Ultra-low flow characterisation of a microfluidic electroosmotic pump using the gravimetric and front track methods
Abstract:
Technological solutions are lacking to accurately calibrate low and ultra-low flow infusion devices, particularly important in clinical environments to reduce errors in precision drug delivery. In an effort to develop calibration methods to enforce accurate and traceable measurements of ultra-low flow rates, a microfluidic on-chip electroosmotic pump was designed and microfabricated at INESC Microsistemas e Nanotecnologias in partnership with IPQ under MeDD II project.
The work entails the characterisation of targeted flow rates for the microfluidic pump, defined to be within 5-100 nL/min. For this, IPQ in collaboration with the Machine Design Group of the NOVA School of Science and Technology, used two calibration methods: 1) gravimetric method and 2) front-track method.
The gravimetric method, a primary method used in National Metrology Institutes (NMI) for measuring and calibrating flow rates, consists on measuring the mass of liquid delivered over time. The front track method relies on tracking the position of the meniscus of the liquid-air interface in a capillary tube over time.
The Volume and Flow Laboratory (LVC) at IPQ is progressing in improving the setup and uncertainty calculations of the gravimetric method and in developing the front track method, in an attempt to enable accurate and traceable measurements of ultra-low flow rates.
The results are expected to bring further insight on flow calibration methodologies and enhance metrological assessment of medical devices.
18HLT08 MeDD II – Metrology for Drug Delivery project (https://drugmetrology.com), is coordinated by IPQ and funded under the EURAMET EMPIR program of the European Commission.
Note: Paper not available
Nanoflow measurement; Microfluidic pump; Gravimetric method; Front track method.
