Detection of the most common corneal dystrophies caused by BIGH3 gene point mutations using a multispot gold-capped...

The localized surface plasmon resonance (LSPR) optical property has recently been well employed as an effective platform for the quantitative detection of protein-protein interactions on the nanoscale. However, its advantage has not been fully explored yet in the DNA diagnosis field, especially in detecting point mutations of DNA. Point mutations of the BIGH3 gene are associated with the most common corneal dystrophies (CDs), such as Avellino corneal dystrophy, Reis-Bucklers corneal dystrophy, and lattice corneal dystrophy. Since the detection of these corneal dystrophies is urgently needed before laser-assisted in situ keratomileusis operation to prevent blindness, genetic analysis of the BIGH3 gene is critical in most ophthalmological clinics. In this study, we report LSPR-based detection of the BIGH3 gene mutations by using a multispot gold-capped nanoparticle array (MG-NPA) chip. The analytical range and sensitivity of the MG-NPA chip were determined by measuring different concentrations of each CD target DNA in the range of 1 fM to 1 microM. Under the optimal conditions, the detection of DNA hybridization with each CD target DNA was performed with a detection limit of 1 pM target DNA. The selective discrimination against a single-base mismatch DNA sequence was also achieved by using both homozygous and heterozygous CD samples. It demonstrates that the label-free LSPR-based optical biosensor system employing the MG-NPA chip provides a new diagnostic platform allowing the selective and sensitive detection of various DNA point mutations, leading to possible diagnosis of mutation-related diseases including corneal dystrophies reported here.