Nitric oxide-releasing S-nitrosated derivatives of chitin and chitosan for biomedical applications

Nitric oxide (NO)-releasing derivatives of chitin and chitosan were prepared through incorporation of the symmetrical dithiols 1,2-ethanedithiol, 1,3-propanedithiol, and 1,6-hexanedithiol, followed by S-nitrosation with tert-butyl nitrite. The NO loading of the materials and their real-time NO release profiles under physiological conditions (pH 7.4 phosphate buffered saline, 37 C-circle) were recorded over 24 hours, and in vitro cytotoxicity studies were performed using human dermal fibroblasts (HDF) to assess the suitability of the materials for biomedical applications. Of the six thiolated parent materials, five exhibited cell viability higher than 70% (MTS assay), an outcome that was corroborated by LIVE/DEAD assay. In all cases, HDF morphology was unaffected by the presence of extracts obtained from the thiolated materials.