PITA Fiscal Year 2009 Projects - Product and Process Design and Optimization

Exploration of the Discovery of Enantiospecific Electrokinetic Interaction between Amino Acids and Quartz

Principal Investigators: Paul J Sides, Andrew J Gellman

Chiral chemistry profoundly affects living organisms. Chiral purity is an important scientific and technological goal. Evidence of chiral recognition leads improvement in manufacture, detection, separation, and meeting places for single enantiomers. Chiral recognition between chiral molecules and surfaces is a basis for sensing, separation, or synthesis. With the aid of a scientific instrument invented at CMU and spun off to a Pennsylvania company, the ZetaSpin zeta potential measuring system of ZetaMetrix Inc, it has been discovered that the electrostatic environment at the interface between single crystal quartz and aqueous histidine reflects chiral recognition. The zeta potential of the (001) plane of S-quartz in contact with 400 molar Lhistidine is 20 mV ± 5 mV less negative at a pH of 7.1 than the zeta potential of S-quartz in contact with the same concentration of D-histidine. The electrokinetic results are remarkable evidence that quartz is enantiosensitive, but questions remain about whether the effect has commercial potential as a principle for separating the enantiomers of racemic mixtures or as the basis of a sensor. The goals of this project are to investigate whether other amino acids than histidine display the same effect and whether the discovery is more suitable as a basis for separation or sensing. The specific work of the project is experimentation with the ZetaSpin instrument with combinations of quartz and a range of amino acids. A quartz crystal microbalance, specially modified to allow exposure of the quartz through a network electrode, also will be used to probe the extent of adsorption of the amino acid. The ZetaSpin instrument indicates interaction, but not the amount adsorbed. Success in this project will help ZetaMetrix Inc expand its market from being a small manufacturer of an arcane instrument to an industrial supplier.