Conductive polylactic-acid filament for dose monitoring insyringe-less wearable infusion pump

Abstract

We have demonstrated the use of conductive polylactic acid (PLA) filament for dose monitoring in a syringe-less wearable infusion pump. A channel reservoir is inlaid with conductive PLA filament. As the liquid medium is dispensed via gas pressurization by an built-in electrolysis chamber, the effective impedance of the conductive PLA filament/liquid medium column changes as well. This allows the dispensed volume to be monitored via the output voltage across a series resistor. Using 5 V sinusoidal input voltage, the output voltage decreased from similar to 1.3 to similar to 0.13 V as the dispensed volume of 0.1 mol/L PBS increased from 0 to 1000 mu L. Similarly, the output voltage for insulin analog decreased from similar to 0.64 to 0.126 V for the same volume displaced. Repeated dispensing runs with 0.1 mol/L PBS showed good consistency (standard deviation less than 10 mV). The rate of change of the output voltage with elapsed timevaried accordingly for the different flow rates (0.25-1.00 mL/h or similar to 4-17 mu L/min). At electrolysis voltages of 1.5 and 5 V, the respective output voltage were 1.04 and 0.33 V. These corresponded to flow rates of similar to 3 and 10 mL/h (similar to 50 and 160 mu L/min). (C) 2017 Elsevier B.V. All rights reserved.