Wound repair is an orchestrated process, encompassing the phases of inflammation, proliferation and tissue remodeling.In this context, sodium hydrogen exchanger 1 (NHE1) is crucial to epidermal barrier integrity and acidification.Recently, we found that extracellular pH (pHe) on wound surfaces is dramatically increased initially after barrier disruption, and that pHe decreases gradually during physiological healing. Additionally, we have shown that spatial NHE1-patterns account for pHe-gradients on surfaces of chronic wounds. Here, we show that NHE1-expression is very low at margins initially after wounding and that it increases massively during the time-course of physiolgical healing. This finding is in accordance with the decrease of pHe on wound surfaces, which we reported on in previous works. Thus, we show that NHE1 is an interesting target when it comes to modification of surface pHe on wounds, both acute and chronic, and that NHE1 is time-dependently regulated in physiological healing.

Mats of cytocompatible polymer fibers are needed as scaffolds in tissue engineering or as wound healing supports. Most recently, they have emerged as matrix-material to allow for in situ chemo- and biosensing inside intact tissue fragments or surrogates. Electrospinning of such fibers from polymer solutions provides extended options to control the structural and functional properties of the resulting fiber mats. We have prepared electrospun polymeric fiber mats from poly­(lactic acid) (PLA), polystyrene (PS), and poly­(vinyl pyrrolidone) (PVP) with two different fiber densities. Mats and individual fibers were characterized with respect to their dimensions, morphology, and their compatibility with human keratinocytes (HaCaT) selected as a biological model. Microscopic inspection revealed that HaCaT cells were viable on mats from all three polymers with only a negligible fraction of dead cells, similar to planar control surfaces. Growth in the presence of the fiber mats did not alter cellular metabolism (ATP, redox state) and did not induce significant production of cytokines (interleukin-6 (IL-6); monocyte chemoattractant protein-1 (MCP-1)). However, we did observe that fiber density changed the overall topography of the resulting mats and led to differences in the establishment of continuous cell sheets. In conclusion, the findings support the suitability of electrospun polymeric fiber mats made from PLA, PS, or PVP as potential biocompatible matrices for future two-dimensional (2D) or three-dimensional (3D) sensing of vital parameters from tissue in health and disease.