Symposium speakers 2015: Piotr Walczak

Neuro X is the title and theme for the May 1 symposium hosted by Johns Hopkins Institute for NanoBioTechnology. The event kicks off with a continental breakfast at 8 a.m. in the Owens Auditorium, between CRB I and CRB II on the Johns Hopkins University medical campus. Talks begin at 9 a.m. Posters featuring multidisciplinary research from across many Hopkins divisions and departments will be on display from 1 p.m. to 4 p.m.

One of this year’s speakers is Piotr Walczak, MD, PhD.

Piotr Walczak, MD, PhD

Piotr Walczak, MD, PhD

Piotr Walczak is an assistant professor in the Johns Hopkins School of Medicine Russell H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance (MR) Imaging. He specializes in magnetic resonance research and neuroradiology with an emphasis on stem and progenitor cell transplantation. Dr. Walczak received his MD in 2002 from the Medical University of Warsaw in Poland. He then completed a research fellowship in cell-based therapy for neurodegenerative disorders at the University of South Florida. After a fellowship in cellular imaging at Johns Hopkins University School of Medicine, Dr. Walczak joined the faculty of Johns Hopkins in 2008. He is an affiliated faculty member at the Kennedy Krieger Institute’s F.M. Kirby Research Center and the Institute for Cell Engineering.

Dr. Walczak’s research focuses primarily on noninvasively monitoring the status of stem and progenitor cells transplanted into the disease-damaged central nervous system. Stem cells are labeled with MR contrast agents, such as iron oxide nanoparticles, to precisely determine the position of the cells after transplantation. By modifying the cells using bioluminescence and MR reporter genes, as well as the use of specific promoter sequences, Dr. Walczak is working to extract information about cell survival and differentiation.

Additional speakers will be profiled in the next few weeks. To register your poster and for more details visit http://inbt.jhu.edu/news/symposium/

For all press inquiries regarding INBT, its faculty and programs, contact Mary Spiro, mspiro@jhu.edu or 410-516-4802.

Nanotech checks on transplanted cell survival

Researchers at Johns Hopkins are using nanotechnology to track the survival and location of transplanted cells. The device, based on nanoscale ph sensors and imaging via magnetic resonance, could help improve outcomes from cell replacement therapies used for conditions such as liver disease or type 1 diabetes.

Cartoon showing nanoscale probe used to detect pH change caused by death of transplanted cell. (McMahon/Nature Materials)

Cartoon showing nanoscale probe used to detect pH change caused by death of transplanted cell. (McMahon/Nature Materials)

“This technology has the potential to turn the human body into less of a black box and tell us if transplanted cells are still alive,” says Mike McMahon, Ph.D., an associate professor of radiology at the Johns Hopkins University School of Medicine principal investigator on the study. “That information will be invaluable in fine-tuning therapies.”

Transplanted cells often fall victim to assault from the body’s immune system, which sees the news cells as foreign invaders. Says McMahon,  “once you put the cells in, you really have no idea how long they survive.”

When cells die there is a change in the acidity nearby. Using this fact, the researchers developed a nanoparticle sensor that could both sense the change in pH and be detected via MRI. The team tested the sensors on mice and found they they were able to track the location of surviving transplanted cells and determine the proportion that had survived.

“It was exciting to see that this works so well in a living body,” says research fellow Kannie Chan, Ph.D., the lead author on the study, which was published in Nature Materials. This should take a lot of the guesswork out of cell transplantation by letting doctors see whether the cells survive, and if not, when they die,” Chan says. “That way they may be able to figure out what’s killing the cells, and how to prevent it.”

Chan works in the laboratory of Jeff Bulte, Ph.D., the director of cellular imaging at Johns Hopkins’ Institute for Cell Engineering. Bulte and McMahon collaborated on the study. Additional authors include Guanshu Liu, Xiaolei Song, Heechul Kim, Tao Yu, Dian R. Arifin, Assaf A. Gilad, Justin Hanes, Piotr Walczak and Peter C. M. van Zijl, all of the Johns Hopkins University School of Medicine. McMahan, Bulte, Gilad, Hanes and van Zijl are all affiliated faculty members of Johns Hopkins Institute for NanoBioTechnology.

Funding for this study was provided by the National Institute of Biomedical Imaging and Bioengineering (grant numbers R01 EB012590, EB015031, EB015032 and EB007825).

Follow this link to read the paper, MRI-detectable pH nanosensors incorporated into hydrogels for in vivo sensing of transplanted-cell viability, in Nature Materials online http://www.nature.com/nmat/journal/vaop/ncurrent/abs/nmat3525.html