Synthesis and characterization of hybrid mesoporous silica-iron oxide nanocomposite as a potential contrast agent for photoacoustic imaging

This study presents the synthesis and characterization of a hybrid mesoporous silica-iron oxide nanocomposite (MCM-48/FeNPs), with the goal of exploring its potential application as a contrast agent in photoacoustic imaging. The FeNPs were grown on the MCM-48 structure by in situ methodology performed by wet impregnation with Fe (III). Detailed structural and morphological analyses were conducted, revealing the successful integration of iron oxide within the silica matrix and the preservation of the mesoporous structure. Scanning and transmission micrographs showed FeNPs in the internal and external areas of MCM-48, increasing the size of the silica pores. The MCM-48/FeNPs had an average size of 260 nm and were spherical. The photoacoustic imaging study of the hybrid nanocomposite using a 532 nm and 1064 nm laser produced images with high contrast, excellent spatial resolution, and strong signal intensity. It is hypothesized that the mesoporous silica matrix contributes to the amplification of the generated signal. These results highlight the promising potential of these nanoparticles for obtaining biomedical images with both spatial and depth resolution. • Iron oxide integrated in silica with preserved mesoporous structure. • Strong photoacoustic signal at both 532 nm and 1064 nm. • Signal boost from FeNPs dispersion and thermal confinement within silica pores.