Wyatt N. Vreeland (Fed)

Wyatt graduated magna cum laude from the University of Tulsa in May of 1997. In 1997 he began his doctoral studies at Northwestern University in Evanston, Illinois in the laboratories of Prof. Annelise E. Barron (currently at Stanford University). During his time at Northwestern, his research focused on developing new methodologies for high-resolution electrophoretic analysis of polymeric macromolecules in capillaries and microfluidic "lab-on-a-chip" devices. These techniques were primarily geared toward DNA analysis for genetic applications.

In 2002, Wyatt joined NIST as an NRC postdoctoral fellow working with Laurie Locascio on applications of liposomes as functional elements in microfluidics. Liposomes were first discovered by Alec Bangham in 1961; liposomes are spherical structures that are made from a bilayer of amphipathic phosphoplipid molecules and are the subject of active research for molecular encapsulation and delivery vehicles. These particles can range in size from tens of nanometers to tens of microns in diameter. As lipids self-assemble into liposomes, they concomitantly encapsulate water-soluble drugs in their aqueous intravesicular lumen and lipophilic drugs in the amphipathic bilayer membrane thus creating small "containers" that can be used to traffic water-soluble agents or lipophilic agents through a bulk aqueous medium while shielding those agents from interaction with the exterior aqueous media. The ability of a liposome to sequester its internal volume from the extravesicular space has lead to a variety of applications in targeted delivery of chemical therapeutic agents. In fact, these particles are synthetic analogues of naturally occurring vesicles used in biological cells for the trafficking of species and materials within the biological cell. Borrowing nature's motif of using vesicles as nano-packages, our initial research focused on using liposomes to package chemicals and release those reagents at controlled times and locations in a microfluidic system.

More recent research has focused on using the precise and reproducible laminar flow conditions available in microfluidic systems to facilitate the self-assembly of amphiphilic molecules into liposomes and other nanoparticles. The exquisite control of fluidic mixing allows precise control of the particles' size and size distribution, obviating the need for post-synthesis homogenization processing steps to control particle size. In concert we have developed a suite of techniques to characterize accurately the particles' size and to quantify the amount of material contained in each liposome.