Dr. Gleason's current research interest is in soft tissue biomechanics and growth and remodeling, with particular emphasis on native vascular tissues and tissue engineered constructs. Two key aims of his research are to develop mathematical theories for soft tissue growth and remodeling that allow for the incorporation of observations made at multiple length scales, and to develop novel experimental models to test the underlying assumptions of theoretical simulations that allow for parallel observations at different length scales.
It is unquestioned that cells can sense and respond to changes in loading. Increased load on focal adhesion sites in vascular smooth muscle, for example, can alter cell-signaling pathways, ultimately leading to altered gene expression. Altered gene expression can manifest itself in many different ways, including an altered production of vasoactive molecules, extracellular matrix and matrix-degrading proteins, cell cycle regulating signals, and cytoskeletal proteins, among many others. The net effect of these, and other, mechanotransduction pathways include increases in cell and matrix turnover, local growth (or atrophy), structural and functional remodeling of existing cells, and remodeling of matrix, cell-matrix and matrix-matrix interactions, all aimed, presumably, toward evolving the local mechanical environment from an undesirable' condition to a desirable' condition. Despite the explosion of information on tissue growth and remodeling, from molecular, intracellular, cellular, cell-matrix, organ, and whole organism levels, attempts at integrating these data into a predictive model is still in its infancy; there is a pressing need for such an integrative, multiscale model. Such predictive models will be essential to further our understanding of many physiological and pathophysiological processes and critical to aid in the development and optimization of clinical interventions and tissue engineering strategies.
Dr. Ku has an active interest in peripheral vascular pathology and unsteady, threedimensional fluid dynamics. One project investigates the relative role of hemodynamics and thrombosis in vascular graft occlusion. Additional studies involve the development of a tissue-engineered vascular graft. Noninvasive magnetic resonance imaging is used to determine the hemodynamics and detect pathology in vivo. Computational solutions explore fluid mechanic variations from geometry. Another project studies the collapsible tube behavior of highly stenotic arteries.
Dr. Ku has an active interest in cardiovascular pathophysiology, unsteady threedimensional fluid mechanics, medical implants, and commercialization of university research. Basic research focuses on sudden cardiac death from platelets subjected to high shear and plaque rupture due to arterial stenosis collapse. His research extends to Translational Technology using applied biomedical engineering to impact patient care and therapy. Projects span from device design to development of bench tests to predict clinical performance. Dr. Ku teaches entrepreneurship and product development to bring technological solutions to the bedside.
Dr. Hesketh's research interests are in Sensors and Micro/Nano-electro-mechanical Systems (MEMS/NEMS). Many sensors are built by micro/nanofabrication techniques and this provides a host of advantages including lower power consumption, small size and light weight. The issue of manipulation of the sample in addition to introduce it to the chemical sensor array is often achieved with microfluidics technology. Combining photolithographic processes to define three-dimensional structures can accomplish the necessary fluid handling, mixing, and separation through chromatography. For example, demonstration of miniature gas chromatography and liquid chromatography with micromachined separation columns demonstrates how miniaturization of chemical analytical methods reduces the separation time so that it is short enough, to consider the measurement equivalent to "read-time" sensing.
A second focus area is biosensing. Professor Hesketh has worked on a number of biomedical sensors projects, including microdialysis for subcutaneous sampling, glucose sensors, and DNA sensors. Magnetic beads are being investigated as a means to transport and concentrate a target at a biosensor interface in a microfluidic format, in collaboration with scientists at the CDC.
His research interests also include nanosensors, nanowire assembly by dielectrophoresis; impedance based sensors, miniature magnetic actuators; use of stereolithography for sensor packaging. He has published over sixty papers and edited fifteen books on microsensor systems.
Our laboratory conducts research into how information about the outside world is encoded by the patterns of spiking neurons in the sensory pathways of the brain. We combine experimental and computational approaches to better understand and control aspects of the neural code. Specifically, we focus on the visual and somatosensory pathways at the junction between the sensory periphery and sensory cortex. Our experimental approaches include multi-site, mutli-electrode recording, optical imaging, behavior, and patterned stimulation. Our computational approaches include linear and nonlinear model estimation, information theory, observer analysis, and signal detection and discrimination. Our long-term goal is to provide surrogate control for circuits involved in sensory signaling, for pathways injured through trauma or disease.
