A reusable optical nucleic acid biosensor applied to the rapid detection of single nucleotide polymorphisms associated with Spinal Muscular Atrophy.

Extract: Current methodologies for single nucleotide polymorphism (SNP) screening often require amplification, followed by time-consuming enzymatic manipulation (e.g., digestion or extension) and separation of the resultant products. Advancements in real-time PCR methods permit simultaneous amplification and quantification. Unfortunately, the ability to provide quantitative determinations can be made difficult by factors such as non-specific amplification and alterations in amplification efficiency owing to secondary-structure and sample matrix effects. Newer sensor and microarray technologies attempt to facilitate SNP analysis but usually require several hours for hybridization and data analysis. Furthermore, microarrays often cannot be reused as a result of limitations in the chemistries more routinely employed for nucleic acid immobilization. Difficulties associated with control of homogeneity of probe distribution, probe density and fidelity of the probe sequences (particularly when assembled by in-situ synthesis) can result in variations in the binding energetics of interfacial hybridization from spot to spot on an array, or even within individual array elements. Regions on the substrate may therefore exhibit variations in the selectivity, kinetics and dynamic range of response. The biosensor technology developed by our group presents an alternative to such an approach by use of controlled immobilization methodologies in a sensor format that provides for a reusable and quantitative technology where selectivity and kinetics may be more finely tuned.