Metal-Free Photoinduced Atom Transfer Radical Polymerization for Highly Sensitive Detection of Lung Cancer DNA

Convenient and sensitive detection of biomolecules is of great significance to disease diagnosis. In this work, a metal-free photoinduced atom transfer radical polymerization (photoATRP) by a reductive quenching pathway as a novel strategy is applied to achieve lung cancer DNA detection. Thiolated PNA is exploited to specifically recognize target DNA, and the initiator of photoATRP is linked to the electrode surface via phosphate-Zr⁴⁺ -carboxylate. Under the excitation of blue light, the reductive quenching pathway is activated with eosin Y (EY) as photoredox catalyst and N,N,N',N'',N'-pentamethyldiethylenetriamine (PMDETA) as electron donor, and numerous polymeric chains are formed. Under optimal conditions, the linear range of this strategy is from 0.1 pm to 10 nm (R² =0.989) with a limit of detection (LOD) of 1.4 fm (14 zmol in 10 μL). The variety of possible light sources for photoATRP and simple operation endow this biosensor with great potential for practical applications.