The authors report on a simplified approach to encapsulate upconversion nanoparticles (UCNPs) in polystyrene spheres by mini-emulsion polymerisation. The resulting particles (PS-UCNP) are hydrophilic, stable and suitable for biomolecular recognition and biosensing applications. Also, a strategy was developed for bioconjugation of antibodies onto the surface of the PS-UCNPs by using the bifunctional fusion protein linker-protein G (LPG). LPG mediates the functionalisation of PS-UCNPs with antibodies against digoxigenin allowing for specific labelling of convective PCR (cPCR) amplicons. Lambda DNA was amplified using cPCR on a heat block for 30 min using the digoxigenin labelled forward and biotin labelled reverse primers. The antibody functionalised PS-UCNPs bind to the digoxigenin end of the cPCR amplicons. Finally, the streptavidin labelled magnetic beads were used to selectively capture the PS-UCNP-labelled cPCR amplicons and the upconversion signal was detected at 537 nm under 980 nm excitation. This sandwich approach enables direct recognition of the target lambda DNA with a detection limit of 103 copies μL−1. The upconversion signal decreased proportionally to the concentration of the lambda DNA with a linear response between 107 and 103 copies of DNA.
- Nucleic acid analysis
- Mini-emulsion polymerisation
- Surface functionalisation
- Magnetic separation
Potluri, P. R., Rajendran, V. K., Tran, C. T., McKenzie, D. R., & Sunna, A. (2019). Linker-protein G mediated functionalization of polystyrene-encapsulated upconversion nanoparticles for rapid gene assay using convective PCR. Microchimica Acta, 186(6), 1-9. . https://doi.org/10.1007/s00604-019-3466-x