A Sensitive Electrochemical Assay for T4 Polynucleotide Kinase Activity Based on Fe <sub>3</sub> O <sub>4</sub> @TiO <sub>2</sub> And Gold Nanoparticles Hybrid Probe Modified Magnetic Electrode
Zaiqiong Liu, Jinpeng Tao, Zhenyu Zhu, Yanli Zhang, Hongbin Wang, Pengfei Pang, Hai‐Bo Wang, Wenrong Yang
Abstract
An ultrasensitive electrochemical assay for T4 polynucleotide kinase (T4 PNK) activity and inhibition was developed based on magnetic Fe 3 O 4 @TiO 2 core–shell nanoparticles and gold nanoparticles hybrid probe (Fe 3 O 4 @TiO 2 -dsDNA-AuNPs) modified magnetic gold electrode (MGE). Fe 3 O 4 @TiO 2 -dsDNA-AuNPs hybrid probe was formed via DNA hybridization between phosphorylated DNA S1 modified Fe 3 O 4 @TiO 2 and complementary DNA S2 assembled AuNPs. [Ru(NH 3 ) 6 ] 3+ was used as an electrochemically active indicator to enhance the electrochemical signal. The proposed method is sensitive for T4 PNK activity assay with a linear range of 0.0001 to 10 U ml −1 and low detection limit of 0.00003 U ml −1 . This strategy can be used to screen the T4 PNK inhibitors, holding a great potential for discovery of nucleotide kinase-target drug and early clinical diagnosis of cancer.