synthesis and characterization of porous silica microparticles capped with cuo for antibacterial drug delivery system application

Porous silica microparticles (smps) are biocompatible and bioinert materials with advantageous properties, including a high surface area and the ability to control particle size distribution. incorporating cuo imparts antibacterial capabilities to these particles, effectively inhibiting bacterial growth and preventing infections. the large surface area of smps facilitates enhanced interactions with surrounding molecules, making them highly suitable for various drug delivery applications, particularly for drugs with large particle sizes. in this work, an antibacterial drug delivery system is designed to enhance the effectiveness of antibacterial treatments by improving drug delivery, reducing side effects, and increasing drug concentration at the infection site. cuo nanoparticles release copper ions (cu2+) into the bacterial cytoplasm, interfering with crucial cellular processes by binding to proteins and enzymes, inhibiting their normal function, and causing cellular dysfunction. additionally, cuo nanoparticles can interact with the bacterial cell membrane, leading to its disruption. a modified sol-gel method was employed for the synthesis of cuo-capped smps. the process involved stirring the appropriate amounts of ctab (surfactant), nh4oh (ph modifier), and teos (the silica precursor) at 80 °c for 2 hours. after 1 hour of stirring, copper nitrate trihydrate in etoh was dropwise added to the mixed solution for 30 minutes, followed by an additional 2 hours of stirring at 400 rpm. this synthesis step contributes to the shaping of silica microparticles and adding copper nitrate to their surface. the slow addition of a small amount of teos contributed to the formation of spherical microparticles instead of nanoparticles. the solution was centrifuged at 8000 rpm for 8 minutes and washed 3 times with etoh and di water. the resulting precipitate was freeze-dried for 12 hours and calcinated in the air at 620 °c for 6 hours, forming porous silica microparticles and formation of cuo on the surface. after coating with cuo, the final microparticle powder revealed noticeable differences in the x-ray diffraction analysis. the amorphous structure of smps transformed into a mixture of crystalline monoclinic cuo (tenorite) with characteristic sharp peaks observed at 2θ values of 32.5°, 35.4°, 35.55°, 38.7°, 38.9°, 46.2°, and 48.8°, along with amorphous phases. field emission scanning electron microscopy (fesem) confirmed the formation of spherical microparticles, with average particle sizes of approximately 1.4 µm and 1.2 µm for smps and cuo-capped smps, respectively. the decrease in particle size distribution can be attributed to the possible erosion from the reaction between copper ions and the silica surface, resulting in variation of silica particle size. energy-dispersive x-ray spectroscopy (eds) confirmed the elemental composition, with 40.23% o, 46.30% si, and 13.48% cu wt% for each element. in conclusion, we successfully synthesized porous silica microparticles capped with cuo using a modified sol-gel method. the resulting microparticles exhibited a crystalline cuo phase and a decreased particle size compared to smps. these cuo-capped smps hold great potential as an antibacterial drug delivery system, offering enhanced drug delivery capabilities