Quantum dots encoded superparamagnetic micron-particles based on layer-by-layer assembly for multiplexed nucleic acid detection

With the rapid development of precise medicine, microbeads-based fluorescence bio-coding technology for multiplexed detection has attracted increasing attentions. However, traditional multiplexed bio-analysis could not meet the demand for multiplexed detection due to the limitations of labeling dyes and microscope channels. Here, a novel fluorescence encoding strategy was proposed by using multi-color quantum dots (QDs) acted as fluorescence tags and micron sized superparamagnetic particle acted as encoding carrier. By adjusting the color and number of labeled QDs, fluorescence encoded superparamagnetic particles (FESPs) with distinct fluorescence colors and intensities were constructed. The FESPs were prepared by metal coordination-based layer-by-layer assembly with excellent binding effect. By binding DNA capture oligonucleotides, FESP probes were constructed for multiplexed detection of miRNA-21, miRNA-122 and miRNA-130b with excellent specificity. Moreover, the miRNA targets could be easily separated within 5 s originated from the excellent superparamagnetism, enabling great simplified bio-analysis process. The results demonstrated here will provide opportunities to realize the full potentials of fluorescence bio-coding in biomedical detection and diagnosis.