초록 |
Surface-enhanced Raman scattering (SERS) can give enhanced Raman signals through adsorbing target molecules on the surface of metal nanostructures with strong electromagnetic fields. However, it is difficult to deposit target molecules without pre-treatment steps. In this research, we introduce SERS-active microgels containing highly-concentrated gold nanoparticles. We prepare water-in-oil-in-water double emulsion drops by counter-flow-microfluidics. The core of the drops contains gold nanoparticles and hydrogel precursors. As imposing positive osmotic pressure on the drops, the water in the core flows out and the concentration of gold nanoparticles increases by a factor of 10-40. Finally, the highly-concentrated gold nanoparticles are trapped through gelation of the core under UV. The microgel system working as a molecular sieve provides molecular selectivity. Well-distributed gold nanoparticles with high concentration provide signal enhancement and reproducibility. |