Thermoreversible hydrogel containing photoactivatable tricarbonyl Mn(i) terpyridine complexes for therapeutic carbon monoxide (CO) release

Abstract

Carbon monoxide (CO) is a well-established gasotransmitter known for its diverse physiological benefits. However, achieving controlled and targeted CO delivery remains challenging. To address this, light-activated carbon monoxide-releasing molecules (photoCORMs) offer a promising strategy. In this study, we report a new terpyridine-based manganese carbonyl complex, Mn·1, along with a known photoCORM, Mn·2, both capable of releasing CO upon light irradiation in various media. For the first time, these CO-releasing compounds were incorporated into the Pluronic F-127 hydrogel matrix, yielding PG@Mn·1 and PG@Mn·2, respectively. Pluronic F-127 was selected due to its known biocompatibility and suitability for biomedical applications. The photo-triggered release of CO from the hydrogels was confirmed through UV-vis absorption and emission-based photokinetic studies. Additionally, time-dependent FTIR spectroscopy corroborated light-induced CO release from the hydrogel matrices. Myoglobin assays revealed that PG@Mn·1 and PG@Mn·2 released 3.5 × 10⁻² μM and 1.71 × 10⁻² μM of CO, respectively. Furthermore, PG@Mn·1 and PG@Mn·2 demonstrated notable antibacterial activities against Staphylococcus aureus and Escherichia coli. These findings suggest that the thermoresponsive, photoactivatable CO-releasing hydrogels PG@Mn·1 and PG@Mn·2 hold significant potential for future biomedical applications.