Our work focuses on how weak forces at the molecular level determine macroscopic properties at larger length scales. We spend equal time understanding the details of molecular-level interactions using NMR, neutron scattering, x-ray scattering, or electron microscopy and making measurements of bulk properties such as rheology, diffusion of proteins in gels, drop sizes of sprays, or pressure drop measurements in porous media. Our work is highly interdisciplinary; many of the projects involve joint advisors and collaborations with researchers at NIH, Argonne National Labs, CNRS in France, or major corporate research centers.

Multifunctional nanoparticles. We have developed a new “flash nanoprecipitation” process for making nearly monodisperse particles of hydrophobic substances by kinetically stabilizing the material with block copolymers. Using this method, we have successfully encapsulated fluorescent dyes, drug substances, and inorganic materials within nanoparticles in a controlled fashion. By using functionalized polymers, we can create targeted nanoparticles for diagnostics and drug delivery. These targeting ligands on the nanoparticles range from sugars and peptides to monoclonal antibodies. In addition to improving long term storage stability, we are also developing processing methods to optimize nanoparticle separation and purification. Our collaborators include Sibtech, Inc., Caliper, Bioscan, Sequella, the Low lab at Purdue University, and the Sinko lab at Rutgers University.
Projects:   Supramolecular assembly of polymer nanoparticles into functional nanoscale materials
                   Formation of Stable Nanocarriers by in situ Ion Pairing in Block-Copolymer-Directed Rapid Precipitation
                   MRI active Nanoparticles as Contrast Agents for Tumor Detection
                   Nanoparticles for Multimodal Imaging
                   Multifunctional Nanoparticle Fabrication for Efficient Therapeutic and Diagnostic Delivery
                   Multifunctional nanoparticles for biomedical imaging applications

Gel microparticles. Micron-sized hydrogel particles are being developed in collaboration with the Stone lab at Princeton University and the Sinko lab at Rutgers University. These particles are specifically designed to target the lungs via the venous flow filtration pathway. Within the gel matrix of these particles various diagnositic and therapeutic materials can be encapsulated and controllably released in the lungs.
Projects:   Microfluidic fabrication of gel microparticles for lung cancer drug delivery

Emulsions. Stabilization of emulsions, foams and thin films requires that the interfaces be kept far enough apart to prevent rupture induced by long-range, London-van der Waals attractions. We study the transport of dispersants to and along interfaces through the synthesis of novel surfactants and emulsifiers, the characteristics of dispersants that improve emulsion stability using microfluidics, and the use of emulsions as scaffolds for creating drug carriers and other microparticles.
Projects:   Dispersant kinetics at the microscale
                   Microcapsule formulation for controlled release