Article by Xu Research Group Cited as Most-Accessed in Prestigious Journal

An article by Old Dominion University chemist and biochemist Xiao-Hong Nancy Xu and her research group has been named by the American Chemical Society journal ACS Nano as one of its "most-accessed" for 2007.

The article, "In Vivo Imaging of Transport and Biocompatibility of Single Silver Nanoparticles in Early Development of Zebrafish Embryos," reports major advances in the use of single nanoparticles as optical biosensors that are about one-millionth the size of a pencil point and could aid in the creation of anticancer vaccines. The article was published in September 2007.

Xu said her research group is exploring the potential of nanoparticles to be imaging and therapeutic agents and hopes to develop an effective and inexpensive in vivo model system to screen biocompatibility and toxicity of nanomaterials. The ACS Nano article reports the group's initial successes in using nanoparticles for diagnostic and therapeutic imaging, while simultaneously evaluating the biocompatibility and toxicity of the nanoparticle probes.

The article reveals that silver nanoparticles showed potential therapeutic effects, as well as toxicity. The findings indicate that organisms in the wild might be affected by nanoparticles that get into rivers and other bodies of water.

Lead authors of the article are Kerry J. Lee and Prakash D. Nallathamby; co-authors include Lauren M. Browning. All three are graduate students working toward their Ph.D. degree in biomedical sciences under the direction of Xu. Christopher J. Osgood, ODU associate professor of biological sciences, a collaborator of Xu, is also a co-author; Xu is the corresponding author of the paper.

Nanoparticles described in the article literally light up living cells and embryos, and allow scientists using a well-designed imaging system (named as SNOMS) developed in the Xu lab to spy on functioning cells and the see the effects of nanoparticles on the cells. Using the inherent brightness and color of individual silver nanoparticles, Xu's imaging system is able to characterize nanometer sizes of individual nanoparticles in real-time, and to trace individual nanoparticles as they are transported through pores and canals into the embryo.

These innovations helped Xu and her group win a 2007 Nanotech Brief Nano 50th award from NASA.

Immediately after publication of the ACS Nano article, summaries of the research findings began appearing on science news Web sites. "I did not expect…the instantaneous positive response from so many colleagues around the world, and media sources hoping to feature this work," Xu said at the time.

Richard Gregory, chair of ODU's Department of Chemistry and Biochemistry, noted that an article about Xu's work was featured in October 2007 on the Nanowerk.Com site and added, "Her work is getting a lot of attention, and deservedly so. She and her group are taking nanoparticle research to new and exciting places."

Beginning about eight years ago, Xu, an associate professor of chemistry and biochemistry at ODU, reported research findings that placed her in the vanguard of scientists using very tiny optical sensors to study living cells. She currently has grants totaling more than $2.5 million from the National Science Foundation and the National Institutes of Health to support her work.

Xu was named in a 2006 article prepared by the National Cancer Institute as a pioneering developer of nanotechnology that can be used in the war against cancer. The article, titled "Mission to the Inside of a Living Cell," noted the benefits of studying biochemical reactions inside live cells, rather than dead cells. Similar studies in the past were conducted with dead cells or purified biomolecules extracted from cells. The article also gave the Xu group high marks for producing silver nanoparticles that are exceedingly bright and do not photodecompose.

Now the Xu group has taken these imaging tools one step further and demonstrated the possibility of imaging living embryos. Zebra fish and humans have genetic and drug-target-site similarities that make the fish particularly useful in research concerning the treatment of human diseases. In addition, zebra fish are small, inexpensive and well-suited for whole-animal studies.