The Surface-Enhanced Raman Spectroscopy Platform Based on Raspberry-Like Au@Au Nanoparticles for Sensitive Estriol Detection

Abstract

As an important secretion during pregnancy, estriol is closely related to fetal growth. Thus, it is very important to develop ultrasensitive and non-invasive detecting approaches for monitoring the concentration of estriol. Here, we provide a non-invasive, fast and sensitive Surface-enhanced Raman Spectroscopy (SERS) detection platform that consist of spiky Au@Au nanoparticles (NPs) for fingerprint analysis of estriol. Based on the “lightning rod effect” and high scattering performance of the composite Au@Au structure, the detection sensitivity can be improved. Even so, the lower scattering cross section of estriol makes it impossible to be directly detected. Considering that, the azo reaction strategy is introduced into our system to improve the molecular scattering cross section, further enhance the detection sensitivity of estriol by forming the N=N bond. As a result, estriol can be detected to nanomolar level, which fully meets the detection requirements of estriol’s actual physiological range. We believe that this work not only provides an effective scope for the hypersensitive detection of estriol, but also provides an idea for improving the scattering cross section of biomarkers by using the analyte manipulating approach, which is very important for the monitoring of human health indicators.