A Nobel Prize winner in Physics, Richard Feynman, predicted decades ago that, “When we get to the very very small world--say circuits of several atoms--we have a lot of new things that would happen that represent completely new opportunities for design. Atoms on a small scale behave like nothing on a large scale, for they satisfy the law of quantum mechanics.”With diameters frequently less than 10 nm, carbon nanotubes fall into the size range where quantum effects become important, and this, combined with their unusual symmetries, has led researchers to predict many remarkable electronic, magnetic, and lattice properties which are quite different from those of their bulk counterparts. Currently, there are several funded nanoscience and nanotechnology research projects going on in Prof. Jiao’s group:
Optimization of Magnetic Photocatalyst Systems for Solar Water Purification: The principal idea of this research is to remove organic pollutants from water through the absorption of sunlight by titanium dioxide, and subsequent conversion of that energy from electrical to chemical energy, which is then capable of breaking down organic pollutants. In order to make the process more efficient, our goal is to synthesize and optimize titanium dioxide particles that have a magnetic core, so that they can be dissolved in water, and then recovered for reused by a magnetic separator. In addition, testing of the effectiveness of these particles requires the development of a new type of solar reactor that allows for illumination of the water by solar light, mixture of the water and catalyst particles, separation of the particles from the water, and finally removal of the clean water. The scope of this project requires it to have an interdisciplinary nature, involving chemical synthesis, materials science, and engineering.
Development of Nano-Modified Anodes for Improved Power Densities of Microbial Fuel Cells: Alternative and renewable energy is becoming increasingly important as the natural energy crisis is a pressing concern. Greater output of energy with less environmental impact is the driving force for advancing technologies in this field. One sustainable approach to power generation is the microbial fuel cell (MFC) [7–8]. MFCs use microorganisms to simultaneously break down bio-mass and generate electricity. One of the greatest challenges in the practical application of MFCs is to sufficiently increase their power generation. One effective effort discovered by Prof. Jiao’s group is to use nanostructures to modify the electrodes of the MFCs [9–12]. In this technique, efficiently transporting electrons across the microbe to the anode surface is the key to increasing the power output. Our research has demonstrated that nanomodification of the anode could offer one possible solution to increase a stronger bond/pathway between the microbe and anode surface and thus to increase the power density of the MFC. The REU participants will be involved in the fabrication and characterization of nanomaterials for the modification of the fuel cell anodes.
Nanoparticulate Adjuvants and Delivery Systems Towards New Generation Vaccines: Vaccination has greatly impacted global public health by controlling and preventing infectious diseases and treating cancers. However, it remains difficult to generate sufficient immunity with vaccines containing insufficient immunogenic antigens. To amplify the interaction between antigens and the immune system, we recently reported that antigen coupled to alumina nanoparticles is 500 times more efficiently processed by dendritic cells for major histocompatibility complex (MHC) class I antigen presentation, and elicits strong cytotoxic T cell response against cancer in vivo (Nature Nanotechnology, 2011, 6,645-50). We now extend these studies to infectious disease, with the goal of utilizing alumina NPs to elicit cytotoxic T cell response to defined pathogen antigens. Herapeutic cancer vaccination is an attractive strategy because it induces T cells of the immune system to recognize and kill tumour cells in cancer patients. However, it remains difficult to generate large numbers of T cells that can recognize the antigens on cancer cells using conventional vaccine carrier systems. We show that α-Al2O3 nanoparticles can act as an antigen carrier to reduce the amount of antigen required to activate T cells in vitro and in vivo. We found that α-Al2O3 nanoparticles delivered antigens to autophagosomes in dendritic cells, which then presented the antigens to T cells through autophagy. Immunization of mice with α-Al2O3 nanoparticles that are conjugated to either a model tumour antigen or autophagosomes derived from tumour cells resulted in tumour regression. These results suggest that α-Al2O3 nanoparticles may be a promising adjuvant in the development of therapeutic cancer vaccines.
