Studies towards a switch-off optical DNA sensor based on poly(p-phenylenevinylene) grafted magnetic beads

Much effort has been devoted towards developing efficient DNA sensors for applications in medical diagnostics, food contamination, forensics, biodefence and environmental monitoring. In this study we further evaluate the selectivity of our recently developed switch-off sensor design that utilises sandwich hybridisation between a photoluminescent anionic conjugated polymer (CP) bound capture probe coated onto magnetic beads, target and the dye labelled signalling probe. The hybridisation-readout in our sensor was monitored by superquenching (switch-off) of the fluorescence of CP by Cy3 dye. We have used two recently synthesised carboxylic functionalised poly( p -phenylene vinylenes) (PPVs), poly-6,6´-((2-(( E )-2,5-dimethoxy-4-(( E )-prop-1-en-1-yl)styryl)-5-methyl-1,4 phenylene)bis(oxy))dihexanoic acid ( PDDMe ) and mono glycol units poly(6,6´-((2-(( E )-2,5-bis(2-methoxyethoxy)-4-(( E )-prop-1-en-1-yl)styryl)-5-methyl-1,4-phenylene)bis(oxy))dihexanoic acid) ( PDMonoG ) to test as part of this sensing design with complementary, non-complementary and mis-matched DNA. PDMonoG demonstrated better selectivity and holds promise towards development of robust platforms for commercial DNA sensors.