Synthesis and Characterization of Nitric Oxide-Releasing Sol−Gel Microarrays

Publisher Website
Google Scholar
Abstract
Diazeniumdiolate-modified sol−gel microarrays capable of releasing low levels of nitric oxide are reported as a viable means for improving the blood compatibility of a surface without fully modifying the underlying substrate. Several parameters are characterized including: (1) NO surface flux as a function of sol−gel composition and microarray geometry; (2) microstructure dimensions and spacing for optimal blood compatibility; and (3) the effect of sol−gel surface modification on analyte accessibility to platinum electrodes. The sol−gel microarrays release biologically relevant levels of NO under physiological conditions for >24 h. In vitro platelet adhesion assays indicate that a NO surface flux of 2.2 pmol cm-2 s-1 effectively reduces platelet adhesion to glass substrates modified with sol−gel microstructures separated by 50 μm. The blood compatibility observed for these micropatterned surfaces is comparable to NO-releasing sol−gel films. When the separation between NO-releasing microstructures is reduced to 10 μm, the NO surface flux required to reduce platelet adhesion is lowered to 0.4 pmol cm-2 s-1. Finally, the oxygen response of platinum electrodes modified with NO-releasing sol−gel microarrays indicates that selective modification via micropatterning enhances analyte accessibility to the sensor surface.