AUSTIN, Texas—A team of engineers from The University of Texas at Austin has developed a promising new process for binding tiny semiconductor crystals known as nanocrystals or “quantum dots” to nerve cells. Their technology could lead to advances in biomedical products ranging from hearing aid implants to robotic prosthetics.
Professor of Biomedical Engineering Christine Schmidt, an expert in neuro-cell culture and nerve engineering, and Brian Korgel, a chemical engineering professor whose specialty is growing nanocrystals, reported the results of their yearlong collaboration in the Nov. 16 issue of Advanced Materials. Doctoral candidate Jessica Winter and senior chemical engineering student Timothy Liu performed key research in both professors’ laboratories.
|Pictured here is the magnification of quantum dot attachment to neurons using antibody (A, B) and peptide (C, D) binding techniques. In B and D, the blue color is the self-fluorescence of the cell’s cytoplasm and the yellow/orange color is the quantum dot luminescence.|
The researchers succeeded in making cadmium sulfide quantum dots about one-four thousandth the width of a human hair in diameter stick one-on-one to human brain neurons, using a short protein chain called a peptide as a tether. That involved modifying what Korgel describes as a “standard chemistry recipe” by substituting the single peptide for two much longer protein antibodies.
Schmidt said most work in the realm of biological-electronic interfaces to date has involved comparatively large silicon-based electrodes and larger tissue areas. “Our goal was to gain more molecular specificity, to target specific receptors on the cell surface,” she said. The next challenge will be to establish communication between the biological and non-biological systems. Because the dots are semiconductors, they become active in the presence of an electrical field.
Korgel said the few previous efforts by other research groups to attach quantum dots to human cells have concentrated strictly on silicon-based dots intended for use as inert dyes. “But we’re working toward putting these quantum dots on nerve cells and then generating local electrical fields that will influence the cells to ‘talk’ to the dots,” he said.
Once that kind of communication is achieved, quantum dots eventually could function as the interface between a wide array of new microelectronic biomedical applications, including pioneering prosthetic limbs and the neural cells of the people using them, the researchers said.
The work was supported by the National Science Foundation, the Welch Foundation, Dupont, the Petroleum Research Fund, the Gillson Longenbaugh Foundation and the Whitaker Foundation.