Naringenin‐Loaded PEG Polymers with Varying Molecular Weights: Preparation and Evaluation of Singlet Oxygen Quenching Activity

Abstract This study presents a facile, cost‐effective strategy to develop functional polymers by non‐covalently loading naringenin‐a bioactive yet poorly water‐soluble flavonoid‐into PEGs with different molecular weights. Unlike conventional encapsulation methods with complex chemical steps, this strategy is rapid, purification‐free, and potentially scalable. The effect of PEG chain length (550, 2k, 5k Da) on naringenin's solubility, interactions, and stability was systematically assessed by UV‐Vis and gravimetric methods. Thermogravimetric analysis further revealed enhanced thermal stability upon naringenin loading, with T max values increasing by 10–15 °C across all PEG matrices. The photochemical behavior of the naringenin‐loaded PEG systems was investigated through singlet oxygen quenching using DPBF degradation, revealing that all formulations exhibited distinct quenching activity, with PEG‐2k achieving the highest efficiency (40.0%), which was nearly identical to that of free naringenin (41.3%). This behavior is likely related to the optimal hydrophilic‐flexible balance of PEG‐2k, which may promote better interaction and stabilization of naringenin. While most studies focus on simple antioxidant carriers or synthetic quenchers, this work demonstrates the feasibility of incorporating natural flavonoids into polymers while maintaining comparable photoreactivity to free naringenin, even at lower loading levels. Moreover, all formulations used a low naringenin‐to‐polymer mass ratio (1:5), suggesting that minimal naringenin can still achieve strong quenching. Overall, this strategy demonstrates the potential for solubilization, photostabilization, and functional retention of flavonoids, suggesting a scalable and cost‐effective design for future biomedical and advanced polymer applications.