11 research outputs found
A Novel Acetylcholinesterase Biosensor: Core–Shell Magnetic Nanoparticles Incorporating a Conjugated Polymer for the Detection of Organophosphorus Pesticides
To construct a sensing interface,
in the present work, a conjugated
polymer and core–shell magnetic nanoparticle containing biosensor
was constructed for the pesticide analysis. The monomer 4,7-diÂ(furan-2-yl)ÂbenzoÂ[<i>c</i>]Â[1,2,5]Âthiadiazole (FBThF) and core–shell magnetic
nanoparticles were designed and synthesized for fabrication of the
biosensing device. The magnetic nanoparticles were first treated with
silica and then modified using carboxyl groups, which enabled binding
of the biomolecules covalently. For the construction of the proposed
sensor a two-step procedure was performed. First, the polyÂ(FBThF)
was electrochemically generated on the electrode surface. Then, carboxyl
group modified magnetic nanoparticles (f-MNPs) and acetylcholinesterase
(AChE), the model enzyme, were co-immobilized on the polymer-coated
surface. Thereby, a robust and novel surface, conjugated polymer bearing
magnetic nanoparticles with pendant carboxyl groups, was constructed,
which was characterized using Fourier transform infrared spectrometer,
cyclic voltammetry, scanning electron microscopy, and contact angle
measurements. This novel architecture was then applied as an immobilization
platform to detect pesticides. To the best of our knowledge, a sensor
design that combines both conjugated polymer and magnetic nanoparticles
was attempted for the first time, and this approach resulted in improved
biosensor characteristics. Hence, this approach opens a new perspective
in the field of enzyme immobilization and sensing applications. Paraoxon
and trichlorfon were selected as the model toxicants. To obtain best
biosensor performance, optimization studies were performed. Under
optimized conditions, the biosensor in concern revealed a rapid response
(5 s), a low detection limit (6.66 × 10<sup>–3</sup> mM),
and high sensitivity (45.01 μA mM<sup>–1</sup> cm<sup>–2</sup>). The <i>K</i><sub>M</sub><sup>app</sup> value of polyÂ(FBThF)/f-MNPs/AChE were determined as 0.73 mM. Furthermore,
there was no considerable activity loss for 10 d for polyÂ(FBThF)/f-MNPs/AChE
biofilm