Electrogenerated Chemiluminescence and Spectroelectrochemistry Characteristics of Blue Photoluminescence Perovskite Quantum Dots

Electrochemiluminescence immunoassay system based on PCN-224-Mn and gold-platinum bimetallic nanoflowers for sensitive detection of ochratoxin A

In this work, a novel Electrochemiluminescence Immunosensor was constructed using PCN-224-Mn and gold-platinum nanoflowers (AuPt NFs) for the ultrasensitive detection of ochratoxin A (OTA). PCN-224 modified with Mn (II) was synthesized as a probe material. The interaction efficiency of PCN-224 with S2O82- was also greatly improved. AuPt NFs were used as the substrate material for the electrodes. It has favorable biocompatibility, large specific surface area and can bind more antigen. Also greatly increased the electroactive surface area and conductivity of the electrode. OTA was detected using a competitive immunoassay strategy, in which OTA in the sample competes with the encapsulated antigen for a finite number of antibodies. ECLIA for the detection of OTA was designed to be highly sensitive, with a linear range from 0.0002 ng mL-1 to 1000 ng mL-1 and a LOD as low as 0.067 pg mL-1. In addition, it was evident from the electrochemical analyses that PCN-224-Mn had a stronger and more stable ECL signal compared to the plain PCN-224. The successful preparation of specific, sensitive and reproducible ECL immunosensors confirms the great promise for the detection of OTA or other small molecule mycotoxins.

Ultrafast charge transfer enhanced nonlinear optical properties of CH3NH3PbBr3 perovskite quantum dots grown from graphene

Halide perovskite quantum dots (PQDs) have exhibited significantly superior nonlinear optical properties compared to traditional semiconductor materials thanks to their peculiar physical and electronic structures. By further improving the nonlinear optical properties of PQDs, it is expected to adapt to ultrafast photonics applications. This work reported the nonlinear optical properties of methylammonium lead bromide-graphene (CH3NH3PbBr3-G) composites synthesized by growing CH3NH3PbBr3 quantum dots directly from a graphene oxide lattice. Our experiments indicate that the combined advantages of the ultrafast charge transport properties from graphene and the strong charge generation efficiency of perovskite can be integrated together. The CH3NH3PbBr3-G composite exhibited enhanced saturable absorption properties with large modulation depth and very low saturation intensity. The transient absorption spectra and carrier dynamics analysis revealed that the enhancement of the saturated absorption properties of the composites mainly arose from the ultrafast charge transfer between G and CH3NH3PbBr3 which promoted the coupling between different states. The results pave the way for the design of optical switches or mode lockers based on saturable absorbers with good performance.

Ternary Electrochemiluminescence Biosensor Based on DNA Walkers and AuPd Nanomaterials as a Coreaction Accelerator for the Detection of miRNA-141

In this study, a ternary electrochemiluminescence (ECL) sensing platform coupled with a multiple signal amplification strategy was proposed for ultrasensitive detection of miRNA-141. The initial signal amplification was achieved via three-dimensional reduced graphene oxide (3D-rGO)@Au nanoparticles (NPs) to form an excellent conductive layer. Then, AuPd NPs as a coreaction accelerator was introduced into the N-(4-aminobutyl)-N-(ethylisoluminol) (ABEI)-H₂O₂ system to facilitate the transformation from H₂O₂ to excess superoxide anion radicals (O₂^•-), which further amplified the ECL emission of ABEI, leading to a significant increase of the ECL signal. Meanwhile, in the presence of miRNA-141 and T7 Exonuclease (T7 Exo), the self-assembled DNA swing arm can be driven to walk autonomously. The DNA walker reaction could result in the release of numerous labeled luminophores, which could react to achieve an extremely weak ECL signal. Surprisingly, the established ECL sensor platform for the detection of miRNA-141 demonstrated excellent sensitivity with a low detection limit of 31.9 aM in the concentration range from 100 aM to 1 nM. Consequently, the designed strategy greatly improves the luminous efficiency of the ternary ECL system and provides a special approach for the detection of nucleic acids and biomarkers in clinical and biochemical analysis.