The sandwich-type aptasensor based on gold nanoparticles/DNA/magnetic beads for detection of cancer biomarker protein AGR2

A simple and stable method for the detection of cancer biomarker anterior gradient homolog 2 (AGR2) using UV–vis spectrometry is described. The sensing system is constructed easily with magnetic beads, aptamer, its complementary probe, and regular-shaped gold nanoparticles. The designed aptasensor exhibits excellent efficiency, selectivity and sensitivity toward AGR2 protein detection, and shows a picomolar range of detection limit. This extraordinary performance can be attributed to the effective separation of magnetic beads, the highly selective Gquadruplex formation of AGR2 proteins recognized by aptamers, the unique optical properties of gold nanoparticles and the special sandwich structure of the aptasensor.