Synthesis of Gold Nanoparticle Stabilized on Silicon Nanocrystal Containing Polymer Microspheres as Effective Surface-Enhanced Raman Scattering (SERS) Substrates.

Developing ideal surface-enhanced Raman scattering (SERS) substrates is significant in biological detection. Compared with free non-aggregated noble metal nanoparticles, loading metal nanoparticles on a large matrix can achieve a higher SERS effect due to the existence of many "hot spots". A novel SERS substrate with intense "hot spots" was prepared through reducing gold ions with silicon nanocrystal containing polymer microspheres. The substrate exhibits high SERS sensitivity with an enhancement factor of 5.4 × 107. By applying 4-mercaptopyridine as a Raman reporter, the developed SERS substrate can realize measurement of pH values. The intensity ratio of 1574 to 1607 cm−1 of 4-mercaptopyridine showed excellent pH sensitivity, which increased as the surrounding pH increased. With good stability and reliability, the pH sensor is promising in the design of biological detection devices. [ABSTRACT FROM AUTHOR]