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Biotechnology development for biomedical applications

Rempe, Susan B.; Rogers, David M.; Buerger, Stephen P.; Kuehl, Michael; Hatch, Anson; Abhyankar, Vinay V.; Mai, Junyu M.; Dirk, Shawn M.; Brozik, Susan M.; De Sapio, Vincent; Schoeniger, Joseph S.

Sandia's scientific and engineering expertise in the fields of computational biology, high-performance prosthetic limbs, biodetection, and bioinformatics has been applied to specific problems at the forefront of cancer research. Molecular modeling was employed to design stable mutations of the enzyme L-asparaginase with improved selectivity for asparagine over other amino acids with the potential for improved cancer chemotherapy. New electrospun polymer composites with improved electrical conductivity and mechanical compliance have been demonstrated with the promise of direct interfacing between the peripheral nervous system and the control electronics of advanced prosthetics. The capture of rare circulating tumor cells has been demonstrated on a microfluidic chip produced with a versatile fabrication processes capable of integration with existing lab-on-a-chip and biosensor technology. And software tools have been developed to increase the calculation speed of clustered heat maps for the display of relationships in large arrays of protein data. All these projects were carried out in collaboration with researchers at the University of Texas M. D. Anderson Cancer Center in Houston, TX.

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TYPE SAND Report YEAR 2010
DOIOSTI

Ion rejection by nanoporous membranes in pressure-driven molecular dynamics simulations

Journal of Computational and Theoretical Nanoscience

Leung, Kevin; Rempe, Susan B.

We perform pressure-driven non-equilibrium molecular dynamics (MD) simulations to drive a 1.0 M NaCI electrolyte through a dipole-lined smooth nanopore of diameter 12 A penetrating a model membrane. We show that partial, about 70-80%, CI- rejection is achieved at a ~68 atmosphere pressure. At the high water flux achieved in these model nanopores, which are particularly pertinent to atomistically smooth carbon nanotube membranes that permit fast water transport, the ion rejection ratio decreases with increasing water flux. The computed potential of mean force of Cl- frozen inside the nanopore reveals a barrier of 6.4 kcal/mol in 1.0 M NaCI solution. The Cl- permeation occurs despite the barrier, and this is identified as a dynamical effect, with ions carried along by the water flux. Na +-CI- ion-pairing or aggregation near the pore entrance and inside the pore, where the dielectric screening is weaker than in bulk water, is critical to Cl- permeation. We also consider negative charges decorating the rim and the interior of the pore instead of dipoles, and find that, with sufficient pressure, CI- from a 1.0 M NaCI solution readily passes through such nanopores. © 2009 American Scientific Publishers.

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TYPE Journal Article YEAR 2009
OSTIScopusOSTIScopus

Exploiting interfacial water properties for desalination and purification applications

Cygan, Randall T.; Jiang, Ying B.; Alam, Todd M.; Brinker, C.J.; Bunker, B.C.; Leung, Kevin; Nenoff, Tina M.; Nyman, May D.; Ockwig, Nathan O.; Orendorff, Christopher; Rempe, Susan B.; Singh, Seema S.; Criscenti, Louise; Stevens, Mark J.; Thurmer, Konrad; Van Swol, Frank B.; Varma, Sameer; Crozier, Paul; Feibelman, Peter J.; Houston, Jack E.; Huber, Dale L.

A molecular-scale interpretation of interfacial processes is often downplayed in the analysis of traditional water treatment methods. However, such an approach is critical for the development of enhanced performance in traditional desalination and water treatments. Water confined between surfaces, within channels, or in pores is ubiquitous in technology and nature. Its physical and chemical properties in such environments are unpredictably different from bulk water. As a result, advances in water desalination and purification methods may be accomplished through an improved analysis of water behavior in these challenging environments using state-of-the-art microscopy, spectroscopy, experimental, and computational methods.

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TYPE SAND Report YEAR 2008
OSTIDOI
Results 151–175 of 196
Results 151–175 of 196
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