Fall 2006
In This Issue:
Focus On Optical Materials
Visiting Faculty Scientist Helps Glass Research Group Immobilize Biomolecules on a Glass Surface for High-Volume Sensors
Low-cost, highly sensitive biologicall and chemical sensors are important tools for many different applications, including biodiagnostics, food quality control, detection of toxic chemicals in the water supply, as well as to detect pathogens in blood. Some optical sensors using visible light have been developed, but the infrared, because of its longer wavelength, is better suited to this type of sensing. Infrared evenescent waves are capable of penetrating up to 200 times more deeply than wavelengths of viisible light, making it possible to probe larger particles, especially large biomolecules.
Thee Pantano group uses glass waveguides coated with a chalcogenide film for infrared sensors. Most biological and chemical agents have characteristic absorption bands in the infrared. Gemanium-based chalcogenide glasses have low absorption in the IR, are relatively inexpensive, and unlike many sensor materials, have low toxicity. This makes them an appealing choice for industrial use.
"In addition to their excellent optical properties, chalcogenide glasses can be intergrated into otherr opto-electronic devices or can be used to guide light with optical circuits. You could have these devices in an area of concern, say a water supply, and you can continuously send light through them to moniitor the safety of the water, to test for toxins, and never have a human involved. It's cheap monitoring, remote sensing," says Joe Ryan, a graduate student in the Pantano group.
The difficulty the researchers encountered is that it is hard to immobilize biomolecules on germanium. Raul Martin-Palma, a visiting faculty scientist from Universidad Autonoma de Madrid, in Spain, has developed a method that he wants to adopt for the types of glasses the Pantan group is using. His method, he says, has already been used successfully on metals, semiconductors, and some kinds of glass.
As a short-term reseach scholar, Dr. Martin-Palma will spend the summer working with the Pantano group, as well as Penn State biologists, and with Lehigh Univeristy glss scientist Himanshu Jain, co-principal investigator with Pantano in the NSF's International Materials Institure New Functionality in Glass. "I first got in touch with Dr. Jain who introduced me to Dr. Pantano," says Martin-Palma. "The best thing about Penn State is that you can collaborate with many different groups and other universities. Also, the Pantano group has internationally recognized expertise in the field of optical materials for application in the infrared."
Martin-Palma hopes that by the time he returns to his teaching duties in the fall, he will have helped Penn State scientists create a more functional biomolecular sensor.
R.J. Martin-Palma is coauthor of Nanotechnology for Microelectronics and Opteolectronics, published by Elsevier. He is a fulll professor of applied pysics at Universidat Autonoma de Madrid.
