3-Isopropyl-2-p-tol­yloxy-5,6,7,8-tetra­hydro-1-benzothieno[2,3-d]pyrimidin-4(3H)-one

In the title compound, C20H22N2O2S, the central thieno­pyrimidine ring system is essentially planar, with a maximum displacement of 0.023 (2) Å. The attached cyclo­hexene ring is disordered over two possible conformations, with an occupancy ratio of 0.776 (12):0.224 (12). Neither inter­molecular hydrogen-bonding inter­actions nor π–π stacking inter­actions are present in the crystal structure. The mol­ecular conformation and crystal packing are stabilized by three intra­molecular C—H⋯O hydrogen bonds and two C—H⋯π inter­actions

One-Pot Hydrothermal Synthesis of Magnetite Prussian Blue Nano-Composites and Their Application to Fabricate Glucose Biosensor

In this work, we presented a simple method to synthesize magnetite Prussian blue nano-composites (Fe3O4-PB) through one-pot hydrothermal process. Subsequently, the obtained nano-composites were used to fabricate a facile and effective glucose biosensor. The obtained nanoparticles were characterized using transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, UV-vis absorbance spectroscopy, cyclic voltammetry and chronoamperometry. The resultant Fe3O4-PB nanocomposites have magnetic properties which could easily controlled by an external magnetic field and the electro-catalysis of hydrogen peroxide. Thus, a glucose biosensor based on Fe3O4-PB was successfully fabricated. The biosensor showed super-electrochemical properties toward glucose detection exhibiting fast response time within 3 to 4 s, low detection limit of 0.5 µM and wide linear range from 5 µM to 1.2 mM with sensitivity of 32 µA∙mM−1∙cm−2 and good long-term stability

An easy compartment-less biofuel cell construction based on the physical co-inclusion of enzyme and mediator redox within pressed graphite discs

We report on the easy and fast immobilization of glucose oxidase (GOD) and laccase by mechanical compression with graphite particles to form disc electrodes. The electrical wiring of GOD and laccase was efficiently carried out by their co-inclusion with ferrocene (Fc) and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) respectively. A glucose/air compartment-less biofuel cell was constructed based on the association of GOD-ferrocene-graphite disc and laccase-ABTS – graphite disc electrodes as bioanode and biocathode respectively. Such biofuel cell yielded a power density of 23 μW cm−2 at 0.33 V as well as an open-circuit voltage and a short-circuit current of 0.63 V and 166 μA, respectively. Keywords: Enzymatic biofuel cell, Graphite disc, Glucose oxidase, Laccas

General Strategy to Fabricate Electrochemiluminescence Sandwich-Type Nanoimmunosensors Using CdTe@ZnS Quantum Dots as Luminescent Labels and Fe₃O₄@SiO₂ Nanoparticles as Magnetic Separable Scaffolds

This work aims to develop universal sandwich-type electrochemiluminescence (ECL) nanoimmunosensors for quantitative detection of biomarkers. A series of low-toxic CdTe@ZnS QDs with different core sizes have been synthesized via hydrothermal method and characterized by UV–vis spectra, photoluminescence spectra, TEM, EDS, and XRD. Especially, the ECL behaviors of CdTe@ZnS QDs have been investigated carefully. The CdTe@ZnS QDs with the highest ECL quantum yields have been chosen as ECL labels for conjugation with secondary antibodies. The QDs-labeled antibodies have been characterized by agarose gel electrophoresis. Meanwhile, Fe₃O₄@SiO₂ magnetic nanoparticles were utilized as nanocarriers for the immobilization of primary antibodies due to magnetic separation ability, large specific surface area, and ease of amination for biofunctionalization. Successful fabrication of the nanoimmunosensor was confirmed by SEM and electrochemical impedance spectroscopy. Carcinoembryonic antigen was detected as a model to prove the feasibility of the above strategy. Under the optimal conditions, the proposed nanoimmunosensor exhibited a wide linear range of 0.01 to 125 ng mL^–1 for carcinoembryonic antigen determination with a low detection limit of 3.0 pg mL^–1 (S/N = 3). Moreover, the nanoimmunosensor also displayed excellent selectivity, good stability, and acceptable reproducibility, indicating its potential applications in clinical diagnostics and immune research

High-Density Gold Nanoparticles Implanted on Mg/Fe LDH Nanoflowers Assisted Lateral Flow Immuno-Dipstick Assay for Visual Detection of Human Epididymal Protein 4

The timelier and more accurate the diagnosis of the disease, the higher the patient’s survival rate. Human epididymal protein 4 (HE4) has great significance as a biomarker of concern for reflecting ovarian cancer. Herein, we prepared a novel optical label that can be used in lateral-flow immuno-dipstick assay (LFIA) for sensitive visual detection of HE4 by implanting hydrophobic gold nanoparticles (Au NPs) at high density in Mg/Fe LDH nanoflowers (MF NFs). MF NFs with large specific surface area, high porosity, abundant active binding sites, and stable structure were employed for the first time as templates to directly anchor Au NPs in the organic phase. After simple modification with an optimized amount of branched polyethyleneimine, not only could MF@Au NFs be dispersed in the aqueous phase, but also amino functional groups were introduced on its surface to facilitate subsequent antibody coupling steps. The limit of detection reaches 50 pM with a detection range of 50 to 1000 pM. This work initially explored how MF NFs can be used to load signal labels with ideal stability and signal amplification capabilities, which greatly improves the practicability of LFIA and highlights its important role in the field of rapid diagnostics

