The Influence Of Structure And Size Of Magnetic Nanoparticles For D-dimer Detection Based On Immunochromatography Assay

Due to easy operation,quick and free of large equipment,lateral flow immunochromatography(LFIA)serving as a mainstream technology in point of care testing has been widely used in medicine,food safety and environmental testing.However,there are some limitations have been found in practice,such as the lower limit of detection and sensitivity,smaller detection flux,no comparable to the large flow-line equipment.The introduction of magnetic nanoparticle(NP)play an important role in improvement of LFIA.Magnetic nanoparticle has lots of advantage,such as easy preparation,high surface area,high surface energy,full signal collection in three dimension,et al.,which has drawn great attention in clinical diagnosis.In current studies,most researches have focused on the selection of material and optimization of signal reading.However,it has been less reported that the influence of size and structure of magnetic nanoparticle on the performance of LFIA.In this study,we analyzed the physical and chemical properties of different size and structure of carboxyl magnetic nanoparticles.Meanwhile,LFIA systems based on different magnetic nanoparticles have been built for D-dimer detection.The influence of size and structure of magnetic nanoparticle on performance of magnetic LFIA have been investigated.This study mainly includes the following several aspects:(1)Au@Fe3O4 GoldMag NPs and Au@Fe3O4 GoldMag Flowerlike NPs were prepared.(2)Seven kinds of magnetic nanoparticles Ocean A,Ocean B,Ocean C,Au@Fe3O4 GoldMag NPs,Au@Fe3O4 GoldMag Flowerlike NPs,Carboxyl-Adembeads and MagSIGNAL-COOH have been characterized in terms of electron microscopy(TEM),ultraviolet spectrophotometer(UV-VIS),dynamic light scattering(DLS),fourier infrared spectroscopy(FT-IR).(3)Based on the seven kinds of magnetic nanoparticles,magnetic LFIA system for D-dimer detection have been established.The influence of different size and structure of magnetic nanoparticles on the performance of magnetic LFIA system has been investigated by comparing the detection range and sensitivity.The results single component Fe3O4 magnetic nano materials from Ocean company shown that the sensitivity and detection range of LFIA decreased as the increase of the particle size.For gold magnetic nanoparticles,significant difference was found on detection range between different structure of nanoparticles.However,the Au@Fe3O4 GoldMag NPs with core-shell structure exhibited higher sensitivity than that found with.Compared with that shown,Au@Fe3O4 GoldMag NPs has wider detection range than MagSIGNAL-COOH NPs which shown similar size and structure as Au@ Fe3O4GoldMag NPs but different component.These results not only provide theoretical foundation for magnetic LFIA improvement,but also provide a reference for clinical application in the future.