Painless paper patch test for glucose levels uses microneedles

Date:
September 14, 2020
Source:
Institute of Industrial Science, The University of Tokyo
Summary:
Researchers have developed a microneedle patch for monitoring
glucose levels using a paper sensor. The device painlessly monitors
fluid in the skin within seconds. Anyone can use the disposable
patch without training, making it highly practical. Additionally,
fabrication is easy, low cost, and the glucose sensor can be
swapped for other paper-based sensors that monitor other important
biomarkers.



FULL STORY ========================================================================== Patches seem to be all the rage these days. There are birth control
patches, nicotine patches, and transdermal medicinal patches, just
to name a few. Now, a team of researchers led by Beomjoon Kim at the
Institute of Industrial Science, The University of Tokyo have developed
a patch of needles connected to a paper sensor for diagnosing conditions
such as prediabetes. Luckily, this patch doesn't multiply the pain and discomfort of a single hypodermic needle. In fact, these microneedles
are painless and biodegradable.


========================================================================== Researchers have been trying to develop a practical way to use
microneedles - - tiny needles less than 1 mm in length -- for routine do-it-yourself medical monitoring. Microneedles are so short that they
stay within the skin and do not make contact with any neurons, meaning
that they cause no pain. Rather than extracting blood, they draw up fluid
in the skin that contains most of the important biomarkers that blood
tests look for. Several types of microneedles exist, but until now,
making a practical device that quickly analyzes the fluid has proved
elusive. "We have overcome this problem by developing a way to combine
porous microneedles with paper-based sensors," says Kim. "The result is low-cost, disposable, and does not require any additional instruments."
To make the patch, the researchers first made the microneedles by pouring
a melted mixture of a biodegradable polymer and salt into the cone-shaped cavities of a micro-mold while applying heat. Then they flipped the mold
and needles upside down and placed them on top of a piece of paper,
this time applying high pressure from above. The high pressure forced
the mixture into the pores of the paper, securing the attachment and
allowing fluid drawn through the needles to pass effortlessly into the
paper. After removal from the mold, the needles were cooled in a solution
that sucked out all the salt, leaving behind thousands of holes, or pores, which are what the fluid flows through on its way to the paper. The salt concentration was a key factor they needed to optimize, testing several concentrations of salt to determine how porous the microneedles should
be. To finish the patch, they used double-sided tape to attach a paper
glucose sensor onto the paper base of the needle array.

The team tested the patch on an agarose gel in which glucose had been dissolved. Fluid from the gel flowed from the gel into the porous
microneedles, and from there into the paper and the sensor layer. The
glucose concentration was accurately recorded as color changes in
the paper.

The patches are disposable, biodegradable, and using them does not
require any medical expertise or training. They are also biocompatible,
meaning that there is no problem if any remain in the skin when the
patch is removed.

"Of course, prediabetes testing is just one application of the
technology," says first author Hakjae Lee. "The paper-based sensor
can vary depending on the biomarker you wish to monitor." After this
success, the next step will be to test the practicality of the device
with human participants and to develop configurations for monitoring other substances, and in turn, determining the presence of other conditions.


========================================================================== Story Source: Materials provided by Institute_of_Industrial_Science,_The_University_of_Tokyo.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Hakjae Lee, Gwenae"l Bonfante, Yui Sasaki, Nobuyuki Takama, Tsuyoshi
Minami, Beomjoon Kim. Porous microneedles on a paper for screening
test of prediabetes. MEDICAL DEVICES & SENSORS, 2020; 3 (4) DOI:
10.1002/ mds3.10109 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200914095848.htm

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