Feb. 4, 2013 A new platform to support and extend the viability of proteins for scientific study has been developed through work done as part of the doctoral studies of a recent University of Alabama in Huntsville doctoral graduate.
Working at UAHuntsville as part of a research team under the guidance of collaborator Dr. John D. Williams, Assistant Professor of Electrical and Computer Engineering and Associate Director of the Nano Micro Devices Center, Khalid Tantawi developed a new porous silicon structure on which to place transmembrane proteins.
A Jordanian who studied in France and is a newly minted UAHuntsville doctoral graduate in electrical engineering (August 2012), Dr. Tantawi said that when biologists wanted to study transmembrane proteins in the past, they put them on sol gel or mica based structures. Compared to the older method, the new structure better maintains the functions of the proteins, extending research time, and allows greater access to them for study. "We are trying to create an environment as close as possible to the native environment."
In living organisms, transmembrane proteins reside in cell membranes and regulate ions that pass into and out of the cell. In this gatekeeper function, transmembrane proteins can play key roles in the cellular uptake of drugs.
"The impact of this is huge because you can make better drugs," Dr. Tantawi said. "The problem with the proteins is that they are very complex and they exist in an even more complex environment."
"The science is remarkable. Growing and electrochemically testing membranes and proteins across a porous silicon template has never been done before," said Dr. Williams, who conducts scientific inquiry with the multidisciplinary approach used when he worked at Sandia National Laboratories in New Mexico. "We have devices on a chip that we have measured to within 5 percent of values obtained by biologists in living organisms."
Protein functionality is determined by its chemistry as well as geometry, which in turn is sensitive to environment such as temperature, acidity or even presence of foreign surfaces, all of which affect the protein's viability. Using the porous silicon structure addresses these issues and also provides means for study from both sides of the structure. Silicon is an ideal material because it is biocompatible, biodegradable, has luminescent properties and can be made porous -- all of which better facilitate protein study.
The process involves creating the structure, depositing a lipid membrane bilayer onto it and then fusing the proteins to that layer. In cellular processes, proteins residing in lipid membranes "are so important that one-third of the human genome is used to engineer them," Dr. Tantawi said.
Project partners included professors from the University of Salamanca in Spain, who trained Dr. Tantawi on making the protein deposits; the University of Alabama at Birmingham, which provided the proteins; and Oakwood University in Huntsville, which trained Dr. Tantawi to use its atomic force microscope for observations.
"Each of them provided equipment and trained me on using it," Dr. Tantawi said. "Collaboration is really important. Not many researchers can find this large a collaborative environment. At UAH, we can work with many universities."
The work has appeared in a peer-reviewed publication, Journal of Medical Engineering and Technology, Vol. 37 no. 1, pp. 28-34 (2012). A second article is currently under review, and the third is being finalized now.
The availability of a cleanroom facility and a scanning electron microscope in the Optics Building on campus were significant aids to his progress, Dr. Tantawi said. "The facilities are very important. We have all the equipment we need. The university's administrative support through the research grants of the Office of the Vice President for Research was also invigorating "
Now a faculty member at Motlow State Community College's Smyrna Center in Tennessee, Dr. Tantawi visits UAHuntsville often and remains involved in research with Dr. Williams.
"Khalid came to me because he had an interest in what I do. He wanted to work in small scale devices and I offered him the chance to make these platforms," said Dr. Williams, who added that learning how to interact and exchange ideas was the one overarching lesson for his student besides the engineering, "He's the type of person who wanted to do it. I'm the type of person who had knowledge, ideas and connections to help him achieve his goals. Khalid not only learned science and engineering, but also how to collaborate independently with other people."
Dr. Tantawi credits Dr. Williams and UAHuntsville with encouraging his sense of exploration and broadening his initial aerospace engineering interests into other fields of inquiry.
"At UAH, I had the opportunity to do any kind of research I liked," he said. "With the University of Alabama System, there is also the opportunity to collaborate with other universities in the state. The teamwork has been very efficient."
Watch a video of Dr. Khalid Tantawi producing porous silicon: http://www.youtube.com/watch?v=iZuTe65K_vw
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- Khalid Hasan Tantawi, Ramon Cerro, Bakhrom Berdiev, M. Elena Diaz Martin, Francisco Javier Montes, Darayas Patel, John D. Williams. Investigation of transmembrane protein fused in lipid bilayer membranes supported on porous silicon. Journal of Medical Engineering & Technology, 2013; 37 (1): 28 DOI: 10.3109/03091902.2012.733056
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