A miniature, single use, skin-adhered, low-voltage, electroosmotic pumping-based subcutaneous infusion system

Abstract

A programmable, skin-attached, 36 × 30 × 8 mm system for subcutaneous infusion of 1.2 mL of a drug solution is described. The system is intended to be replaced daily. It comprises a 20 × 14 × 8 mm electronic controller and power source, an 8 mm diameter 2 mm thick electroosmotic pump, a two-compartment reservoir for a pumped water and a drug solution, an adhesive tape for attachment to the skin, and a 6 mm long 27 gauge needle. Its removable electronic controller programs the dose rate and dose and is re-used. The electroosmotic pump consists of a porous ceramic membrane sandwiched between a pair of Ag/Ag2O plated carbon paper electrodes. It operates below 1.23 V, the thermodynamic threshold for water electrolysis without gassing. The flow rate can be adjusted between 4 and 30 μL min(-1) by setting either by the voltage (0.2-0.8 V) or the current (30-200 μA). For average flow rates below 4 μL min(-1), the pump is turned on and off intermittently. For example, a flow rate of 160 μL day(-1), i.e., 0.13 μL min(-1) for basal insulin infusion in type 1 diabetes management, is obtained when 10 s pulses of 75 μA is applied every 15 min. High flow rates of 10-30 μL min(-1), required for prandial insulin administration, are obtained when the pump operates at 50-200 μA. To prevent fouling by the drug, only pure water passes the pump; the water pushes a drop of oil, which, in turn, pushes the drug solution.

Low-Voltage Nongassing Electroosmotic Pump and Infusion Device with Polyoxometalate-Encapsulated Carbon Nanotubes

“…The flux of the driven fluid is linearly dependent on the applied voltage and current. Hence, the fluid delivered can be directly related to the coulomb consumed, the most attractive factor of EOPs, and can be used in monitoring of infused drugs or nutrients in infusion devices a device usually used in a situation where drugs or nutrients are impractical, expensive, or unreliable if delivered manually by nursing staff. Other applications of electroosmotic phenomena are preparation of well-defined arrangement of colloidal particles and controlled transport of biological molecules and complex fluids. , The demonstration in fuel cell applications to remove the water flooding at the cathode and microfluidic devices has been reported.…”

Nafion-Coating of the Electrodes Improves the Flow-Stability of the Ag/SiO2/Ag2O Electroosmotic Pump

“…The pumps were similar to, but not identical with, those described. , Briefly, 8 mm o.d., 6 mm i.d. pumps were made by sandwiching a phosphosilic acid coated silica membrane between two identical flow-through Ag/Ag 2 O-coated carbon paper electrodes.…”

“…For this reason, maintenance of the flow required its dynamic monitoring and adjusting with control, i.e., feedback, loops . Because the Ag/Ag 2 O-ceramic membrane-Ag/Ag 2 O pump has consumable electrodes, it operates at low voltages where water is not electrolyzed. , In the absence of gassing, one would have expected the maintenance of a fixed flow-rate at a particular voltage or current without a control loop, but the actual flow-rate decreased during the operation of the pumps because of accumulation of dissolved Ag + cations.…”

AC Electrokinetics of Physiological Fluids for Biomedical Applications

“…18 Various electrokinetic pump designs have been proposed. 19, 20 The electrolysis pump, for instance, can be applied to generate fluid motion in a microchannel. 16 ACEF flow represents another promising method for fluid pumping in microchannels.…”