Browsing by Author "Zubarev, Eugene R."
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Item Adsorption and Unfolding of a Single Protein Triggers Nanoparticle Aggregation(American Chemical Society, 2016) Dominguez-Medina, Sergio; Kisley, Lydia; Tauzin, Lawrence J.; Hoggard, Anneli; Shuang, Bo; Indrasekara, A. Swarnapali D.S.; Chen, Sishan; Wang, Lin-Yung; Derry, Paul J.; Liopo, Anton; Zubarev, Eugene R.; Landes, Christy F.; Link, StephanThe response of living systems to nanoparticles is thought to depend on the protein corona, which forms shortly after exposure to physiological fluids and which is linked to a wide array of pathophysiologies. A mechanistic understanding of the dynamic interaction between proteins and nanoparticles and thus the biological fate of nanoparticles and associated proteins is, however, often missing mainly due to the inadequacies in current ensemble experimental approaches. Through the application of a variety of single molecule and single particle spectroscopic techniques in combination with ensemble level characterization tools, we identified different interaction pathways between gold nanorods and bovine serum albumin depending on the protein concentration. Overall, we found that local changes in protein concentration influence everything from cancer cell uptake to nanoparticle stability and even protein secondary structure. We envision that our findings and methods will lead to strategies to control the associated pathophysiology of nanoparticle exposure in vivo.Item Gold nanorods: Synthesis, structural manipulation, and self -assembly(2009) Khanal, Bishnu Prasad; Zubarev, Eugene R.This work describes methods for the synthesis, structural manipulation, and self-assembly of one-dimensional gold nanostructures. The thesis begins with an efficient technique for the synthesis and separation of gold nanorods from a complex mixture, which has been a long standing challenge in the field of inorganic nanocrystals. The key aspect of our approach is the combination of partial oxidative dissolution and gravitational sedimentation of gold nanostructures. In addition, the length of nanorods can be tuned using reversible elongation and shortening of rods when Au (I) and Au (III) ions are used, respectively. The synthesis of extremely long gold nanowires measuring up to ∼25 µm was accomplished by this novel synthetic approach. The width of gold nanowires can also be precisely controlled by adjusting the concentration of Au (I) ions in the growth solution. This thesis also describes a procedure for the large scale synthesis of gold nanorods. The gram quantity of nearly monodisperse single crystalline nanorods was synthesized by slow reduction of Au (I) ions on the surface of pre-formed gold nanorods. This results in the amplification of nanorods without the formation of any undesirable shapes. Finally, the surface functionalization technique described in this thesis allows for the synthesis of polymer-functionalized gold nanorods. Our investigation revealed their unique ability to undergo spontaneous self-organization into ring-like superstructures. This process is templated by water microdroplets which condense from the air when a volatile organic solvent evaporates. This self-assembly does not require any lithographic technique and can organize millions of gold nanorods into rings in a matter of seconds.Item High-yield synthesis of gold nanorods with optical absorption at wavelengths greater than 1000nm using hydroquinone(2015-02-17) Vigderman, Leonid; Zubarev, Eugene R.; Rice University; United States Patent and Trademark OfficeThe present invention provides improved methods for preparing cetyltrimethylammonium bromide-capped gold nanoparticles through the use of hydroquinone as a reducing agent. Such methods generally comprise the steps of: (1) providing a seed solution comprising a gold nanoparticle; (2) providing an aqueous growth solution comprising: (i) cetyltrimethylammonium bromide, (ii) hydrogen tetrachloroaurate, and (iii) hydroquinone; and (3) adding a quantity of the seed solution to the aqueous growth solution.Item Pancreatic tumor microenvironmental acidosis and hypoxia transform gold nanorods into cell-penetrant particles for potent radiosensitization(AAAS, 2022) Rauta, Pradipta Ranjan; Mackeyev, Yuri; Sanders, Keith; Kim, Joseph B.K.; Gonzalez, Valeria V.; Zahra, Yasmin; Shohayeb, Muhammad A.; Abousaida, Belal; Vijay, Geraldine V.; Tezcan, Okan; Derry, Paul; Liopo, Anton V.; Zubarev, Eugene R.; Carter, Rickey; Singh, Pankaj; Krishnan, SunilCoating nanoparticles with stealth epilayers increases circulation time by evading opsonization, macrophage phagocytosis, and reticuloendothelial sequestration. However, this also reduces internalization by cancer cells upon reaching the tumor. We designed gold nanorods (GNRs) with an epilayer that retains stealth properties in circulation but transforms spontaneously in the acidotic tumor microenvironment to a cell-penetrating particle. We used a customized stoichiometric ratio of l-glutamic acid and l-lysine within an amphiphilic polymer of poly(l-glutamic acid-co-l-lysine), or P(Glu-co-Lys), to effect this transformation in acidotic environments. P(Glu-co-Lys)-GNRs were internalized by cancer cells to facilitate potent in vitro radiosensitization. When administered intravenously in mice, they accumulate in the periphery and core of tumors without any signs of serum biochemical or hematological alterations, normal organ histopathological abnormalities, or overt deterioration in animal health. Furthermore, P(Glu-co-Lys)-GNRs penetrated the tumor microenvironment to accumulate in the hypoxic cores of tumors to potently radiosensitize heterotopic and orthotopic pancreatic cancers in vivo.