Effect of particle on the lasing threshold of optofluidic laser based on Fabry–Pérot microcavity.

Enzyme-linked immunosorbent assay (ELISA) is a powerful analytical method for biomolecular analysis due to high sensitivity and specificity. The large background fluorescence can be eliminated by using optofluidic laser-based ELISA. However, the detection time is too long, especially for the detection of low concentration of analyte. Such a drawback can potentially be overcome by using particle with high surface-to-volume ratio. The effect of particle on the lasing threshold of optofluidic laser based on Fabry–Pérot microcavity was demonstrated, which is a fundamental issue on magnetic particle-based optofluidic laser ELISA. The 1 mM R6G ethanol solution and different concentrations of magnetic particles (Fe 3 O 4) solution (5, 10, 20, 40 and 80 μ g/ml) with the diameter 30 or 100 nm was be tested the effect of particle on optofluidic laser. The results show that the lasing threshold increases with the concentration and diameter of particles increasing, but the adverse effect is very small for the detection of low concentration of analyte. Our work will lead to the development of magnetic particle-based optofluidic laser ELISA, which can shorten the detection time and push the detection limit. [ABSTRACT FROM AUTHOR]