Self-assembled anionic and cationic Au nanoparticles with Au nanoclusters for the exploration of different biological responsiveness in cancer therapy

Self-assembly overcomes the biodegradation resistance of some traditional inorganic drug carriers. Herein, we prepared self-assembled Au nanocluster-based nanoparticles with different sizes and charges based on solvent- and cation-induced self-assembly nanotechnology as anti-cancer drug vehicles to solve the potential metabolism problems of solid gold nanoparticles. We also systematically explored the responsiveness of cancer cells to self-assembled Au nanocluster-based nanoparticles with different sizes and surface modified properties. We discovered that self-assembled nanoparticles inherited molecular-like properties of small-size Au NCs and exhibited an aggregation-induced emission (AIE) phenomenon with intense luminescence. Self-assembled Au nanocluster-based nanoparticles (Au NPs and cAu NPs) taking advantage of their size and positive charge exhibited better cell uptake than Au NCs. Encouraged by the excellent biological compatibility and cell uptake of these nanomaterials, we prepared drug-loaded nanomaterials by diffusion absorption and hydrophobic-induced embedding. cAu NPs@DOX showed an excellent anti-cancer effect owing to efficient cell internalization; Au NPs@DOX exhibited slow release of cargo drugs which might be significant to in vivo drug delivery. This work plays a crucial role in the rational design of self-assembled multifunctional gold-based nanoparticles in the application of nanomaterial-assisted multifunctional drug delivery systems (DDSs).