Triggered and Tunable Hydrogen Sulfide Release from Photogenerated Thiobenzaldehydes

Hydrogen sulfide (H₂S) has been identified as an important cell-signaling mediator and has a number of biological functions, such as vascular smooth muscle relaxation, neurotransmission, and regulation of inflammation. A facile and versatile approach for H₂S production initiated by light irradiation and controlled by reaction with an amine or an amino acid was developed. The donor was synthesized in a one-pot reaction, and simple crystallization led to a yield of approximately 90 %. The synthetic strategy is scalable and versatile, and the H₂S donors can be expressed ina number of different molecular and macromolecular forms, including crystalline small-molecule compounds, water-soluble polymers, polystyrene films, and hydrogels. The H₂S donors based on polystyrene film and hydrogel were used as cell-culture scaffolds. The H₂S donor based on water-soluble polymer was applied in photocontrolled inhibition of P-selectin expression on human platelets and subsequent regulation of platelet aggregation. This study provides the simplest controllable H₂S source to study its biological functions. The developed materials are also new therapeutic platforms to deliver H₂S, as there is no accumulation of toxic byproducts, and the donor materials from polystyrene films and hydrogels can be readily removed after releasing H₂S.