Tech Briefs

This research contributes to the development of bio/nano interfaces and new classes of biotic/abiotic materials.

During 2007, progress was made on several fronts in a research program oriented toward developing capabilities for biocompatible and biomimetic self-assembly of nanostructures that could perform desired functions as interfaces between biological and nanotechnological systems ("bio/nano" interfaces). These capabilities are expected to contribute, in turn, to development of new classes of biotic/abiotic materials and to understanding of responses of cells to diseases, injuries, stresses, and therapies. The approach followed in this research has been one of striving to understand and exploit celldirected assembly (CDA).

The objectives for 2007 and the efforts to attain those objectives are summarized below.

• Objective: Understand cell-directed assembly and use it to direct the formation of new bio/nano interfaces and unique cellular behaviors.

This Fluorescence Image, obtained by confocal scanning microscopy, show slices of yeast cells immobilized in silica matrices that were patterned partly by use of dihexanoylphosphatidylcholine (a lipid) and palmitoyl oleoyl phosphatidylcholine liposomes.
The pursuit of this objective included an investigation of the inclusion of multiple amphipathic components to control and tailor interfacial structures and functions. This investigation was prompted in part by the observation that plasma membranes in cells incorporate multiple amphipathic components, including phospho- and glycolipids, cholesterol, and integral and peripheral proteins. The amphipathic components studied in this investigation included water-soluble lipids and water-soluble liposomes (see figure).

The pursuit of the abovementioned objective included a demonstration of creation of new interfaces through modification of cells to incorporate non- native functional proteins. In this demonstration, by use of a novel technique, a CDA process was used to incorporate, into surface layers of yeast cells, bacteriorhodopsin from Halobacterium salinarum.