Edwin L. Aguirre
Cancer is one of the leading causes of death among children and adults in the United States, according to the U.S. Centers for Disease Control and Prevention. The good news is that, due to medical advances, people are living longer after being diagnosed with cancer.
The key to increasing patients’ survival rate is early screening for cancerous cells or tumors so appropriate treatment, therapy or surgery can be implemented immediately.
A team of researchers led by Soumitra Satapathi, a Ph.D. candidate in the Department of Physics and Applied Physics and a researcher at UMass Lowell’s Center for Advanced Materials, has developed a novel method of examining cancer cells in the laboratory that could someday help in the early detection and diagnosis of the disease.
“Our technique provides a unique way for non-invasive, high-contrast imaging of cancer cells,” he says. “This process can potentially be extended as a tool to replace conventional endoscopy and colonoscopy procedures.”
Other faculty/staff researchers involved in the study include Prof. Jayant Kumar, Asst. Prof. Dhimiter Bello, Lian Li and Lynne Samuelson as well as biomedical engineering graduate student Anoop Pal and researcher Suresh Gadde from Brigham and Women’s Hospital.
Using Laser to Make Nanoparticles Glow
Obtaining 3-D optical images of cancer cells in a living body has always posed a serious challenge for scientists, says Satapathi.
“Biological tissues strongly scatter light, making deep, high-resolution imaging using traditional fluorescence technique almost impossible,” he explains. “Our method overcomes this limitation.”
The team first places semiconducting polymer nanoparticles (measuring billionths of a meter) in a petri dish containing live leukemia cells. The nanoparticles get absorbed by the cells mainly through the diffusion process. Using powerful, femtosecond pulses of laser, the team is then able to excite the nanoparticles, causing them to “fluoresce,” or glow, inside the cells.
“The nanoparticles emit light by the ‘two-photon fluorescence’ phenomenon, making them detectable with high precision,” says Satapathi. “Biocompatibility tests show that these water-soluble nanoparticles are non-toxic to human cells.”
The quality of the image of cancer cells is much better than those obtained using a conventional confocal microscope, he says.
“Our research opens up the possibility of using the two-photon fluorescence technique as a high-contrast imaging tool for the efficient detection of cancer cells,” says Satapathi. “Our future project involves combining anticancer drugs with this platform so it can both image cancer cells and deliver drugs to the affected area.”
More multidisciplinary work needs to be carried out, however, before any clinical human testing can be done, especially when dealing with new contrast agents, such as polymer nanoparticles. Challenges that need to be addressed include assessing the long-term acute and prolonged toxicity and accumulation of nanoparticles in healthy organs and the inherent difficulties in making precise, targeted delivery of the nanoparticles to the affected organ(s).