Designing lab-on-a-chip with electrically increased liquid flow

Kolkata, May 26 (IANS) A team of Indian researchers has shown how electric fields can be used to enhance peristalsis - successive wave-like motions which helps you keep chewed food down and ferry it to your stomach - in a finding which, they say, may act as a model for the design of lab-on-a-chip devices.

At the Microfluidics Laboratory of the Indian Institute of Technology-Kharagpur, researchers have envisaged exploring massive augmentation in peristaltic flow through on-chip control, by simply applying an external electric field.

"Such an advantageous mechanism has the potential to aid researchers in studying targeted drug delivery, augmenting biophysical fluid transport in human bodies, and observing and controlling chemical reaction and mixing in surface-modulated fluid flow environments," said Suman Chakraborty, leader of the Microfludics Laboratory and head of the School of Medical Science and Technology.

Peristalsis refers to the mechanism of fluid transport by means of travelling waves along the surface of a flexible tube and the process is responsible for transport of chewed food through the human digestive tract where the surface movement is obtained by means of muscle relaxation and contraction.

Natural mechanisms and processes have been central in driving the study of on-chip devices which aim to mimic the same functionality, for example: a kidney filtration process or digestive system, on a miniature device.

This method of transport moves fluids without a separate pump - saving precious space in lab-on-a-chip. But this transport method is difficult to finely control in miniaturised devices.

Chakraborty said through theoretical analysis, the team has shown that by keeping the same peristalsis hardware, an enhanced on-the-fly controllability of the flow rate could be obtained by augmenting the device with electric fields.

This study, published in the Physics of Fluids journal in May, has been co-authored by Chakraborty, Aditya Bandopadhyay, who is presently a postdoctoral researcher in Geosciences Rennes (France) and by Dharmendra Tripathi, a faculty member at the Manipal University.

Bandopadhyay highlighted electric fields as being the "most efficient way of manipulating fluid flow and particulate motion through tubes at millimeter and micrometer ranges, without the involvement of any moving mechanical parts".