• Fawzy, Amr
• Priyadarshini, Balasankar Meera

Abstract

<p>In this work, the commercial polyvinylpyrrolidone (PVP)-capped silver nanospheres (Ag-NSP) were surface decorated with chlorhexidine gluconate (CHXg) for potentiating the antibacterial properties of Ag-NSP. Different formulations of CHXg-loaded AgNSP (Ag-NSP/CHXg) were prepared by varying the incubation times (0.5, 1.5, and 3 h). A thorough characterization of Ag-NSP/CHXg nanospheres has been carried out by dynamic light scattering (DLS), transmission electron microscopy (TEM), energy-dispersive surface elemental composition spectral analysis (SEM/EDX), Fourier transform infrared spectroscopy (FTIR), percentage (%) CHXg loading efficiency (LE), in vitro CHXg and Ag+ion release, antibacterial/biofilm inhibition assay, and human mesenchymal stem cells (hMSCs) cytotoxicity evaluation. DLS measured nanospheres to be &lt;160 nm and indicated that CHXg treatment drastically shifted the surface charge from negative to high positive values, with homogenous distribution. TEM revealed spherical Ag-NSP/CHXg nanospheres with a clearly visible surface coating of CHXg. FTIR confirmed association of CHXg with Ag-NSP nanospheres, whereas SEM/EDX data verified presence of spectral peaks specific to silver (Ag), CHXg, and PVP. The % LE gradually increased with increasing incubation times. In vitro CHXg release exhibited a bi-phasic fashion showing maximum release of similar to 74.83 +/- 20.67% from Ag-NSP/CHXg-3h at 14 days. A slow release of Ag+ions was detected; however, the surface decoration of Ag-NSP substantially hampered/restricted the liberation of ions. Agar well diffusion, MTS (3-(4,5-dimethylthiazol- 2-yl)-5-(3-carboxymethoxyphenyl)-2-(4sulfophenyl)- 2H-tetrazolium), and crystal violet assay suggested good antibacterial/antibiofilm activity of AgNSP/ CHXg that correlated with the increasing % LE of nanospheres. hMSCs cytotoxicity study showed low toxicity properties of all nanosphere formulations, except for Ag-NSP/CHXg-3h, affecting the cell viability at all proposed concentrations and exposure time points. CHXg accentuated the antibacterial properties of Ag-NSP.</p>

Topics

• surface
• silver
• scanning electron microscopy
• transmission electron microscopy
• Energy-dispersive X-ray spectroscopy
• toxicity
• Fourier transform infrared spectroscopy
• dynamic light scattering