Past Nano@Tech News
2008
May 27, 2008
Nano@Tech Meeting
Dr. Richard Brown, the Dean of the College of Engineering at the University of Utah gave a presentation entitled "Electrochemical Neurosensor Systems."
Abstract:
Arrays of silicon neurosensors that detect both electrical signals and neurotransmitter levels in human neuron cultures have been fabricated. Neurochemical sensing of dopamine and its metabolites is provided by voltammetry. Five versions of the passive device were fabricated with platinum working electrode areas as small as 4 mm2 and silver/silver chloride pseudo-reference electrodes. Living human neuron cultures survived and produced data on passive devices throughout a study period of seventy-five days. Calibration curves for dopamine taken in culture media with equipment optimized for the sensors suggests detection limits for dopamine below 100 nM.
To minimize system noise, prototype devices incorporating active circuitry were developed. The active devices are formed by post-processing standard foundry-fabricated CMOS circuits from the MOSIS service to form the sensor-specific features. Data from these devices, and early results from in vivo electrochemical neurosensors, will be presented. Circuits developed for these active brain probes and for other implantable biosensors highlight several goals of circuits for biological applications: small system size; small electronics size, low voltage, and low power.
May 13, 2008
Nano@Tech Meeting
Dr. Michael Fonseca, Ph.D., the Director of Operations & Engineering at CardioMEMS gave a presentation entitled " Development of Implantable Wireless Pressure Sensors for Chronic Disease Management."
Abstract:
CardioMEMS is a medical device company that has developed and is commercializing a proprietary wireless sensing and communication technology for the human body. Our technology platform is designed to improve the management of severe chronic cardiovascular diseases such as heart failure and aneurysms. Our miniature wireless sensors can be implanted using minimally invasive techniques and transmit cardiac output, blood pressure and heart rate data that are critical to the management of patients. Due to their small size, durability, and lack of wires and batteries, our sensors are designed to be permanently implanted into the cardiovascular system. Using radiofrequency (RF) energy, our sensors can transmit real-time data to an external electronics module, which then communicates this information to the patient’s physician.
April 22, 2008
Nano@Tech Meeting
Kurt Pennell, an associate professor in the School of Civil and Environmental Engineering here at Georgia Tech, gave a presentation entitled "Transport and Retention of Nanoscale C-60 Aggregatess in Water-Saturated Porous Media."
Abstract:
Experimental and mathematical modeling studies were performed to investigate the transport and retention of fullerene nanoparticles (n-C60) in water-saturated porous media. Eight experiments were conducted in glass columns packed with either 40-50 mesh glass beads or Ottawa sand. Following pulse injections of solutions containing 1 to 3 mg/L of n-C60 aggregates (95 nm dia.) applied at a Darcy velocity of 2.8 m/d, media were extracted to obtain particle retention profiles. In the presence of 1.0 mM CaCl2, n-C60 effluent breakthrough curves gradually increased to a maximum value and then decreased sharply upon re-introduction of n-C60-free solution. Retention of n-C60 in the glass bead columns ranged from 8 to 49% of the introduced mass, while up to 77% of the injected mass was retained in Ottawa sand columns. This retention behavior was consistent with the delayed breakthrough observed in the Ottawa sand columns and was corroborated by batch retention data.
In the absence of background electrolyte, effluent n-C60 concentrations coincided with those of a non-reactive tracer (Br-), demonstrating the important role that electrostatic interactions play in n-C60 transport.
Effluent concentration and retention profile data were accurately simulated using a numerical model that incorporated a retention term to account for n-C60 attachment kinetics and a limiting retention capacity.
April 8, 2008
Nano@Tech Meeting
Peter Kottke, a research engineer in the School of Mechanical Engineering here at Georgia Tech, gave a presentation entitled "Scanning Mass Spectrometry (SMS) Probe."
Abstract:
He described the SMS probe, a tool currently under development for mass spectrometric imaging of live biological samples in vitro. In order to obtain spatially resolved images of chemical species distributions in vitro, an ion source is needed that samples from a small volume of liquid. The SMS probe is based on a novel approach to electrospray ionization (reverse-Taylor-cone electrospray), which requires a reversal of orientation of conventional electrospray ionization (ESI) sampling. Electrospray ionization mass spectrometry (ESI-MS) has the advantage of providing a means for transferring large biological molecules directly from solution into the gas phase under atmospheric pressure. The unique advantages of the reverse-Taylor-cone ionization concept are the minimum and highly localized (in space) sample volume (i.e., high resolution) that is being probed and, most importantly, its unique suitability for use in scanning probe chemical imaging applications, including imaging biological samples under physiological conditions (i.e., in aqueous solution).
