The current structure of medical pumps does not allow real-time measurement of different parameters of drug delivery in general and low flow rates (μL/min) in particular. The current structure wherein only indirect measurements are performed (commonly pressure) makes it difficult to detect failures (e.g. air bubbles, occlusion, infiltration) in real-time on the one hand and can cause false alerts on the other hand. As a result, their operation in open loop necessitates expensive and accurate pumps. Very few sensors exist for measuring low flow rates (e.g. thermal flow sensors) as most technology is geared towards high flow rates.

We have developed a miniaturized, precise, bi-directional and low-cost electro-chemical flow sensor intended for low flow rates (μl/min) and produced using MEMS technology. Integration of the sensor (including its electronics and signal processing) within the drug delivery system (pump, infusion set) will enable direct and accurate measurement of the flow rate and different parameters of the drug in real-time.

ADVANTAGES OVER EXISTING TECHNOLOGIES
• No need for heating up the fluid as in thermal sensor.
• High signal to noise ratio due to the ability to significantly change the resistance while drug delivery applications limit the maximum temperature rise that is allowed.
• Ability to directly sense the drug through electrical measurements to enable the detection of the type of drug through its unique impedance signature, as well as detection of micro-bubbles.
• Channel bifurcations for multiple and parallel sensing of the drug delivery.

APPLICATIONS
• Integrated sensor within a pump or using a closed loop control.
• Possible analysis of the flow sensor signal for early detection of air bubble, occlusion, infiltration.
• The addition of more functionalities: impedance sensor for monitoring of micro-bubbles, particles and bacteria, working as lab-on-a-line.

INTELLECTUAL PROPERTY
US and EU patents pending

REFERENCES
Park, S., Abu-Rjal, R., Rosentsvit, L., and Yossifon, G., Novel Electrochemical Flow Sensor Based on Sensing the Convective-Diffusive Ionic Concentration Layer, ACS Sens., 4, 7, 1806–1815 (2019).