Design and Evaluation of Gellan/Boron-dipyrromethene as a Photoactive Hydrogel and Efficiency as Antiyeast Activity

The development of fluorescent sugar hydrogels has addressed robust challenges in health safety, low cost, versatile functionality, and bio-inspired utilization for application purposes. Here, we introduce a fluorescent sugar hydrogel prepared using crosslinked, low-priced gellan (GN) as a sugar resource and a synthesized boron-dipyrromethene derivative (BODIPY) that GN@BODIPY serves as a yeast inhibitor and singlet oxygen photosensitizer. The GN@BODIPY hydrogel showed maximum emission at ∼590 nm under 490 nm excitation, with a quantum yield (Φ) of 0.403, indicating efficient photoemission suitable for optical applications. The excited-state dynamics of the hydrogel, including the intersystem crossing rate, were studied using femtosecond transient experiments. GN@BODIPY showed a singlet oxygen quantum efficiency (Φ_Δ ≈ 0.57 in methanol) and good photostability, making it a photoinitiator and catalyst. Antifungal assays against Pichia sp. strain KG2 showed a 90 % reduction in colony-forming units within 24 h, supported by fluorescence imaging. Its hydrophilic sugar-rich network enhances cellular uptake, leading to notable light-induced cytotoxicity in RAW 264.7 macrophages. Molecular docking with concanavalin A, a model lectin, showed good protein-ligand interactions that may enhance yeast inhibition. GN@BODIPY acts as a multifunctional platform, a fluorescent gel, a photoinitiator/catalyst, and a potential antifungal and photodynamic therapy agent.