More biocompatible electrochemical sensors using nitric oxide release polymers

The response characteristics and biocompatibility of potentiometric ion-selective electrodes (ISEs) and amperometric oxygen sensors prepared with various polymeric materials that spontaneously release nitric oxide (NO) are examined. Plasticized polymer films (polyurethane and poly(vinyl chloride)) formulated with three distinctly different types of diazeniumdiolate NO donors are shown to release NO for extended periods time of time ( > 48 h) while also exhibiting a dramatic decrease in platelet adhesion and activation both in vitro and in vivo. Potentiometric ISEs for pH and K⁺ prepared by doping these NO release polymeric materials with appropriate ionophores (tridodecylamine and valmomycin, respectively) display the same analytical response properties (slope and selectivity) as conventional electrodes without NO release capability. Similarly, it is shown that NO release polymer films can be utilized as outer gas permeable membranes for construction of Clark style amperometric oxygen sensors without altering the oxygen sensitivity and response times of such devices. It is concluded that the use of NO release polymers to fabricate catheter style electrochemical sensors may be the solution to lingering biocompatibility and concomitant performance problems encountered when trying to employ these sensors for continuous intravascular measurements of blood gases and electrolytes.