Bioceramic Structure-Reactivity Towards T-Lymphocytes and Human Mesenchymal Stem Cells
Speaker: Nita Sahai, University of Wisconsin
Date & Time: November 17, 2009 - 12:10pm
Location: CCR 201
Interfacial Materials Chemistry is an interdisciplinary science focused on understanding the interactions of biological cells and bioorganic molecules with inorganic solid surfaces, from the nano- to micro-meter size range. Our research combines experimental and high-level computational chemistry approaches to understand the physical-chemical forces controlling such interactions, with special emphasis on surface structure contributions. Cellular and biomolecular interactions at inorganic materials and minerals surfaces are relevant to a wide range of processes from tissue engineering and the design of biomaterials to pre-biotic polymerization of organics, the early evolution of bacterial cell membranes, biomineralization, and environmental geochemistry.
In this seminar, I will focus on the results of our cellular experiments at the surfaces of oxide and silicate-based bioceramics, which are used as orthopedic implants and have potential for tissue engineering applications. We have used Atomic Force Microscopy to show that the attachment strength of the Jurkat cell-line of T lymphocytes, a kind of human immune-system cell, at bioceramic surfaces depends on the surface charge or isoelectric point (IEP) of the oxide. The IEP itself is a direct function of ceramic crystal structure and composition. Thus, the early immune cell response to a bioceramic implant may be predicted based on surface chemistry. In another interdisciplinary study, we have used molecular biology, genetic, and surface spectroscopy/microscopy tools to investigate how the crystal structure and surface roughness of calcium silicate (CaSiO3) orthopedic implants control soluble and surface factors that stimulate human mesenchymal stem cells (hMSC) attachment, toxicity, proliferation, and differentiation into osteoblasts (bone-forming cells) with formation of hydroxyapatite (bone-mineral), thus establishing a link between implant crystal structure and its reactivity towards stem cells.
2000-present: Professor, Department of Geoscience; Materials Science Program; Environmental Chemistry and Technology Program, University of Wisconsin-Madison (UW).
1998-2000 NSF Post-Doctoral Research Fellow: Advisor: Prof. John A. Tossell, Department of Chemistry, University of Maryland, College Park. Quantum-chemical investigation of silica and apatite biomineralization mechanisms.
1997-1998 Post-Doctoral Research Associate. Advisor: Prof. Peggy A. O'Day, Arizona State University.
X-ray Absorption Spectroscopy Study of Strontium Adsorption at Oxide and Silicate Surfaces.
1992-1997 Ph.D., Johns Hopkins University, Baltimore, MD. Advisor: Prof. Dimitri Sverjensky.
Solvation and Electrostatic Model for Specific Electrolyte Adsorption.
1990-1992 M.S., Geochemistry, University of Rochester, Rochester, NY. Calibrating the Cosmogenic 21Ne Clock
1987-1990 B.Sc., 1st rank in graduating class, Geology Honors, St. Xavier's College, Bombay University, India
Host: Richard Riman