The complex wound healing process involves many different cell types and molecular key players. To promote tissue repair multifunctional wound dressings providing mechanical support, biochemical cues, adequate gas exchange, and prevention of bacterial infection are advantageous. Recently, nanoporous anodized aluminum oxide (AAO) membranes were introduced as mechanically stable and biocompatible wound dressing with controlled nanotopography and antimicrobial properties (1). Nevertheless, they do not provide any biochemical cues from proteins like fibrinogen and collagen, which are crucial in wound healing as they contribute to the formation of blood clots and the extracellular matrix. Hence, the aim of this project is the development of multifunctional wound healing systems, which combine biochemical cues from protein nanofibers mimicking the natural wound environment with the advantages of AAO nanopores.
Different self-assembly methods were used to modify AAO membranes with pore diameters between 20 and 200 nm with protein nanofibers of collagen and fibrinogen. Scanning electron microscopy (SEM) revealed that collagen nanofibers with diameters around 150 nm could be assembled directly on AAO membranes. Using a novel self-assembly and transfer method (2) AAO membranes could also be modified with fibrinogen nanofibers, which were 100 to 300 nm in diameter. To mimic the native wound environment more closely nanofibrous composites containing both proteins were prepared on AAO membranes. The thickness of the respective protein fiber layer in the composites could be adjusted by controlling the protein concentration.
Initial cell culture experiments with fibroblasts and keratinocytes on bare AAO membranes revealed that the metabolic activity of both cell types was comparable to glass references. SEM analysis showed that fibroblasts in particular exhibited a spread morphology on AAO membranes indicating a close interaction with the ceramic nanopores.
These results provide a good base for future cell culture studies on our novel ceramic composites consisting of AAO nanopores with tailored protein nanofiber modifications.