Lipid Dip-Pen Nanolithography for Model Bio-Membrane Systems

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The overall objective of this proposal is to merge top-down and bottom-up strategies to assemble nanoscale biomimetic lipid membranes relevant to immune transduction and cell adhesion. Specifically, we aim to develop tools for high throughput patterning of lipids on surfaces and to understand the fundamentals of lipid deposition and organization. Subsequently, we will use these capabilities to probe how geometrically-defined and chemically-tailored lipid structures affect cellular processes.There is growing evidence that the various properties of biological membranes strongly depend on both two- and three-dimensional heterogeneities (e.g. protein clustering, lipid rafts, and plasma membrane curvature). Furthermore, many cellular signaling processes respond to signaling agents at sub-cellular length scales. For studying spatially-resolved, supramolecular biological structure-function relationships, it is therefore increasingly important to interrogate these signaling events at the nanometer to micron length scales. We have previously developed Dip-Pen Nanolithography (DPN), a direct-write chemical deposition technique, capable of generating large-scale patterns with nanometer size features, and in the first three years of NSF-ICC funding, a toolkit for depositing lipids was developed. This lipid DPN (L-DPN) currently allows for the integration of two or more different membrane components on a surface with sub-cellular nanoscale spatial resolution and square centimeter per minute throughput. In addition, we have shown that L-DPN enables the investigation of cellular interactions with patterned surfaces that mimic biological structures.This proposal aims to exploit these biomimetic lipid patterns generated by L-DPN to examine two model cell signaling systems that are relevant to molecular biology and biochemistry: immunological mast cell activation by IgE; and cadherin-mediated epithelial cell adhesion. To fully enable these studies, additional multi-component lipid inks will be formulated and characterized according to deposition parameters and component distribution. The goals will be twofold: first, to answer specific fundamental questions related to cell-surface interactions; and second, to develop a new tool that will allow researchers to study these nanoscale interactions with high spatial control.