Micropatterning of functional lipid domains for toxin detection

We present a method for patterning receptor-populated lipid domains at the micrometer scale. The receptors contained in these domains are functional and can bind toxin fragments, thus serving as potential components of biosensors. To pattern the lipid domains we have made use of a novel micro-patterning technique, which involves the etching of a polymer coating to expose specific areas of a silicon substrate [1]. The chip is then incubated with lipid vesicles, which fuse onto the silicon surface and form lipid bilayers as described by Orth et al. [2]. Polymer lift-off, following lipid deposition, reveals lipid patterns on the exposed areas of the silicon chip. The lipid domains range in size from 0.5-76 μm with square and rectangular shapes. Toxin fragment binding has been detected by epifluorescence down to 1 nM concentration suggesting this as a suitable technique for the detection of pathogenic proteins below infectious levels. Microfluidic network integration allows for preparation of independent lipid domains with different receptors to achieve simultaneous detection of several toxins in one chip.