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2019
Conference Paper
Titel
Anisotropic fluorescence emission at the surface of 1D-photonic crystal biochips
Abstract
Novel disposable optical biochips based on one-dimensional photonic crystals (1DPC) sustaining Bloch surface waves (BSW) are a desirable tool for the detection of several disease-related biomarkers. In particular, cancer biomarkers have gained considerable attention, due to the increasing demand for cancer treatment. Within this framework, the herein proposed optical biochips can quantify low concentration (sub ng/mL) of the ERBB2 breast cancer biomarker in biological complex matrices. To discriminate ERBB2 levels in several different cell lysate samples, we made use of a biosensing platform based on 1DPC biochips and on a reading instrument that can work in both a label-free and a fluorescence detection mode. Such combined configuration provides the advantage of complementary information and lower limit of detection (LoD) in the fluorescence mode [1]. In the label-free configuration the BSW excitation is achieved by a prism coupling system (Kretschmann-Raether configuration), like in the surface plasmon resonance (SPR) technique, resulting in a dip in the angular reflectance spectrum, shifting its position due to the refractive index changes [2]. The fluorescence mode is carried out by making use of dye labeled antibodies bound at the 1DPC surface. Coupling between the dye labels and a BSW results in strongly directional fluorescence emission. The advantages brought by the 1DPC, when compared to metal structures, are smaller energy dissipation and narrower resonances [3].