Long period fiber grating nano-optrode for cancer biomarker detection

Analyte recognition and capture were confirmed with a parallel on fiber ELISA-like assay using, in pilot tests, the biotinylated protein and HRP-labeled streptavidin for its detection. Dose-dependent experiments showed that the detection is linearly dependent on concentration within the range between 0 and 4 ng/mL, while antibody saturation occurs for higher protein levels. The system is characterized by a very high sensitivity and specificity allowing the ex-vivo detection of sub ng/ml concentrations of human Tg from needle washouts of fine-needle aspiration biopsies of thyroid nodule from different patients.