Congratulations to Declan!
Congratulations to our Declan Oller for winning the Brown Institute for Brain Science Graduate Research Award!
Congratulations to Carlos!
Congratulations to our Carlos Bledt for winning the National Defense Science and Engineering Graduate Fellowship!
Congratulations to Hongsik Park
Congratulations to our Hongsik Park's breakthrough research at IBM-Research!
Congratulations to Jeffrey Shainline
Congratulations to our Jeffrey Shainline for his third award - National Research Council Fellowship and the launch of his own research program in Integrated Single-Photon Chips at NIST.
Congratulations to Jeffrey Shainline
Congratulations to Jeffrey Shainline for being elected to receive the 2011 'Beyer Award for Excellence in Scholarship and Service' from the Department of Physics, Brown University
Congratulations to Daniel Deisley
Congratulations to Daniel Deisley on his receiving the 2010-2011 Doris M. and Norman T. Halpin Prize for Interdisciplinary Senior Capstone Projects. With this prize, Daniel will be able to continue his research on functional nanocomposite with built-in sensors, EMI shielding, and active cooling.
Awards go to Stuart Elston and Jeffrey Shainline for their work on resonant cavities
A collaborative work between the Valles group and ours has been listed as one of the 'Top Ten Physics Stories of 2007' - AIP Physics News Update, Number 850 #1, December 13 , 2007
Congratulations to Michael Stewart of the Valles group and Nick Yin of the Xu group for their collaboration with professors Jim Valles and Jimmy Xu which led to the discovery of Cooper pairs in an amorphous insulating nanopatterned bismuth film. This discovery of Cooper pairs being responsible for an insulating state is the first of its kind. To read more about this story and the other top ten physics stories of 2007, follow this link. The findings, published in Science, can be accesed at this link.
Engineered Nanomaterials for Drug Delivery and the Prevention of Infectious Diseases with The Miriam Hospital
We are working with Dr. Bharat Ramratnam of The Miriam Hospital in Providence, RI on engineering nanotubes and nanorods for timed-release localized drug delivery and the prevention of infectious diseases. Such drug delivery mechanisms have many benefits, including increased efficiency, reduced side effects, and convenience. Infectious diseases are a serious global problem, affecting both developing and industrialized countries. Infections can cause illness, disability, and death in individuals; they can also disrupt entire populations, economies, and governments.
In vivo uptake of labeled nanotubes (nanotubes in bright red, cell nuclei in blue).
We are using the properties of carbon nanotubes and biodegradable nanorods to (1) develop a timed-release non-invasive (topical cream or pill) drug delivery system and (2) prevent viral infection at the earliest possible point (the mucosal linings of the body). We are using our in vivo studies on mice and in vitro studies on human cancer cells to guide our nanorod/nanotube functionalization and conjugation methods and get ready for another set of in vivo studies.
Silicon Nanophotonic Devices
The creation of optically active devices in the silicon medium has been a goal for several generations of solid state scientists. The proud legacy continues at Brown University where Professor Jimmy Xu, graduate students and postdoctoral fellows in the Department of Physics and Division of Engineering (Electrical Sciences and Materials Sciences) are leading a collaboration with members of the Brown engineering and physics departments as well as members of the Electrical Engineering Department at the State University of New York, Stony Brook, materials scientists and physicists at Harvard University and photonic device physicists at Cornell University.
The demonstration of laser action in nanopatterned silicon at Brown in 2005 was an important breakthrough, marking the first realization of lasing based on the optical activity of point defects in silicon. The research also indicates the potential to enhance the optical properties of silicon via nanoscale manipulation. Continued research associated with these collaborations is focused on the controlled introduction of optically active defects in silicon, new methods of nanoscale modification which allow for active tuning of the optical and electronic properties of silicon structures, and on novel new configurations wherein silicon is coupled to other emissive media, such as metals with a large plasmonic response or polymers with an excitonic response. The ongoing research is exciting both from the point of view of the nanoscale physicist and from the point of view of the optoelectronic engineer.
