An Unlabeled Electrochemical Immunosensor Uses Poly(thionine) and Graphene Quantum Dot-Modified Activated Marigold Flower Carbon for Early Prostate Cancer Detection.

The activated carbon from marigold flowers (MG) was used to make an unlabeled electrochemical immunosensor to determine prostate cancer. MG was synthesized by hydrothermal carbonization and pyrolysis. MG had a large surface area, was highly conductive, and biocompatible.

Portable unibody semi-flow injection voltammetric sensor for on-site screening of illegal additive sibutramine in food supplements.

In this study, a simple, portable, unibody semi-flow injection system was coupled with a screen-printed electrode (SFI/SPE) for the on-site electrochemical screening of sibutramine (SBM) in food supplements. The SFI was fabricated by laser engraving acrylic plastic and was attached to a modified SPE with double-sided adhesive tape. The SPE was modified with a nanocomposite of nitrogen-doped graphene nanoflakes and carbon nanotubes synthesized using hydrothermal and ultrasonic methods.

Single laser synthesis of gold nanoparticles-polypyrrole-chitosan on laser-induced graphene for ascorbic acid detection.

The simultaneous synthesis of gold nanoparticles (AuNPs) and graphene by laser ablation was demonstrated. The in-situ synthesis was performed by laser ablation of a polymer substrate covered with a gold precursor dispersion. The gold precursor was prepared in a copolymer solution of pyrrole (Py) and chitosan (Chi) to improve the nucleation of gold embedded on the laser-induced graphene electrode (LIGE).

Voltammetric co-determination of lead and copper in gunshot residue based on iron oxide particle/spent coffee grounds-modified electrode.

A novel electrochemical sensor was developed for the detection of lead (Pb) and copper (Cu) ions using spent coffee grounds decorated with iron oxide particles (FeO/SCG). The FeO-decorated SCG was used to modify a glassy carbon electrode (GCE). FeO, SCG, and FeO/SCG were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR).

Waste DVD polycarbonate substrate for screen-printed carbon electrode modified with PVP-stabilized AuNPs for continuous free chlorine detection.

An electrochemical free chlorine sensor was developed by modifying a lab-made screen-printed carbon electrode (SPCE) with gold nanoparticles synthesized with polyvinylpyrrolidone (AuNPs-PVP). The electrode was made by screen printing carbon ink on a waste digital versatile disc (SPC-wDVD). PVP was used to stabilize AuNPs.

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.

Single-drop electrodeposition of nanoneedle-like bismuth on disposable graphene electrode for on-site electrochemical detection of cadmium and lead.

A novel cost-effective disposable porous graphene electrode (P-GE) modified with bismuth nanoneedles (nano-BiNDs) is proposed as a "mercury-free" sensor for detecting heavy metals through smartphone-assisted electrochemical sensing. The P-GE was fabricated using screen-printing. Nano-BiNDs were generated on the P-GE by potentiostatic electrodeposition.

Fabrication of a 96-electrode array using carbon dioxide laser ablation.

The 96 laser-induced multigraphene electrode (96L-MGE) integrated microwell plate (96 L-MGE-MP) is described. Each cell includes separate working, auxiliary, and reference electrodes, and the array sits on a poly-methyl methacrylate (PMMA) well. The 96 electrochemical cells were fabricated by laser ablation of polyimide adhesive tape, which created laser-induced graphene electrodes (L-GE).

Nano-palladium-decorated bismuth sulfide microspheres on a disposable electrode integrated with smartphone-based electrochemical detection of nitrite in food samples.

Nitrite (NO) is widely used as an additive to extend the shelf life of food products. Excessive nitrite intake not only causes blood-related diseases but also has the potential risk of causing cancers. A disposable screen-printed electrode was modified with nano‑palladium decorated bismuth sulfide microspheres (nanoPd@BiSMS/SPE), and integrated with a smartphone-interfaced potentiostat to develop a portable, electrochemical nitrite sensor.

A reusable screen-printed carbon electrode-based aptasensor for the determination of chloramphenicol in food and environment samples.

An electrochemical aptasensor was developed for the determination of chloramphenicol (CAP) in fresh foods and food products. The aptasensor was developed using Prussian blue (PB) and chitosan (CS) film. PB acts as a redox probe for detection and CS acts as a sorption material.

