A micro-lab on a chip detects blood type within minutes
A novel lab-on-a-chip device reveals the blood type within minutes,
holding much potential for use in an emergency

Date:
July 13, 2020
Source:
Tokyo University of Science
Summary:
The need to first zero in on a blood group can delay blood
transfusions in emergency situations, and this in turn can prove
fatal. Thus, to speed up the process, a team of scientists has
developed a lab-on-a-chip device that can not only tell the blood
type within five minutes but allows medical staff to read the
results through simple visual inspections.



FULL STORY ========================================================================== Blood transfusion, if performed promptly, is a potentially life-saving intervention for someone losing a lot of blood. However, blood comes in
several types, some of which are incompatible with others. Transfusing an incompatible blood type can severely harm a patient. It is, therefore,
critical for medical staff to know a patient's blood type before they
perform a transfusion.


========================================================================== There are four major blood types -- O, A, B, and AB. These types differ
based on the presence or absence of structures called A antigens and B
antigens on the surfaces of red blood cells. Blood can be further divided
into positive and negative types based on the presence or absence of
D antigens on red blood cells. Medical professionals usually tell a
patient's blood type with tests involving antibodies against the A and
B antigens. When antibodies recognize the corresponding antigens, they
bind to them, causing the blood cells to clump together and the blood
to coagulate. Thus, specific antigen-antibody combinations tell us what
the blood type of a blood sample is.

Yet, while the concept sounds straightforward, the equipment and
techniques required are often very specialized. Tests, therefore,
are non-portable, have high personnel cost, and can take over half an
hour to yield results. This can prove problematic in several types of
emergency situations.

Aiming to solve these problems, a team of scientists at Japan's Tokyo University of Science, led by Dr Ken Yamamoto and Dr Masahiro Motosuke,
has developed a fully automated chip that can quickly and reliably
determine a patient's blood type. In the words of Dr Motosuke, he and
his colleagues "have developed a compact and rapid blood-typing chip
which also dilutes whole blood automatically." The chip contains a
micro-sized "laboratory" with various compartments through which the
blood sample travels in sequence and is processed until results are
obtained. To start the process, a user simply inserts a small amount
of blood, presses a button, and waits for the result. Inside the chip,
the blood is first diluted with a saline solution and air bubbles are introduced to promote mixing. The diluted blood is transported to a
homogenizer where further mixing, driven by more intensely moving bubbles, yields a uniform solution. Portions of the homogenized blood solution
are introduced into four different detector chambers. Two chambers each
contain reagents that can detect either A antigens or B antigens. A third chamber contains reagents that detect D antigens and a fourth chamber
contains only saline solution, with no reagent, and serves as a negative control chamber in which the user should not observe any results.

Antigen-antibody reaction will cause blood to coagulate, and by looking
at which chambers have coagulated blood, the user can tell the blood
type and whether the blood is positive or negative.

Further, the user does not require specialized optical equipment to
read the results. The design of the detector chambers allows the easy identification of coagulated blood with the naked eye. The device is
also highly sensitive and can even detect weak coagulation.

During testing, the research team screened blood samples from 10 donors
and obtained accurate results for all 10 samples. The time needed to
determine a single sample's blood type was only five minutes.

Reflecting on the potential benefits of his team's invention, Dr Motosuke remarks, "The advancement of simple and quick blood test chip technologies
will lead to the simplification of medical care in emergency situations
and will greatly reduce costs and the necessary labor on parts of medical staff." Given the highly portable nature of the chip, Professor Motosuke
also speculates that it could be used during aerial medical transport
and in disaster response settings. This is a chip that has the potential
to change the way emergency medical support is given.


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


========================================================================== Journal Reference:
1. Ken Yamamoto, Ryosuke Sakurai, Masahiro Motosuke. Fully-automatic
blood-
typing chip exploiting bubbles for quick dilution and detection.

Biomicrofluidics, 2020; 14 (2): 024111 DOI: 10.1063/5.0006264 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200713120012.htm

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