An Automatic Lab-on-Disc System for Blood Typing

Microfluidics-Based Blood Typing Devices: An In-Depth Overview

Identification of correct blood types holds paramount importance in understanding the pathophysiological parameters of patients, therapeutic interventions, and blood transfusion. Considering the wide applications of blood typing, the requirement of centralized laboratory facilities is not well suited on many occasions. In this context, there has been a significant development of such blood typing devices on different microfluidic platforms. The advantages of these microfluidic devices offer easy, rapid test protocols, which could potentially be adapted in resource-limited settings and thereby can truly lead to the decentralization of testing facilities. The advantages of pump-free liquid transport (i.e., low power consumption) and biodegradability of paper substrates (e.g., reduction in medical wastes) make it a more preferred platform in comparison to other microfluidic devices. However, these devices are often coupled with some inherent challenges, which limit their potential to be used on a mass commercial scale. In this context, our Review offers a succinct summary of the recent development, especially to understand the importance of underlying facets for long-term sustainability. Our Review also delineates the role of integration with digital technologies to minimize errors in interpreting the readouts.

A portable point-of-care testing device for forward blood typing with hemophilia diagnosis

This paper presents a portable point-of-care testing (POCT) device to conduct simultaneous and on-site tests of ABO and Rh(D) forward blood typing and hemophilia diagnosis using only a small amount of human whole blood sample. The POCT device consisted of a spinning module, a measuring circuit, an interdigitated electrode (IDE) for hemophilia diagnosis, and three disposable microfluidic chips for bioassays with anti-A, anti-B, and anti-D, respectively, and measurement of the concentration of factor VIII. Agglutination will occur if red blood cells (RBCs) are exposed to the corresponding antibody. To evaluate the degree of RBC agglutination, a linear sweep voltage, ranging from - 0.5 to + 0.5 V, was applied to the electrodes of the microfluidic chip and the resulting current was measured. For different levels of agglutination, the measured I-V curves were explicitly discriminated, providing five clinical levels from non-agglutination (level 0) to strong agglutination (level 4). The quantitative norm obtained from cubic fitting function of each I-V curve served as the criterion to represent this agglutination level. The ABO blood type was determined by both agglutination levels of the blood sample reacting with anti-A and anti-B. The degree of agglutination with anti-D gave the Rh(D) type. Moreover, the concentration of factor VIII was detected for the determination of hemophilia. Without requiring expensive equipment, this POCT device is especially suitable for usage in emergency or natural disasters to provide quantitative testing in rescue and relief operations.

Irregular Antibody Screening Using a Microdroplet Platform

The screening procedure for antibodies is considered the most tedious among the three pretransfusion operations, i.e., ABO and Rhesus (Rh) typing, irregular antibody screening/identification, and crossmatching tests. The commonly used screening method for irregular antibodies in clinics at present is a manual polybrene test (MP). The MP test involves numerous reagent replacement and centrifuge procedures, and the sample volume is expected to be relatively less. Herein, screening red blood cells (RBCs) and serum irregular antibodies are encapsulated in microdroplets with a diameter of ~300 μm for a hemagglutination reaction. Owing to the advantage of spatial limitation in microdroplets, screening RBCs and irregular antibodies can be directly agglutinated, thereby eliminating the need for centrifugation and the addition of reagents to promote agglutination, as required by the MP method. Furthermore, the results for a large number of repeated tests can be concurrently obtained, further simplifying the steps of irregular antibody screening and increasing accuracy. Eight irregular antibodies are screened using the proposed platform, and the results are consistent with the MP method. Moreover, the volume of blood samples and antibodies can be reduced to 10 μL and 5 μL, respectively, which is ten times less than that using the MP method.

