The effect of active ingredient-containing chitosan/polycaprolactone nonwoven mat on wound healing: in vitro and in vivo studies.

The use of an electrospun polycaprolactone (PCL) nonwoven mat that is coated with a layer of chitosan (CS) containing active ingredient [tea tree oil (TTO)] represents an effective strategy for producing functional dressings. CS-coated porous PCL nonwoven mat (CS3/PCLNM) with various concentrations of active ingredients were produced and investigated. In vitro, active ingredient-containing CS3/PCLNM is effective in inhibiting the formation of nitrite and the growth of Staphylococcus aureus. Both active ingredient TTO and CS have been proven to reach their maximum amount of releases within 24 h of contact with water-based environment. In vivo, full-thickness skin removal (1.2 cm × 1.2 cm) was performed on the back of the C57BL6/J mice in noninfected and infected animal models. Four groups of functional dressings were tested in this work including Tegderm™, PCLNM, CS3/PCLNM, and 100 µL TTO-CS3/PCLNM. After 7 days post-treatment, the bacterial levels were found to be significantly lower in both CS3/PCLNM and 100 µL TTO-CS3/PCLNM-treated groups than in the control group (81.6 ± 18.1% and 93.7 ± 9.57% of reductions in the bacterial load in the pus relative to the control group, respectively). Additionally, based on the histological analyses, the 100 µL TTO-CS3/PCLNM-treated group outperformed all other groups in wound healing.

Active ingredient-containing chitosan/polycaprolactone nonwoven mats: characterizations and their functional assays.

This study demonstrates a facile method developed to generate a chitosan/polycaprolactone (CS/PCL) nonwoven mat. All nonwoven mats are composed of microfibers with an average diameter of 2.51±0.69 µm. The X-ray photoelectron spectroscopy data indicate that positively charged nitrogen was generated on the surface of the mats after undergoing CS coating. By using a non-contacting electrostatic voltmeter, we determined that the nonwoven mats exhibited a positive potential and the charge density of the CS/PCL nonwoven mat was in proportion to the thickness of the CS overlayer. Moreover, platelet aggregation and anti-bacterial ability were enhanced by the CS/PCL nonwoven mat as compared to that of PCL nonwoven mat alone. The enhancements of the CS/PCL nonwoven mat on platelet aggregation are further promoted by incorporating a 1mM calcium ion in its CS overlayer. We also find that the addition of tea tree oil in the CS overlayer significantly inhibited LPS-induced nitrite formation in Raw 264.7 macrophages. In conclusion, our CS/PCL nonwoven mat possesses pharmacological effects including an increase of platelet aggregation, anti-bacterial, anti-adhesive, and anti-inflammatory activities. The performance of this CS/PCL nonwoven mat can be further promoted by incorporating active compounds to exert therapeutic effects in wound healing.