Biological building blocks, particularly dipeptides, have the ability to self-assemble into well-organized structures with functional properties, making them valuable in both biology and nanotechnology. Dipeptide building blocks can be designed and synthesized to produce bioinspired nanostructured materials that can be self-assembled into various nanostructures, including nanotubes, vesicles, fibrils, and wires, with improved properties and wider application.Nanostructured dipeptide self-assemblies exhibiting quantum confinement are of great interest due to their potential applications in the field of materials science as ecofriendly optoelectronic materials for energy harvesting devices due to their biocompatibility and flexibility of fabrication and functionalization. Cyclic dipeptides are an emerging outstanding group of ring-shaped dipeptides, which, because of multiple interactions, self-assemble in supramolecular structures with different morphologies (nanospheres, nanotubes, nanowires) showing quantum confinement and photoluminescence. Chiral cyclic dipeptides may also display piezoelectricity and pyroelectricity properties with potential applications in new sources of nano energy. Among those, aromatic cyclo-dipeptides containing the amino acid tryptophan are wide-band gap semiconductors displaying the high mechanical rigidity, photoluminescence and piezoelectric properties to be used in power generation.As cyclodipeptides exhibit high thermal stability and mechanical strength, we utilized these properties to make nanofiber systems incorporating dipeptides into appropriately chosen functionalized biopolymer matrixes produced by electrospinning.As such, here we report the fabrication of hybrid systems based on chiral cyclo-dipeptide L-Tryptophan-L-Tryptophan and cyclo-L-Tryptophan-L-Tyrosine incorporated into biopolymer electrospun fibers. The micro/nanofibers contain self-assembled nanostructures embedded into the polymer matrix, are wide-band gap semiconductors with 4.0 eV bandgap energy, and display blue photoluminescence as well as relevant piezoelectric and pyroelectric properties. A piezoelectric nanogenerator was proposed, tested and shown to be capable of producing 0.18 µWcm-2 of power density and have a piezoelectric coefficient of 57 pCN-1 for Cyclo(L-Trp-L-Trp)@PLLA. Therefore, the fabricated hybrid mats are promising systems for future thermal sensing and energy harvesting applications [1]. [1] D. Santos, et al., Materials. 16, 2477 (2023). DOI: 10.3390/ma16062477
