Label-Free Biosensing Based on Multilayer Fluorescent Nanocomposites and a Cationic Polymeric Transducer

This study describes the preparation and characterization of a DNA sensing architecture combining the molecular recognition capabilities of a cationic conjugated polymer transducer with highly fluorescent core-shell nanoparticles (NPs). The very structure of the probe-labeled NPs and the polymer-induced formation of NP aggregates maximize the proximity between the polymer donor and acceptor NPs that Is required for optimal resonant energy transfer. Each hybridization event is signaled by a potentially large number of excited reporters following the efficient plasmon-enhanced energy transfer between target-activated polymer transducer, and fluorophores located in the self assembled core-shell aggregates, resulting, in direct molecular detection of target nucleic acids at femtomolar concentrations.