Start
Feb 27, 2012 - 16:00
End
Feb 27, 2012 - 17:00
Venue
Room 118 (Creativity Hall) Ground Floor Chemical Engineering Department
Event Type
Speaker
Dr. Amit Dutta NRC Postdoctoral Research Associate National Institute of Standards and Technology 100 Bureau Drive Gaithersburg MD 20899 USA.
Title
Macromolecules at Solid-Liquid Interfaces
Abstract: Engineering a surface for desired properties is very important for many industrial and medical applications. The rational design of a surface requires fundamental understanding of the interactions between macromolecules and solid-liquid interfaces. The mechanical properties of an adsorbed layer are important factors for assessing the behavior of surfaces. The goals of the research described here are (i) to develop a new method to study protein cross-liking (ii) to control the rheological properties of a surface for use as a biosensor. Increasing the stability of proteins and polypeptides via cross-linking is commonly used to minimize bio-fouling and to increase the life time of enzymes. Determining the extent of cross-linking using say glutaraldehyde is often accomplished by noting changes in viscosity that require large amounts of sample at high concentration. Here we have implemented a highly sensitive quartz crystal microbalance with dissipation (QCM-D) technique to address this limitation. On the other hand to use a surface for sensor applications we should be able to control its physico-chemical properties. We have developed a counter-ion responsive-poly(L-lysin) (PLL)-based surface the viscoelastic properties of which can be reversibly controlled. In principle this controllable PLL molecule could be used as an ionic gate for drug delivery. The second part of my presentation will be on development of a surface plasmon resonance (SPR) based method to analyze glycosylation of monoclonal antibody. Current analytical methods for characterizing glycosylation such as high performance liquid chromatography and mass spectrometry are capable of rigorously determining composition sequence linkage and stereoisomerism of glycans. Although powerful techniques they are time consuming and require considerable expertise. In this work lectins were immobilized on a self assembled monolayer (SAM) of HS-(CH2)_11-(OCH2CH2)_6-OCH_2-COOH and the interactions between lectins concanavalin A (ConA) wheat germ agglutinin (WGA) peanut agglutinin (PNA) and rituximab were analyzed using SPR. We found that covalent attachment of ConA to the SAM first followed by adsorption of rituximab results in reversible binding. In contrast covalent attachment of rituximab first followed by adsorption of ConA resulted in irreversible adsorption of ConA. In summary we have focused our attention on macromolecules at solid-liquid interfaces and measured the protein/polypeptide-surface interactions in order to engineer surfaces with particular properties for specific applications.