Enhanced anti-microbial activity of ofloxacin-loaded mesoporous silica nanoparticles against clinical isolates of drug-resistant microbes

The current study focused on the preparation of amine-functionalized mesoporous silica nanoparticles (MSNs) as an advanced drug delivery platform. The prepared MSNs were loaded with amine functionalities, followed by the loading of ofloxacin. Structural and morphological characteristics were analyzed using various spectro-analytical methods, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis), zeta potential measurements, field emission scanning electron microscopy (FE-SEM), and Brunauer–Emmett–Teller surface area analysis. Antimicrobial efficacy was tested against Staphylococcus aureus, Enterococcus faecalis, Proteus mirabilis, and Pseudomonas aeruginosa clinical isolates. All the isolates exhibited resistance to pure, free form ofloxacin. Upon loading ofloxacin onto the aminated MSNs, the antimicrobial activity improved significantly, with inhibition zone diameters reached to 37.00 mm with enhanced antibiofilm effects. The antioxidant capacity of MSNs-NH₂-ofloxacin demonstrated superior antioxidant activity when compared with MSNs-NH₂. Furthermore, hemolysis tests confirmed that MSNs-NH₂-ofloxacin had negligible hemolytic activity, demonstrating cyto-compatibility and bio-use safety, particularly at lower concentrations. The nanocomposite also showed sustained drug release and improved delivery of ofloxacin, thereby effectively maintaining the bioavailability. These findings suggested that the MSNs-NH₂-ofloxacin is a promising drug delivery vehicle that enhances the therapeutic efficacy and bioactivity of the antibiotic, offering a potential solution to combat multidrug-resistant bacterial infections under clinical conditions.