Surface Modification of Graphene with Various Metal and Metal oxide Nanocrystals for Renewable Energy Applications: The principle of this project is to develop a very simple, scalable and environmentally-benign process to hybridize high crystalline graphene with various noble metal and alloy and metal oxide nanocrystals, which is suitable for clean and renewable energy materials. Three categories of interest within the clean energy category that have be focused: energy storage (supercapacitors), energy conversion (fuel cells), and energy production (water splitting). More specifically, surface decoration of conductive graphene with transition metal oxide, such as Fe3O4 and Mn3O4, for high-performance supercapacitor; Hybridization exfoliated graphene with Pt and Pt-based alloys as electrode materials for direct methanol fuel cells; Graphene supported TiO2 and N-doped TiO2 as efficient photocatalyst for water splitting. The project goal is scalable manufacturing high-performance graphene-based hybrids with industrial level.
Tuning High Aspect Ratio Materials for Drug Delivery and Intracellular Sensing: Understanding the mechanisms behind immune response and cellular internalization pathways has long been a pursuit for many purposes including cancer vaccine optimization. Recent developments within the Dr. Jun Jiao research group have identified alpha alumina as a key candidate for future cancer vaccine development. Alpha alumina nanoparticles successfully delivered antigen to T-cells which, in turn, allows them to recognize and kill cancer cells. The next step in this project is to determine the mechanism underlying the successful activation of T-cells using these alpha alumina adjuvants. Solid state sensors are under development to probe these mechanisms using both electrochemical and biological regimes for generating feedback that can be correlated to the behavior of cancer cells.
Manufacturing Processes for Graphene-Based Gas Sensing Devices: The idea behind this research is to develop sensors based upon graphene with metal nanocrystals deposited on it surface. The use of different metals will allow for sensing various gases, for instance it is well established that hydrogen reacts palladium in order to produce palladium hydride. We theorize that a graphene hybrid device could exhibit better sensitivity due to the increased surface area and better efficiency due to the inherent conductivity of the graphene. In order to produce these devices we are developing lithography and vapor deposition techniques so that we can select optimal samples. Finally the response will be characterized to controlled amounts of gas in order to determine its sensitivity and response time.
Functionalizing Aluminum Oxide Nanoparticles for Improving Efficiency in Cancer Treatment
Nanoparticles have been very important in cancer research, since they are ideal for vaccine delivery. Their small size allows them to penetrate cell walls, making it possible to deliver the vaccine within the cells. Aluminum oxide nanoparticles stimulate one of the strongest anti-tumor responses in the immune cells. These nanoparticles can be combined with other molecules to further increase effectiveness. The current experiments are dealing with cervical cancer and human papillomavirus (HPV). The E6, E7 proteins of HPV is culpable in causing cancer. We functionalize the aluminum oxide nanoparticles with different molecules and conjugate them with the E6, E7 proteins. We vaccinate mice and analyze the immune response from different molecules to determine which molecule is most effective at strengthening the immune response. This research is being done in collaboration with Dr. Hong-Ming Hu at the Cancer Research Center at Providence Hospital in Portland, OR.
Optimization of Carbon Nanotube-Based Gas Sensors: The electronic transport properties of carbon nanotubes have been shown to be strongly dependent upon the constituent gases of the ambient environment. In order to improve upon the capabilities of these promising sensors, it is essential to completely understand the adsorption process and the nature of their interaction with gas molecules. Three principle techniques are used to further this understanding. Raman spectral mapping with sub-micron spatial resolution is used to structurally characterize the carbon nanotube channel and to quantify the number of lattice defects. A custom micro-environmental probe station system is used to measure the response of the electronic channel to ambient gas concentration, temperature and pressure, and to photonic stimulation (via a tunable infrared laser). In combination, these stimuli provide a great deal of information about the electronic state of the channel. These measurements are correlated to various ab initio computations, such as band structure and density of states, to provide a complete picture of how the ambient gas molecules influence the transport properties of the carbon nanotubes.