Photonics of Hydrothermally Treated β‐Lactoglobulin Amyloids

Increased temperature and high pressure are applied to β‐lactoglobulin fibrils in the autoclave, resulting in the acquisition of a composite material comprised of partially disassembled amyloid fibrils and carbon dots. Confirmation of the preservation of the β‐sheet motif attributed to amyloids in the hydrothermally treated fibrils is obtained through wide‐angle X‐ray scattering and ThT assay. Z‐scan analysis reveals a two‐photon absorption (2PA) enhancement in the low‐lying transition band (La) of tyrosine, while quantum chemical calculations demonstrate a correlation between the yield of 2PA and the interspace distance between aromatic residues. Overall, the intrinsic optical properties of amyloid fibrils treated in a subcritical water environment are found to be linked with the π‐conjugation of tyrosine units and their through‐space coupling. The resulting composite material is employed as a coating for a commercial ultraviolet light‐emitting diode lamp, showcasing the potential utility of sustainable biomaterials with improved optical properties for photonics applications.