Plasmonic-polymer hybrid hollow microbeads for surface-enhanced Raman scattering (SERS) ultradetection.

Hybrid composites are known to add functionality to plasmonic nanomaterials. Although these substrates can be produced by common synthetic methods, the percentage of metal loaded into the functional material is usually small. Herein, we exploit a phase inversion precipitation method to incorporate large amounts of silver nanoparticles inside the polymeric matrix of polysulfone microbeads. The composite material combines the high SERS activity resulting from the plasmonic coupling of highly interacting nanoparticles and the ability to accumulate analytes of the polysulfone porous support. This allows for the quantitative SERS detection down to the nanomolar level, with a liner response that extends over an impressive concentration range of five orders of magnitude.