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Highlights: [•] Electrochemical fabrication of a novel ionic liquid based polymeric film electrode. [•] Studies on voltammetric behaviors of estradiol at the polymeric film electrode. [•] Effective oxidation peak current for the voltammetric determination of estradiol. [•] Application of the polymeric film electrode for estradiol assay in real sample. [ABSTRACT FROM AUTHOR]

A molecularly imprinted sensor was fabricated for alpha-fetoprotein (AFP) using an ionic liquid as a functional monomer. Ionic liquid possesses many excellent characteristics which can improve the sensing performances of the imprinted electrochemical sensor. To demonstrate this purpose, 1-[3-(N-cystamine)propyl]-3-vinylimidazolium tetrafluoroborate ionic liquid [(Cys)VIMBF4] was synthesized and used as a functional monomer to fabricate an AFP imprinted polymerized ionic liquid film on a gold nanoparticle modified glassy carbon electrode (GCE) surface at room temperature. After removing the AFP template, a molecularly imprinted electrochemical sensor was successfully prepared. The molecularly imprinted sensor exhibits excellent selectivity towards AFP, and can be used for sensitive determination of AFP. Under the optimized conditions, the imprinted sensor shows a good linear response to AFP in the concentration range of 0.03 ng mL−1~5 ng mL−1. The detection limit is estimated to be 2 pg mL−1. [ABSTRACT FROM AUTHOR]

Abstract A novel ionic liquid, 3-(3-aminopropyl)-1-methylimidazolium hexafluorophosphate (APMimPF 6), with high hydrophobic property was successfully applied as the functional monomer for the halide perovskite preparation. The new hydrophobic ionic liquid significantly facilitates the perovskite forming a 2-dimensional structure with good passivation, particularly at the grain boundaries because of the high hydrophobic character and large size of ionic liquid molecule. The perovskite solar cell fabricated with this new perovskite based on the hydrophobic ionic liquid was found possessing excellent properties: the maximum value of J sc = 22.9 mA cm−2, V oc = 1.05 V, and PCE = 17.3%. In addition, the perovskite solar cell also shows good long-term stability, which benefited from the protecting effect of the high hydrophobic ionic liquid. In a typical stability test, the cells stored under the conditions with a relative humidity of 57% for 40 days, the PCE was able to retain 98% of its initial value. Therefore, the present study demonstrated a significant protocol for the development of highly stable perovskite solar cells. Graphical abstract Image 1 Highlights • 3-(3-Aminopropyl)-1-methylimidazolium hexafluorophosphate ionic liquid was synthesized. • Perovskite based on ionic liquid as functional monomer was prepare. • Solar cell based on ionic liquid functionalized perovskite was fabricated. • Solar cell with high performance and stability was demonstrated. [ABSTRACT FROM AUTHOR]

Ionic liquid functionalized tungsten disulfite nanosheets (IL-WS 2 ) were prepared by using 1-vinyl-3-(3-aminopropyl)-imidazolium bromide (VAPimBr) ionic liquid as an auxiliary reagent to exfoliate WS 2 bulk crystals in N-methyl pyrrolidone with ultrasonication. Hollow gold nanospheres (HGNs) were controllably synthesized by using 1,3-di(3-bromopropyl)-imidazolium bromide ionic liquid as the functional monomer. HGNs were integrated onto IL-WS 2 nanosheet surface to fabricate a HGNs/IL-WS 2 nanocomposite through the interaction between S and Au atoms. VAPimBr ionic liquid and HGNs can significantly enhance the photocurrent response of IL-WS 2 nanosheets. Human epididymis protein 4 antibody (anti-HE4) was immobilized onto the HGNs/IL-WS 2 nanocomposite modified glassy carbon electrode (GCE) surface. Followed by being treated with glutaraldehyde vapor and bovine serum albumin (BSA), a photoelectrochemical immunosensor for human epididymis protein 4 (HE4) was successfully constructed and denoted as anti-HE4/HGNs/IL-WS 2 /GCE. The photoelectrochemical variation upon interacting with HE4 was used for the quantitative assay. Experimental conditions including the exfoliation time, the amount of VAPimBr ionic liquid, HGNs size, ascorbic acid concentration, incubation time, incubation temperature have been optimized. Under optimal conditions, HE4 was determined by using the photoelectrochemical immunosensor in a dynamic linear range from 0.1 pg mL −1 to 10 ng mL −1 with a detection limit of 0.03 pg mL −1 (S/N = 3). HE4 in clinical serum samples were also accurately determined with satisfied results. [ABSTRACT FROM AUTHOR]

