Plasmonic Sensor and Surface Enhanced Fluorescence Imaging Based on Hollow Nanocone Arrays

Hollow nanocone arrays are fabricated by a low-cost and efficient colloidal lithography (CL) technique. The hollow nanocone arrays are then reversed to make only the tips contact the substrate. The optical properties of the obverse and inverse hollow nanocone arrays are determined by the surrounding environment, showing different reflection spectra and structure dependence. The inverse hollow nanocone arrays show a relative index sensitivity of 70% per RIU with strict linearity. The fluorescence of fluorophore or staining cells can be facilely enhanced by placing them on the tips of the hollow nanocone arrays, while having no quenching effect. The study of the obverse and inverse hollow nanocone arrays can benefit the understanding of the effect of the environment on the plasmonic resonances. The hollow nanocone arrays are promising to serve as high-performance plasmonic sensors and versatile substrates for surface-enhanced fluorescence imaging.