Hg²⁺, a highly toxic heavy metal, poses significant environmental and health risks, necessitating rapid detection methods. In this study, we employed an electrochemical aptasensor for rapid and sensitive detection of Hg²⁺ based on DNA strands (H2 and H3) immobilized graphene aerogels-Au nanoparticles (GAs-AuNPs) hybrid recognition interface and exonuclease III (Exo III)-mediated cyclic amplification. Firstly, Gas-AuNPs were modified on the surface of the ITO electrode to form a sensing interface to increase DNA loading and accelerate electron transfer. Then, DNA helper was generated with the addition of Hg²⁺ via Exo III-mediated cycling. Finally, the hairpin structures of H2 and H3 were opened with the DNA helper, and then the methylene blue (MB) functionalized DNA (A1 and A2) combined with the H2 and H3 to form an H-shaped structure. The current response of MB as an electrochemical probe was proportional to the concentration of Hg²⁺. Under optimal conditions, the aptasensor showed excellent performance for Hg²⁺, achieving a linear range from 1 fM to 10 nM and a detection limit of 0.16 fM. Furthermore, the aptasensor was used to detect Hg²⁺ in spiked milk samples, achieving a high recovery rate and demonstrating promising application prospects.

Herein, a rapid and highly sensitive amperometric biosensor for the detection ofα-ketoglutarate (α-KG) was constructed via an electrochemical approach, in which the glutamate dehydrogenase (GLUD) was modified on the surface of reduced graphene oxide-gold nanoparticle composite (rGO-Au_nanocomposite). The rGO-Au_nanocomposite was one-step electrodeposited onto glassy carbon electrode (GCE) surface and was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electrochemical techniques. In addition, the rGO-Au_nano/GCE was also found to electrocatalyze the oxidation ofβ-nicotinamide adenine dinucleotide (NADH) at the peak potential of 0.3 V, which was negatively shifted compared with that at bare GCE or Au_nano/GCE, illustrating better catalytic performance of rGO-Au_nano. After the modification of GLUD, the GLUD/rGO-Au_nano/GCE led to effective amperometric detection ofα-KG through monitoring the NADH consumption and displayed a linear response in the range of 66.7 and 494.5 μM, with the detection limit of 9.2 μM. Moreover, the prepared GLUD/rGO-Au_nano/GCE was further evaluated to be highly selective and used to testα-KG in human serum samples. The recovery and the RSD values were calculated in the range of 97.9–102.4% and 3.8–4.5%, respectively, showing a great prospect for its real application.

Correction for ‘Excellent performance of one-pot synthesized Fe-containing MCM-22 zeolites for the selective catalytic reduction of NO_x with NH₃’ by Jialing Chen et al., Catal. Sci. Technol., 2020, 10, 6583–6598, DOI: 10.1039/D0CY00989J.

In this work, a novel electrochemical aptasensor for the detection of ochratoxin A (OTA) was developed using a three-dimensionally ordered macroporous (3DOM) reduced graphene oxide–Au nanoparticles–molybdenum disulfide (RGO-AuNPs-MoS₂) composite material as the sensing interface and Au nanoparticles–carbon-coated ferroferric oxide (AuNPs-Fe₃O₄@C) composite as the signal amplifier. The 3DOM RGO-AuNPs-MoS₂ composite exhibited excellent conductivity and catalytic activity. The 3DOM RGO-AuNPs-MoS₂ film was electrodeposited onto the Au electrode surface to immobilize DNA capture probe (CP), which was then hybridized with DNA helper strands (HS) and OTA aptamer (OPT) to form a Y-shaped structure. In the presence of OTA, the OPT was released from the electrode and then combined with AuNPs-Fe₃O₄@C containing the signal DNA1-metheylene blue (S1-MB) and DNA2-metheylene blue (S2-MB). The current response coming from MB was proportional with the OTA concentration. Under optimal conditions, the linear range of the aptasensor was 1 fg/mL to 0.1 μg/mL, with a detection limit as low as 0.56 fg/mL. The aptasensor was also used to detect OTA in rice and wheat samples, and the results were in agreement with those obtained by liquid chromatography-mass spectrometry (HPLC-MS).

Synaptic devices are progressing towards large-scale integration, but artificial neuron device research is still in its infancy. NbOx is an artificial neuron core material, but the Vth, Vhold of the threshold shift of NbOx will shift within a certain range, which will be unfavorable for making oscillating neurons.In this paper, We explore the Vth and Vhold shift and electrical properties of NbOx volatile memristor in different temperatures. The results indicate that the window of I-V behaves more stable at low temperatures, and higher temperatures would make the window stochastic increasing and more prone to failure. Furthermore, this suggests that the reduction of the high resistance state of the volatile NbOx memristor is due to the reduction of the Schottky barrier.