ABSTRACT
Polymers have attracted attention as luminophores due to their excellent electrochemiluminescence (ECL) properties. However, the current research and application of polymers mainly focus on anode emission, and ECL efficiency is not high enough, thus showing a limited application. This work exploited the persulfate-mediated dual-emission characteristics of poly[2,5-dioctyl-1,4-phenylene] polymer nanoparticles (PDP PNPs). The two ECL emissions were collected synchronously at -2.0V and +1.0V with persulfate (S2O82-) as cathodic coreactant and 3-(dibutylamino) propylamine (TDBA) as anodic coreactant, respectively. Interestingly, S2O82- can simultaneously mediate the double emissions, significantly enhancing both cathode emission and anode emission. The dual-emission mechanism was explored carefully and enhancement mechanism of cathodic coreactant S2O82- to anodic emission was hypothesized to be attributed to SO4∙− radicals, which was produced from S2O82- during cathodic potential scanning and oxidized PDP PNPs to generate more cation radical, thus enhancing anodic emission of PDP PNPs. Moreover, the black hole quencher-2 (BHQ2) was exploited as dual-function moderator to quench dual emissions of PDP PNPs synchronously. PDP PNPs coupled with BHQ2 to build ECL ratiometric system for detecting SARS-CoV-2 RdRp gene and its limit of detection was 25.1 aM. Persulfate-mediated double emissions provided a new way to improve the efficiency of ECL emission from polymers and expand their application. The clever integration of dual-emitting PDP PNPs and dual-regulating BHQ2 created a promising single-luminophore-based ratiometric ECL platform, developed an attractive ECL method for detecting SARS-CoV-2 RdRp gene.
ABSTRACT
The morphology of electrochemiluminescence (ECL) emitters is closely related to ECL properties, thus the control of their morphology is greatly essential for ECL applications. Herein, a facile nanoprecipitation method was developed to realize controllable morphology of iridium complex nanomaterials by modulating the volume ratio of poly(styrene-co-maleicanhydride) (PSMA) to tris (2-phenylpyridine) iridium(Ⅲ) (Ir(ppy)3). Furthermore, ECL properties of iridium complex nanomaterials with different morphologies were explored through a series of experiments. Iridium complex nanoparticles (Ir NPs) with excellent ECL performance were selected as admirable ECL emitters to construct biosensors. Ir NPs served as the matrix to stepwise capture primary antibody, antigen of SARS-CoV-2 nucleocapsid protein (ncovNP) and secondary antibody bioconjugate coupled with dual quenchers and detection antibody. Taking advantage of the significant quenching effect of noradrenaline (NA) and gold nanoparticles (Au NPs) in the secondary antibody bioconjugate on ECL emission from Ir NPs, the developed ECL biosensor realized the sensitive detection of ncovNP and the detection limit was as low as 47 fg/mL. The integration of morphology-controlled iridium complex nanomaterials and dual quenchers NA and Au NPs provides a promising ECL platform.
ABSTRACT
The enrichment of co-reactants is one of the keys to improving the sensitivity of electrochemiluminescence (ECL) detection. This work developed a novel hydrophobic localized enrichment strategy of co-reactants utilizing the inner hydrophobic cavity of ß-cyclodextrin (ß-CD). Pt nanoparticles (Pt NPs) were grown in situ on the coordination sites for metal ions of ß-CD to prepare the ß-CD-Pt nanocomposite, which could not only enrich co-reactant 3-(dibutylamino) propylamine (TDBA) highly efficiently through its hydrophobic cavity but also immobilize TDBA via the Pt-N bond. Meanwhile, the carboxyl-functionalized poly[2,5-dioctyl-1,4-phenylene] (PDP) polymer nanoparticles (PNPs) were developed as excellent ECL luminophores. With SARS-CoV-2 nucleocapsid protein (ncovNP) as a model protein, the TDBA-ß-CD-Pt nanocomposite combined PDP PNPs to construct a biosensor for ncovNP determination. The PDP PNPs were modified onto the surface of a glassy carbon electrode (GCE) to capture the first antibody (Ab1) and further capture antigen and secondary antibody complexes (TDBA-ß-CD-Pt@Ab2). The resultant biosensor with a sandwich structure achieved a highly sensitive detection of ncovNP with a detection limit of 22 fg/mL. TDBA-ß-CD-Pt shared with an inspiration in hydrophobic localized enrichment of co-reactants for improving the sensitivity of ECL detection. The luminophore PDP PNPs integrated TDBA-ß-CD-Pt to provide a promising and sensitive ECL platform, offering a new method for ncovNP detection.