Long Jia,Yongxia Liu,Yanqing Zhang,Shuofeng Zhang,Xiaowei Cao,Yemin Xu,Yi Zhao,Bin Deng
To facilitate rapid, efficient, and accurate detection of miR-96-5p associated with gastric cancer (GC), we developed a bioanalytical platform by integrating surface-enhanced Raman spectroscopy with lateral flow assay (SERS-LFA). With these SERS-LFA strips, miR-96-5p within the specimen competed with Au rhombic dodecahedron (AuRD) conjugated single-stranded DNA (ssDNA) to bond to the immobilized hairpin DNA (hpDNA) probe on the T line. Consequently, higher abundance of miR-96-5p led to reduced conjugation of AuRD on the T line, thereby resulting in diminished SERS intensity. The biosensor exhibited a detection time of approximately 30 min and demonstrated a low limit of detection (LOD) for miR-96-5p in PBS buffer solution, down to 3.7 fM. To validate its clinical utility for the early diagnosis of patients with different degrees of gastric lesions, we performed quantitative evaluations in cohorts that included healthy individuals, patients with mild intraepithelial neoplasia, patients with severe intraepithelial neoplasia, as well as patients diagnosed with GC. The results obtained from the SERS-LFA strips were in agreement with those obtained from the quantitative real-time polymerase chain reaction (qRT-PCR). Given the accomplishments, this biosensor has significant potential for the clinical diagnosis of GC, offering a promising avenue for timely detection and improved patient prognoses.
Surface-enhanced Raman spectroscopy (SERS) technology has been increasingly integrated with lateral flow immunoassay (SERS-LFA) to enable sensitive and quantitative detection, but SERS-LFA still faces notable challenges. One of the biggest problems is signal variations caused by random distributions of plasmonic SERS immunoprobes. Herein, we develop a sensitive, accurate quantification platform that overcomes this problem with a plasmonic internal standard (PIS), referred to as PIS-LFA. The PIS is achieved by decorating nitrocellulose membranes with Raman reporter molecule-embedded silver-gold alloy nanoparticles . By simultaneously measuring signals of plasmonic immunoprobes and IS and calculating their intensity ratios for signal normalization, we can mitigate signal variations and improve assay sensitivity. Comparing with SERS-LFA in carcinoembryonic antigen (CEA) detection, we show that PIS-LFA achieves a 1.8-fold higher uniformity and 3.2-fold lower limit of detection. We further demonstrate that PIS-LFA exhibits accurate quantification capability in duplex detection of CEA and neuron-specific enolase (NSE) in human sera by performing spike-recovery experiments and validating with electrochemiluminescence immunoassays. As a proof-of-concept, PIS-LFA differentiates levels of serum CEA and NSE between 12 early-stage lung cancer patients and 12 healthy individuals. We believe that PIS-LFA will open up avenues for affordable, rapid, and non-invasive disease screening in point-of-care settings.
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