705-P: Increasing the Longevity of an Insulin Pump by Removal of Phenolic Excipients within the Cannula through Electrooxidation

Insulin pumps provide an alternative way to conveniently and effectively bring blood glucose level under control. However, insulin pump users often face unexpectable failure of insulin delivery despite the lack of pump occlusions or insulin denaturing. One possible reason for this loss of insulin efficacy is due to phenolic excipients in insulin formulations that can induce cell death and inflammation. Here, we propose an electrochemical method that removes the phenol and m-cresol from insulin to preserve the longevity of the insulin and pump site. To achieve our goal, we modified carbon fiber paper electrodes with polydopamine to increase its hydrophilicity and introduce reaction site. Poly-L-lysine (PLL) was further covalently bound to polydopamine coating, reducing undesirable protein interactions. To reduce electrode passivation and fouling due to phenol deposition on the electrode, we incorporated copper ions to the PLL to form a PLL-Cu complex that mimics the catalytic center of tyrosinase, facilitating the conversion of phenolic compound to a more soluble quinone oxidation product rather than insoluble polyphenols. Figure shows the electrochemical modification scheme as well as cyclic voltammograms and chronoamperometric curves of 30 mM phenol in PBS buffer with 20 mg/mL glycerol on various electrodes at an applied potential of 0.75 or 0.6 V (stirring rate: 1100 min−1).