Magnetite Nanoparticles Bonded Carbon Quantum Dots Magnetically Confined onto Screen Printed Carbon Electrodes and their Performance as Electrochemical Sensor for NADH

Abstract

Hybrid magnetite/carbon quantum dots (MagNP/C‐dots) were prepared and their characterization performed by high resolution transmission electron microscopy (HR‐TEM), X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). Because of their suitable magnetization and electrochemical properties, they were used as versatile electrode modifiers after magnetically confining onto screen printed carbon electrodes (SPE), with the aid of a miniature external magnet. The reported strategy introduces a convenient procedure for assembling modified electrodes, since the nanoparticles can be easily released by removing the magnet. The non‐enzymatic magnetic biosensor showed excellent performance in the determination of NADH at the concentration range 2×10−7 to 5×10−6 mol L−1, exhibiting a sensitivity of 0.15 μmol L−1 and detection limit of 20 nmol L−1. The MagNP/C‐dots/SPE sensor was also successfully applied for the determination of NADH in serum samples. The interference of typical biological molecules has also been investigated.

One‐Step Synthesis of Silica‐Coated Carbon Dots with Controllable Solid‐State Fluorescence for White Light‐Emitting Diodes

“…As shown by high resolution transmission electron microscopy (HRTEM) images, CDots are evenly wrapped inside silica matrix and possess very similar particle size, with the average particle sizes of 2.46±0.57, 3.12±0.52, and 3.71±0.48 nm for B‐silica/CDots, Y‐silica/CDots, and O‐silica/CDots (Figure d–f), respectively, indicating that the emission wavelength of silica/CDots composites is independent on the size of CDots . And the three CDots have highly crystalline carbon structure with an interplanar distances of about 0.21, 0.204, and 0.20 nm by the 2D lattice fringes of the CDots (Figure d–f, insets), which are attributed to the (100), (102), and (102) lattice planes of graphitic (sp 2 ) carbon, respectively …”

Facile Preparation of Fe3O4/C Nanocomposite and Its Application for Cost-Effective and Sensitive Detection of Tryptophan

“…Nanostructured transition metal oxides such as TiO 2 [15,16], SnO 2 [9], CuO [11], and Ta 2 O 5 [34] have been utilized for the detection of Trp. Despite the wide variety of transition metal oxides available, Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs) are highly encouraged as sensing materials because of their low fabrication cost, environmental friendliness, and excellent electrochemical properties [35]. Moreover, the good biocompatible nature of Fe 3 O 4 NPs endows them attractive candidates for various biosensors [36].…”

Carbon Nanodots in Electrochemical Sensors and Biosensors: A Review

“… A picture of carbon screen‐printed electrode (SPE) containing a tiny magnet. Adapted from Ref [89] . with permission; Copyright (2017) Wiley‐VCH GmbH.…”