Quantitative Evolutionary Genetics. After 15 years working on genomic approaches to complex traits in Drosophila, my group has spent much of the past 10 years focusing on human quantitative genetics. We start with the conviction that genotype-by-environment and genotype-by-genotype interactions are important influences at the individual level (even though they are almost impossible to detect at the population level). We use a combination of simulation studies and integrative genomics approaches to study phenomena such as cryptic genetic variation (context-dependent genetic effects) and canalization (evolved robustness) with the main focus currently on disease susceptibility.
Immuno-Transcriptomics. As one of the early developers of statistical approaches to analysis of gene expression data, we have a long-term interest in applications of transcriptomics in ecology, evolution, and lately disease progression. Since blood is the most accessible human tissue, we’ve examined how variation is distributed within and among populations, across inflammatory and auto-immune states, and asked how it relates to variation in immune cell types. Our axes-of-variation framework provides a new way of monitoring lymphocyte, neutrophil, monocyte and reticulocyte profiles from whole peripheral blood. Most recently we have also been collaborating on numerous studies of specific tissues or purified cell types in relation to such diseases as malaria, inflammatory bowel disease, juvenile arthritis, lupus, and coronary artery disease.
Predictive Health Genomics. Personalized genomic medicine can be divided into two domains: precision medicine and predictive health. We have been particularly interested in the latter, asking how environmental exposures and gene expression, metabolomic and microbial metagenomics profiles can be integrated with genome sequencing or genotyping to generate health risk assessments. A future direction is incorporation of electronic health records into genomic analyses of predictive health. Right now it is easier to predict the weather ten years in advance than loss of well-being, but we presume that preventative medicine is a big part of the future of healthcare.
Manufacturing, Mechanics of Materials, Bioengineering, and Micro and Nano Engineering. Advanced manufacturing and materials processing of metallic, polymeric, ceramic, and composite materials for applications in life sciences, propulsion, and energy.
Professor Das directs the Direct Digital Manufacturing Laboratory and Research Group at Georgia Tech. His research interests encompass a broad variety of interdisciplinary topics under the overall framework of advanced design, prototyping, direct digital manufacturing, and materials processing particularly to address emerging research issues in life sciences, propulsion, and energy. His ultimate objectives are to investigate the science and design of innovative processing techniques for advanced materials and to invent new manufacturing methods for fabricating devices with unprecedented functionality that can yield dramatic improvements in performance, properties and costs.
The biomechanics of locomotion of organisms and robots on and within complex materials. Physics of granular media.
My research integrates my work in complex fluids and granular media and the biomechanics of locomotion of organisms and robots to address problems in nonequilibrium systems that involve interaction of matter with complex media. For example, how do organisms like lizards, crabs, and cockroaches cope with locomotion on complex terrestrial substrates (e.g. sand, bark, leaves, and grass). I seek to discover how biological locomotion on challenging terrain results from the nonlinear, many degree of freedom interaction of the musculoskeletal and nervous systems of organisms with materials with complex physical behavior. The study of novel biological and physical interactions with complex media can lead to the discovery of principles that govern the physics of the media. My approach is to integrate laboratory and field studies of organism biomechanics with systematic laboratory studies of physics of the substrates, as well as to create mathematical and physical (robot) models of both organism and substrate. Discovery of the principles of locomotion on such materials will enhance robot agility on such substrates.
Biomechanics, mechanobiology, glaucoma, ophthalmology, osteoarthritis, regenerative medicine
Biomechanics and mechanobiology, glaucoma, osteoarthritis, regenerative medicine, intraocular pressure control, optic nerve head biomechanics.
We work at the boundaries between mechanics, cell biology and physiology to better understand the role of mechanics in disease, to repair diseased tissues, and to prevent mechanically-triggered damage to tissues and organs. Glaucoma is the second most common cause of blindness. We carry out a range of studies to understand and treat this disease. For example, we are developing a new, mechanically-based, strategy to protect fragile neural cells that, if successful, will prevent blindness. We are developing protocols for stem-cell based control of intraocular pressure. We study the mechanobiology and biomechanics of neurons and glial cells in the optic nerve head. We also study VIIP, a major ocular health concern in astronauts. Osteoarthritis is the most common cause of joint pain. We are developing paradigms based on magneto-mechanical stimulation to promote the differentiation and (appropriate) proliferation of mesenchymal stem cells.