High-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip supports for AFP detection

- A novel strategy combined the high temperature with chemical swelling technology is designed.
- Based on hydrophobic interaction and polymer thermal motion, QDs and Fe3O4 were effectively packaged into microbeads.
- The fluorescence-encoded magnetic microbeads show long-term fluorescent encoding and immunodetection stability.

Fluorescence-encoded magnetic microbeads (FEMMs), with the fluorescence encoding ability of quantum dots (QDs) and magnetic enrichment and separation functions of Fe3O4 nanoparticles, have been widely used for multiple biomolecular detection as microfluidic protein chip supports. However, the preparation of FEMMs with long-term fluorescent encoding and immunodetection stability is still a challenge. In this work, we designed a novel high-temperature chemical swelling strategy. The QDs and Fe3O4 nanoparticles were effectively packaged into microbeads via the thermal motion of the polymer chains and the hydrophobic interaction between the nanoparticles and microbeads. The FEMMs obtained a highly uniform fluorescent property and long-term encoding and immunodetection stability and could be quickly magnetically separated and enriched. Then, the QD-encoded magnetic microbeads were applied to alpha fetoprotein (AFP) detection via sandwich immunoreaction. The properties of the encoded microspheres were characterized using a self-designed detecting apparatus, and the target molecular concentration in the sample was also quantified. The results suggested that the high-performance FEMMs have great potential in the field of biomolecular detection.

We designed a novel strategy to prepare a kind of high-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip support with long-time fluorescent encoding and immunodetection stability for AFP detection.282