Direct Nanoscale Conversion of Biomolecular Signals into Electronic Information
The Laboratory of Emerging Technology, led by Professor Jimmy Xu, at Brown has been a leading participant in a Multi-University Research Initiative (MURI) of the DoD for ?úDirect nanoscale conversion of biomolecular signals into electronic information?? This is a first major national initiative to interface biomolecules and nanoelectronics by developing a technology suite to engineer redox proteins and DNA and peptides to enable transduction of biomolecular activities into electronic information via self-assembling, self-addressing, and scalable nanoelectronic probe arrays. This work draws from expertise in the fields of biochemistry, electrochemistry, nanomaterials science, electrical engineering, microfluidics and nanoelectronics from multiple institutions ??Brown, Boston College, University of Pittsburgh. Drexel University, University of Toronto, University of Florida, Naval Research Laboratory, and University of Virginia. To do this, we have devised several approaches to effectively interface biomolecules with nano- and micro-electronic circuitry in a way that preserves and enhances their inherent biological function. These systems developed to date are self-assembling and self-organizing by virtue of programmable molecular linking systems involving peptides, coiled coils and nucleic acids. This feature lends the systems scalability and renewability. Although the project is driven in the interest of basic science research, it has several immediate applications in arenas such as biosensors and bio-fuel cells.
Nanotechnology platforms for DNA Sorting and Identification
The Laboratory of Emerging Technologies has been in the pursuit of developing novel ?úNanotechnology platforms for DNA sequencing?? A potential application is in DNA Identification, and it has been the focus of an collaboration with Robin Smith and Karen Lynch at the crime lab of the Rhode Island State and Lt. Dennis Pincince at the RI State Police Criminal Identification Unit, Professor Beth Zielinski-Habershaw at the University of Rhode Island, and Professor Anubhav Tripathi of fluidic mechanics at Brown. Three platforms are being developed to further basic science research of DNA-nanotube/nanopore interactions and to help speed up the DNA identification process in criminal investigation. The goal on this front is to develop fast, portable, disposable NanoChips (containing sieving nanotube or nanopore arrays) for forensic STR profiling.
Our lab also collaborates with Bharat Ramratnam?ôs team at the Lifespan/ Tufts/ Brown Center for AIDS Research Resesarch (CFAR) at the Miriam Hospital in Providence, RI. This collaboration is focused on infectious disease prevention using carbon nanotubes and other nanomaterials (to be realized in the form of a cream, a pill, or an injection). The hope is to stop the infections at the mucosal lining, where the virus enters the body and the infection begins. So far, we have successfully delivered DNA and fluorophores into rectal tissue in vivo, and are working on delivering siRNA, getting effective oral delivery, and modifying our cargo.
DNA Functionalized Nanotube Array Technology
The Emerging Technology lab leads a multidisciplinary research effort and collaborates with researchers from Brown, Boston College, and Drexel University in developing novel materials designed using DNA nanotechnology. Funded under an Air Force MURI program, the five year grant has delivered technology solutions capable of detecting biological analytes on a nanoelectronic sensor platform. Housing the design, fabrication, and material analysis and processing facilities, this lab is able to tailor highly ordered carbon nanotube arrays geometrical and chemical properties.
Highly ordered arrays of carbon nanotubes whose chemical properties can be used to conjugate nanoparticle labeled DNA. By controlling the location of DNA conjugation sites, gold nanoparticles can be self-assembled to the designated particular spot on a nanotube in an array, and subsequently zinc oxide nanowires can be grown at the site of the gold nanoparticle.
Integrated zinc-oxide carbon nanotube wires were grown atop of the tip of carbon nanotubes selected in accordance with the instruction encoded in the DNA self-assembling process. The resultant Zinc Oxide nanowire ??carbon nanotube heterojunction demonstrates its potential in nano-scale ultra-violet sensing.
Carbon Nanotube Nanoneedles
The Laboratory of Emerging Technologies has been developing a new device based on carbon nanotubes assembled into a nanoneedle. These nanoneedles can be as small as a few nanometers and as long as tens of microns, are mechanically strong, electrically highly conductive, and can be chemically functionalized. These devices could enable intracellular and biomolecular explorations that push the size, volume, and sensitivity limits.
In collaboration with Professor Stephen Helfand of cell biology, we utilized these nanoneedles in glucose detection of sample volumes less than one micro litter. In collaboration with researchers in biochemistry at Boston College and Brown, we are exploiting the use of the nanoneedles for DNA detection. In collaboration with Professor Anubhav Tripathi?ôs group in fluidic engineering and Professor Mierke Dale of molecular biology, we have begun the development of a new platform to enable single protein activity detection.
The Impossible Is Possible: Laser Light from Silicon!
Silicon has made its way into everything from computers to cameras. But a silicon laser? Physically impossible – until now. A Brown University research team led by Jimmy Xu has engineered the first directly pumped silicon laser by changing the structure of the silicon crystal through a novel nanoscale technique. [Read More...]
Sylvain G. Cloutier, Pavel A. Kossyrev, and Jimmy Xu, "Optical gain and stimulated emission in periodic nanopatterned crystalline silicon", Nature Materials, 2005.