Plasmonic AuNP/g‑C3N4 Nanohybrid-based Photoelectrochemical Sensing Platform for Ultrasensitive Monitoring of Polynucleotide Kinase Activity Accompanying DNAzyme-Catalyzed Precipitation Amplification

• Published in: ACS applied materials & interfaces Vol. 7; no. 15; pp. 8330 - 8338
• Main Authors: Zhuang, Junyang, Lai, Wenqiang, Xu, Mingdi, Zhou, Qian, Tang, Dianping
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22.04.2015
• Subjects: Biosensing Techniques - instrumentation; Catalysis; Conductometry - instrumentation; DNA, Catalytic - chemistry; Enzyme Activation; Equipment Design; Equipment Failure Analysis; Gold - chemistry; Materials Testing; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Nitriles - chemistry; Nucleic Acid Amplification Techniques - instrumentation; Photochemistry - instrumentation; Polynucleotide 5'-Hydroxyl-Kinase - analysis; Polynucleotide 5'-Hydroxyl-Kinase - chemistry; Surface Plasmon Resonance - instrumentation; gold-decorated g-C3N4 nanosheets; photoelectrochemistry; surface plasmon resonance; T4 polynucleotide kinase; isothermal amplification
• DOI: 10.1021/acsami.5b01923
• ISSN: 1944-8244

A convenient and feasible photoelectrochemical (PEC) sensing platform based on gold nanoparticles-decorated g-C3N4 nanosheets (AuNP/g-C3N4) was designed for highly sensitive monitoring of T4 polynucleotide kinase (PNK) activity, using DNAzyme-mediated catalytic precipitation amplification. To realize our design, the AuNP/g-C3N4 nanohybrid was initially synthesized through in situ reduction of Au­(III) on the g-C3N4 nanosheets, which was utilized for the immobilization of hairpin DNA1 (HP1) on the sensing interface. Thereafter, a target-induced isothermal amplification was automatically carried out on hairpin DNA2 (HP2) in the solution phase through PNK-catalyzed 5′-phosphorylation accompanying formation of numerous trigger DNA fragments, which could induce generation of hemin/G-quadruplex-based DNAzyme on hairpin DNA1. Subsequently, the DNAzyme could catalyze the 4-chloro-1-naphthol (4-CN) oxidation to produce an insoluble precipitation on the AuNP/g-C3N4 surface, thereby resulting in the local alternation of the photocurrent. Experimental results revealed that introduction of AuNP on the g-C3N4 could cause a ∼100% increase in the photocurrent because of surface plasmon resonance-enhanced light harvesting and separation of photogenerated e–/h+ pairs. Under the optimal conditions, the percentage of photocurrent decrement (ΔI/I 0, relative to background signal) increased with the increasing PNK activity in a dynamic working range from 2 to 100 mU mL–1 with a low detection limit (LOD) of 1.0 mU mL–1. The inhibition effect of adenosine diphosphate also received a good performance in PNK inhibitor screening research, thereby providing a useful scheme for practical use in quantitative PNK activity assay for life science and biological research.