The basic concept of lab-on-a-chip for point-of-care diagnosis is to simplify and pack the entire diagnostic laboratory into a single microfluidic device. Unfortunately, many solutions still require bulky auxiliary equipment such syringe pumps, pressure controllers and power supplies. The research community often mocks this dilemma as the “chip-in-the-lab” problem. For applications in remote and resource-poor locations, a simple robust solution is needed for fluid and sample handling, without the need for electric power.

The collaboration between the microfluidics team at the Queensland Micro- and Nanotechnology Centre of Griffith University and Prof. Weihua Li’s team at the University of Wollongong resulted in a unique solution for particle and cell separation that is hand-powered.

“With the support of the fabrication facility of ANFF-Q at Griffith University we fabricated a microchannel with grooves. Similar groove geometry has been used for enhancing mixing. We utilised these grooves for inertial phenomena to separate particles with different sizes,” said Prof. Nam-Trung Nguyen, one of the senior authors of this work.

The device is deceptively simple: a syringe is attached to the microfluidic device, the user depresses the syringe plunger by hand and the sample is pushed through cell sorting grooves.

“The device can be implemented in the form of a syringe for purification and separation of body fluids such as blood. We have demonstrated the manual separation of platelets from peripheral blood mononuclear cells. The beauty of this concept is its robustness. The fluctuation in flow rate due to the user’s unsteady hand does not affect the separation performance. We have achieved almost 100% purity of platelets by simply pushing the sample through the device,” said Prof. Nam-Trung Nguyen.

The device concept has the potential to be implemented in robust point-of-care diagnostics devices for improvised conditions such as remote locations or in the battlefield.