A channel-resolved approach coupled with magnet-captured technique for multianalyte chemiluminescent immunoassay

A concept of channel-resolved multianalyte immunoassay (MAIA) and a semi-automated flow-through chemiluminescent (CL) MAIA system coupled with magnet-captured technique were proposed for rapid quantitation of different analytes in a single run. Using α-fetoprotein (AFP), carcinoembryonic antigen (CEA) and carcinoma antigen 125 (CA 125) as model analytes. They were firstly incubated in the mixtures of capture antibodies-immobilized paramagnetic microspheres (PMs) and corresponding alkaline phosphatase-labeled antibodies under stir and pumped into three parallel detection channels, the PMs were simultaneously captured by magnet, and the CL signals from the three channels were then sequentially collected with the aid of optical shutters to perform quantitative detection. AFP, CEA and CA 125 could be rapidly assayed in the ranges of 1.0-40 μg/l, 0.20-30 μg/l and 1.0-50 kU/l with the detection limits of 0.60 μg/l, 0.080 μg/l and 0.70 kU/l at 3σ, respectively. After manual dispensing of specimen and reagents the whole assay process could be completed in 18 min. The assay results of clinical serum samples with the proposed method were in acceptable agreement with the reference values. This system, based on the designed channel-resolved strategy and magnet-captured technique provides a semi-automated, reusable, simple, sensitive, rapid and low-cost approach for MAIA without using of expensive array detector.