During emergencies, blood transfusions can be delayed by the need to first identify the exact blood group. At times, this can even prove fatal.
Therefore, to accelerate the process, a research team from Tokyo University of Science, Japan, has created a lab-on-a-chip device that not only detects blood type within five minutes but also enables medical staff to read the results with simple visual inspections.
If performed quickly, blood transfusion is a potentially life-saving intervention for patients who have lost a lot of blood. But there are several groups of blood, a few of which are incompatible with others. Transfusion of an incompatible blood type could prove harmful to a patient. Thus, it is crucial for medical staff to identify the blood type of a patient before a transfusion is performed.
O, A, B, and AB are the four major blood groups. These groups vary based on the presence or absence of the so-called A antigens and B antigens on the surfaces of red blood cells. Blood can be further classified into positive and negative types, based on whether or not D antigens are present on red blood cells.
In general, medical professionals identify the blood group of a patient through tests that involve using antibodies against the A and B antigens. Upon identifying the corresponding antigens, the antibodies bind to them, making the blood cells to clump together, which results in the coagulation of blood. Thus, particular antigen-antibody combinations indicate the blood type of a blood sample.
However, the concept might sound straightforward, but the techniques and equipment needed are usually very specialized. Thus, tests are non-portable, incur high personnel costs, and can require more than half an hour to yield results. This could be problematic in various types of emergency conditions.
To address these issues, a team of researchers from Japan’s Tokyo University of Science, headed by Dr Ken Yamamoto and Dr Masahiro Motosuke, has created a completely automated chip with the potential to reliably and rapidly identify the blood type of a patient. According to Dr Motosuke, he and his colleagues “have developed a compact and rapid blood-typing chip which also dilutes whole blood automatically.”
The chip includes a micro-sized “laboratory” containing different compartments through which the blood sample passes in sequence and is processed until results can be obtained. A user starts the process by simply inserting a small amount of blood. Then, a button is pressed and the user waits for the result. The blood is first diluted within the chip using a saline solution, and air bubbles are introduced to boost the mixing process.
The diluted blood is then sent to a homogenizer to obtain a uniform solution through further mixing, which is achieved by bubbles that move more intensely. Portions of the homogenized blood solution are then inserted into four different detector chambers.
Two of the chambers contain reagents with the ability to detect either A antigens or B antigens. A third chamber includes reagents that can detect D antigens. A fourth chamber includes only saline solution, without any reagent, and acts as a negative control chamber where the user should not see any results.
Due to the antigen-antibody reaction, the blood gets coagulated, and by observing the chambers that contain coagulated blood, users can identify the blood type and whether the blood is positive or negative.
Moreover, the user does not need specialized optical equipment to interpret the results. The design of the chambers of the detector enables easy identification of coagulated blood with the naked eye. Furthermore, the device is highly sensitive and can detect even weak coagulation.
As part of the testing, the researchers screened blood samples from 10 donors and achieved accurate results for all the samples. The time required to identify the blood type of a single sample was just five minutes.
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.
Dr Masahiro Motosuke, Tokyo University of Science
Dr Motosuke reflected on the potential advantages of his group’s invention.
As the chip is highly portable, Professor Motosuke also proposes that it could even be used in disaster response settings and during aerial medical transport. This is chip could transform how emergency medical support is administered.
Yamamoto, K., et al. (2020) Fully-automatic blood-typing chip exploiting bubbles for quick dilution and detection. Biomicrofluidics. doi.org/10.1063/5.0006264.
A Lab on a Chip That Detects Blood Type Within Minutes
In emergency situations that require blood transfusion, waiting to determine the blood type can be a life-threatening problem. Currently used blood type detection technology is expensive, bulky, and specialized, and can take over half-an-hour to produce results. Can there be a faster way to tell the blood type? And can technology have a role to play? Video Credit: Tokyo University of Science.