A New Gold Nanoparticles and Paclitaxel Co-Delivery System for Enhanced Anti-Cancer Effect Through Chemo-Photothermal Combination

Limited chemotherapeutic efficiency, drug resistance and side effect are primary obstacles for cancer treatment. The development of co-delivery system with synergistic treatment modes should be a promising strategy. Here, we fabricated a multi-functionalized nanocarrier with a combination of chemotherapeutic agent and gold nanoparticles (AuNPs), which could integrate chemo-photothermal therapy and improve entire anti-cancer index. Particularly, Paclitaxel nanocrystals (PTX NC) were first fabricated as a platform, on surface of which AuNPs were decorated and polydopamine (PDA) layer act as capping, stabilizing and hydrophilic agents for PTX NC, providing a bridge connecting AuNPs to PTX. These AuNPs decorated PTX NC exhibited good physico-chemical properties like optimal sizes, stability and photothermal efficiency. Compared to other PTX formulations, they displayed considerably improved biocompatibility, selectivity, intracellular uptake, cytotoxicity, apoptosis induction activity and P-glycoprotein (Pgp) inhibitory capability, owing to a synergistic/cooperative effect from AuNPs, PTX and NIR treatment, photothermal- triggered drug release and nano-scaled structure. Mitochondria-mediated signaling pathway is underlying mechanism for cytotoxic and apoptotic effect from AuNPs decorated PTX NC, in terms of Mitochondria damage, a loss of Mitochondrial membrane potential, intensified oxidative stress, DNA breakage, Caspase 3 activation, up-regulated expression in pro-apoptotic genes like p53, Caspase 3 and Bax and down- regulated level in anti-apoptotic gene like Bcl-2.