Materials and scaffolds with antimicrobial properties are of great importance in would dressing and other tissue engineering applications. The objective of the present work was to fabricate scaffolds made from nanocomposites of polycaprolactone (PCL) and quaternary ammonium salt-modified montmorillonite (MMT) by the electrospinning technique, and then characterize their antimicrobial and other properties for wound dressing applications. The effect of MMT on the structure, morphology, and thermal behavior of the electrospun wound dressings was assessed by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM); the swelling capacity, antibacterial activity, and cytotoxicity were also evaluated. The results of XRD and SEM analyses showed MMT was successfully incorporated into the PCL polymeric matrix and its inclusion reduced the size and thickness of the electrospun fibers compared to pure PCL fibers. The TGA results illustrated an increase in the thermal stability of nanocomposites upon incorporation of nano clay into the PCL matrix. The swelling capacity of the wound dressings was reduced by increasing the amount of MMT in the PCL matrix due to the increased hydrophobicity of the original MMT resulting from its modification with quaternary ammonium salt. The in vitro curcumin (Cur) release profile revealed an initial burst release followed by a sustained release, with the burst release level reduced by the introduction of MMT into the polymeric matrix. Increasing the nano clay content further reduced the curcumin release, with the PCL/20%MMT/Cur dressings having the lowest curcumin release of all those tested. The beneficial effect of MMT on the antibacterial behavior of electrospun wound dressings based on PCL/MMT nanocomposites was confirmed, with the introduction of both MMT and curcumin into the PCL matrix resulting in lower bacterial viability. PCL/10%MMT/Cur demonstrated higher antimicrobial activity and the greatest bacterial colony reduction compared to both pure PCL and PCL/10%MMT. The cytotoxicity evaluation indicated low toxicity and confirmed the potential of PCL/MMT nanocomposite scaffolds for wound dressing applications.

Nanofibrous-based pH sensors have shown promise in a wide range of industrial and medical applications due to their fast response time and good mechanical properties. In the present study, we fabricated pH-sensitive sensors of nanofibrous membranes by electrospinning polyurethane (PU)/poly 2-acrylamido-2-methylpropanesulfonic acid (PAMPS)/graphene oxide (GO) with indicator dyes. The morphology of the electrospun nanofibers was examined using scanning electron microscopy (SEM). The effect of hydrophilic polymer ratio and concentration of GO on the sensing response time was investigated. The sensitivity of the membranes was studied over a wide pH range (1–8) in solution tests, with color change measured by calculating total color difference using UV-vis spectroscopy. The membranes were also subjected to vapor tests at three different pH values (1, 4, 8). SEM results show the successful fabrication of bimodal fiber diameter distributions of PU (mean fiber diameter 519 nm) and PAMPS (mean fiber diameter 78 nm). Sensing response time decreased dramatically with increasing concentrations of PAMPS and GO. The hybrid hydrophobic/hydrophilic/GO nanofibrous membranes are capable of instantly responding to changes in solution pH as well as detecting pH changes in chemical vapor solution in as little as 7 s.

The capability to hinder microbial growth on the implant surfaces is of great interest in medical applications. This paper presents our study on the synthesis of zeolite/silver-graphene oxide (Zeo/Ag-GO) nanocomposite to enhance antibacterial activities of bone implants. Zeo/Ag-GO was synthesized using via semi-powder metallurgy and then characterized in terms of microstructure, antibacterial activities, and biocompatibility. Our microstructure results demonstrated that the Ag particles were anchored and uniformly distributed in the composite structure; assessment of antibacterial activity against the Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) revealed that Zeo/Ag-GO was better than Zeo/Ag, but Zeo has no antimicrobial activity observed; and biocompatibility assays showed that both Zeo/Ag and Zeo/Ag-GO had no negative effect on the proliferation of MG-63, while Zeo/Ag-GO promoted better cell viability. Taken together, Zeo/Ag-GO has great antimicrobial performance with suitable cytocompatibility, thus potentially being used to reduce implant-associated infections.