Preparation Of High Stable Flourescent Nanoparticles With Eu(Ⅲ) Complex And Its Application For Suspension Chip

Suspension chip based on fluorescence-encoded microspheres is one of the main methods to achieve high-throughput,multi-target detection,and is widely used in genetic disease screening,drug screening and clinical diagnosis.Fluorescence-coded microspheres prepared with multicolor organic dyes or inorganic quantum dots are the most important elements in the suspension chip.However,there are still problems that the emission spectrum is wide or the organic dyes still require multicolor laser excitation.The rare earth complexes have attracted much attention in the field of biological detection due to their extremely narrow emission peak and large Stokes shift.However,due to the rare earth complex fluorescence susceptible to polar solvent quenching and the excitation band in the ultraviolet region and other factors limit its biological detection or as the application of fluorescent microspheres.In this paper,we first prepared highly stable and bright rare earth complex nanoparticles with mesoporous silica as the matrix,and then loaded them onto the microspheres.Combined with the preparation of the host-guest structures,and the three color encoded microspheres with single laser excitation were fabricated.The feasibility of its application in suspension chip was discussed.It is divided into the following three research areas:(1)Fluorescence particles(MSN-EuLC)were prepared by co-condensation method and the mesoporous channels were sealed with hydrophobic photoactive polymer polyvinyl carbazole(PVK)to avoid quenching.mPEG-COOH was used to stabilize the surface of the particles to improve their hydrophilicity.Fluorescence-stabilized fluorescent rare earth complex nanoparticles were prepared,but the particles were agglomerated and excited band is difficult to adjust to the visible area,more difficult to meet the application requirements of the encoded microspheres.(2)Ir-Eu-MSN was prepared by in-situ reaction of metal complexes with Ir ligand.Ir-Eu-MSN was modified by PEI on the surface of mesoporous silica to obtain Ir-Eu-MSN@PEI,the particles have good hydrophilicity and fluorescence stability,the excitation band extends to the visible light area.(3)Based on the preparation method of host-guest assembly microspheres,Ir-Eu-MSN @ PEI was electrostatically adsorbed onto the surface of magnetic polystyrene microspheres loaded with two-color quantum dots.To obtain three-color rare earth fluorescent/quantum dot-encoded microspheres.As a proof of concept,27 tricolor fluorescent encoded microspheres with the same lasers(375 nm excitation)were obtained by adjusting the number of encoded host microspheres and the fluorescence intensity of the rare earth complex nanoparticles.