Ion-chelation based digital barcodes for multiplexing of a suspension array

Ion-chelated microbeads (ICMs) for suspension arrays can be prepared by chelating metal ions (MIs), which are used as encoding materials. Stimulating the ICMs, laser induced breakdown spectra (LIBs) can be obtained and the atomic spectra of the chelated ions are chosen as the decoding signals. Our ICMs show digital characteristics with high stability due to the properties of LIBs. And, since there are many available coding materials and different kinds of coding materials can be easily combined, the coding capacity can be considerably enlarged. Further, the background interference in fluoroimmunoassay detection could be avoided, because the ICMs contain no fluorescence emission. In our studies, we achieved a total of 15 types of barcodes by taking full advantage of 4 kinds of ions, then a fluoroimmunoassay was performed to demonstrate the specificity and detection performance of our ICMs in multiplexing and the detection limit could reach 1.49 × 10−10 M, showing promising potential in applications.