Fluorescent spray lights up tumors for easy detection during surgery


Date:
October 13, 2021
Source:
American Chemical Society
Summary:
The prognosis for a cancer patient who undergoes surgery is
better if the surgeon removes all of the tumor, but it can be
hard to tell where a tumor ends and healthy tissue begins. Now,
scientists report that they have developed a fluorescent spray that
specifically lights up cancerous tissue so it can be identified
readily and removed during surgery.



FULL STORY ==========================================================================
The prognosis for a cancer patient who undergoes surgery is better if
the surgeon removes all of the tumor, but it can be hard to tell where
a tumor ends and healthy tissue begins. Now, scientists report in ACS
Sensors that they have developed a fluorescent spray that specifically
lights up cancerous tissue so it can be identified readily and removed
during surgery.


========================================================================== Surgeons often use sight and touch to identify cancerous tissue, but
this approach can miss small tumors, as well as diseased cells at the
margins between a tumor and healthy tissue. Fluorescence-guided surgery
is an emerging technology that could enhance this difference. The method
relies on fluorescent probes that target cancerous tissue and heighten its visibility. But some of these compounds must be administered many hours
or days before surgery - - sometimes necessitating a long hospital stay
-- and they might not reveal tiny tumors. In addition, these compounds
can require a large dose if they're injected, or a washing step to get
rid of excess dye if they're applied to the tumor site. So Ching-Hsuan
Tung and colleagues set out to develop a fluorescent probe to rapidly
visualize diseased tissue, even on a small scale, when sprayed on a
surgical site or injected.

The researchers started with a compound they had previously designed
that remains nearly invisible at the neutral pH of healthy tissue, but fluoresces brightly in the near-infrared range in the acidic environment
of tumors. That initial compound linked a pH-sensitive amino group with
a cyanine fluorophore.

It worked when injected, but didn't produce a signal when applied as
a spray, so the team replaced some of its methyl groups with isopropyl
groups. That made the new compound more responsive to the acidic tumor environment. When sprayed, it delineated tumor edges in mice within
minutes, without the need for washing.

And when injected in the abdomen of mice, it illuminated ovarian
tumors as small as 1 mm in diameter in an hour. The researchers say
the compound could enhance a surgeon's ability to visualize and remove cancerous tissue.

The authors acknowledge funding from the National Institutes of
Health. Tung and other authors are co-inventors of a patent application
for the fluorescent spray. Two of the authors are employees of Molecular Targeting Technologies Inc.

========================================================================== Story Source: Materials provided by American_Chemical_Society. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ching-Hsuan Tung, Myung Shin Han, Zhenhua Shen, Brian D. Gray,
Koon Y.

Pak, Jianguang Wang. Near-Infrared Fluorogenic Spray for Rapid
Tumor Sensing. ACS Sensors, 2021; DOI: 10.1021/acssensors.1c01370 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211013114049.htm

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