Microfluidic PMMA-based microarray sensor chip with imaging analysis for ABO and RhD blood group typing.

BACKGROUND AND OBJECTIVES: Solid phase microarrays have been described for use in blood typing; red blood cells (RBCs) captured on immobilized antibodies were detected using surface plasmon resonance or fluorescence. We present antibody microarray on Poly (methylmethacrylate) (PMMA) surface coupled with microfluidic system for ABO and RhD blood typing. After immobilized by antigen-antibody interaction, the RBCs were detected by image recognition. MATERIALS AND METHODS: The sensor surface was produced from grafted aminopropyltriethoxysilane (APTES) on photochemical modified PMMA surface by UV irradiation and subsequently reacted with glutaraldehyde cross-linking. The amine group of monoclonal antibody of anti-A, anti-B and anti-D was reacted with an aldehyde group on the glutaraldehyde modified surface, forming an imine linkage. RBCs were captured by the coated antibody via antigen-antibody interaction, and blood grouping was determined by microarray image cell counting. RESULTS: Suitable condition for RBC detection was 10% RBC concentration at 10 µl/min flow rate. This setting eliminated non-specific RBC binding resulting in correct blood groups identification of all 136 samples tested. The platform showed good reproducibility with coefficient of variation of 2·17%, 3·62% and 2·51% for anti-A, anti-B and anti-D respectively. The antibody-coated surface can be stabilized by stabilizer coating and stored for long-term use. CONCLUSION: The PMMA array chip demonstrated its good accuracy and precision in rapid blood group testing. For its high throughput, the method has potential for use in large blood donation centre.

Miltenberger blood group typing by real-time polymerase chain reaction (qPCR) melting curve analysis in Thai population.

OBJECTIVES: To develop reliable and convenient methods for Miltenberger (Mi(a) ) blood group typing. AIM: To apply real-time polymerase chain reaction (qPCR) melting curve analysis to Mi(a) blood group typing. BACKGROUND: The Mi(a) blood group is the collective set of glycophorin hybrids in the MNS blood group system. Mi(a+) blood is common among East Asians and is also found in the Thai population. Incompatible Mi(a) blood transfusions pose the risk of life-threatening haemolysis; therefore, Mi(a) blood group typing is necessary in ethnicities where the Mi(a) blood group is prevalent. METHODS/MATERIALS: One hundred and forty-three blood samples from Thai blood donors were used in the study. The samples included 50 Mi(a+) samples and 93 Mi(a-) samples, which were defined by serology. The samples were typed by Mi(a) typing qPCR, and 50 Mi(a+) samples were sequenced to identify the Mi(a) subtypes. Mi(a) subtyping qPCR was performed to define GP.Mur. Both Mi(a) typing and Mi(a) subtyping were tested on a conventional PCR platform. RESULTS: The results of Mi(a) typing qPCR were all concordant with serology. Sequencing of the 50 Mi(a+) samples revealed 47 GP.Mur samples and 3 GP.Hop or Bun samples. Mi(a) subtyping qPCR was the supplementary test used to further define GP.Mur from other Mi(a) subtypes. Both Mi(a) typing and Mi(a) subtyping performed well using a conventional PCR platform. CONCLUSION: Mi(a) typing qPCR correctly identified Mi(a) blood groups in a Thai population with the feasibility of Mi(a) subtype discrimination, and Mi(a) subtyping qPCR was able to further define GP.Mur from other Mi(a) subtypes.