Micro-lab on a chip can detect blood type within minutes

Written by Rhiannon Finnie

A team of researchers from Tokyo University of Science (Japan) have developed a compact fully automated chip that can rapidly and reliably determine a patient’s blood type.  This technology could be used to assist medical professionals with quickly identifying a patient’s blood type which is necessary for various life-saving interventions, such as blood transfusions.

Medical professionals currently identify which of the four major blood types (i.e., O, A, B and AB) a patient’s blood is with tests relating to antibodies against A and B antigens that are found on red bloods cells. However, this technology is currently expensive, non-portable and can take over half an hour to complete a test. This can be problematic for patients requiring blood transfusions in emergency situations. Similarly, administering an incompatible blood type can be severely harmful, or even fatal, to a patient.

In response to this problem, the team from Tokyo University of Science developed their blood-typing chip.  This chip contains various compartments through which a blood sample travels in sequence until results are attained.  To begin, a small sample of blood is inserted into the chip and the user presses a button.  Inside the chip, the blood is first diluted with saline solution and air bubbles are introduced to promote mixing.  The diluted sample is then transported to a homogenizer in which further mixing occurs, promoted by more moving air bubbles, until a uniform solution is achieved.  At the bottom of the device, portions of the homogenized blood solution are then introduced into four detector chambers.  Two of these chambers each contain reagents that can detect either A or B antigens.  A third chamber contains reagents that detect D antigens and the fourth chamber contains only saline solution to act as a negative control.

Within the chambers, antigen-antibody reactions will cause the blood sample to coagulate.  The user can then determine the patient’s blood type and whether the blood is categorized as positive or negative by eye. Unlike previous tests, the user does not require specialized optical equipment to read these results. Additionally, the device is reported to be highly sensitive and can detect even weak coagulation.

For their results, recently published in Biomicrofluidics, the team screened blood samples from 10 donors and reported accurate results for all samples.  Of note, the test only requires 5 minutes to determine the blood type, compared to previous tests which required at least 30 minutes.

Masahiro Motosuke, team lead from Tokyo University of Science, concluded: “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.” The team hopes their technology will be useful for aerial medical transport and in disaster response settings and believes their chip has the ability to change the way emergency medical support is given.

Sources: Yamamoto K, Sakurai R, Motosuke M. Fully-automatic blood-typing chip exploiting bubbles for quick dilution and detection. Biomicrofluidics 14, 024111 (2020); www.tus.ac.jp/en/mediarelations/archive/20200713_2345.html

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