Flexible, wearable X-ray detector doesn't require heavy metals

Date:
August 4, 2021
Source:
American Chemical Society
Summary:
X-ray imaging is a fast and painless way for doctors to see
inside a person. But radiation detectors, which go under the
body part being imaged, are rigid panels that contain harmful
heavy metals, such as lead and cadmium. Now, researchers report
a proof-of-concept wearable X-ray detector prepared from nontoxic
metal-organic frameworks (MOFs) layered between flexible plastic
and gold electrodes for high-sensitivity sensing and imaging.



FULL STORY ========================================================================== X-ray imaging is a fast and painless way for doctors to see inside
a person.

But radiation detectors, which go under the body part being imaged,
are rigid panels that contain harmful heavy metals, such as lead and
cadmium. Now, researchers in ACS' Nano Letters report a proof-of-concept wearable X-ray detector prepared from nontoxic metal-organic frameworks
(MOFs) layered between flexible plastic and gold electrodes for high-sensitivity sensing and imaging.


==========================================================================
Most X-ray detectors are integrated into big, immobile instruments,
such as computerized tomography (known as CT) and mammography equipment,
or are stiff, like the sharp-edged bitewing detectors used in dental
offices. Detectors that could conform to rounded body parts or mold to the inside of confined spaces could be beneficial in some radiation monitoring
and medical imaging applications. Previous researchers have used MOFs for flexible radiation detectors because they are semiconducting materials
that respond to electromagnetic radiation by creating an electrical
current. However, some of these MOFs still include lead, just like the
X-ray detectors that are currently in use. So, Shuquan Chang, Shenqiang
Ren and colleagues wanted to create a heavy-metal-free MOF for a flexible
X-ray detector and imager.

The researchers mixed a solution of nickel chloride salt and 2,5- diaminobenzene-1,4-dithiol (DABDT) for several hours, creating a
MOF in which nickel linked the DABDT molecules. In initial tests,
the nickel-containing MOF was more sensitive than recently reported
detectors when irradiated with 20 keV X-rays, equivalent to the energy
released during medical diagnostic imaging.

Then, to make a flexible X-ray radiation detector, the team sandwiched the nickel-containing MOF between gold film electrodes, one of which was on
a flexible plastic surface. They used copper wires to transmit current
from each pixel of a 12x12 array and covered the whole device with a silicone-based flexible polymer. Finally, they placed an aluminum letter
"H" on the detector and irradiated it with X-rays, measuring a much lower current output underneath the H than under the unimpeded material. The researchers say that their proof- of-concept device is promising for the
next generation of radiology imaging equipment and radiation detection
when wearable or flexible devices are needed.

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


========================================================================== Journal Reference:
1. Zheng Li, Shuquan Chang, Haiqian Zhang, Yong Hu, Yulong Huang,
Lu Au,
Shenqiang Ren. Flexible Lead-Free X-ray Detector from Metal-Organic
Frameworks. Nano Letters, 2021; DOI: 10.1021/acs.nanolett.1c02336 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210804123552.htm

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