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The replacement of plastic with eco-friendly and biodegradable materials is one of the most stringent environmental challenges. In this respect, cellulose stands out as a biodegradable polymer. However, a significant challenge is to obtain biodegradable materials for high-end photonics that are robust in humid environments. Here, we demonstrate the fabrication of high-quality micro- and nanoscale photonic and plasmonic structures viareplica molding using pure cellulose and a blended version with nonedible agro-wastes. Both materials are biodegradable in soil and seawater according to the ISO 17556 standard. The pure cellulose films are transparent in the vis–NIR spectrum, having a refractive index similar to glass. The microstructured photonic crystals show high-quality diffractive properties that are maintained under extended exposure to water. Nanostructuring the cellulose transforms it to a biodegradable metasurface manifesting bright structural colors. A subsequent deposition of Ag endowed the metasurface with plasmonic properties used to produce plasmonic colors and for surface-enhanced Raman scattering.

Multifunctional bioplastics have been prepared by amorphous reassembly of cellulose, hemicelluloses (xylan), and hydrolyzed lignin. For this, the biopolymers were dissolved in a trifluoroacetic acid–trifluoroacetic anhydride mixture and blended in different percentages, simulating those found in natural woods. Free-standing and flexible films were obtained after the complete evaporation of the solvents. By varying xylan and hydrolyzed lignin contents, the physical properties were easily tuned. In particular, higher proportions of hydrolyzed lignin improved hydrodynamics, oxygen barrier, grease resistance, antioxidant, and antibacterial properties, whereas a higher xylan content was related to more ductile mechanical behavior, comparable to synthetic and bio-based polymers commonly used for packaging applications. In addition, these bioplastics showed high biodegradation rates in seawater. Such new polymeric materials are presented as alternatives to common man-made petroleum-based plastics used for food packaging.

Here, we show the production of nanofibrous mats with controlled mechanical properties and excellent biocompatibility by combining fibroin with pure cellulose and cellulose-rich parsley powder agro-waste. To this end, trifluoroacetic acid was used as a common solvent for all of the involved biomaterials, achieving highly homogeneous blends that were suitable for the electrospinning technique. Morphological analysis revealed that the electrospun composite nanofibers were well-defined and defect-free, with a diameter in the range of 65–100 nm. Mechanical investigations demonstrated that the fibrous mats exhibited an increased stiffness when pure fibroin was combined with cellulose, whereas they possessed an increased flexibility when the parsley waste was added to fibroin. Lastly, the produced mats were highly biocompatible, as demonstrated by the promoted proliferation of fibroblast cells. The characteristics of the hybrid fibroin–cellulose nanofibers, in terms of nanoscale topography, mechanical properties, and biocompatibility, are attractive and potentially applicable in the biomedical sector.