Intelligent liquid crystals may soon be integral in lab-on-a-chip technology, according to researchers from the Netherlands and Canada.

Anastasia Elias at the University of Alberta, Canada, used UV light to irradiate liquid crystals comprised of two types of long thin molecule. The resulting polymer reversibly changed shape with changes in temperature.

Selective irradiation through a mask can lead to intricate miniaturised printing of the polymer. Suitably patterned films are similar to circuit boards and can act as intelligent materials, responding to changes in temperature. Such materials already exist, but are limited by their degree of response and their ease of processing by photopatterning.

Elias hopes that 'Ultimately such materials will be fully integrated into microelectromechanical devices, such as the emerging lab-on-chip applications.'

This technology, characterised by small volume and high-throughput analysis, is increasingly important in the pharmaceutical industry and medicine, owing to the opportunity of multiple screening.

Ingo Dierking, author of Textures of Liquid Crystals, concurs: 'The introduction of photo-patterning is a step forward towards applications of such micro-mechanical systems, as reversible changes in size can be achieved on a controlled microscopic scale.'

Further development this line of work 'could have real impact in the field of projection displays or tuneable micro-optic devices', Dierking said.

Alan Holder