High-resolution episcopic microscopy (HREM): a useful technique for research in wound care

Analysing the three-dimensional (3D) texture of skin substitute materials and evaluating their performance after covering skin defects is essential for improving their design and for optimising surgical procedures and post implantation wound treatment regimes. Here we explore the capacities of the recently developed High-resolution episcopic microscopy (HREM) method for generating digital volume data that permit structural 3D analysis of native and implanted collagen-elastin matrices. We employed HREM to visualise native collagen matrices and collagen matrices seeded with keratinocytes. In a second step, we visualised the appearance and the revascularisation of the matrices after their implantation beneath split skin grafts used for covering skin defects in the porcine model. For this, HREM data were generated from biopsies harvested 5, 10, and 15 days after surgery. In all instances, the high quality and resolution of the HREM data in combination with the relative large field of view proved to be sufficient for visualizing the exact fibre architecture by employing quick volume rendering algorithms. Precise analysis of the 3D distribution of keratinocytes in the matrices populated with keratinocytes and of the detailed topology of the sprouting blood vessels in the implanted matrices was feasible. Our results show that high-resolution episcopic microscopy can be adapted to serve as a tool for evaluating collagen-elastin materials ex- and in vivo.