Chemists in the US have developed microfluidic valve structures for lab-on-a-chip devices that reduce the number of controllers required off the chip.

Richard Mathies and colleagues at the University of California, Berkeley, created microfluidic valves that can be held open for minutes by pressure pulses as short as 120 ms. These are controlled independently using an on-chip pneumatic demultiplexer, a device that can control many outputs from a small number of inputs. These structures allow many on-chip valves to be controlled independently using only a few off-chip components.

Lab-on-a-chip devices shrink entire chemical or biochemical assays down to small microfluidic chips. The goal is now to shrink the controls: the off-chip computers, valves, switches and pumps that operate the chip. By decreasing the number of these controllers Mathies hopes to reduce the size, power consumption and cost of the chips.

On-chip pneumatic valves and pumps play an important role in lab-on-a-chip devices, but each independent valve currently requires a separate off-chip controller. This can lead to problems because a single chip may have hundreds of these valves.

Albert van den Berg, head of the lab-on-a-chip group at the University of Twente, the Netherlands, said this work is a major contribution to the microfluidics field. ‘The possibility of controlling a thousand independent valves with only eleven pneumatic controls is remarkable,’ he said.

‘The future lies in programmable lab-on-a-chip devices, generic platforms that can perform thousands of different assays simply by providing different inputs and running different programs,’ said Mathies. ‘Integrating the basic logic of device operation on-chip is a crucial first step toward realising this goal of programmable lab-on-a-chip devices,’ he said. 

Sarah M Corcoran

BY :saeed zeigham jehani