Label-free identification of DNA single-base mutation for clinical diagnostics based on plasmonic SiNW@AgNP arrays

Surface-enhanced Raman spectroscopy (SERS) has exhibited great potential in deoxyribonucleic acid (DNA) analysis. Rapid and label-free identification of single-base mutation in DNA is still limited by the sensitivity and reproducibility of SERS substrates. In this work, we develope plasmonic SiNW arrays decorated with Ag nano particles (SiNW@AgNP arrays) via hexadecyltrimethylammonium bromide (CTAB)-assisted galvanic reaction to address these challenges, which show excellent sensitivity and reproducibility. Under optimized experimental conditions, plasmonic SiNW@AgNP arrays enable detection of DNA bases of adenine (A), guanine (G), cytosine (C), and thymine (T) in solution at concentration down to pM-mu M range, and multiple detection ability with mixture of DNA bases. More significantly, our study demonstrates the SiNW@AgNP arrays may serve as excellent SERS substrates in discriminating DNA single-base mutation between sickle cell anemia gene and normal hemoglobin gene in serum samples, which can be exploited in a wide range of plasmonic enhanced sensing applications for a fast, real-time, label-free and cost-effective clinical diagnosis.