Research
Dye-doped silica nanoparticles
Silica nanoparticles (SiNPs) have enjoyed numerous applications including drug delivery and use as biomarkers due to their facile synthesis, low toxicity, and ease of modification. Fine-tuned control over the growth of SiNPs provides greater access to robust surface modifications and attachments to other functional nanomaterials. Several syntheses are known to produce SiNPs with various diameters, shapes, and monodispersity. The Stöber method, a sol-gel process that uses ammonia as a catalyst, is most commonly used for the mass production of SiNPs, but its lack of monodispersity among particles less than 50 nm in diameter has encouraged the exploration of a different synthetic processes. Our lab utilizes a bilayer system consisting of deionized water, l-arginine, cyclohexane, and tetraethyl orthosilicate (TEOS) that, when heated and stirred for 24-48 hours, produced monodisperse SiNPs of diameters less than 50 nm. The particles can then be funcitonalized with with a fluorescent dye, rhodamine B, and regrown using the same bilayer system as the original growth to create a protective outside shell that prevents further desorption of rhodamine B. These monodisperse dye-doped SiNPs will serve as a model for biomarkers and drug delivery applications. Future work includes surface modification for specific binding and encapsulating other fluorophores and bioactive agents.
DNA-functionalized Gold Nanorods
The field of plasmonics holds great promise in the research areas in nanoscience and nanotechnology. Chemical synthesis of metal nanostructures with well-controlled size and morphology embodies a versatile bottom-up approach for accessing nanoscale plasmonic building blocks. Gold nanorods (GNRs) displays a tunable longitudinal surface plasmon resonance (LSPR) that depends on the GNR aspect ratio (AR). Independently controlling the AR and size of GNRs remains challenging but is imperative because the scattering intensity strongly depends on the GNR size. Our current research is specified in the development of gold nanorod synthesis and purification techniques for applications in nanocomplex architectures. Key roles include diagnosing the utility of salt-additives to promote monodisperse gold nanorod formation under reproducible ambient conditions and exploring numerous reaction vessels to economically utilize reagents. Our current work is focused on functionalizing the GNR surface to promote guided aggregate formation in heterogeneous nanoparticle assemblies.
DNA Origami
Recent advances in nanomaterials have shown great promise in the fields of drug delivery, biomarker development, and photo-voltaic (PV) cells, to name a few. These materials promise to overcome inefficiencies associated with the bulk design of current state-of-the-art technologies by fine tuning physical, chemical, and electronic properties at the nano scale. However, many novel nanomaterials fail to realize full application due to challenges in top-down design and spatial control. DNA-based nanostructures are well-suited to answer this challenge by providing a platform for bottom-up, high spatial resolution scaffolds to organize heterogeneous nanomaterials. DNA origami, a structure created from hybridizing a long ssDNA scaffold strand with multiple synthetic complimentary 'staple strands', is particularly attractive for this application as synthetic ssDNA segments allow for sub-nanometer inclusion of selective binding moieties. Thus, DNA is able to serve as a structural peg board to organize a variety of other materials. We are currently designing and modeling potential DNA origami candidates to aggregate anisotropic nanoparticle aggregates.
Science Diplomacy
The American Association for the Advancement of Science (AAAS) provides opportunities for scientists of all backgrounds to leverage their expertise at the policy and programmatic levels of government in Washington DC. This experience brings much needed scientific methodology to the Federal Government while also providing unique experiences to researchers. I served as an officer in the Biosecurity Engagement Program (BEP) at the U.S. Department of State from 2015-2016 working with an international group of scientists to reduce biological threats.