Generation of mesoscopic patterns of viable Escherichia coli by ambient laser transfer

We have generated mesoscopic patterns of viable Escherichia coli on Si(1 1 1), glass, and nutrient agar plates by using a novel laser-based transfer p rocess termed matrix assisted pulsed laser evaporation direct write (MAPLE DW). We observe no alterations to the E. coli induced by the laser-material interaction or the shear forces during the transfer. Transferred E. coli p atterns were observed by optical and electron microscopes, and cell viabili ty was shown through green fluorescent protein (GFP) expression and cell cu lturing experiments. The transfer mechanism for our approach appears remark ably gentle and suggests that active biomaterials such as proteins, DNA and antibodies could be serially deposited adjacent to viable cells. Furthermo re, this technique is a direct write technology and therefore does not invo lve the use of masks, etching, or other lithographic tools. (C) 2001 Elsevi er Science Ltd. All rights reserved.