A dual-mode biosensor constructed based on photoelectrochemical (PEC) and electrochemical (EC) property was developed for assaying circulating tumor DNA (ctDNA), which is commonly used for triple-negative breast cancer diagnosis. Ionic liquid functionalized two-dimensional Nd-MOF nanosheets were successfully synthesized through a template-assisted reagent substituting reaction. Nd-MOF nanosheets integrated with gold nanoparticles (AuNPs) were able to improve photocurrent response and supply active sites for assembling sensing elements. To achieve selective detection of ctDNA, thiol-functionalized capture probes (CPs) were immobilized on the Nd-MOF@AuNPs modified glassy carbon electrode surface, thereby generating a "signal-off" photoelectrochemical biosensor for ctDNA under visible light irradiation. After the recognition of ctDNA, ferrocene-labeled signaling probes (Fc-SPs) were introduced into the biosensing interface. After hybridization between ctDNA and Fc-SPs, the oxidation peak current of Fc-SPs generated from square wave voltammetry can be employed as a "signal-on" electrochemical signal for ctDNA quantification. Under the optimized conditions, a linear relationship was obtained to the logarithm of ctDNA concentration in between 1.0 fmol L−1 to 10 nmol L−1 for the PEC model and 1.0 fmol L−1 to 1.0 nmol L−1 for the EC model. The dual-mode biosensor can provide accurate results for ctDNA assays, effectively eliminating the probable occurrence of false-positive or false-negative results in single-model assays. By switching DNA probe sequences, the proposed dual-mode biosensing platform can serve as a strategy for detecting other DNAs and possesses broad applications in bioassay and early disease diagnosis. [Display omitted] • A template-assisted reagent substituting reaction was used for synthesizing Nd-MOF nanosheets. • Ionic liquid and gold nanoparticles enhance PEC performance of Nd-MOF nanosheets based interface. • A PEC-EC dual-mode biosensor was fabricated for high-performance sensing human serum ctDNA. • The dual-model biosensor provides a criterion for mutual confirmation of the detection accuracy. • Practicability of the PEC-EC biosensor was demonstrated by assaying ctDNA in human serum samples. [ABSTRACT FROM AUTHOR]

Abstract: 1,3-Di(4-amino-1-pyridinium)propane tetrafluoroborate (DAPPT) ionic liquid was successfully synthesized, and was used as a modifier to functionalize graphene nanosheets through covalent binding of amino groups and epoxy groups in an alkaline solution. The as-prepared graphene-DAPPT nanosheets (Gr-DAPPT) were confirmed with transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/vis and FTIR spectroscopy. A biocompatible platform based on Gr-DAPPT was constructed for the immobilization of hemoglobin (Hb) through a cross-linking step with chitosan and glutaraldehyde. The direct electron transfer and bioelectrocatalytic reaction of Hb immobilized on Gr-DAPPT surface were achieved. A pair of reversible redox peaks of hemoglobin was observed, and bioelectrocatalytic activity toward the reduction of H2O2 was also demonstrated, displaying a potential application for the fabrication of novel biosensors to sense H2O2. Such results indicated that Gr-DAPPT based interface would be a promising platform for biomacromolecular immobilization and biosensor preparation. [Copyright &y& Elsevier]