Synthesis of flower-like ZnO nanoparticles for label-free point of care detection of carcinoembryonic antigen.

In this work, flower-like ZnO nanoparticles (ZnONPs) were synthesized using zinc nitrate (Zn(NO) 6HO) as a precursor with KOH. The morphology of the ZnONPs was controlled by varying the synthesis temperature at 50, 75 and 95 °C. The morphology and structure of ZnONPs were characterized using Scanning Electron Microscopy, and X-Ray Diffraction and Brunauer-Emmett Teller analysis.

A portable electrochemical immunosensor for ovarian cancer uses hierarchical microporous carbon material from waste coffee grounds.

A simple label-free electrochemical immunosensor for ovarian cancer (OC) detection was developed using a hierarchical microporous carbon material fabricated from waste coffee grounds (WCG). The analysis method exploited near-field communication (NFC) and a smartphone-based potentiostat. Waste coffee grounds were pyrolyzed with potassium hydroxide and used to modify a screen-printed electrode.

Electrochemical sensor based on molecularly imprinted polymer cryogel and multiwalled carbon nanotubes for direct insulin detection.

Insulin is the polypeptide hormone that regulates blood glucose levels. It is used as an indicator of both types of diabetes. An electrochemical insulin sensor was developed using a gold electrode modified with carboxylated multiwalled carbon nanotubes (f-MWCNTs) and molecularly imprinted polymer (MIP) cryogel.

Electrochemical Impedimetric Study of Non-Watson-Crick Base Pairs of DNA.

Electrochemical impedance spectroscopy (EIS) was used to detect non-Watson-Crick base pairs of DNA. Thiol-modified DNA as a probe and mercaptohexanol (MCH) were co-immobilized to form a DNA/MCH mixed self-assembled monolayer on a gold electrode surface and then hybridized with complementary DNAs. The DNA layers were measured by the EIS method and interpreted by equivalent circuits.

Magnetic microsphere sorbent on CaCO templates: Simple synthesis and efficient extraction of trace carbamate pesticides in fresh produce.

Polypyrrole magnetic microspheres were synthesized and used to extract carbaryl, carbofuran, and methomyl before analysis by a high-performance liquid chromatography with diode array detection. Under optimal conditions, four times the preconcentration was achieved with the use of only 1.2 mL of sample.

Printable Heterostructured Bioelectronic Interfaces with Enhanced Electrode Reaction Kinetics by Intermicroparticle Network.

Printable organic bioelectronics provide a fast and cost-effective approach for the fabrication of novel biodevices, while the general challenge is to achieve optimized reaction kinetics at multiphase boundaries between biomolecules and electrodes. Here, we present an entirely new concept based on a modular approach for the construction of heterostructured bioelectronic interfaces by using tailored functional "biological microparticles" combined with "transducer microparticles" as modular building blocks. This approach offers high versatility for the design and fabrication of bioelectrodes with a variety of forms of interparticle spatial organization, from layered-structures to more advance bulk heterostructured architectures.

Polypyrrole-coated alginate/magnetite nanoparticles composite sorbent for the extraction of endocrine-disrupting compounds.

Magnetite nanoparticles incorporated into alginate beads and coated with a polypyrrole adsorbent were prepared (polypyrrole/Fe3 O4 /alginate bead) and used as an effective magnetic solid-phase extraction sorbent for the extraction and enrichment of endocrine-disrupting compounds (estriol, β-estradiol and bisphenol A) in water samples. The determination of the extracted endocrine-disrupting compounds was performed using high-performance liquid chromatography with a fluorescence detector. The effect of various parameters on the extraction efficiency of endocrine disrupting compounds were investigated and optimized including the type and amount of sorbent, sample pH, extraction time, stirring speed, and desorption conditions.

Pure Nanoscale Morphology Effect Enhancing the Energy Storage Characteristics of Processable Hierarchical Polypyrrole.

We report a new synthesis approach for the precise control of wall morphologies of colloidal polypyrrole microparticles (PPyMPs) based on a time-dependent template-assisted polymerization technique. The resulting PPyMPs are water processable, allowing the simple and direct fabrication of multilevel hierarchical PPyMPs films for energy storage via a self-assembly process, whereas convention methods creating hierarchical conducting films based on electrochemical polymerization are complicated and tedious. This approach allows the rational design and fabrication of PPyMPs with well-defined size and tunable wall morphology, while the chemical composition, zeta potential, and microdiameter of the PPyMPs are well characterized.

Polypyrrole/silica/magnetite nanoparticles as a sorbent for the extraction of sulfonamides from water samples.

A magnetic solid-phase extraction sorbent of polypyrrole/silica/magnetite nanoparticles was successfully synthesized and applied for the extraction and preconcentration of sulfonamides in water samples. The magnetite nanoparticles provided a simple and fast separation method for the analytes in water samples. The silica coating increased the surface area that helped to increase the polypyrrole layer.

Affinity sensor using 3-aminophenylboronic acid for bacteria detection.

Boronic acid that can reversibly bind to diols was used to detect bacteria through its affinity binding reaction with diol-groups on bacterial cell walls. 3-aminophenylboronic acid (3-APBA) was immobilized on a gold electrode via a self-assembled monolayer. The change in capacitance of the sensing surface caused by the binding between 3-APBA and bacteria in a flow system was detected by a potentiostatic step method.