With the support of the Organic Dynamics Program in the Chemistry Division, Professor Vincent Rotello at the University of Massachusetts- Amherst will develop robust and versatile strategies for the protein-mediated assembly of nanoparticles in which the protein and the particle play equal roles in terms of both assembly and materials properties. Previous studies on the self-assembly of nanoparticles using proteins, produced structured aggregates that displayed controlled optical and magnetic properties. This research will extend this study focusing on both the self-assembly process and the properties of the assembled materials. These properties are intermediate between bulk material and molecular compounds and strongly depend on the particle size and the shape of the nanoparticles. When assembled into organized ensembles, these materials gain collective properties that are often quite different from the isolated particles. This collective behavior is highly dependent on issues such as interparticle spacing and nanocomposite morphology. Combining nanocomposite behavior with the structural properties of proteins including size, shape, redox state, and structural stability provides a means to control this ensemble behavior. This collective modulation paves the way for pragmatic technological applications such as biosensors, as well as more ambitious prospects such as biocomposite devices and biological computing.
This research by Professor Rotello at the University of Massachusetts- Amherst is highly multidisciplinary featuring tools and techniques from the fields of chemistry, materials science, physics, and biology. One of the primary goals of nanoscience research is the preparation of controlled assemblies of nanoparticles, providing useful building blocks for devices such as biosensors, switches and high-density magnetic storage arrays. The graduate and undergraduate students working on this research will gain an integrated understanding of these diverse methodologies, enhanced through weekly meetings to discuss research. Further training as well as dissemination of research will be provided by sending the students to National Meetings including the Materials Research Society and the American Chemical Society. Finally, Professor Rotello has developed a multimodal partnership with Professor José Rivera (U. Puerto Rico, Rio Piedras) designed to enhance the development of minority researchers at many levels. This partnership includes faculty mentoring by Professor Rotello (with visits between UPR and UMass) and the regular exchange of graduate and undergraduate students between our respective groups as a tool for broadening their scientific and cultural education.
Research in this grant focused on developing new strategies for assembling nanoparticles and proteins. The broad goal of this research is to develop new strategies for interfacing biological and synthetic systems. In our studies, we developed new methods for "gluing" together nanoparticles and proteins. The resulting conjugates add structural and physical properties of the nanoparticles while retaining the biological properties of the proteins or enzymes used for the assembly. In addition to fundamental studies, our research spurred two projects that have direct applicability for human health. In the first project, we have developed a new strategy for creating biocompatible surfaces for applications in implants such as stents where protein fouling would have negative consequences. Our strategy uses nanoparticles developed in this project as "paint" that can be applied to a variety of surfaces. These surfaces are designed to use the fact that our particles bind proteins reversibly without denaturing them. Once painted, the surfaces are stable in serum, whereas unpainted surfaces are rapidly covered with protein multilayers. We are currently extending these studies to plasma and whole blood testing, with the ultimate goal of developing new coatings for stents. The second project focuses on the creation of test strip based sensors for detecting bacteria in water. This research builds upon our ability to reversibly interacting nanoparticles and enzymes. In practice, nanoparticles and proteins are printed onto paper., with the nanoparticle inhibiting the enzyme. In the presence of bacteria, the particle is displaced from the enzyme, reactivating catalysis. Through use of colorigenic substrates we created strips where the presence of bacteria is detected through visible generation of colored spots on the test strips. This research is currently being moved towards general use through development of inkjet-based printing strategies suitable for scale-up.