March 25, 2008
Nano@Tech Meeting
Clint Wimbish, an Associate at Kilpatrick Stockton, LLP gave a presentation entitled "Technology Transfer and Aspects of Patentability - Commercializing Nanotechnology."
Abstract:
Technology transfer is the critical process of capturing discoveries and innovations in the laboratory and turning such discoveries and innovations into useful applications for the benefit of society. In this seminar, the technology transfer process was discussed in relation to the field of nanotechnology. In addition to the technology transfer process, various aspects of patentability were discussed with a focus on nanotechnology. Practical tips for protecting inventions in view of United States and international patent laws were also covered.
March 11, 2008
Nano@Tech Meeting
Prof. Ali Adibi, an associate professor in the School of Electrical and Computer Engineering here at Georgia Tech, gave a presentation entitled "Novel Silicon Nanophotonic Structures for Ultra-compact Integrated Lab-on-a-chip Sensing."
Abstract:
The development of ultra-compact and sensitive sensing structures with minimal sample requirement for accurate sensing have been of great recent interest for multiple applications including bio and environmental sensing, chemical agent detection, and bio- threat detection. With recent advancement in the development of design and fabrication tools for photonic nanostructures, integrated photonic platforms are a strong candidate for the development of such sensing structures.
In this talk, Prof. Ali Adibi first presented the requirements for the development of photonic lab-on-a-chip sensing structures. Then he explained how these requirements are met by two recent developments in our group in the area of silicon photonics, i.e., ultra-high Q micro-resonators, and ultra-compact photonic crystal on-chip spectrometers with orders of magnitude smaller size compared to the other implementations with the same performance. These spectrometers are enabled by dispersion engineering in photonic crystal to simultaneously achieve the superprism effect, negative diffraction, and negative refraction. Details of the design of such structures along with their experimental demonstrations will be presented.
February 12, 2008
Nano@Tech Meeting
Prof. Carson Meredith, an associate professor in the School of Chemical and Biomolecular Engineering here at Georgia Tech, gave a presentation entitled "High-Throughput Screening of Advanced Polymeric Materials."
Abstract:
In this talk Professor Meredith reviewed recent advances in the high-throughput screening of polymers for advanced materials. Two applications were reviewed: proton exchange membranes (PEM) and biomaterials for cell adhesion and growth. After decades of research the essential requirements of successful PEMs are understood reasonably well. But still, even with design information available, there are millions of potential candidate materials: more than can be reasonably evaluated experimentally. A new approach for searching this space of materials more efficiently would lead to PEMs with significantly better performance-to-price characteristics. This talk reviewed a combinatorial screening system that integrates synthesis of sample libraries based on composition gradients, high-throughput screening of conductivity, mechanical properties, and transport properties. A significant challenge encountered in high-throughput research and development of organic and polymeric materials is the reproducible preparation of combinatorial libraries with programmed variations in composition. A number of examples of discrete and gradient library preparation techniques have been presented in the literature, which were reviewed in this talk.
The application of these novel techniques to polymeric biomaterials was also covered. The HTS protocol has been utilized to discover microphase-separated patterns that enhance cell attachment and proliferation for osteoblasts (bone). Informatics processing and models that enable optimization of large materials data sets was also discussed in reference to biomaterials screening.
January 22, 2008
Nano@Tech Meeting
Dr. Christine Kranz, a senior research scientist in the School of Chemistry and Biochemistry here at Georgia Tech, gave a presentation entitled "Introduction to Focused Ion Beam Technology and its Application."
Abstract:
Within the last decade Focused Ion Beam technology has developed from a routine semiconductor tool into a versatile research instrument for characterization and prototyping. A major step towards the convergence of nanotechnology and nanoscience is the development and utilization of technologies, which allow precise patterning and assembly of features at a nanoscale. Dual beam FIB/SEM technology provides unsurpassed control and resolution during milling, deposition, and characterization at the nanoscale, thereby enabling high-resolution 3-D prototyping, machining, and structuring crucial to the development of next-generation functional nanodevices. An unambiguous advantage of FIB technology is the possibility for maskless milling and deposition processes. Application of FIB technology includes failure analysis, circuit repair and mask repair in microelectronics and TEM sample preparation. Recently, FIB has been also used in fabrication of scanning probe tips, optical devices and sensor technology. Nanostructuring using focused ion beams is governed by different parameters given by the beam profile, by the angle of incidence, by ion species, ion dose, and energy, and by the structural and chemical change of the sample by ion implantation.
Within this presentation an overview of this technology along with novel applications but also limitations were presented.