Synthesis of Urchin-Like Au@TiO₂ Nano-Carriers as a Drug-Loading System Toward Cancer Treatment

In recent years, improving the pharmaceutical properties of drug delivery for anti-cancer treatment has become increasingly important. This is necessary to address challenges related to absorption, distribution, and stability. One potential approach solution is to attach the drug to a carrier system, such as functional noble nanomaterials, in order to improve the control of drug release and stability. Core-satellite nanoparticles (CSN) with an anisotropic morphology have enormous potential for targeted drug delivery and cancer treatment because of their large surface area, exceptional stability, and biocompatibility. We used a simple seed-mediated approach to synthesize urchin-like gold nanoparticles (ULGNPs) with a high aspect ratio and a dense network of 49 nm-sized branches, using seed solution, silver nitrate, and ascorbic acid. The ULGNPs were synthesized without a surfactant and then encapsulated with thin layers of amorphous TiO₂ (ULGNPs@TiO₂), resulting in an average overall size of 136±15 nm with a 27.5 nm TiO₂ layer. Doxorubicin (Dox) was chosen as a model drug to assess the distribution carrier ability of ULGNPs@TiO₂ core-satellite nanoparticles. The results showed 86.5 % Dox loading and 72.3 % release capacity at pH 5. The anti-cancer ability of ULGNPs@TiO₂-Dox was meticulously assessed using breast cancer MCF-7 cells in the WST-1 assay. The results revealed that ULGNPs@TiO₂-Dox exhibited approximately 92 % toxicity in MCF-7 cells compared to the free Dox of 89.6 % at low concentrations (5 ppm). Based on the simulation results for loading ULGNPs@TiO₂ with Dox, it was observed that a structure containing five layers of Au (111) with three fixed bottom layers and two relaxed top layers, in addition to six TiO₂ (100) layers, was analyzed using Grimme's DFT-D3 dispersion corrections (Scheme 1). The density functional theory (DFT) adsorption energy (E_ads) shows that the amorphous TiO₂ increases the Dox loading activity of ULGNPs, with E_ads=-3.85 eV, negatively higher than isolated ULGNPs (E_ads=-2.87 eV) and TiO₂ alone (E_ads=-3.61 eV). This drug carrier design has the potential to revolutionize anti-cancer treatment.