Nafcillin-Loaded Photocrosslinkable Nanocomposite Hydrogels for Biomedical Applications

Abstract

Skin infections are frequently treated via intravenous or oral administration of antibiotics, which can lead to serious adverse effects and may sometimes contribute to the proliferation of resistant bacterial strains. Skin represents a convenient pathway for delivering therapeutic compounds, ensured by the high number of blood vessels and amount of lymphatic fluids in the cutaneous tissues, which are systematically connected to the rest of the body. This study provides a novel, straightforward method to obtain nafcillin-loaded photocrosslinkable nanocomposite hydrogels and demonstrates their performance as drug carriers and antimicrobial efficacy against Gram-positive bacteria. The novel formulations obtained, based on polyvinylpyrrolidone, tri(ethylene glycol) divinyl ether crosslinker, hydrophilic bentonite nanoclay, and/or two types of photoactive (TiO2 and ZnO) nanofillers, were characterized using various analytical methods (transmission electron microscopy (TEM), scanning electron microscopy–energy-dispersive X-ray analysis (SEM-EDX), mechanical tests (tension, compression, and shear), ultraviolet-visible spectroscopy (UV-Vis), swelling investigations, and via specific microbiological assays (“agar disc diffusion method” and “time-kill test”). The results reveal that the nanocomposite hydrogel possessed high mechanical resistance, good swelling abilities, and good antimicrobial activity, demonstrating a decrease in the bacteria growth between 3log10 and 2log10 after one hour of direct contact with S. aureus.

Nanocomposite Hydrogel Films Based on Sequential Interpenetrating Polymeric Networks as Drug Delivery Platforms

“…The area that covers the pores in the image is 43.7%. The pore size variation follows the same trends as in our previous work [32]. However, in this case, the pore sizes are considerably smaller due to the double crosslinking strategy adopted in this study.…”

“…However, in some areas, the zinc involved in the ionic bonds with alginate units are visible as denser regions on EDX mapping, following the pathway of the ionic crosslinking sites. In contrast, even if the presence of TiO2 nanoparticles inside the synthesized hydrogels was confirmed by TEM-EDAX analysis, Ti was not visible on EDX mapping, The pore size variation follows the same trends as in our previous work [32]. However, in this case, the pore sizes are considerably smaller due to the double crosslinking strategy adopted in this study.…”

“…Nafcillin was introduced into the lyophilized nanocomposite hydrogels to examine the release characteristics of the active ingredient for each formulation. Our previous work [32] extensively details the procedures followed for monitoring the nafcillin loading and releasing processes from analogous hydrogels. Briefly, an aqueous nafcillin solution (5 × 10 −3 M) was utilized for the loading of nanocomposite hydrogel samples weighing approximately 30 mg. Nafcillin release experiments were conducted in PBS (pH = 7.4, 37 • C).…”

“…Recurrent samplings (1 mL) at predetermined time intervals were used to measure UV-Vis absorbance at 330 nm and correlate the values obtained with the corresponding nafcillin concentration. The release patterns of the nanocomposite hydrogels were plotted using data from the UV-Vis study and compared to evaluate and identify the mathematical model [32].…”

“…In the second step, the five nafcillin-loaded nanocomposite hydrogel samples were applied for the in vitro evaluation against Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli bacteria. Their antimicrobial activity was evaluated by the Agar disk-diffusion method, which is suitable for samples like antibiotic-loaded hydrogels [32].…”