Immobilization of Thai Population-specific Human Leukocyte Antigens on Magnetic Nanoparticles Integrated with Nuclear Magnetic Resonance Technology

Kidney disease, as a global health problem, can progress to kidney failure. Kidney transplantation is a treatment option for end-stage disease and an alternative to dialysis. Complement-dependent cytotoxicity tests and flow cytometry are methods used to test for compatibility between autoantibodies and donor recipient. Antibodies against donor human leukocyte antigens (HLAs), linked to hyperacute or severely acute rejection, frequently result in graft loss. Currently, fluorescent bead assay (Luminex^®) technology is used in Thailand for HLA–antibody typing tests. However, each test requires specific location and time, expensive equipment, and high costs. The goal of such research is that, HLA–antibody typing tests can be performed wherever it is the most convenient for recipients and hospitals. A further advantage is that the surgeon can perform a final test for confirmation before the surgery. Numerous technologies are currently available for this purpose. The focus of this study was on the Fe₃O₄ magnetic nanoparticles (MNPs) immobilized with HLAs frequently found in the Thai population. These were examined using nuclear magnetic resonance (NMR) to measure HLA antibody typing. MNPs have recently attracted considerable attention because of their strong magnetization and large surface areas. Immobilization reactions with antigens and the straightforward magnetic separation of MNPs are low-cost techniques. Hence, the commercialization of Fe₃O₄ MNPs is favorable. In this study, MNPs were functionalized with 3-aminopropyl triethoxysilane (APTES) in toluene and ethanol, and the nanoparticles were streptavidin activated after APTES treatment. A specific biotinylated HLA for the Thai population was used and immobilized on streptavidin. The MNPs were effectively immobilized. The magnetic properties can be modified by adding other ions to Fe₃O₄. We discovered that the shape and size variations of Fe₃O₄ MNPs may have an impact on the amount of functionalized and immobilized surface area.