A Novel Composite of Aptamer-Based Ti3C2Tx and Molecularly Imprinted Polymer with Double Recognition Property for Sensitive Electrochemical Detection of Ofloxacin

A novel composite of aptamer-based Ti3C2Tx and molecularly imprinted polymer (Apt-Ti3C2Tx-MIP) with double recognition property was prepared for sensitive electrochemical detection of ofloxacin (OFL). First, Ti3C2Tx@SiO2 was synthesized using multi-layer Ti3C2Tx and tetraethyl orthosilicate (TEOS) in alkaline conditions. Amino Ti3C2Tx@SiO2 was then prepared through Ti3C2Tx@SiO2 in the presence of (3-aminopropyl)triethoxysilane. Carboxyl OFL aptamers were then grafted onto amino Ti3C2Tx@SiO2 to prepare aptamer-modified Ti3C2Tx@SiO2. A novel composite of Apt-Ti3C2Tx-MIP was prepared with sol-gel method in the presence of Ti3C2Tx@SiO2-Apt-OFL and TEOS. The Apt-Ti3C2Tx-MIP sensor exhibited double recognition for OFL because of aptamer specificity and imprinted binding sites. The electrochemical response of Apt-Ti3C2Tx-MIP sensor for OFL was 2.29 and 2.75 times that of Apt-Ti3C2Tx-NIP and Ti3C2Tx-MIP sensors, respectively, demonstrating the double recognition of Apt-Ti3C2Tx-MIP for OFL. The Apt-Ti3C2Tx-MIP sensor with double recognition displayed a linear peak current to OFL centration from 0.025 to 10 mu M with a detection limit of 10 nM. The Apt-Ti3C2Tx-MIP sensor had excellent selectivity for OFL and has been successfully applied to the detection of OFL in a wastewater sample.