Designing nanofibrous poly(ε-caprolactone)/hydroxypropyl cellulose/zinc oxide/Melilotus Officinalis wound dressings using response surface methodology.

Nanofibrous wound dressing is one of the most prominent stratagems for wound caring/management. This research is an approach for designing an electrospun wound dressing based on poly(ε-caprolactone)/hydroxypropyl cellulose/zinc oxide nanoparticles (PCL/HPC/n-ZnO), in which response surface methodology (RSM) was utilized to ascertain the optimum sample. It was observed that the addition of n-ZnO and Melilotus Officinalis (MO) extract could increase the fibers mean diameter, pore size, and crystallinity of mats. The mentioned quantities for a sample with the highest MO content (PHZM10) were equal to 469±105 nm, 544±370 nm, and 49.67%, respectively. Moreover, enhancing the amount of MO led to an increase in mechanical properties. In this respect, the PHZM10 sample had the modulus, strength, and toughness of 82.41±0.61, 20.45±0.30 MPa, and 4194.86 mJ, respectively. Also, according to the MTT assay, no cytotoxicity was reported from any of the manufactured samples. Besides, it was concluded that the antibacterial activity and nanofibrous structure of mats, and also their potential for release of MO extract could accelerate the wound healing. Hence, the wound closure index for the PHZM10 group was 99.3±1.1%. Based on all noted results, the PCL/HPC/n-ZnO/MO electrospun mats can be proposed as reassuring wound dressing candidates.

Reducing cytotoxicity of poly (lactic acid)-based/zinc oxide nanocomposites while boosting their antibacterial activities by thymol for biomedical applications.

In the present study, ternary blends based on poly (lactic acid)/poly (ε-caprolactone)/thermoplastic starch were prepared at different concentrations of synthesized zinc oxide nanoparticles (ZnO-NPs) and thymol. The sizes of ZnO-NPs with an average diameter of about 30-50 nm were detected by FE-SEM analysis. Moreover, the effect of ZnO-NPs and thymol on morphological, FT-IR spectrum, UV absorption, thermal stability, cytotoxicity, and antibacterial properties of neat blend was investigated. TGA analysis showed that the addition of ZnO-NPs and/or thymol diminished thermal stability of the system. Incorporating ZnO-NPs improved antibacterial activities of the neat blend, but MTT-assay and AO fluorescent staining test results depicted a decrease in cell viability to less than 20% by the addition of 5 wt% ZnO-NPs. In such a condition, the addition of thymol to the nanocomposites exhibited a dose-dependent increase in cell survival mostly due to thymol antioxidant properties. Interestingly, the antibacterial performance of compounds was also improved by the presence of thymol. Therefore, the obtained nanocomposites have potential to extend applications of innovative biomedical devices for future research in which both high cell viability and superior antibacterial properties are needed such as an antibacterial wound healing film.