Nanoparticle Labeling And Single Particle Model ICP-MS Coupled With Magnetic Immunoassay To Detect Biomarkers In Human Serum

The newly developed elemental labeling strategy based on inductively coupled plasma mass spectrometry（ICP-MS）provides a powerful approach for quantitative analyses of biomolecules.With elemental tags,ICP-MS based approach is prosperous for biomolecules quantification in recent years with the merits of simple quantification,high sensitivity,low matrix effects,wide dynamic range,and outstanding ability for multiple targets analyses.Element tagging with ICP-MS showed the potential to achieve multiplex analysis for massive bioassays and clinical diagnosis.Nanoparticles（NPs）as labels have attracted considerable interest for sensitivity improvement,due to their good biocompatibility,multiplexing capability and inherent miniaturization.Single particle ICP-MS（SP-ICP-MS）is a very promising technique for nanoparticles detection and characterization.In SP-ICP-MS,the transient signals induced by the events of ions in the plasma torch form the ionization of nanoparticles tagged on antibody.The frequency of transient signals is directly correlated the concentration of nanoparticle tags.This article focuses on developing the application of magnetic immunoassay using SP-ICP-MS.The main contents and results were introduced as follows:1.A highly sensitive magnetic immunoassay based on ICP-MS detection in single particle ode,with Cu O NPs serving as model tags,was proposed.Amino-modified magnetic nanoparticles（AMNPs）were synthesized and conjugated with primary squamous cell carcinoma antigen（SCCA）antibody to extract the target biomarker.Cu O NPs labeled secondary antibody was synthesized by simple one-pot method.The frequency of the transient signal of Cu in Cu O NPs labeled with secondary antibodies was analyzed by SP-ICP-MS.Under the optimal experimental conditions,the linear range of SCCA concentration is 0.01-50 ng·m L^-1 with the correlation coefficient of 0.9930,and the detection limit of SCCA is 3.3 pg·m L^-1.This method has been successfully applied to the determination of SCCA in human serum with a recovery of96%to 100%.2.A new method for simultaneous determination of CEA and CA15-3 was developed by SP-ICP-MS based magnetic immunoassay.Carboxyl-functionalized up-conversion nanoparticles（UCNPs）and amino-functionalized cerium dioxide nanoparticles（Ce O₂-Si O₂ NPs）were prepared for labeling secondary antibodies.Amino functionalized magnetic nanoparticles with good dispersibility and water solubility were synthesized and conjugated with CEA and CA15-3primary antibodies to extract the target biomarker.The quantitation of CEA and CA15-3 was carried out by SP-ICP-MS.The linear concentrations ranges of CEA and CA15-3 are 0.02-100ng·m L^-1 and 0.05-50 U·m L^-1,with the correlation coefficient of 0.9940 and 0.9870,respectively.Detection limits of CA19-9 and CA 24-2 are 0.0067 ng·m L^-1 and 0.0167 U·m L^-1.This method has been successfully applied to simultaneous detection of CEA and CA15-3 in human serum,with the recoveries of 95.2%to 98.9%.3.A new method for simultaneous determination of CA19-9 and CA24-2 was developed by SP-ICP-MS based magnetic immunoassay.The simple one-pot method is used to synthesize Au NPs and Pt NPs with the advantages of small particle size and a larger specific surface area.Streptomycin-coated magnetic beads were used to capture primary antibody and extract the target biomarker.Au NPs and Pt NPs labeled CA19-9 and CA24-2 secondary antibodies,respectively.Simultaneous determination of CA19-9 and CA24-2 was completed by SP-ICP-MS.The linear concentrations ranges of CA19-9 and CA24-2 are 0.2-50 U·m L^-1and 0.55-220 U·m L^-1with the correlation coefficient of 0.9970 and 0.9850,respectively.Detection limits of CA19-9and CA24-2 are 0.06 U·m L^-1 and 0.18 U·m L^-1,respetively.This method has been successfully applied to simultaneous detection of CA19-9 and CA 24-2 in human serum,with the recoveries of 95%to 99.5%.