Sustainable Nonwoven Scaffolds Engineered with Recycled Carbon Fiber for Enhanced Biocompatibility and Cell Interaction: From Waste to Health.

Carbon fibers, driven by ever-increasing demand, are contributing to a continuous rise in the generation of waste and byproducts destined for landfills or incineration. Recycling carbon fibers presents a promising strategy for reducing carbon emissions and conserving resources, thus contributing to more sustainable waste management practices. Discovering applications of recycled carbon fibers (rCFs) would inevitably accelerate the targeted integration of sustainable materials, fostering a circular economy. Herein, we have engineered rCF-based needlepunched nonwoven scaffolds and their blends with polypropylene (PP) fibers, providing the first example of investigating their interactions with human lung epithelial cells (Calu-3) and murine fibroblast cells (NIH/3T3). To promote the adsorption of extracellular matrix proteins such as laminin, these three-dimensional (3D) nonwoven scaffolds are designed and developed to feature tunable porous characteristics and wetting properties. Although cell adhesion and laminin adsorption are minimal on PP fibers, cells are preferentially organized on the rCFs. These nonwovens, composed exclusively of rCFs or their blends with PP fibers, exhibit no cytotoxic effects, with both cell types showing proliferation on the scaffolds and a progressive increase in cell numbers over time. Cell viability and apoptosis assays are also employed to comprehensively evaluate biocompatibility. Thus, our study proves rCF-based nonwoven scaffolds as potential candidates for artificial lung tissue scaffolds.