A dual stimuli-responsive cellulose-based double network hydrogel crosslinked with fluorescent carbon dots for controlled drug release

Cellulose-based carbon dots (C-CDs) with fluorescence and non-toxicity properties have attracted wide attention in the field of biomedicine. However, constructing dual-stimuli hydrogels incorporated with C-CDs using biomass-based raw materials with biodegradable and antimicrobial characteristics for drug sustained-release remains a challenge. Herein, an interpenetrated-network method was proposed in which the N-isopropyl acrylamide (NIPAM) monomer, regarded as the second network, was polymerized via photo-initiation. Additionally, C-CDs derived from lychee waste were used as cross-linking agent, which was introduced into β-cyclodextrin (β-CD)/carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) first-network system, to fabricate a dual-network fluorescence hydrogels called β-CD/CMC-(PVA-NIPAM). The design of dual-network hydrogel can effectively enhance swelling and water retention abilities within a certain time. To evaluate the biomedical application of the obtained hydrogel, ibuprofen, as a poorly water-soluble model drug, was loaded into the hydrogel utilizing advantages of possessing hydrophobic inner cavity of β-CD and the highly dense structure of double-network hydrogels, to complete release behavior under different pH and temperature, with the maximum release rate reaching up to 96 %. Furthermore, it is noted that the cellulose-based interpenetrated-network hydrogel has access to cells but exhibits no cytotoxicity in vitro. Herein, this dual-responsive fluorescent hydrogel is expected to play a potential role in drug delivery and drug tracking.