Dual-Signal-Encoded Barcodes with Low Background Signal for High-Sensitivity Analysis of Multiple Tumor Markers

The suspension array technology (SAT) is promising for high-sensitivity multiplexed analysis of tumor markers. Barcodes as the core elements of SAT, can generate encoding fluorescence signals (EFS) and detection fluorescence signals (DFS) in the corresponding flow cytometer channel. However, the bleed-through effect of EFS in the DFS channel and the reagent-driven non-specific binding (NSB) lead to background interference for ultrasensitive assay of multiple targets. Here, we report an ingenious method to eliminate background interference between barcode and reporter using low-background dual-signal-encoded barcodes (DSBs) based on microbeads (MBs) and quantum dots (QDs). The low-background DSBs were prepared via combination strategy of two signals containing scatter signals and fluorescence signals. Three types of MBs were distinguished by the scattering channel of flow cytometer (FSC vs. SSC) to obtain the scattered signals. Green quantum dots (GQDs) or red quantum dots (RQDs) were coupled to the surface of MBs by sandwich immune structure to obtain the distinguishable fluorescent signals. Furthermore, the amount of conjugated capture antibody on the MB’s surface was optimized by comparing the change of detection sensitivity with the addition of capture antibody. The combination measurements of specificity and NSB in SAT platform were performed by incubating the capture antibody-conjugated MBs (cAb-MBs) with individual QD-conjugated detection antibody (QDs-dAb). Finally, an SAT platform based on DSBs was successfully established for highly sensitive multiplexed analysis of six tumor markers in one test, which suggests the promising tool for highly sensitive multiplexed bioassay applications

Dual-Signal-Encoded Barcodes with Low Background Signal for High-Sensitivity Analysis of Multiple Tumor Markers

The suspension array technology (SAT) is promising for high-sensitivity multiplexed analysis of tumor markers. Barcodes as the core elements of SAT, can generate encoding fluorescence signals (EFS) and detection fluorescence signals (DFS) in the corresponding flow cytometer channel. However, the bleed-through effect of EFS in the DFS channel and the reagent-driven non-specific binding (NSB) lead to background interference for ultrasensitive assay of multiple targets. Here, we report an ingenious method to eliminate background interference between barcode and reporter using low-background dual-signal-encoded barcodes (DSBs) based on microbeads (MBs) and quantum dots (QDs). The low-background DSBs were prepared via combination strategy of two signals containing scatter signals and fluorescence signals. Three types of MBs were distinguished by the scattering channel of flow cytometer (FSC vs. SSC) to obtain the scattered signals. Green quantum dots (GQDs) or red quantum dots (RQDs) were coupled to the surface of MBs by sandwich immune structure to obtain the distinguishable fluorescent signals. Furthermore, the amount of conjugated capture antibody on the MB’s surface was optimized by comparing the change of detection sensitivity with the addition of capture antibody. The combination measurements of specificity and NSB in SAT platform were performed by incubating the capture antibody-conjugated MBs (cAb-MBs) with individual QD-conjugated detection antibody (QDs-dAb). Finally, an SAT platform based on DSBs was successfully established for highly sensitive multiplexed analysis of six tumor markers in one test, which suggests the promising tool for highly sensitive multiplexed bioassay applications

One-Pot Green Synthesis of High Quantum Yield Oxygen-Doped, Nitrogen-Rich, Photoluminescent Polymer Carbon Nanoribbons as an Effective Fluorescent Sensing Platform for Sensitive and Selective Detection of Silver(I) and Mercury(II) Ions

This work reports on a facile, economical, and green preparative strategy toward water-soluble, fluorescent oxygen-doped, nitrogen-rich, photoluminescent polymer carbon nanoribbons (ONPCRs) with a quantum yield of approximately 25.61% by the hydrothermal process using uric acid as a carbon–nitrogen source for the first time. The as-prepared fluorescent ONPCRs showed paddy leaf-like structure with 80–160 nm length and highly efficient fluorescent quenching ability in the presence of mercury­(II) (Hg²⁺) or silver (Ag⁺) ions due to the formed nonfluorescent metal complexes via robust Hg²⁺-O or Ag⁺-N interaction with the O and N of fluorescent ONPCRs, which allowed the analysis of Hg²⁺ and Ag⁺ ions in a very simple method. By employing this sensor, excellent linear relationships existed between the quenching degree of the ONPCRs and the concentrations of Hg²⁺ and Ag⁺ ions in the range of 2.0 nM to 60 μM and 5.0 nM to 80 μM, respectively. By using ethylenediaminetetraacetate and ammonia as the masking agent of Hg²⁺ and Ag⁺ ions, respectively, Hg²⁺ or Ag⁺ ions were exclusively detected in coexistence with Ag⁺ or Hg²⁺ ions with high sensitivity, and the detection limits as low as 0.68 and 1.73 nM (3σ) were achieved, respectively, which also provided a reusable detection method for Hg²⁺ and Ag⁺ ions. Therefore, the easily synthesized fluorescent ONPCRs may have great potential applications in the detection of Hg²⁺ and Ag⁺ ions for biological assay and environmental protection