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Colorectal cancer (CRC) remains a significant contributor to the global mortality rate, and a single biomarker cannot meet the specificity required for CRC screening. To this end, we developed a multiplexed, pump-free surface-enhanced Raman scattering (SERS) microfluidic chip (LoC-SERS) using a one-step recognition release mechanism; the aptamer-functionalized novel Au nanocrown array (AuNCA) was used as the detection element embedded in the detection zone of the platform for rapid and specific detection of protein markers in multiple samples simultaneously. Here, the corresponding aptamer specifically captured the protein marker, causing the complementary strand of the aptamer carrying the Raman signal molecule to be shed, reducing the SERS signal. Based on this platform, sensitive and specific detection of the target can be accomplished within 15 min with detection limits of 0.031 pg/mL (hnRNP A1) and 0.057 pg/mL (S100P). Meanwhile, the platform was consistent with ELISA results when used to test clinical. By substituting different aptamers, this platform can provide a new solution for the rapid and sensitive detection of protein markers, which has promising applications in future disease detection. [Display omitted] • A POCT platform was developed for rapid and sensitive detection of protein markers. • The prepared AuNCA has good SERS signal amplification effect. • The platform can complete the detection of a target in less than 15 min. • The platform has a promising application in clinical testing. [ABSTRACT FROM AUTHOR]

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]

Detection of tumor biomarkers is of great significance for early diagnosis of cancer. Herein, we fabricated a novel lab-on-a chip surface-enhanced Raman scattering (SERS) (LoC-SERS) biosensing platform for highly sensitive and specific detection of thrombin and platelet-derived growth factor-B (PDGF-B) using aptamer recognition technology. This strategy relies on the specific aptamer recognition between SERS probes (Ag–Au core–shell nanorods (Ag–AuNRs) modified with Raman reporter molecules and detection aptamer) and SERS capture substrate (Au nanoflower (AuNF) substrates modified with capture aptamer), which significantly amplify the plasmonic coupling effect that allows the ultrasensitive and high specificity SERS detection. The limits of detection (LODs) are as low as 3.62 fM for thrombin and 2.86 fM for PDGF-B. Such LoC-SERS platform is further employed to simultaneously detect two types of gastric carcinoma-related with high sensitivity and specificity, which meanwhile exhibit robust capacity of resisting disturbance in practical samples. The results revealed that the present LoC-SERS platform displayed excellent analytical performance, including superior reproducibility, specificity, and sensitivity. Satisfactory results were obtained in real sample analysis with the LoC-SERS platform. [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]

[Display omitted] • A competitive recognition binding strategy regarding the aptamer was designed. • An integrated SERS-enabled LoC system was fabricated for gastric cancer detection. • VEGF and PDGF-B in human serum was directedly quantified with an ultralow LOD. Multiplex detection of biomarkers is nontrivial for gastric cancer diagnosis. Herein, we presented a lab-on-a-chip surface-enhanced Raman scattering (LoC-SERS) sensing system for the detection of vascular endothelial growth factor (VEGF) and platelet-derived growth factor-B (PDGF-B). The sensing system includes three parallel channels, each channel consists of two detection chambers, enabling the simultaneous analysis of multiple samples. The capillary structure provides self-driving power without the need of external pumps. The ordered gold nano-bipyramids (GNBPs) array in the detection chamber can form uniform and dense "hot spots", due to the homogeneous double-tip structure and narrow gaps, resulting in better SERS performance. During the analysis process, VEGF and PDGF-B in the serum can lead to the change of aptamer conformation. Raman reporter-labeled complementary DNA is shed from the aptamer due to competition of the target. The entire process only requires 20 min, which is rapid. By monitoring the changes in Raman intensity and fitting it with the logarithm of concentration, the correlation between the intensity and concentration can be clearly reflected as a mathematical relationship. The LoC-SERS sensing system has been verified to have excellent selectivity and reproducibility. Via the sensing system, the limits of detection (LOD) of VEGF and PDGF-B are as low as 0.342 pg/mL and 0.265 pg/mL in serum, respectively. In addition, the accuracy was verified through enzyme-linked immunosorbent assay (ELISA). Therefore, the proposed LoC-SERS sensing system has great potential for clinical detection of gastric cancer. [ABSTRACT FROM AUTHOR]