Chitosan-based biocomposites as H₂S vehicules

The design of vehicles to target deliver drugs at a controlled rate, and a predefined time is an emerging field as they may increase the effectiveness of treatments.

Hydrogen sulphide (H₂S) is commonly known due to its toxicity and rotten egg smell. However, it is also a gasotransmitter together with nitric oxide (NO) and carbon monoxide (CO). The exogenous delivery of H₂S has many therapeutic applications (e.g., wound healing and cardiovascular diseases) yet its use is challenging, and it is crucial to maintain its level in the body within the therapeutic window.

The direct use of the gas and their salts have many drawbacks. Synthetic molecules capable of releasing H₂S through a specific stimulus have been proposed yet some by-products may be toxic. The use of porous materials as H₂S vehicles have not been much explored.

In this context, we conducted the first studies to evaluate Chitosan biocomposites produced with porous materials (type A zeolites and an activated carbon obtained from glycerine) as H₂S vehicles.

The biocomposites were characterised by the usual techniques. Volumetric method and Ellman´s reagent were used to evaluate the H₂S adsorption capacity and release profile in aqueous solution at pH 7, respectively.

Cytotoxicity assays using HeLa cells for all Chitosan biocomposites were performed, as well as for the H₂S loaded material that showed the most promising aqueous solution release results.