Written by Abby Vogel

Nanomedicine is an emerging field of engineering and life sciences that promises to revolutionize medicine and medical technology. At Georgia Tech and Emory University, nanomedicine focuses on developing nanoprobes, whose unique properties open the possibility of investigating the dynamics of cellular processes over time and detecting disease in its earliest, most easily treatable, pre-symptomatic stage.

The Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University is the only academic department in the United States to host three National Institutes of Health (NIH) centers focused on nanomedicine. They are:

• The Program of Excellence in Nanotechnology, funded by the National Heart, Lung, and Blood Institute and led by Gang Bao, the Robert A. Milton Chair in Biomedical Engineering and College of Engineering Distinguished Professor;
• The Nanotechnology Center for Personalized and Predictive Oncology, funded by the National Cancer Institute and led by Shuming Nie, The Wallace H. Coulter Distinguished Chair and Director for Nanotechnology and Bioengineering in the Winship Cancer Institute at Emory University; and
• The Nanomedicine Development Center, funded by the NIH Roadmap Initiative in Nanomedicine and led by Bao.

Detecting Cardiovascular Disease

The $11.5 million Program of Excellence in Nanotechnology awarded in April 2005 focuses on creating advanced nanotechnologies to analyze cardiovascular disease, which is commonly caused by plaque buildup in arterial blood vessels. Plaques can rupture and block blood vessels, leading to heart attack or stroke.

The center includes Coulter Department biomedical engineers and Emory University cardiologists Kathy Griendling, David Harrison, Charles Searles, W. Robert Taylor and Wayne Alexander.

“Having the cardiologists involved has been very beneficial – they understand the biological and clinical issues that we need to address with the tools we are engineering,” says Bao.

Researchers in the center aim to develop methods to detect plaque at its early stages. For one project, researchers are testing the use of magnetic resonance imaging (MRI) to detect plaque. By injecting magnetic nanoparticle probes that are designed to accumulate at the plaque site, the location of the buildup can be detected in an MRI scan.

In a similar project, Taylor – a professor in the Coulter Department and Emory’s Division of Cardiology – is using quantum dots, nanometer-scale light-emitting particles that have unique optical properties, to visualize proteins present on the surface of blood vessels when plaques are forming. He observes the quantum dots with two-photon excitation laser scanning microscopy.

Another project, led by Bao, is investigating the use of quantum dots to test blood samples for certain enzymes indicative of the stability of plaques, with the goal of determining if a plaque is about to rupture.

Taylor and Niren Murthy, a Coulter Department assistant professor, are evaluating whether inflammation may be the key to detecting plaque at its early stages. Since artery walls swell and become inflamed when plaques begin to form, the researchers have created nontoxic nanoparticles that allow them to image trace amounts of hydrogen peroxide, which is thought to be overproduced by cells when inflammation is present.

Bringing Cancer into View

The Emory-Georgia Tech Nanotechnology Center for Personalized and Predictive Oncology began in October 2005 and boasts six projects and five support teams that focus on developing nanotechnologies for cancer applications. The amount awarded is expected to reach $27 million over a five-year period, with $19 million from the National Cancer Institute.

Center researchers are developing nanoparticles to image cancer inside the body and examine metastasis. They are also developing probes to study gene expression of cancer cells and treat cancer.

One group of researchers is targeting tumors with surface-enhanced Raman nanoparticle tags. With antibodies, peptides or small molecules attached, these nanoparticles can be used to target malignant tumors with high specificity and affinity. They also shine considerably more brightly than semiconductor quantum dots and can be spectroscopically detected to locate prostate or kidney cancer cells inside the body.

Bao and Barbara Boyan, the Price Gilbert, Jr. Chair in Tissue Engineering and a Georgia Research Alliance Eminent Scholar in Tissue Engineering, are developing novel molecular beacons to study gene expression in cancer cells.

May Dongmei Wang, a Coulter Department assistant professor and Georgia Cancer Coalition Distinguished Scholar, leads a major effort in integrating biological nanotechnology with computing and bioinformatics for personalized medicine.

“A unique strength of this center is that we have broad faculty expertise from translational bioinformatics to clinical oncology, which will allow us to move some of these technologies into clinical trials in the next two to three years,” says Nie.

Repairing DNA

The Nanomedicine Center for Nucleoprotein Machines was awarded in October 2006 and focuses on a nano-sized cellular mechanism that repairs DNA double-strand breaks inside the body. The breaks can be caused by ionizing radiation or ultraviolet light.

The cellular machine, called the non-homologous end-joining complex, has an intrinsic ability to delete, insert and rejoin DNA sequences at the break sites. Researchers at eight institutions are collaborating to better understand the role of each component in the system, the pathway by which it assembles and disassembles, and the signaling and control mechanisms of DNA damage repair.

To track the assembly of the machine’s parts deep within living cells, the researchers are developing new fluorescence probes, protein-tagging strategies, controlled methods of creating double-strand breaks and sensitive high-resolution imaging techniques.

“Our long-term goal is to adapt and redesign these machines to carry out novel functions,” says Bao. “Ultimately, we want to cure common diseases by creating machines that are able to correct genes that are defective in certain people.”

The center will receive between $10 and $12 million from the NIH for five years and almost $3 million from the Georgia Research Alliance, a public-private partnership of Georgia universities, businesses and government created to build the state’s technology industry.