Macrophages mediate mammalian inflammation in part by the release of the gasotransmitter, nitric oxide (NO). Electrochemical methods represent the best means of direct, continuous measurement of NO, but monitoring continuous release from immunostimulated macrophages remains analytically challenging. Long release durations necessitate consistent sensor performance (i.e., sensitivity and selectivity for NO) in proteinaceous media. Herein, we describe the fabrication of an electrochemical sensor modified by an electropolymerized 5-amino-1-naphthol (poly(5A1N)) film in conjunction with a fluorinated xerogel topcoat. The unique combination of these membranes ensures selective detection of NO that is maintained over extended periods of use (>24 h) in biological media without performance deterioration. The hydrophobic xerogel topcoat protects the underlying NO-selective poly(5A1N) film from hydration-induced desorption. The bilaminar sensor is then readily adapted for measurement of the temporal NO-release profiles from immunostimulated macrophages.
Keywords: 5-amino-1-naphthol; electrochemical detection; macrophage; nitric oxide; permselectivity; sensocompatibility; xerogel.