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Sensitive Surface Enhanced Raman Scattering-Based Detection of a BIGH3 Point Mutation Associated with Avellino Corneal Dystrophy

Kim, Saetbyeol, Jeong, Su-Nam, Bae, Sangsu, Chung, Hoeil, Yoo, So Young
Analytical chemistry 2016 v.88 no.23 pp. 11288-11292
DNA, Raman spectroscopy, detection limit, genes, genetic disorders, heterozygosity, homozygosity, nucleotide sequences, point mutation, temperature
Surface enhanced Raman scattering (SERS) is highly useful for sensitive analytical sensing; however, its practical availability for detecting a point mutation associated with disease in clinical sample was rarely proved. Herein, we present a toehold-mediated, DNA displacement-based, SERS sensor for detecting point mutations in the BIGH3 gene associated with the most common corneal dystrophies (CDs) in a clinical setting. To diagnose Avellino corneal dystrophy (ACD), selectivity was ensured by exploring optimal DNA displacement conditions such as length of toehold and hybridization temperature. A SERS-efficient Ag@Au bimetallic nanodendrite was employed to ensure sensitivity. Optimization for a clinical setting showed that discrimination was maximized when toehold length was 6-mer (T6), and hybridization temperature was 36 °C. On the basis of tests that used clinical homozygous and heterozygous CD samples, a single-base mismatched DNA sequence was identifiable within 30 min with a limit of detection (LOD) of 400 fM. From the results, we conclude that our toehold-mediated, DNA displacement-based, SERS sensor allows a rapid and sensitive detection of a BIGH3 gene point mutation associated with Avellino corneal dystrophy, indicating the practical ability of the method to diagnose genetic diseases caused by point mutations.