Electrochemiluminescent immunosensor for prostate specific antigen based upon luminol functionalized platinum nanoparticles loaded on graphene.

A novel label-free electrochemiluminescent (ECL) immunosensor based upon luminol functionalized platinum nanoparticles loaded on graphene sheets (Lu-Pt@GS) as sensing platform was fabricated for highly sensitive and selective determination of prostate specific antigen (PSA). In this work, for the first time luminol was employed as both ECL luminescence reagent and reductants to in-situ reduce H2PtCl6 forming Pt NPs on surface of GS. A great deal of luminol could be attached onto the surface of Pt NPs within the reduction process, which can generate strong ECL emission. Pt NPs not only could enhance ECL signals of luminol but supply active sites for the immobilization of PSA antibodies with micro friendly environment. For preventing the consecutive reaction among luminol and H2O2, single-step cycle pulse was adopted, resulting in stable and strong ECL signals. Under optimized experimental conditions, the proposed ECL immunosensor acquired a wide linear range of 1 pg/mL to 10 ng/mL with a relatively low detection limit of 0.3 pg/mL for PSA. Furthermore, due to high sensitivity, simplicity and cost-effectiveness, the designed immunosensor provides a new method for detecting other important biomarkers in clinical analysis.

Nature and strength of chalcogen-π bonds.

Chalcogen-π interactions occur between a covalently bound chalcogen atom that enters into a non-covalent interaction with an unsaturated moiety, a bonding motif found in various structures, such as, proteins. In this work, we have systematically explored and analyzed chalcogen-π interactions in model systems X2DA (with D = O, S, Se, Te; X = halogen; A = acetylene, ethylene and 2-butyne), using relativistic density functional theory (DFT). The nature and trends in stability of the chalcogen-π bonds are analyzed and interpreted in terms of quantitative MO theory in combination with a matching canonical energy decomposition analysis (EDA) scheme. We find that chalcogen-π bonds increase in strength as the X-D electronegativity difference becomes greater. Moreover, 2-butyne was found to participate in the strongest non-covalent interaction due to enhanced orbital interactions.

Synergistic Effect of Au-PdO Modified Cu-Doped K2W4O13 Nanowires for Dual Selectivity High Performance Gas Sensing.

Both 3-hydroxy-2-butanone and triethylamine are highly toxic and harmful to human health, and their chronic inhalation can cause respiratory diseases, eye lesions, dermatitis, headache, dizziness, drowsiness, and even fatality. Developing sensors for detecting such toxic gases with low power consumption, high response with superselectivity, and stability is crucial for healthcare and environmental monitoring. This study presents a typical gas sensor fabricated based on AuPdO modified Cu-doped K2W4O13 nanowires, which can selectively detect 3-hydroxy-2-butanone and triethylamine at 120 and 200 °C, respectively. The sensor displays excellent sensing performance at reduced operating temperature, high selectivity, fast response/recovery, and stability, which can be attributed to a synergistic effect of Cu dopants and AuPdO nanoparticles on the K2W4O13 host. The enhanced sensing response and selectivity could be attributed to the oxygen vacancies/defects, bandgap excitation, the electronic sensitization, the reversible redox reaction of PdO and Cu, the cocatalytic activity of AuPdO, and Schottky barrier contacts at the interface of tungsten oxide and Au. The significant variations in the activation capacities of Cu-doped K2W4O13, Pd/PdO, and Au nanoparticles toward 3H-2B and TEA, and the diffusion depth of the two gases in the coated sensing layer may cause dual selectivity. The designed gas sensor materials can serve as a sensitive target for detecting toxic biomarkers and hold broad application prospects in food and environmental safety inspection.