Facile Fabrication of Nano-sized SiO2 by an Improved Sol–Gel Route: As an Adsorbent for Enhanced Removal of Cd(II) and Pb(II) Ions

Antifouling nanoplatform for controlled attachment ofE. coli

Biofouling is the most common cause of bacterial contamination in implanted materials/devices resulting in severe inflammation, implant mobilization, and eventual failure. Since bacterial attachment represents the initial step toward biofouling, developing synthetic surfaces that prevent bacterial adhesion is of keen interest in biomaterials research. In this study, we develop antifouling nanoplatforms that effectively impede bacterial adhesion and the consequent biofilm formation. We synthesize the antifouling nanoplatform by introducing silicon (Si)/silica nanoassemblies to the surface through ultrafast ionization of Si substrates. We assess the effectiveness of these nanoplatforms in inhibitingEscherichia coli(E. coli) adhesion. The findings reveal a significant reduction in bacterial attachment on the nanoplatform compared to untreated silicon, with bacteria forming smaller colonies. By manipulating physicochemical characteristics such as nanoassembly size/concentration and nanovoid size, we further control bacterial attachment. These findings suggest the potential of our synthesized nanoplatform in developing biomedical implants/devices with improved antifouling properties.

Composite Nanoarchitectonics of Magnetic Silicon Dioxide-Modified Chitosan for Doxorubicin Delivery and In Vitro Cytotoxicity Assay

Developing drug delivery carriers for highly selective, controlled, and sustained release of the anti-cancer drugs is one of the crucial issues in the cancer strive. We herein report the synthesis of Fe3O4 (M) and SiO2 (S) nanoparticles and their nanocomposites with chitosan (CS) for high loading efficiency and subsequent release potentiality of Doxorubicin (DOX) anticancer drug. The as-synthesized nanostructures were characterized using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and thermal analysis techniques. The average crystallite sizes of the as-prepared M, S, CS/M, CS/S, and CS/M/S nanostructures were found to be 5, 15, 70, 22, and 29 nm, respectively. The loading and cumulative release of Doxorubicin for the produced nanostructures were examined, and the results exhibited loading efficacy of 71%, 95%, 96%, 79%, 17%, and 42% for M, S, CS, CS/M, CS/S, and CS/M/S nanostructures, respectively. The Doxorubicin releasing results revealed a promising cumulative release percentages at pH 4.2 and pH 5 compared with those at pH 7.4. At pH 4.2, the cumulative release percentages for DOX-M, DOX-S, DOX-CS, DOX/M, and DOX/CS/M/S were 94%, 96%, 92%, 95%, and 98%, respectively. While the corresponding percentages at pH 5 were 97%, 90%, 46%, 43%, and 70%. The percentage for DOX-CS/S was 60% at pH 5, though. The in-vitro cytotoxicity of M-DOX, CS-DOX, and M/CS-DOX was explored against two human cancer cell lines (MCF-7 and Hep-G2) using SRB (Sulforhodamine B) assay. The DOX-loaded M/CS exhibited the highest cytotoxicity and its IC50 values were 2.65 and 2.25 μg/mL against Hep-G2 and MCF-7 cell lines, respectively, compared to the corresponding values of 5.1 and 4.5 μg/mL for free DOX. The results indicated that M/CS nanocomposite is a good candidate as drug delivery nano-carrier for the Doxorubicin anti-cancer drug.