Intramolecular photoinitiator induced atom transfer radical polymerization for DNA electrochemical detection
A novel electrochemical biosensor was firstly reported to achieve DNA highly sensitive detection based on photoinduced atom transfer radical polymerization (photoATRP). In this work, PNA was applied as capture probes to specifically recognize the target DNA (TDNA), and we utilized lung cancer DNA as TDNA. ATRP initiator was introduced to the electrode surface via phosphate-Zr4+-carboxylate chemistry. The photoATRP was activated under the irradiation of blue light based on photoinitiator I2959, which produced free radicals via homolytic cleavage. Subsequently, Cu2+ was reduced to Cu+ under the assistance of the free radicals, and numerous electroactive probes were grafted onto the electrode surface. Under optimal conditions, limit of detection (LOD) of this method was 3.16 fM (S/N=3, R2=0.992), and the linear range was from 10 fM to 1.0 nM. More importantly, the prepared process of this biosensor was simple and less laborious with low background, suggesting a good potential in practical application.