Search

An innovative surface-enhanced Raman spectroscopy and lateral flow assay (SERS-LFA) biosensor combined with aptamer recognition had been developed for the convenient, rapid, sensitive and accurate detection of thrombin and platelet-derived growth factor-BB (PDGF-BB) associated with prostate cancer simultaneously. During the biosensor operation, thrombin and PDGF-BB in the sample were recognized and combined by thiol-modified aptamers immobilized on Au–Ag hollow nanoparticles (Au–Ag HNPs) surface and biotinylated aptamers immobilized on the test lines of the biosensor. Thus, thrombin and PDGF-BB were simultaneously captured between detection aptamers and capture aptamers in a sandwich structure. Finite difference time domain simulation confirmed that 'hot spots' appeared at the gaps of Au–Ag HNPs dimer in the enhanced electromagnetic field compared to that of a single Au–Ag HNP, indicating that the aggregated Au–Ag HNPs owned a good SERS signal amplification effect. The detection limits of thrombin and PDGF-BB in human plasma were as low as 4.837 pg ml−1 and 3.802 pg ml−1, respectively. Moreover, the accuracy of the biosensor which was applied to detect thrombin and PDGF-BB in prostate cancer plasma had been verified. This designed biosensor had broad application prospects in the clinical diagnosis of prostate cancer. [ABSTRACT FROM AUTHOR]

A novel surface-enhanced Raman scattering and lateral flow assay (SERS–LFA) biosensor with multiple channels based on an aptamer has been proposed in this work. The developed biosensor was designed for the rapid, convenient, sensitive and specific detection of vascular endothelial growth factor (VEGF) and osteopontin (OPN) in several samples simultaneously. During the assay, VEGF and OPN were recognized by detection aptamers immobilized on cuprous oxide nanocubes (Cu2O NCs) and captured by capture aptamers to form a sandwich structure on the test lines. In this way, generous numbers of "hot spots" formed by the aggregation of Cu2O NCs remarkably enhanced the SERS signals of Raman reporters (NBA and 4-ATP). The detection limits were as low as 0.78 pg mL−1 for the VEGF and 0.86 pg mL−1 for OPN in the human serum within 15 min, respectively. Additionally, the biosensor possesses favorable specificity, reproducibility, uniformity and stability. In the clinical analysis of serum specimens, patients with cervical cancer can be differentiated from healthy volunteers. Consequently, the presented aptamer-based SERS–LFA biosensor with multiple channels provides a powerful tool for the early diagnosis of cervical cancer. [ABSTRACT FROM AUTHOR]