Mesoporous vs wrinkle silica nanoparticles: architecture driven loading of luminescence Ruthenium complexes

Abstract Silica nanoparticles (SNP) are widely recognized as versatile carriers for drug delivery and theranostics due to their exceptional properties, including tuneable pore structures, high surface area, biocompatibility, and chemical stability. In this study, we synthesized and characterized three types of SNP with distinct morphologies and pore distributions: classical mesoporous silica nanoparticles (MSNP) and two wrinkle silica nanoparticles (WSNP) prepared using isopropanol (WSNP-ipa) or pentanol (WSNP-p) as co-solvents. The ability of these SNP to adsorb and encapsulate three different luminescent ruthenium(II) complexes, promising candidates in photodynamic therapy (PDT) for cancer, was systematically evaluated. Advanced characterization techniques, including transmission electron microscopy (TEM), FT-IR spectroscopy, dynamic light scattering (DLS), and N₂ adsorption/desorption analysis, highlighted the morphological, physico-chemical, and surface properties of the synthesized SNP. WSNP displayed hierarchical pore structures, larger pore volumes, and superior surface charge compared to MSNP, significantly enhancing their drug-loading capacity and encapsulation efficiency. Spectroscopic analyses confirmed that the ruthenium complexes retained their intrinsic optical properties upon encapsulation. These studies underscore the pivotal role of silica nanoparticle architecture in modulating drug-loading efficiency, stability, and photophysical behaviour of therapeutic agents. Furthermore, the encapsulation of ruthenium complexes within optimized WSNP offers a promising approach for advanced PDT applications, combining efficient drug delivery with enhanced luminescence for potential theranostic use. Graphical Abstract