Layered silicate clay functionalized with amino acids: wound healing application

Natural materials such as healing clays in mud spas have been used for healing of skin ailments and wounds since prehistoric times. In this study, laponite, a synthetic clay mineral with similar properties to natural healing clays has been functionalized with different amino acids for the purpose of wound dressing application. Physico-chemical properties of prepared laponite/amino acid gels were characterised using various analytical methods. X-ray diffraction and thermogravimetric analysis confirmed the presence of these amino acids in the prepared materials. The release profile of amino acid in simulated wound exudate fluid demonstrated the highest release from laponite/lysine groups with up to 50% of the intercalated lysine released. The effect of the extracts (obtained from the prepared laponite/amino acid gels) was tested on human skin fibroblast. Cell proliferation, oxidative stress, antioxidant properties, and in vitro wound healing (scratch assay model) were assessed. The extracts obtained from laponite alone and laponite combined with arginine, lysine and leucine promoted fibroblast proliferation whereas the extract from laponite/glutamic acid significantly inhibited cell proliferation. Based on the in vitro results presented in this work, laponite/arginine, laponite/leucine and laponite/lysine can be potentially applied as a wound dressing to promote the healing process.