Functional mesoporous silica decorated with Ag nanoparticles as chemo-photothermal agents

This work reports the synthesis, characterization, and evaluation of the photothermal effect of silica-based mesoporous materials (SBA-15), functionalized and decorated with silver nanoparticles (AgNP) for photothermal analysis and drug delivery applications. The synthesis of SBA-15 occurred by the hydrothermal method following functionalization with APTS amino silanes, resulting in the SBA15-NH2 sample. The AgNP were synthesized by reduction method, using hemiaminal groups on the surface of SBA15-NH2 modifiers as reduction agents (SBA15-xAg with x = 4, and 10 mM of AgNO3). FTIR, XRD, N2 Sorption, SEM, TEM, zeta potential, diffuse reflectance, and UV–Vis spectroscopy characterized the materials. The samples were explored in applications such as photothermal agents and drug delivery. The photothermal analysis showed temperature variations above 22 °C. Besides, most suspensions prepared exhibit good photothermal stability. These features indicate that materials are promising as photothermal agents. The release tests indicated that only the SBA15-4Ag sample showed an increasing trend in curcumin release after being exposed to a 785 nm laser. It confirms that the smaller amount of silver nanospheres in the aforementioned sample was more effective in propagating the heat. Therefore, the results showed promising materials as nano heaters, especially the SBA15-4 Ag sample, which presents the good formation of silver nanorods, high heat degree, high photothermal efficiency values (η), and time-dependent.