uniform morphology and good dispersion.Based on the synthesized above,The fluorescence imaging application of BSA-AuNCs@ThT@PEI hybrid nanomaterial was investigated by using microbi al cells and He La cells.The cytotoxicity and stability of the materials were evaluated.In addition,the capability of BSA-AuNCs@ThT@PEI in the detectio n of heavy metal ions(Hg²⁺and Cu²⁺)and the photocatalytic transformation of coenzyme NADH were studied.