WEB Protein-modified nanoporous ceramics to support wound healing
Wound dressings to support skin regeneration require adequate mechanical support, biochemical cues and prevention of bacterial infection. Previously, nanoporous anodized aluminum oxide (AAO) membranes were introduced as wound dressing with controlled nanotopography.1 Nevertheless, porous ceramics do not provide any biochemical cues to promote cell growth. Hence, we introduce a new composite for wound healing, which combines biochemical cues from protein nanofibers with the advantages of AAO nanopores. AAO nanopores were silanized and subsequently modified with collagen and fibrinogen nanofibers using either pH- or salt-induced self-assembly.2,3 AAO membranes with collagen nanofibers were subsequently used to study the interaction with cells involved in wound healing using 3T3 fibroblasts and HaCaT keratinocytes. Cell growth on collagen-modified AAO substrates was compared to bare and silanized AAO by analyzing the metabolic cell activity with a WST proliferation assay. The cell morphology was studied with scanning electron microscopy (SEM) and fluorescence microscopy.
Using pH-induced self-assembly collagen nanofibers with diameters around 150 nm were directly assembled on AAO nanopores. Salt-induced self-assembly was combined with a transfer step to modify AAO membranes with fibrinogen nanofibers in the range of 100-300 nm. Moreover, fabrication of protein composites on AAO was successfully realized by combining and tailoring the two different self-assembly routines. The thickness of the respective protein fiber layers could be adjusted by controlling the protein concentration. Cell culture experiments with 3T3 fibroblasts and HaCaT keratinocytes revealed that the metabolic activity of both cell types on bare and silanized ceramic nanopores was comparable to glass references. However, fibroblast and keratinocyte proliferation were slightly decreased on collagen-modified AAOs. SEM analysis showed that keratinocytes and fibroblasts exhibited a spread morphology, thus indicating a close interaction with the collagen-AAO composites. Our results provide a good base for future long-term cell culture studies on AAO nanopores with tailored protein nanofiber modifications. As a next step it will be important to tailor the mechanical characteristics of our novel composites to mimic the mechanical properties of native skin more closely.
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|Presentation||Figure||Figure 1: SEM images of (A) AAO nanopores in side view and (B) self-assembled collagen nanofibers on AAO nanopores in top view. Yellow arrows indicate areas where the underlying AAO nanopores are visible.||89 KB||Download|