Metal-free DNA sensor based on 10-phenylphenothiazine photo-ATRP signal amplification

Abstract

The development of ultrasensitive deoxyribonucleic acid (DNA) sensors related to the disease is of great significance for early diagnosis and prevention of the disease. Here, an ultrasensitive DNA sensor based on the photocatalytic atom transfer radical polymerization (photo-ATRP) strategy was prepared. In this strategy, the target DNA was specifically recognized by sulfhydryl-modified peptide nucleic acid (PNA), and α-bromophenylacetic acid (BPAA) was grafted onto the DNA via phosphate-Zr(IV)-carboxylate. In the presence of photocatalyst 10-phenylphenothiazine (PTH), α-Br was reduced under 365 nm UV light to generate active radicals, and the polymer chain containing electrochemical signaling molecule (ferrocene) was introduced to the electrode surface by mediated ATRP. Finally, the peak current value was measured by square wave voltammetry (SWV) and the concentration of DNA was evaluated. The biosensor was constructed based on a green strategy for ATRP reaction without using a heavy metal catalyst (metal-free), thus reducing the pollution of the environment. Moreover, under optimal conditions, the relationship between the DNA sensor and the target was linear in the concentration range of 0.1 fM ∼ 10 pM, and the limit of detection was 79 aM. The sensor has the advantages of high sensitivity, interference-free and good stability, which indicates that it has great practical application potential in the field of life science and medical research.