Metal‐doped Nanoparticles for Detection of Carbohydrate Antigen 15‐3 in Human Serum Using a Sandwich‐Type ICP‐MS Immunoassay

摘要

This work presents a method to determine carbohydrate antigen 15a??3 (CA15a??3) in serum using sandwicha??type inductively coupled plasma-mass spectrometry immunoassay. For this, Cd, Csa??doped magnetic nanoparticles (MNPs) for target extraction and ratiometric measurement to enhance the calibration linearity were synthesized by coa??precipitation, of which the size was in the size range of 21a??24a??nm. The numbers of doped Cd and Cs atoms were in the range of 2.5a????a??103 to 3.5a????a??103 per MNP. The new synthetic method simplifies the synthetic procedure significantly with high flexibility for doping. Rare earth metala??doped silica NPs (SNPs), i.e., Gd, Eu, or Ce, were also synthesized for detection through metala??chelation and microemulsion method, with a final size range of 70a??85a??nm. For application, carbohydrate antigen 15a??3 (CA15a??3) was spiked into a human serum and determined by the sandwicha??type ICPa??MS immunoassay using the synthesized nanoparticles after blank subtraction. The obtained limit of detection (LoD) without any sample treatment was 2.70a????a??10a??4 U/mL, which was about 2.28a????a??104 times better than that of enzymea??linked immunosorbent assay (ELISA).