Harvard University researchers have developed a parallel technique for fabricating complex patterns of bacteria by controlling the size, shape, and distance between features of bacteria. This technique uses stamps consisting of a layer of agarose -- a common polymer -- with a micropatterned-surface containing features in bas-relief; the pattern on the surface of the stamp defines the pattern of bacteria to be printed. Stamps are made using either techniques commonly employed in semiconductor fabrication or a procedure we have developed that can be performed in any standard academic/industrial laboratory.
The micropatterned surface of a stamp is inked with suspensions of bacteria. The liquid is adsorbed into the stamp leaving cells of bacteria on its surface. When the stamp is brought in contact with media plates for culturing bacteria, only the cells on the raised features of the stamp are transferred to the culture plate. The stamp transfers only a small percentage of cells that are on its surface to the agar (or other material) at a time; it is thus possible to replica pattern hundreds of times with a single inking. When culture media is included in the agarose stamp, cells divide and thrive on the surface. The resulting "living stamp" regenerates its "ink", and can be used to pattern surfaces repetitively for a month. The stamp can be likened to a bacterial printing press that regenerates its ink.
The researchers have demonstrated the first general technique for creating complex patterns of multiple bacteria rapidly and reproducibly with control over the shape, size, and distance between features of bacteria. Using this technique we are studying a variety of medically-relevant phenomena, including biofilm formation (occurring, for example, in the biofouling of catheters) and the inter- and intra-species communication between bacteria (implicated in the pathogenesis of bacteria). We believe that this method will be useful to a broad range of scientists (chemists, biologists, and microbiologists) interested in generating patterns of bacteria on cell culture media or other surfaces for studying the interactions between bacteria, bacteria and chemicals, and bacteria and surfaces. These areas of research are all medically-relevant.
This technique was developed by Douglas Weibel, Andrew Lee, Michael Mayer, and Professor George. M. Whitesides in the Department of Chemistry and Chemical Biology at Harvard University, and was funded by the National Institutes of Health, the Department of Energy, and the Materials Research Science and Engineering Center at Harvard University. A poster describing this work was presented at the Annual Meeting of the American Society for Microbiology meeting in Atlanta, GA on June 8, 2005.
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