Ultrasensitive and Selective Electrochemical Diagnosis of Breast Cancer Based on a Hydrazine–Au Nanoparticle–Aptamer Bioconjugate

Abstract

Human epidermal growth factor receptor 2 (HER2) and HER2-overexpressing breast cancer cells were detected using an electrochemical immunosensor combined with hydrazine and aptamer-conjugated gold nanoparticles (AuNPs). The sensor probe was fabricated by covalently immobilizing anti-HER2 onto a nanocomposite layer that was composed of self-assembled 2,5-bis(2-thienyl)-1H-pyrrole-1-(p-benzoic acid) (DPB) on AuNPs. The hydrazine-AuNP-aptamer bioconjugate, where the hydrazine reductant was directly attached onto AuNPs to avoid the nonspecific deposition of silver on the sensor surface, was designed and used to reduce silver ion for signal amplification selectively. The silver-stained target cells were visualized easily by the bare eye and an optical microscope, and the cells were quantitatively analyzed using stripping voltammetry. The parameters affecting the analytical response were optimized. The proposed sensor was capable of differentiating between HER2-positive breast cancer cells and HER2-negative cells. This method exhibited an excellent diagnosis method for the ultrasensitive detection of SK-BR-3 breast cancer cells in human serum samples with a detection limit of 26 cells/mL.

Applications of Conductive Polymers to Electrochemical Sensors and Energy Conversion Electrodes

“…67) This method exhibited an excellent diagnosis method for the detection of SK-BR-3 breast cancer cells. A highly sensitive and selective sensor for daunomycin was developed using phosphatidylserine (PS) and aptamer as bioreceptors.…”

Biomarkers towards Ovarian Cancer Diagnostics: Present and Future Prospects

“…Using the mono-antibody of HER2 (anti-HER2) and a bioconjugate of hydrazine-AuNP (Gold Nanoparticle)-Aptamer (Hyd-AuNP-Apt), target molecules and cells can be quantitatively measured using stripping voltammetry. Using this technique, the SK-BR-3 breast cancer cells could be detected in human sera as low as 26 cells/ml 97 . Mucin1 (MUC1), a glycoprotein expressed on most epithelial cell surfaces, was discovered as an important tumor marker in the diagnosis, screening and prognosis of ovarian cancer.…”

Aptasensors Based on Stripping Voltammetry

“…In the past decades, many strategies to enhance the response of the aptasensor on the basis of electrochemical signals have been developed. Different functional nanomaterials were employed such as metal nanoparticles [36], semiconductor nanoparticles [26,37,38], magnetic nanoparticles [39], polymeric nanoparticles [31], carbon-based nanomaterials [40], and nanocomposite materials [22,41,42] in order to meet the growing demands for ultrasensitive detection [43]. Additionally, other multiple amplification strategies, such as PCR, strand-displacement amplification (SDA), hybridization chain reaction (HCR) amplification, rolling circle amplification (RCA), and cyclic target-induced primer extension (CTIPE), are also utilized to improve the sensitivity of electrochemical aptasensors [23,27,44,45].…”