An intriguing electrochemical impedance aptasensor based on a porous organic framework supported silver nanoparticles for ultrasensitively detecting theophylline

Porous organic frameworks (POFs) are excellently stable porous materials, which can be employed as host platforms to support metal nanoparticles as functional composites for various applications. Herein, a novel POF is successfully prepared via Friedel-Crafts reaction. Silver nanoparticles (Ag NPs) are embedded in the prepared POF to generate an Ag@POF composite, which not only possesses high surface area, outstanding physicochemical stability and outstretched pi-conjugation skeleton, but also exhibits preferable electrochemical stability and conductivity. This composite is able to immobilize a mass of aptamer strands to fabricate an intriguing electrochemical aptasensor. Electrochemical impedance spectroscopy (EIS) is a commonly used technology to analyze the electrochemical signal variation. The Ag@POF-based biosensor shows the excellent electrochemical detection behavior through analyzing EIS. For instance theophylline as a research mode, the Ag@POF based electrochemical aptasensor reveals ultra-sensitiveness, high selectivity, remarkable stability, good repeatability and simple operability even in various real samples. Notably, this aptasensor has the sensitive detection performance with the limit of detection of 0.191 pg/mL (1.06 pmol/L) in a wide concentration range of 5.0 x 10(-4) - 5.0 ng/mL (2.78 x 10(-3 )- 27.8 nmol/L). (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

A novel POF was prepared via Friedel-Crafts reaction, in which silver nanoparticles were embedded to generate an Ag@POF composite for fabricating an intriguing electrochemical aptasensor. The biosensor showed excellent electrochemical detection behavior, with ultra-sensitiveness, high selectivity, remarkable stability, good repeatability, and simple operability, even in various real samples, with a limit of detection of 0.191 pg/mL in a wide concentration range.