The focus of the Biomaterials Research Laboratory is to understand microscopic processes that bring about macroscopic changes in material properties. The lab employs a number of spectroscopic techniques to evaluate the production of free radicals in sterilized implants. This work has led to changes in the manufacturing processes used by the orthopedic industry. Over the last decade, the lab has expanded to provide analytical services for most of the world's orthopedic manufacturers.
The laboratory has a state-of-the-art Electron Spin Resonance (ESR) Radical Analyzer (Bruker Instruments). The ESR technique is unique in its ability to elucidate molecular defect sites in various materials, which are often pre-cursors to material property degradation. The laboratory also employs a number of optical emission and spectroscopic techniques, including UV/VIS/NIR spectrophotometry, thermoluminescence and radiation-induced emission. These experimental techniques can be carried out at material temperatures from 25 to 500 Kelvin.
These powerful scientific tools allow researchers to put together a fundamental understanding of material behavior in various environments. The ultimate result is a predictive model that can be used to improve man-made materials like those used in hip and knee joint replacements. Researchers work closely with colleagues at Los Alamos National Laboratory, providing experimentation and expertise to assist with the US Nuclear Stockpile Stewardship program.
- Electron Spin Resonance (ESR)
- Bruker EMX with cryogenic and elevated sample temperature control (150 K to 400 K)
- Varian E4 EPR Spectrometer with cryogenic sample control (15 K to 300 K)
- ESR can directly detect free radicals. A free radical is a molecule with one or more missing electrons causing it to become highly reactive. Free Radicals can speed up oxidation and aging.
- Optical Spectroscopy
- UV/VIS/NIR Spectrophotometry
- Measures the wavelengths of light absorbed or transmitted through a material, which helps to describe its molecular structure.
- Optical Emission
- Radioluminescence, Fluorescence, Phosphorescence
- Thermally Stimulated Luminescence (Thermoluminescence)
- Luminescence is emission of light. Thermoluminescence is a form of luminescence that is exhibited by materials when previously absorbed energy from electromagnetic radiation or other ionizing radiation is re-emitted as light when the material is heated. This is a good method to determine if something has been exposed to certain quantities of radiation, or to determine how old something is.
- Environmental Simulation
- High-energy X-Ray for irradiation (50kV, 40mA source)
- Gamma- and Ebeam-irradiation through third-party contractor
- Cryogenic to elevated temperatures
- Plasma Cleaner
- Plasma treatment involves the modification of surfaces and the removal of impurities and contaminants. Gases such as argon and oxygen are used. The plasma is created by using high frequency voltages to ionize the gas.
Analytical Services for Industry and Research Institutions
The Physics department has a wealth of analytical resources that can be applied to industrial Research and Development projects on a fee-for-service basis. For example, faculty and researchers support various industrial organizations in the fields of polymer research and orthopedics like Cambridge Polymer Group, Smith & Nephew Orthopedics, Wright Medical Technologies, Inc., and a host of others. All information is kept completely confidential to preserve the proprietary intellectual property interests.
Research in free radicals is applied in areas such as medical devices, artificial joints, sunscreen products, and a range of agricultural applications. Application of free radical research also involves studying the amount of radiation exposure, such as from a nuclear reactor incident like that in Japan.
Examples of Analytical Services:
- Quantification of Free Radical Concentration in crosslinked and conventional polyethylene
- Characterization of the reflectivity properties in tanning lotion formulae using optical Absorption/Transmission/Reflection measurements
Examples of Ongoing Projects
- Free Radicals in Biomaterials
- Polyethylene components of hip and knee replacements
- Polyurethane binder in nuclear stockpile materials
- Polymer aging
- Surface modification and sterilization effects in biomaterials
Collaborators and Affiliates
- University of Memphis Biosurface Center
- Los Alamos National Lab
- Smith & Nephew
- Cambridge Polymer Group, Inc.
- Massachusetts General Hospital
- Wright Medical
For more information, please contact Dr. M. Shah Jahan at firstname.lastname@example.org or 901.678.2620.