A recyclable biointerface based on cross-linked branched DNA nanostructures for ultrasensitive nucleic acid detection.

The detection of specific nucleic acids is becoming increasingly important in the discovery of genetic diseases and clinical molecular diagnostics. Here we report a DNA nanostructure-based platform which enables a recyclable biointerface for ultra-sensitive detection of nucleic acid. We created a chemically cross-linked branched DNA nanostructure (CCLB-DNA) as the probe DNA to engineer the biointerfaces, thereby increasing probe distance, exposing more DNA probes from the interface into the solution phase, and thus enhancing the signal dramatically. In addition, DNA functionalized Fe3 O4 nanoparticles were utilized for further signal amplification. The detection limit could go as low as 500 fM. Moreover, CCLB-DNA could endure denaturation conditions without disruption of duplex integrity; as a result, the recognition layer could be easily regenerated and the biointerface could be reused. Our CCLB-DNA represents an excellent prospect in the engineering of recyclable biointerface, which will be beneficial to many biosensing systems.