(293e) Liposome Microarrays for Toxin Detection

The technology of protein microarrays (or ?protein chips?) is a recent innovation used for screening of the binding interactions of proteins (e.g. an antigen, a cell membrane receptor, an enzyme) with potential binding partners or ligands. The ligands can be other proteins (e.g. antibodies or hormones), enzyme substrates, or small synthetic molecules such as oligopeptides, or their analogues (peptoids, etc.) prepared as part of a combinatorial chemistry library. In this work, we have developed a new microarray platform for arraying membrane receptors for multiplexed screening of the binding interactions of these receptors with binding ligands. We used interferometric lithography to make large areas of periodic photoresist structures on a Si wafer for use as templates for metal deposition. Following metal deposition, the photoresist was removed, leaving ordered metal arrays on a flat Si surface. The bottom of the wells was subsequently functionalized with an amine termination by backfilling with an amine silane. The amine functionalized wells were then conjugated to Neutravidin labeled with a FITC dye. As a proof of concept experiments, we used the intact liposome microarray format and known receptor-ligand system to check the applicability of the liposome microarray platform for biodetection. Monoganglioside GM1 was incorporated in the lipid bilayer of liposomes and these receptor liposomes were arrayed onto the chemically functionalized microwell patterned substrates. These GM1 receptor incorporated liposome arrays were used to detect specific binding of Cholera Toxin Subunit B (CTB) to the surface receptors using confocal laser scanning microscopy.