Nanotechnology and MEMS Research
After an MT attaches and caps, it becomes stable and the process can be reversed to disassemble the MTs that did not attach. Proteins don’t conduct electricity. So after they are attached, copper molecules are deposited on them to form wires. A Significant Breakthrough This is where the NIRT team has achieved a significant breakthrough. If the MTs are coated on the outside, the resulting wires are about 45 nanometers in diameter. But Raghavan and his students have discovered a way to control the coating process so that only the inside of the tube is coated. This results in wires that are 15 nanometers in diameter. Because the tubes are coated on the inside, they’re insulated by the protein coating. “So if you think about two tubules crossing each other, the metals are not going to touch,” Deymier said. “This cuts down on the number of circuit layers needed in the chip and reduces processing costs.” Other Promising Applications In their natural state, MTs are involved in mitosis. Some cancer treatments depend on blocking mitosis to stop cancer cell growth.
Anticancer drugs are tested now by putting them in a test tube with MTs to see if MT growth slows. But the MTs are not in a configuration that mimics their natural placement in a cell. “Since we can make the MTs grow in specific patterns, we also could grow them in a configuration that is an analog of how they are ordered in a cell, and we could test the drugs in a more realistic environment,” Deymier said. In another area, researchers in university and industry labs are building transistors that are only as large as a single molecule. One of the big issues is how to connect them to the outside world. One answer might be to connect them using MTs. In addition, microtubules might become the link between the outside world and proteins that act like solar cells.
Microtubules might become the link between the outside world and proteins that act like solar cells.
Researchers at the University of Tennessee are using plant proteins to efficiently convert sunlight to electricity, but their main problem is getting those electrons out into micro-size circuits where they can be used. Microtubules might be used to bridge that gap.
OT H E R P R OJE C TS Pierre Deymier and his students are at the forefront of research in the science and engineering of materials based on the use of biomolecules (DNA, proteins) or entire cells as templates or building blocks for technological applications. Examples include the use of proteinaceous microtubules as templates for the manufacture of nanoscale interconnects for integrated circuits. Mark Riley and his research group in Agricultural and Biosystems Engineering are developing ways to interface animal cell cultures with optical sensing methods to quantify changes in cell physiology and function in response to stresses. This approach can be used to evaluate cell behavior and to detect pathogens and toxins in the environment.
Professor Jeong-Yeol Yoon, of Agricultural and Biosystems Engineering, and his team of researchers are developing an on-site/point-of-care lab-on-a-chip device for detecting microbes in water or disease markers in blood serum. His group is also working on developing a protein nanoarray system capable of single-molecule detection. Stanley Pau and his research group in Optical Sciences are using their expertise in nanofabrication to create novel photonic devices that have engineered electrical and optical properties. The optical properties of many materials change drastically as their dimensions are reduced to optical and de Broglie wavelengths of the quasi-particle transitions. Optical and impedance spectroscopy are key techniques to probe and understand these nanostructures
university of arizona | college of engineering | progress report 2009 | 21