Glycosylated Polymers Toward Stable Protein-Based Lighting

Abstract

Protein-based optoelectronics faces two challenges to keep the performance of conventional technologies: stabilizing proteins through water-free fabrication methods and developing bio-friendly interfaces. In this context, bio-hybrid lighting, which integrates fluorescent protein (FP) based photon down-converting filters, represents an emerging concept toward ensuring a sustainable lighting sector. They promise to replace rare earth and/or toxic emitters applied for photon down-conversion in white commercial LEDs with FP-polymer color filters. A key component is a branched polyethylene oxide that stabilizes FPs in a water-less environment upon film forming. Recently sugar additives are successfully used as natural desiccation protectants against osmotic dehydration stress to further enhance FP stability by reinforcing intra-protein H-bonding. Herein, the glycosylation of the branched polymer is disclosed to stabilize FPs in coatings that resulted in 300-fold enhanced device stability due to a significant reduction of the heat generation and slow-down of the H-transfer-assisted emission deactivation process compared to reference polymer coatings. Thermal and spectroscopic techniques suggest that this finding is related to the higher crystallinity of the coatings and rigid environment provided by the glycosylated polymers. Overall, this work reinforces the use of sugars (additives or glycosylated polymers) to preserve the emission/thermal properties of FPs in water-less environments for optoelectronics.