Electrospun PCL nanofibers loaded with carvacrol for wound dressing applications

Introduction In chronic wounds, an appropriate protection is necessary for a correct healing and actual passive wound dressings are not suitable in these cases. For acute or chronic wounds properties that reduce healing... [ view full abstract ]

Introduction

In chronic wounds, an appropriate protection is necessary for a correct healing and actual passive wound dressings are not suitable in these cases. For acute or chronic wounds properties that reduce healing times and associated pain at the same time that maintain humidity, pH and optimum temperature are required. An important property of dressing materials is the formation of an effective barrier against the entry of pathogens.
Essential oils (of thyme, cinnamon, sage, etc.) have antimicrobial properties and some also have demonstrated anti-inflammatory, analgesic and healing properties. Besides they present lower cytotoxicity against eukaryotic cells, and a reduced tendency to promote bacterial resistance than synthetic antimicrobials (e.g. antibiotics).
Electrospinning is a fast and easy method to obtain nanofibers whit high surface area, high surface to volume ratio and good mechanical properties. Biocompatible synthetic and natural polymers as poly-caprolactone (PCL) and chitosan can be used. Furthermore, by this process nanofibers can be loaded with the mentioned natural compounds.
In this work a fast and easy method to produce PCL nanowebs loaded with carvacrol, a natural active compound that have antimicrobial properties, is reported. This compound was selected because minimal bactericidal concentration (MBC) values are below 0.2 mg/mL and 0.4 mg/mL against S. Aureus and E. Coli respectively.

Methods

For the electrospinning process a 10% w/w PCL solution in DCM:DMF 1:1 has been prepared. Then, the appropriate amount of carvacrol has been added to the solution to obtain a 20% w/w in the fibers. Feeding flowrate was 1 mL/h, nozzle-to-plate-distance was 18 cm and voltage used was the necessary to stabilize the Taylors’s cone. Drug loading achieved has been determined by GC-MS and the obtained fibers have been characterized by SEM and FTIR.

Results and conclusions

The average diameters of the obtained PCL nanofibers were: 240±40 nm. FTIR spectra show bands related to the natural compounds beside those of PCL corroborating the formation of the composite. Essential oil loading measured by GC-MS was 11.15±0.97% w/w.