Magnetic Glassy Carbon Research Articles

A green EC/ECL dual-mode biosensing platform for detection of Vibrio parahaemolyticus

Here, a green EC/ECL dual-mode biosensing platform was designed for sensitive and accurate detection of Vibrio parahaemolyticus (VP). When VP was present, Apt on Fe3O4@SiO2-cDNA/Apt was specifically bound to VP and detached to obtain Fe3O4@SiO2-cDNA. Subsequently, aDNA on Zn-TCPP@AgNPs-aDNA was hybridized with cDNA on Fe3O4@SiO2-cDNA to obtain magnetic conjugates, which were quickly collected by magnetic force and then one-step assembled onto a magnetic glassy carbon (MGCE) electrode for EC/ECL dual-mode measurement. Under the optimal experimental conditions, the detection linear range of VP was 10 ∼ 107 CFU/mL, and the detection limits (LOD) were as low as 7 CFU/mL (EC) and 3 CFU/mL (ECL), respectively, with good repeatability, storage stability and selectivity. In addition, Fe3O4@SiO2-cDNA/Apt and Zn-TCPP@AgNPs-aDNA could be regained by adding Apt into the magnetic conjugates recovered after EC/ECL test, thus the biosensing platform was regenerated with the signal still remaining up to 91.7% (EC) and 92.8% (ECL) after 10 cycles of recovery. With homogeneous recognition and good regeneration, this EC/ECL dual-mode sensing platform provides a green, simple and reliable pathway for the analysis of VP or other foodborne pathogens.

Electrochemical Enantioanalysis of D- and L-Cysteine with a Dual-Template Molecularly Imprinted Sensor

The present work describes a faithful strategy of dual-template molecularly imprinted polymers (MIP) to chiral recognize and quantify D-Cystine (D-Cys) and L-Cystine (L-Cys) at ultra-trace level through “vector method.” Briefly, one has to saturate association D-Cys while analyzes L-Cys, and vice versa. Herein, the working electrode, magnetic glassy carbon (MGCE), was initially drop-coated with molybdenum disulfide-ionic liquid (MoS2-IL) dispersion liquid for large specific surface area and excellent electrical conductivity. After the working electrode was dried naturally, chitosan (CS) was electrodeposited on. And the strong electrostatic interactions between CS and Fe[(CN)6]3−/4− could further enhance the electric signal. Next, dual-template MIP dispersion liquid was drop-coated on the working electrode. Moreover, Fe3O4 nano-particles (NPs) was regard as the support skeleton material of dual-template MIP, which could significantly improve the bonding strength with MGCE. Herein, the proposed sensor demonstrated good analytical figures of merits with Differential Pulse Voltammetry (DPV), showing that the LOD of L-Cys and D-Cys were 0.7402 pg ml−1 and 0.6136 pg ml−1 respectively, with linear response ranges from 1 pg ml−1 to 12 pg ml−1 for both enantiomers. Furthermore, the proposed sensor exhibited great potential in chiral recognition and biochemical analysis.