Reducing O sensitivity in electrochemical nitric oxide releasing catheters: An O-tolerant copper(II)-ligand nitrite reduction catalyst and a glucose oxidase catheter coating.

Electrocatalytic nitric oxide (NO) generation from nitrite (NO) within a single lumen of a dual-lumen catheter using Cu-ligand (Cu-L) mediators have been successful at demonstrating NO's potent antimicrobial and antithrombotic properties to reduce bacterial counts and mitigate clotting under low oxygen conditions (e.g., venous blood). Under more aerobic conditions, the O sensitivity of the Cu(II)-ligand catalysts and the reaction of O (highly soluble in the catheter material) with the NO diffusing through the outer walls of the catheters results in a large decreases in NO fluxes from the surfaces of the catheters, reducing the utility of this approach. Herein, we describe a new more O-tolerant Cu-L catalyst, [Cu(BEPA-EtSO)(OTf)], as well as a potentially useful immobilized glucose oxidase enzyme-coating approach that greatly reduces the NO reactivity with oxygen as the NO partitions and diffuses through the catheter material. Results from this work demonstrate that very effective NO fluxes (>1*10 mol min cm) from a single-lumen silicone rubber catheter can be achieved in the presence of up to 10% O saturated solutions.