Cell number and cell viability are important parameters of cell cultures. These parameters can be determined using the Amphasys impedance flow cytometer. A central part of the flow cytometer is a microfluidic chip. Microelectrodes integrated into the microfluidic chip produce an electric field. The electric field changes when cells pass the microelectrodes. These changes in the electric field allow for the determination of certain cell properties.
The cell suspension is transported from the flask to the microfluidic chip via fine tubings with a small inner diameter. At the inlet of the microfluidic chip, there is an abrupt and massive decrease in the flow channel diameter that is bridged by a microfluidic connector. To allow the cell suspension to freely flow into the microfluidic chip, the connector must provide a precise and tight fit with as low dead volume as possible.
Different options of microfluidic connectors were identified and analysed. The fluid flow within the microfluidic chip was simulated.
The project consisted of:
▪ Description of applicable microfluidic principles and related state-of-the-art technology (literature and patent search)
▪ Evaluation of commercially available microfluidic connectors
▪ Simulation of the liquid flow within the microfluidic chip
▪ Laboratory experiments to verify the simulation results
A search was conducted to clear the state of the art for microfluidic connectors. Commercially available connectors were evaluated for their suitability for the impedance flow cytometer.
Microfluidic chip of the Amphasys impedance flow cytometer
To optimize the geometry of the microfluidic flow channel, the liquid flow within the microfluidic chip was simulated using FEM. Different shapes of the chip’s inlet were studied.
Simulation results were verified using light microscopy. The behaviour of particles within the microfluidic channel was determined.