Spontaneous Implantation of Gold Nanoparticles on Graphene Oxide for Salivary SERS Sensing

Clean SERS substrates that can be prepared without using polymer stabilizers and highly toxic reducing agents play a pivotal role in trace amount detection. Herein well-dispersive graphene oxide (GO)-supported Au (GO-Au) nanocomposites have been synthesized using the hydrothermal method in alkaline environment, in the absence of traditionally used reductants and surfactants. The nanocomposites have been subsequently used to manufacture a SERS sensor. The silk-liked GO multirole as reductant for the synthesis of Au nanoparticles (NPs), surfactant for Au NPs and support to uniformly distribute Au NPs. Moreover, the in situ obtained Au NPs could provide efficient ‘hot spots’, and therefore ensured the favorable SERS analytical performance of the GO-Au nanocomposites-based sensor which featured enhancement factor of 8.1 × 107. To further evaluate its practical clinical applications, the prepared SERS sensor was utilized to analyze eight salivary amino acids, which are gastric cancer (GC) biomarkers, in 44 saliva samples. The results revealed that the performance of the prepared sensor was satisfactory for salivary SERS sensing and the selectivity and sensitivity of the sensor for diagnosing GC were excellent. Therefore, this simple synthesis strategy could provide a novel idea for preparing clean SERS sensor substrates with potential application prospects in clinical field.