Controllable Preparation of Thiol-Silica Particles via Optimized Water-to-Ethanol Volume Ratio

This study focuses on investigating the effects of the water-to-ethanol volume ratio on the preparation of thiol-functionalized silica (SH-SiO₂) particles. Using 3-mercaptopropyltrimethoxysilane (MPTMS) as the silane precursor and ammonia as the catalyst, the size, morphology, and chemical composition of the synthesized SH-SiO₂ particles were systematically characterized across a gradient of water-to-ethanol volume ratios. Raman spectroscopy was utilized to quantitatively analyze the variations in the contents of thiol (-SH) and disulfide (S-S) groups within the SH-SiO₂ matrix. In addition to comprehensive material characterizations, the as-prepared SH-SiO₂ particles were evaluated as dual-functional platforms, which act as both adsorbents for Au³⁺ ions and carriers for the loading and sustained release of doxorubicin (DOX). Notably, the SH-SiO₂ particles fabricated under the condition of 90% (v/v) water content demonstrated a superior DOX loading capacity and well-regulated release kinetics, highlighting the significant regulatory role of the water content in optimizing the functional performance of SH-SiO₂ particles.