Abstract
Detecting microRNA (miRNA) biomarkers expression is of great significance for the diagnosis and treatment of lung cancer. Surface-enhanced Raman scattering (SERS) has achieved microRNA sensing for the diagnosis of primary liver cancers. In this work, we developed a SERS technology for the rapid detection of lung cancers-related miRNA (miR-196a) using bimetallic Au-Ag nanowire (AgNW@AuNPs) substrates coupled with the target hairpin DNA. The finite-difference time-domain simulation proved that a large number of “hot spots” were generated between the AgNW and AuNPs, which resulted in a huge enhancement of the signal of Raman reporters. Filter paper treated by hexadecenyl succinic anhydride hydrophobic and modified with AgNWs@AuNPs was used as capturing substrate. The detection limits of miR-196a in PBS and serum were as low as 96.58 aM and 130 aM, respectively. Studies on nonspecific sequence and single-base mismatch of miRNA demonstrated that SERS-based platform was highly selective, excellent uniform, and reproducible. Finally, the platform was used to show that the miR-196a expression in the serum of lung cancer patients was much higher than that in healthy people. The detection results indicated that the SERS platform had potential applications in cancer diagnosis and might be a viable alternative to the conventional miRNA detection method, the real-time polymerase chain reaction (RT-PCR) technology.
Highlights
MicroRNAs are a class of small, highly conserved, noncoding RNAs that play critical regulatory roles in a range of biological processes, including cell proliferation, differentiation, apoptosis, and immunoregulation [1, 2]. e abnormal expression of miRNAs is related to many pathological processes, such as metabolic disorders and immune system dysfunction
Many studies have indicated that the expression of miR-196a is significantly upregulated in the serum of different tumor patients and revealed that miR-196a is involved in the proliferation, migration, and invasion of a number of cancer cells [4,5,6,7]. erefore, the detection of miR-196a expression is vital for the diagnosis of tumors
finite-difference time-domain (FDTD) had proved that a strong Surface-enhanced Raman scattering (SERS) signal could be produced by hot spots formation in the gaps of Ag nanowires (AgNWs)@Au nanoparticles (AuNPs)
Summary
MicroRNAs (miRNAs) are a class of small, highly conserved, noncoding RNAs that play critical regulatory roles in a range of biological processes, including cell proliferation, differentiation, apoptosis, and immunoregulation [1, 2]. e abnormal expression of miRNAs is related to many pathological processes, such as metabolic disorders and immune system dysfunction. MicroRNAs (miRNAs) are a class of small, highly conserved, noncoding RNAs that play critical regulatory roles in a range of biological processes, including cell proliferation, differentiation, apoptosis, and immunoregulation [1, 2]. Traditional detection methods for miRNAs, such as Northern hybridization, in situ hybridization, real-time quantitative PCR, Journal of Chemistry and microarray technology, are complex and time-consuming and exhibit low sensitivities, and, they have difficulty meeting the needs of cell sample detection. Guven et al [16] constructed SERS probes using Raman 5,5′-dithiobis (2-nitrobenzoic acid) (DTNB) and miRNA-21-modified Au nanorods and fixed the DNA chains on the surfaces of the Au substrates to form capture probes, which could be paired with SERS probes to form Sandwich detection structures. With the enhanced performance of the SERS probes and the SERS signal of DTNB, the detection limit of the highly sensitive miR-21 was 0.85 nM. With the complementary pairing of DNA and let-7b and the restriction endonuclease acting on the complementary double-strand, the “hot spots” between the nanoparticles disappeared and the SERS signal intensity weakened. e let-7b detection could be realized based on the change of the SERS signal, and the detection limit was up to 0.3 fM
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