Spray-by-spray alginate hydrogels containing a tea tree oil microemulsion for wound dressing.

The use of hydrogels as wound dressing materials in the healthcare industry is well documented in the literature. In particular, alginate (Alg) hydrogels find large applications for the treatment of chronic and exuding wounds. In the present communication, we report on in situ-forming alginate hydrogels obtained by layer-by-layer spray deposition. This application method is particularly useful in wound healing in the case of irregular and large cavities. A microoemulsion (ME) containing Tea Tree Oil (TTO) was homogeneously dispersed within the hydrogel. TTO is an essential oil steam-distilled from the Australian native plant Melaleuca alternifolia, characterized by antimicrobial, antiviral and antifungal properties, and recent studies showed that nanoencapsulation enhances water solubility and antimicrobial activity. MEs are of great interest in drug delivery, as they represent a convenient way to encapsulate hydrophobic drugs within a hydrophilic matrix, and have emerged as novel vehicles for sustained or controlled release for many administration routes of drugs. The antimicrobial Alg wound dressings incorporating TTO microemulsions (MeTTO) were characterized for structural and antimicrobial properties.