Lignins and lignin-derived compounds are known to have antibacterial properties. The wound healing agents in the form of dressings produce faster skin repair and decrease pain in patients. In order to create an efficient antimicrobial agent in the form of dressing in the treatment of chronic wounds, a composite hydrogel of bacterial cellulose (BC) and dehydrogenative polymer of coniferyl alcohol (DHP), BC-DHP, was designed. Novel composite showed inhibitory or bactericidal effects against selected pathogenic bacteria, including clinically isolated ones. The highest release rate of DHP was in the first hour, while after 24 h there was still slow release of small amounts of DHP from BC-DHP during 72 h monitoring. High-performance liquid chromatography coupled with mass-spectrometry showed that BC-DHP releases DHP oligomers, which are proposed to be antimicrobially active DHP fractions. Scanning electron microscopy and atomic force microscopy micrographs proved a dose-dependent interaction of DHP with BC, which resulted in a decrease of the pore number and size in the cellulose membrane. The Fourier-transform infrared absorption spectra of the BC-DHP showed that DHP was partly bound to the BC matrix. The swelling and crystallinity degree were dose-dependent. All obtained results confirmed BC-DHP composite as a promising hydrogel for wounds healing.

Regenerative medicine therapy is inspired by current research advances in cellular biology, genetic engineering, synthetic biology, material sciences and so far contributes to the traditional therapy, making resistant diseases curable. Nowadays, chronic wound healing is possible due to cell-based regenerative technologies and recent non-cell therapeutic approaches. Here we review clinical applications of human stem cells, as well as cellular and tissue products as alternatives to the traditional therapy of non-healing wounds. The cell-based technologies for tissue regeneration and bioengineering utilize stem cells that are either injected into bloodstream or positioned directly into the target area. Cell-free regeneration technologies require either stem cell products, i.e., secretomes or their separate components, extracellular membrane vesicles, or tissue products. The stem cell therapies are designed to replace critically absent components of wounded or degenerative tissue. The stem cell secretome can promote the repair of damaged tissues independently of parent cells. Extracellular membrane vesicles mimic and recapitulate the mechanisms of stem cells in tissue regeneration and therefore might be promising for chronic wound and severe burns healing. The tissue products traditionally remain efficient wound healing remedies along with emerging advanced technologies. K e y w o r d s: wound healing, cell and cell-free technologies, stem cells, secretomes, extracellular membrane vesicles, tissue products