Multiplexed Luminescence Oxygen Channeling Immunoassay Based on Dual‐Functional Barcodes with a Host–Guest Structure: A Facile and Robust Suspension Array Platform

Abstract The development of a powerful immunoassay platform with capacities of both simplicity and high multiplexing is promising for disease diagnosis. To meet this urgent need, for the first time, a multiplexed luminescent oxygen channeling immunoassay (multi‐LOCI) platform by implementation of LOCI with suspension array technology is reported. As the microcarrier of the platform, a unique dual‐functional barcode with a host–guest structure composed of a quantum dot host bead (QDH) and LOCI acceptor beads (ABs) is designed, in which QDH provides function of high coding capacity while ABs facilitate the LOCI function. The analytes bridge QDH@ABs and LOCI donor beads (DBs) into a close proximity, forming a QDH@ABs–DBs “host–guest–satellite” superstructure that generates both barcode signal from QDH and LOCI signal induced by singlet oxygen channeling between ABs and DBs. Through imaging‐based decoding, different barcodes are automatically distinguished and colocalized with LOCI signals. Importantly, the assay achieves simultaneous detection of multiple analytes within one reaction, simply by following a “mix‐and‐measure” protocol without the need for tedious washing steps. Furthermore, the multi‐LOCI platform is validated for real sample measurements. With the advantages of robustness, simplicity, and high multiplexing, the platform holds great potential for the development of point‐of‐care diagnostics.