Published in the journal Biomaterials, investigators in the Schoenfisch Group describe the synthesis, material characterization, and in vitro biocompatibility of S-nitrosothiol (RSNO)-modified xerogels. Thiol-functionalized xerogel films were formed by hydrolysis and co-condensation of 3-mercaptopropyltrimethoxysilane (MPTMS) and methyltrimethoxysilane (MTMOS) sol–gel precursors at varying concentrations. Subsequent thiol nitrosation via acidified nitrite produced RSNO-modified xerogels capable of generating nitric oxide (NO) for up to 2 weeks under physiological conditions.
Xerogels also exhibited NO generation upon irradiation with broad-spectrum light or exposure to copper, with NO fluxes proportional to wattage and concentration, respectively. Xerogels were capable of storing up to ~1.31 μmo NO mg-1, and displayed negligible fragmentation over a 2-week period. Platelet and bacterial adhesion to nitrosated films was reduced compared to non-nitrosated controls, confirming the antithrombotic and antibacterial properties of the NO-releasing materials. Fibroblast cell viability was maintained on the xerogel surfaces illustrating the promise of RSNO-modified xerogels as biomedical device coatings.
Nitric oxide (NO) is the focus of intense research primarily because of its wide-ranging biological and physiological actions. To understand its origin, activity, and regulation, accurate and precise measurement techniques are needed. Unfortunately, analytical assays for monitoring NO are challenged by NO's unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life.
Moreover, NO concentrations may span the picomolar-to-micromolar range in physiological milieus, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. As published in Annual Review of Analytical Chemistry, the Schoenfisch Group review the most common spectroscopic and electrochemical methods, with a focus on the underlying mechanism of each technique and on approaches that have been coupled with modern analytical measurement tools to create novel NO sensors.