Ratiometric electrochemical direct sensing of ciprofloxacin antibiotic via electroless plating of silver on graphynes

Abstract

The abuse of ciprofloxacin (CIP) antibiotic has aroused severe harm to the humans, thus achieving its sensitive and reliable detection is very important. Herein, by using a rising-star material graphynes (GDY) as the substrate, we firstly revealed Ag⁺ can be self-reduced via simple electroless plating process to form tiny silver (Ag⁰) nanoparticles (Ag NPs) and obtained a novel Ag@GDY nanohybrid. For this nanohybrid, the resulted Ag NPs can not only improve the conductivity and resolve the aggregation of GDY, but also can be used as an internal reference to construct a ratiometric electrochemical sensor; meanwhile, GDY can provide the affinity ability to CIP molecules via π-π interaction, and the band theory analysis also demonstrated the Ag@GDY nanohybrid could exhibit the synthetical catalysis advantages from Ag NPs and GDY, showing enhanced greatly catalytical activity compared to the pure GDY. On the basic of these comprehensive superiorities, a sensitive ratiometric electrochemical direct sensing platform for CIP was then developed for the first time by using Ag@GDY modified electrode, which was confirmed to be linear with the CIP concentrations from 0.09 to 5.0 μM via adopting the current ratio between CIP and Ag⁰ as the read-out signal. Under the optimized conditions, the detection limit for CIP is as low as 23.0 nM in this work, and the constructed Ag@GDY sensor for CIP detection in the real samples was also confirmed, which thus showed important potential applications.