Seminar - Non-Invasive Optics for Evaluation of Skin Damage and Wound Healing
Date: April 17, 2009
Time: 4:00 PM
Location: Matheson Hall, Room: 109
Elisabeth S. Papazoglou, Ph.D.
School of Biomedical Engineering, Science & Health Systems
Chronic wounds are a growing problem as the world’s population ages and the prevalence of diabetes increases. The objective of our group is to non-invasively quantify the wound healing process using optical methods so that wound treatments can be evaluated objectively and rapidly. We have developed a frequency-domain device that uses diffuse near infrared (NIR) light to measure the absorption and reduced scattering coefficients of tissue, which reflect the hemoglobin concentration and oxygenation status of probed tissue at depths ranging from several millimeters to several centimeters. We have tested this device through several animal studies of wound healing in diabetic, obese, and normal rats. The results of the animal studies indicated that NIR data can be used to distinguish impaired from normal healing, and that measured changes in optical absorption and hemoglobin concentration correlate to histological changes in blood vessel density over time. A pilot human study was recently conducted to evaluate the potential of using diffuse NIR to monitor changes in tissue hemoglobin concentration in diabetic foot ulcers. Hemoglobin concentration was measured by our NIR device in 12 human wounds for a period ranging from 10 to 61 weeks. In all wounds that healed completely, gradual decreases in optical absorption coefficient, oxygenated hemoglobin concentration, and total hemoglobin concentration were observed between the first and last measurements. In non-healing wounds, the rates of change of the above properties were nearly zero or slightly positive, and a statistically significant difference (p<0.05) was observed in the rates of change between healing and non-healing wounds. Differences in the variability of NIR measurements over time were observed between healing and non-healing wounds and this variance may also be a useful indicator of non-healing wounds. Our results demonstrate that frequency-domain NIR technology can differentiate healing from non-healing diabetic foot ulcers, and indicate that it may have clinical utility in the evaluation of wound healing potential.
Future work involves the development of a non-contact version of the NIR device so that the probe does not need to come in contact with the wound, the expansion of this technology to burn evaluation, and the use of the device to evaluate novel wound therapies in both human and animal studies. Additionally, we have used other optical technologies such as diffuse reflectance spectroscopy and fluorescence spectroscopy to quantify changes in collagen and skin structure during wound healing in our animal studies, and future research will involve further development of these devices.
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Dr. Elisabeth Papazoglou is a Research Associate Professor in the School of Biomedical Engineering, Science and Health Systems. She holds a Master's in Chemical Engineering from the University of Delaware, where her thesis focused on optimum manufacturing and performance of thin films with chemical vapor deposition. Her Ph.D. work in the Department of Macromolecular Engineering at Case Western Reserve University predicted bulk properties of medium and high molecular weight amorphous polymers based on thermodynamics. Dr. Papazoglou has 14 years of industry experience, working with multi-disciplinary teams on compatibilization and stabilization problems in polymers, and she has developed two laboratories for polymer characterization and controlled delivery formulations. She holds 5 patents and is the author of more than 40 publications and several book chapters in the areas of modeling, stabilization and compatibility.
Dr. Papazoglou's current research at Drexel includes skin research, specifically in the areas of wound healing, deployment of non-invasive technologies for skin characterization, and correlation of spectroscopic and imaging information to skin chemistry.
Matheson Hall is located at 32nd and Market Streets.