Laser induced disruption of bacterial spores on a microchip

Abstract

We report on the development of a laser based spore disruption method. Bacillus globigii spores were mixed with a laser light absorbing matrix and co-crystallized into 200-µm-wide and 20-µm-deep nanovials formed in a polydimethylsiloxane (PDMS) target plate. Surface tension effects were exploited to effect up to 125-fold spore enrichment. When the target zones were illuminated at atmospheric pressure with pulsed UV-laser light at fluences below 20 mJ cm⁻² a change in spore morphology was observed within seconds. Post illumination PCR analysis suggests the release of endogenous DNA indicative of spore disruption. For laser fluences above 20 mJ cm⁻², desorption of spores and fragments was also observed even without a matrix being employed. Desorbed material was collected in a PDMS flowcell attached to the target plate during laser illumination. This opens up a route towards the direct extraction of released DNA in an integrated spore disruption–PCR amplification microchip device.