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

• Published in: Langmuir 2004-11, Vol.20 (23), p.10296-10302
• Main Authors: Robbins, Mary E, Hopper, Erin D, Schoenfisch, Mark H
• Format: Article
• Language: English
• Subjects: Biocompatible Materials - chemical synthesis; Biocompatible Materials - chemistry; Blood; Delayed-Action Preparations; Dimethylpolysiloxanes - chemistry; Electrodes; Gels; Humans; In Vitro Techniques; Materials Testing; Microarray Analysis; Microscopy, Atomic Force; Nitric Oxide - administration & dosage; Nylons - chemistry; Platelet Adhesiveness; Surface Properties
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la048368n

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.