Recent advances in aptamer-based sensors for breast cancer diagnosis: special cases for nanomaterial-based VEGF, HER2, and MUC1 aptasensors.

Cancer is one of the most common and important diseases with a high mortality rate. Breast cancer is among the three most common types of cancer in women, and the mortality rate has reached 0.024% in some countries. For early-stage preclinical diagnosis of breast cancer, sensitive and reliable tools are needed. Today, there are many types of biomarkers that have been identified for cancer diagnosis. A wide variety of detection strategies have also been developed for the detection of these biomarkers from serum or other body fluids at physiological concentrations. Aptamers are single-stranded DNA or RNA oligonucleotides and promising in the production of more sensitive and reliable biosensor platforms in combination with a wide range of nanomaterials. Conformational changes triggered by the target analyte have been successfully applied in fluorometric, colorimetric, plasmonic, and electrochemical-based detection strategies. This review article presents aptasensor approaches used in the detection of vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), and mucin-1 glycoprotein (MUC1) biomarkers, which are frequently studied in the diagnosis of breast cancer. The focus of this review article is on developments of the last decade for detecting these biomarkers using various sensitivity enhancement techniques and nanomaterials.