Lasers Promise to Cut Wait Time for Blood Tests for Deadly Sepsis
Posted on April 13, 2016
Not having to wait 48 to 72 hours for a blood culture when sepsis is suspected could save thousands of lives a year-and research by Duquesne's biomedical engineering program shows the time might be slashed by lasers.
Sepsis-blood poisoning-strikes more than a million Americans each year, killing more than prostate cancer, breast cancer and AIDS combined, reports the National Institutes of Health (NIH).
Generally, doctors prescribe expensive, broad-spectrum antibiotics while waiting for test results, hoping to bolster the immune system's response to infection. But the broad spectrum medications might not be enough to tame the specific reaction that can cause organ failure or lead to blood clots and impaired blood flow.
Research by Dr. John Viator, director of the biomedical engineering program, his students and collaborators, shows that bacteriophages-viruses that infect and flourish within bacteria-are part of an answer.
A phage, which is intent upon reproducing, is formed with a balloon-like structure circled by smaller, attached balloon-like structures called capsids. The capsids are important to replication-and also offer a way to transport color along with the genetic material, Viator said.
Certain phages are specific to certain bacteria, including sepsis. So if sepsis-specific phages that have dye in their capsids are introduced to a blood sample, a zap with a laser can immediately identify if phages are attaching to the partner bacteria. If they are, that demonstrates-without the agonizing wait for a culture-that sepsis is present, Viator explained.
Viator received a $1.4 million, five-year grant from the NIH's National Cancer Institute to refine laser-based photoacoustics to detect melanoma circulating in the blood stream before it metastasizes into a tumor. Similar principles were applied to this work with sepsis, developed in connection in the University of Pittsburgh.
"This is related to the NIH technique, but is a totally different application," said Viator, explaining that the dye carried by the phage absorbs the laser and turns some of the light into a high frequency pulse, so that a visual signal also is returned.
"This is very preliminary work," Viator said. "But if we can identify sepsis earlier and faster, without needing culture time, we could save thousands upon thousands of lives by identifying bacteria cells under a microscope within a couple of hours of having the sample."