BUFFALO, N.Y. – Located deep in the human gut, the small
intestine is not easy to examine. X-rays, MRIs and ultrasound
images provide snapshots but each suffers limitations.
Help is on the way.
University at Buffalo researchers are developing a new imaging
technique involving nanoparticles suspended in liquid to form
“nanojuice” that patients would drink. Upon reaching
the small intestine, doctors would strike the nanoparticles with a
harmless laser light, providing an unparalleled, noninvasive,
real-time view of the organ.
July 6 in the journal Nature Nanotechnology, the advancement
could help doctors better identify, understand and treat
“Conventional imaging methods show the organ and
blockages, but this method allows you to see how the small
intestine operates in real time,” said corresponding author
Jonathan Lovell, PhD, UB assistant professor of biomedical
engineering. “Better imaging will improve our understanding
of these diseases and allow doctors to more effectively care for
people suffering from them.”
The average human small intestine is roughly 23 feet long and 1
inch thick. Sandwiched between the stomach and large intestine, it
is where much of the digestion and absorption of food takes place.
It is also where symptoms of irritable bowel syndrome, celiac
disease, Crohn’s disease and other gastrointestinal illnesses
To assess the organ, doctors typically require patients to drink
a thick, chalky liquid called barium. Doctors then use X-rays,
magnetic resonance imaging and ultrasounds to assess the organ, but
these techniques are limited with respect to safety, accessibility
and lack of adequate contrast, respectively.
Also, none are highly effective at providing real-time imaging
of movement such as peristalsis, which is the contraction of
muscles that propels food through the small intestine. Dysfunction
of these movements may be linked to the previously mentioned
illnesses, as well as side effects of thyroid disorders, diabetes
and Parkinson’s disease.
Lovell and a team of researchers worked with a family of dyes
called naphthalcyanines. These small molecules absorb large
portions of light in the near-infrared spectrum, which is the ideal
range for biological contrast agents.
They are unsuitable for the human body, however, because they
don’t disperse in liquid and they can be absorbed from the
intestine into the blood stream.
To address these problems, the researchers formed nanoparticles
called “nanonaps” that contain the colorful dye
molecules and added the abilities to disperse in liquid and move
safely through the intestine.
In laboratory experiments performed with mice, the researchers
administered the nanojuice orally. They then used photoacoustic
tomography (PAT), which is pulsed laser lights that generate
pressure waves that, when measured, provide a real-time and more
nuanced view of the small intestine.
The researchers plan to continue to refine the technique for
human trials, and move into other areas of the gastrointestinal
Additional authors of the study come from UB’s Department
of Chemical and Biological Engineering, Pohang University of
Science and Technology in Korea, Roswell Park Cancer Institute in
Buffalo, the University of Wisconsin-Madison, and McMaster
University in Canada.
The research was supported by grants from the National
Institutes of Health, the Department of Defense and the Korean
Ministry of Science, ICT and Future Planning.