RESUMEN
There is interest in developing sustainable materials displaying circularly polarized room-temperature phosphorescence, which have been scarcely reported. Here, we introduce biobased thin films exhibiting circularly polarized luminescence with simultaneous room-temperature phosphorescence. For this purpose, phosphorescence-active lignosulfonate biomolecules are co-assembled with cellulose nanocrystals in a chiral construct. The lignosulfonate is shown to capture the chirality generated by cellulose nanocrystals within the films, emitting circularly polarized phosphorescence with a 0.21 dissymmetry factor and 103 ms phosphorescence lifetime. By contrast with most organic phosphorescence materials, this chiral-phosphorescent system possesses phosphorescence stability, with no significant recession under extreme chemical environments. Meanwhile, the luminescent films resist water and humid environments but are fully biodegradable (16 days) in soil conditions. The introduced bio-based, environmentally-friendly circularly polarized phosphorescence system is expected to open many opportunities, as demonstrated here for information processing and anti-counterfeiting.
RESUMEN
Photocured room temperature phosphorescent (RTP) materials hold great potential for practical applications but are scarcely reported. Here, we develop photocured RTP materials (P-Lig) using a combination of lignosulfonate, acrylamide, and ionic liquid (1-ethyl-3-methylimidazolium bromide). With this design, lignosulfonate simultaneously serves as RTP chromophore and photoinitiator. Specifically, lignosulfonate in the ionic liquid generates radicals to polymerize the acrylamide upon UV irradiation. The resulting lignosulfonate is automatically confined in an as-formed crosslinked matrix to provide RTP. As such RTP with an emission lifetime of ~110 ms is observed from the confined lignosulfonate in P-Lig. Additionally, energy transfer occur between P-Lig and Rhodamine B (RhB), triggering red afterglow emission when P-Lig is in situ loaded with RhB (P-Lig/RhB). As a demonstration of potential applications, the P-Lig and P-Lig/RhB are used as photocured RTP coatings and RTP inks for fabricating 3D materials and for information encryption.
RESUMEN
BACKGROUND: Recent studies have suggested that both poly(l-lactide-co-1,5-dioxepan-2-one) (or poly(LLA-co-DXO)) and poly(l-lactide-co-ε-caprolactone) (or poly(LLA-co-CL)) porous scaffolds are good candidates for use as biodegradable scaffold materials in the field of tissue engineering; meanwhile, their surface properties, such as hydrophilicity, need to be further improved. METHODS: We applied several different concentrations of the surfactant Tween 80 to tune the hydrophilicity of both materials. Moreover, the modification was applied not only in the form of solid scaffold as a film but also a porous scaffold. To investigate the potential application for tissue engineering, human bone marrow mesenchymal stem cells (hMSCs) were chosen to test the effect of hydrophilicity on cell attachment, proliferation, and differentiation. First, the cellular cytotoxicity of the extracted medium from modified scaffolds was investigated on HaCaT cells. Then, hMSCs were seeded on the scaffolds or films to evaluate cell attachment, proliferation, and osteogenic differentiation. The results indicated a significant increasing of wettability with the addition of Tween 80, and the hMSCs showed delayed attachment and spreading. PCR results indicated that the differentiation of hMSCs was stimulated, and several osteogenesis related genes were up-regulated in the 3% Tween 80 group. Poly(LLA-co-CL) with 3% Tween 80 showed an increased messenger Ribonucleic acid (mRNA) level of late-stage markers such as osteocalcin (OC) and key transcription factor as runt related gene 2 (Runx2). CONCLUSION: A high hydrophilic scaffold may speed up the osteogenic differentiation for bone tissue engineering.
