51视频

01/24/2017
By Edwin L. Aguirre

Recent advances in optics research hold out promise for a new tool to detect early onset of epithelial ovarian cancer from just a single drop of a patient鈥檚 blood.

Noureddine Melikechi, dean of the Kennedy College of Sciences, and researchers from Delaware State University, the Fox Chase Cancer Center in Philadelphia and the University of Toulouse in France have developed a technique that uses intense pulses of laser to break down the blood sample to search for biomarkers. Biomarkers are measurable substances in the patient鈥檚 blood produced by the tumor or surrounding tissues whose presence is indicative of the disease.

The technique, called 鈥渢ag laser-induced breakdown spectroscopy,鈥� or Tag-LIBS, can quickly and precisely detect and identify biomarkers associated with epithelial ovarian cancer, which involves the cells covering the outer lining of the ovaries.

鈥淭he Tag-LIBS approach is a relatively easy and inexpensive way to test for ovarian cancer. It鈥檚 sensitive, accurate and, unlike a biopsy, it鈥檚 non-invasive,鈥� says Melikechi. 鈥淚f we can detect the biomarkers early enough, before the cancer has a chance to spread beyond the ovaries, then the patient鈥檚 survival rate could increase [from 45 percent] to 90 to 95 percent.鈥�

A Challenging Disease

鈥淒espite intensive research efforts, early detection and diagnosis of ovarian cancer remains a significant challenge,鈥� says Melikechi. In the United States, approximately 22,000 women are diagnosed with the disease each year. Ovarian cancer is the leading cause of death among gynecological cancers, claiming about 14,000 lives annually.

鈥淭he cancer typically develops without specific symptoms,鈥� notes Melikechi. 鈥淭herefore, the majority of cases are discovered when the disease is already at an advanced stage. Hence, successful early detection and diagnosis would be particularly useful for improving prognosis and decreasing the mortality rate.鈥�

In the Tag-LIBS method, researchers 鈥渢ag鈥� a specific protein biomarker 鈥� called cancer antigen 125 鈥� with metal microparticles. This allows them to track the biomarker and find out whether that biomarker exists in the blood even at the very lowest concentration possible (down to the parts-per-million level), indicating the presence of the cancer.聽

To accomplish this, the researchers vaporize the blood samples using powerful infrared laser pulses, creating a cloud of charged particles. An instrument called a spectrograph records the light emitted by the particles for analysis. Using special algorithms, the investigators process the data to look for telltale signs of the metal microparticles.聽

The method was successfully tested in lab mice, and the results were published in September in the journal 鈥淪pectrochimica Acta.鈥� Melikechi鈥檚 cancer research is supported with grants from the National Science Foundation and NASA.

鈥淧rof. Melikechi is internationally recognized as one of the key leaders in the emerging field of laser-induced breakdown spectroscopy, especially as a pioneer in the use of Tag-LIBS for the sensitive and accurate detection and identification of ovarian cancer biomarkers,鈥� says Andrzej W. Miziolek, a retired research physicist at the U.S. Army Research Laboratory and renowned expert in applied spectroscopy who is a longtime collaborator of Melikechi. 鈥淭he beauty of his technique is that it opens the door to detect, simultaneously, multiple biomarkers in a single laser pulse.鈥�

LIBS has the potential for widespread impact on everything, from rapid analysis of drinking water for toxic elements to food safety and verifying the authenticity of food products, Miziolek says.

Explorer of Mars

The LIBS technique is also being used to analyze the surface composition of Mars. NASA鈥檚 robotic rover, named 鈥淐uriosity,鈥� is equipped with , an instrument that fires intense pulses of laser on distant rocks, boulders or soil. The resulting flash of light is picked up by ChemCam鈥檚 built-in telescope and fed to a spectrometer, which breaks down the light into its component colors. An onboard computer identifies the different chemical elements present in the target rock, and the data is transmitted to Earth for analysis.

Image by NASA

Melikechi has been involved with ChemCam鈥檚 data analysis. He has also been selected as a member of the science team for the next robotic Mars rover mission, which is scheduled to launch in 2020.

A Scientist of Light

In October, Melikechi was elected a fellow of the Optical Society of America (OSA), the leading professional association in optics and photonics founded in 1916, in recognition of his 鈥減ioneering scientific, technological and educational contributions to optics, including novel methodologies in laser-induced breakdown spectroscopy for space exploration and cancer diagnosis.鈥� The number of elected fellows each year is limited to approximately 0.5 percent of the OSA鈥檚 membership, which totals more than 19,000 in 100 countries.

鈥淚鈥檓 truly honored by this recognition from my peers and for being inducted into this very select group,鈥� says Melikechi, who first joined the OSA as a graduate student in the early 1980s. 鈥淭his doesn鈥檛 happen just because of my efforts. It鈥檚 the result of the effort, support and encouragement of many, many people over the years. This is their accomplishment more than mine.鈥�

鈥淒r. Melikechi鈥檚 work represents the type of creative, interdisciplinary research we seek to foster here at 51视频,鈥� says Julie Chen, vice chancellor for research and innovation. 鈥淭o achieve the success he has, Noureddine clearly has the ability to lead and work as part of a team. 聽This, as well as his enthusiasm for educating the next generation, will all be talents that we know he will impart to faculty and students as the new dean of the Kennedy College of Sciences.鈥