Novel blood typing method by discrimination of hemagglutination and rouleaux using an erythrocyte aggregometer

BACKGROUND: In pretransfusion blood typing, pretreatments such as centrifugation and suspension of red blood cells (RBCs) and mixing them with sufficient amounts of reagents are required, but these steps are time-consuming and costly. OBJECTIVE: Aiming to develop a new blood typing method that requires no dilution and only a small amount of reagent, we attempted to determine blood type using syllectometry, an easy-to-use and rapid optical method for measuring the RBC aggregation that occurs when blood flow is abruptly stopped in a flow channel. METHODS: Samples of whole blood from 20 healthy participants were mixed with antibody reagents for blood typing at mixing ratios of 2.5% to 10% and measured with a syllectometry device. RESULTS: Amplitude (AMP), one of the aggregation parameters, showed significant differences between agglutination and non-agglutination samples at mixing ratios from 2.5% to 10%. Although there were significant individual differences in aggregation parameters, calculation of AMP relative to that of blood before reagent mixing reduced the individual differences and enabled determination of blood type in all participants. CONCLUSIONS: This new method enables blood typing with a small amount of reagent, without the time-consuming and labor-intensive pretreatments such as centrifugation and suspension of RBCs.

Effective Optical Image Assessment of Cellulose Paper Immunostrips for Blood Typing

Novel high-performance biosensing devices, based on a microporous cellulose matrix, have been of great interest due to their high sensitivity, low cost, and simple operation. Herein, we report on the design and testing of portable paper-based immunostrips (IMS) for in-field blood typing in emergencies requiring blood transfusion. Cellulose fibrils of a paper membrane were functionalized with antibodies via supramolecular interactions. The formation of hydrogen bonds between IgM pentamer and cellulose fibers was corroborated using quantum mechanical calculations with a model cellulose chain and a representative amino acid sequence. In the proposed immunostrips, paper with a pore size of 3 µm dia. was used to enable functionalization of its channels with antibody molecules while blocking the red blood cells (RBC) from channel entering. Under the optimized test conditions, all blood types of AB0 and Rh system could be determined by naked eye examination, requiring only a small blood sample (3.5 µL). The durability of IgM immunostrips against storing has been tested. A new method of statistical evaluation of digitized blood agglutination images, compatible with a clinical five-level system, has been proposed. Critical parameters of the agglutination process have been established to enable future development of automatic blood typing with machine vision and digital data processing.

Fully-automatic blood-typing chip exploiting bubbles for quick dilution and detection

A compact, fully-automatic blood-typing test device is developed. The device conducts sequential processes of whole-blood dilution, homogenization, and reaction with reagents. The lab-on-a-chip device can detect the weakest reaction between red blood cells (RBCs) and reagents even without using optics such as a camera and detector. This high sensitivity is achieved by implementing 50-μm-thick reaction chambers in which a clear contrast between the RBC agglutinations and non-reacted RBCs can be obtained. The dilution and the homogenization are enhanced by injecting bubbles into the microchannel so that the test result can be obtained 5 min after the test start. With an assumption that the device will be used by medical staffs, the device is designed to require minimum operation for the users, namely, loading whole blood, starting pumps, and looking inside the reaction chambers by their eyes to observe the test result. As the device is applicable to the cross-matching test by mixing RBCs with serum instead of the reagents, it is expected that the device provides not only the quick blood-typing but also a safer and quicker blood transfusion in emergency rooms.

Blood-typing and irregular antibody screening through multi-channel microfluidic discs with surface antifouling modification

A novel surface modification technology for microfluidic disks was developed for multichannel blood-typing detection and irregular antibody screening. The antifouling material, poly(ethylene glycol) methacrylate (PEGMA), was used to modify the surface of the microfluidic disk for improving its hydrophilicity and blood compatibility. With the modification of PEGMA, the hydrophilicity was sufficiently improved with a 44.5% reduction of water contact angle. The modified microfluidic disk also showed good biocompatibility with a reduction of hemolytic index (from 3.4% to 1.2%) and platelet adhesion (from 4.6 × 10⁴/cm² to 1.9 × 10⁴/cm²). Furthermore, the PEGMA modification technique conducted on the microfluidic disk achieved successful adjustment of burst frequency for each chamber in the microchannel, allowing a sequential addiction of reagents in the test protocol of manual polybrene (MP) blood typing. Clinical studies showed that the proposed MP microfluidic disk method not only performed at extremely high consistency with the traditional tube method in the identification of ABO/RhD blood types, but also accomplished an effective screening method for detecting irregular antibodies. In conclusion, this study demonstrated that the easily mass-produced MP microfluidic disk exhibited good blood-typing sensitivity and was suitable for clinical applications.