Synthesis of Au/lignin–tannin particles and their anticancer application

Abstract

Gold (Au) nanoparticles are widely adopted as nonbiological-toxic and biocompatible biomaterials. In this study, Au nanoparticles supported on lignin–tannin (LT) micro-/nanoparticles were prepared via a green and novel method without the use of an additional reducing agent. Soluble lignin oligomers and tannin were first obtained from H₂O–tetrahydrofuran (THF) solvothermal treatment of the corncob residue and bayberry bark, which are industrial and forestry wastes of biomass, respectively. With outstanding self-assembly capability, the lignin oligomers induced the co-self-assembly of tannins into LT particles considerably, which enhanced the density of ortho-phenolic hydroxyls on the hydrophilic shell. Consequently, Au³⁺ can be stabilized and subsequently reduced into Au⁰ particles that were highly dispersed on the LT particles. Upon increasing the proportion of tannins, the amount of Au species on LT particles and the Au⁰/Auⁿ⁺ ratio increased, accompanied by the inferior thermal stability of the particles. In addition, the as-prepared Au/LT particles can be taken up by cells and can reduce the vitality of several cancer cells, indicating a potential biotherapy application.