Integration of Water-Mediated H-Bonds-Domestication and Optical Skin-Transparency Strategy for Microplastics-Free Bio-based Materials Revolution

Emerging bio-based plastics offer a promising next-generation solution to address two persistent challenges in the plastics industry: environmental pollution and the hazards posed by microplastics (MPs). Here, we propose a microplastics-free transparent bio-based plastic (MCBP) substitute derived from pre-processed natural skin by an integrative water-mediated hydrogen-bond domestication and optical skin-transparency strategy. The MCBP retains the intact fibrous 3D-network and multi-hierarchical structure of natural skin, predominantly composed of collagen fibers, resulting in exceptional physicochemical properties, including biodegradability, viscoelasticity, toughness, softness, and mechanical strength. By simultaneously regulating glycerol (Gly) and water content to modulate hydrogen bonds and removing non-collagenous components from the skin, the arrangement of collagen fibers shows more control-oriented with the reduced hydrogen bonding among the binary solvent and collagen fibers, thus minimizing light scattering and further achieving plastic-like optical transparency of natural skin. The strategy imparts water-responsive shape-memory to MCBP, enabling it to be processed into diverse two-dimensional or three-dimensional shapes, significantly extending its practical service life and recyclability. Notably, MCBP achieves MPs-free production while also enabling the adsorption and removal of MPs throughout its life cycle. Furthermore, MCBP has been shown to substantially enhance food shelf-life when used for active food packaging, underscoring its potential for diverse practical applications.