Water-dispersible molecularly imprinted nanohybrids via co-assembly of carbon nanotubes with amphiphilic copolymer and photocrosslinking for highly sensitive and selective paracetamol detection

Abstract

A novel kind of water-dispersible molecularly imprinted nanohybrids containing multi-walled carbon nanotubes (MWCNTs) was prepared via the combination of co-assembly and photocrosslinking, and employed to construct an electrochemical sensor. A photo-crosslinkable amphiphilic copolymer (Poly(AA-co-VMc-co-EHA), PDHES) was firstly synthesized, which could co-assemble with MWCNTs in the presence of template molecule (paracetamol, PCM) in aqueous solution, generating photo-crosslinkable molecularly imprinted nanohybrids (MIP-MWCNTs). A robust MIP-MWCNTs film was formed on the electrode surface via the deposition of MIP-MWCNTs nanohybrids and the subsequent photo-crosslinking. After extracting paracetamol molecules, an electrochemical MIP-MWCNTs sensor was successfully developed. The as-prepared MIP-MWCNTs sensor showed a significantly wide linear detection range (0.1–2500 μM) and low detection limit (0.02 μM), owing to the large surface area of MIP-MWCNTs nanohybrids and superior electrical conductivity of MWCNTs, which affords a direct channel for the electron transfer from the recognition cavities to the electrode surface and thus enhances the response signal. In addition, good selectivity toward paracetamol (the imprinting factor α is 7.5) and ultrafast response time (less than 180 s) of MIP-MWCNTs sensor have also been demonstrated. The MIP-MWCNTs sensor also exhibited satisfactory repeatability and stability, which has been successfully utilized to measure paracetamol in urine samples with good results, demonstrating a promising feature for applications in medical diagnostics.