Rapid detection of single nucleotide polymorphisms associated with spinal muscular atrophy by use of a reusable fibre‐optic biosensor

Rapid (<2 min) and quantitative genotyping for single nucleotide polymorphisms (SNPs) associated with spinal muscular atrophy was done using a reusable (approximately 80 cycles of application) fibre-optic biosensor over a clinically relevant range (0‐4 gene copies). Sensors were functionalized with oligonucleotide probes immobilized at high density (~7 pmol/cm 2 ) to impart enhanced selectivity for SNP discrimination and used in a total internal reflection fluorescence detection motif to detect 202 bp PCR amplicons from patient samples. Realtime detection may be done over a range of ionic strength conditions (0.1‐1.0 M) without stringency rinsing to remove non-selectively bound materials and without loss of selectivity, permitting a means for facile sample preparation. By using the timederivative of fluorescence intensity as the analytical parameter, linearity of response may be maintained while allowing for significant reductions in analysis time (10‐100-fold), permitting for the completion of measurements in under 1 min.