Anti-C-Ret (C-terminal) polyclonal antibody

Upconversion nanoparticles (UCNP) are increasingly used due to their advantages over conventional fluorophores, and their use as resonance energy transfer (RET) donors has permitted their application as biosensors when they are combined with appropriate RET acceptors such as graphene oxide (GO). However, there is a lack of knowledge about the design and influence that GO composition produces over the quenching of these nanoparticles that in turn will define their performance as sensors. In this work, we have analysed the total quenching efficiency, as well as the actual values corresponding to the RET process between UCNPs and GO sheets with three different chemical compositions. Our findings indicate that excitation and emission absorption by GO sheets are the major contributor to the observed luminescence quenching in these systems. This challenges the general assumption that UCNPs luminescence deactivation by GO is caused by RET. Furthermore, RET efficiency has been theoretically calculated by means of a semiclassical model considering the different nonradiative energy transfer rates from each Er3+ ion to the GO thin film. These theoretical results highlight the relevance of the relative positions of the Er3+ ions inside the UCNP with respect to the GO sheet in order to explain the RET-induced efficiency measurements. (C) 2020 Elsevier Inc. All rights reserved.

Herein, a facile one-pot intrapolymerization strategy to synthesize manganese-eumelanin coordination nanocomposites (Mn-Eu) was introduced to quench the electrochemiluminescence (ECL) behavior of luminol/H2O2 system. Bimetallic PtCo and CuFe2O4 nanoparticles decorated with reduced graphene oxide was prepared to combine with luminol via electrostatic attractions (Lu-PtCo-CuFe2O4-rGO) which possessed excellent ECL signals. PtCo-CuFe2O4-rGO not only exhibited well electrocatalytic activity toward the electrooxidation reactions of luminol and H2O2, but also facilitated the electroreduction of H2O2 producing more reactive oxygen species (ROSs) which can further enhance the ECL intensity of luminol. To sensitively detect pmcalcitonin, Mn-Eu labeled-secondary antibodies were employed to specific recognize antigen which incubated with primary antibodies/Lu-PtCo-CuFe2O4-rGO. The quenching mechanism may be via the synergistic effect between Mn-Eu inhibiting the electrooxidation of H2O2 and ECL resonance energy transfer (ECL-RET) from ECL donor luminol to ECL acceptor Mn-Eu. Under optimal experiments, the ECL immunosensor for detecting procalcitonin with a wider linear range from 0.005 pg/mL to 100 pg/mL and a detection limit of 0.0021 pg/mL (S/N = 3) was obtained. The suggested strategy possessed great potential in bioanalysis and will broaden the application of Mn-Eu.