Au nanocone array with 3D hotspots for biomarker chips

Abstract

AFP-L3 is one of the most important biomarkers for the early diagnosis of liver cancer. Surface-enhanced Raman scattering is a suitable tool for AFP-L3 detection thanks to its high-sensitivity analytical ability with the fingerprint effect. Here, nanocone arrays were prepared as SERS-active substrate based on nanosphere lithography. When controlling the deposition angle, the period of the patterned array, and the growth time, the distances between adjacent Au nanocones were reduced and the sharpness of the tips was changed so as to provide a significant SERS signal as 3D hotspots. The changes of the incident angle of the light source increased the number of hotspots to provide more significant SERS signals. Based on the peak shift analysis of the characteristic peaks of the probe molecule 4-MBA, AFP-L3 could be detected at a concentration down to 0.5 ng ml⁻¹.