A technique has been developed to selectively attach bacteria to solid supports using poly-l-lysine. The patterned biofilms were labeled with green fluorescent protein (GFP) or a nucleic acid stain and imaged using both confocal microscopy and GFP stereomicroscopy. E. coli DH10B, E. coli MC1061, and Pseudomonas sp. GJ1 were selectively attached to regions coated with poly-l-lysine but not to uncoated regions. In contrast, E. coli DH5 alpha, W3110 and 33456 attached indiscriminately to the coated and uncoated regions of the surface. Those organisms that selectively attached to the poly-l-lysine coated regions formed biofilms twice as thick as the organisms that attached indiscriminately to the surface. This technique can be used for selectively patterning surfaces with genetically engineered microorganisms for biosynthesis of secondary metabolites and biodegradation or for developing a bacterial-based microscale medical diagnostic tool.