A novel 3D-printed portable electroplating device enhances latent fingerprints on metal substrates.

This work introduces a 3D-printed portable electroplating device for the visualization of latent fingerprints (LFPs) on metallic substrates. An electroplating solution of Ag-Cu in a deep eutectic solvent (DES) is used. The electroplating is performed by two electrodes equivalent to an anode (+) and a cathode (-).

Electropolymerization of poly(phenol red) on laser-induced graphene electrode enhanced adsorption of zinc for electrochemical detection.

We present a highly sensitive and selective electrode of laser-induced graphene modified with poly(phenol red) (P(PhR)@LIG) for measuring zinc nutrition in rice grains using square wave anodic stripping voltammetry (SWASV). The physicochemical properties of P(PhR)@LIG were investigated with scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier infrared spectroscopy (FT-IR) and Raman spectroscopy. The modified electrode demonstrated an amplified anodic stripping response of Zn due to the electropolymerization of P(PhR), which enhanced analyte adsorption during the accumulation step of SWASV.

A dual-electrode label-free immunosensor based on in situ prepared Au-MoO-Chi/porous graphene nanoparticles for point-of-care detection of cholangiocarcinoma.

A novel label-free electrochemical immunosensor was prepared for the detection of carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) as biomarkers of cholangiocarcinoma (CCA). A nanocomposite of gold nanoparticles, molybdenum trioxide, and chitosan (Au-MoO-Chi) was layer-by-layer assembled on the porous graphene (PG) modified a dual screen-printed electrode using a self-assembling technique, which increased surface area and conductivity and enhanced the adsorption of immobilized antibodies. The stepwise self-assembling procedure of the modified electrode was further characterized morphologically and functionally.

Molecularly imprinted polymer dual electrochemical sensor for the one-step determination of albuminuria to creatinine ratio (ACR).

The urinary albumin to creatinine ratio (ACR) is a convenient and accurate biomarker of chronic kidney disease (CKD). An electrochemical sensor for the quantification of ACR was developed based on a dual screen-printed carbon electrode (SPdCE). The SPdCE was modified with carboxylated multiwalled carbon nanotubes (f-MWCNTs) and redox probes of polymethylene blue (PMB) for creatinine and ferrocene (Fc) for albumin.

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.

Craft-and-Stick Xurographic Manufacturing of Integrated Microfluidic Electrochemical Sensing Platform.

An innovative modular approach for facile design and construction of flexible microfluidic biosensor platforms based on a dry manufacturing "craft-and-stick" approach is developed. The design and fabrication of the flexible graphene paper electrode (GPE) unit and polyethylene tetraphthalate sheet (PET)6/adhesive fluidic unit are completed by an economic and generic xurographic craft approach. The GPE widths and the microfluidic channels can be constructed down to 300 μm and 200 μm, respectively.

Novel biosensor platform for glucose monitoring via smartphone based on battery-less NFC potentiostat.

Near-field communication (NFC) was used to control a portable glucose biosensor for diabetes diagnosis. The system comprised a smartphone and an NFC potentiostat connected to a screen-printed carbon electrode (SPCE) modified with Prussian blue-graphene ink and functionalized with gold nanoparticles-embedded poly (3,4ethylene dioxythiophene):polysulfonic acid coated with glucose oxidase (GOx-AuNPs-PEDOT:PSS/PB-G). GOx catalyzed the glucose redox reaction while the conductivity and sensitivity of the AuNPs-PEDOT:PSS composite enhanced electron transfer to the PB-G, which was used as a mediator.

Disposable label-free electrochemical immunosensor based on prussian blue nanocubes for four breast cancer tumor markers.

A compact and low-cost multi-electrode array (MEA) is presented, comprising four working electrodes with shared reference and auxiliary electrodes. Prussian blue was electrodeposited on the MEA using chronoamperometry with a positive potential of 0.3 V.

A wireless smartphone-based "tap-and-detect" formaldehyde sensor with disposable nano-palladium grafted laser-induced graphene (nanoPd@LIG) electrodes.

We developed a fully integrated smart sensing device for on-site testing of food to detect trace formaldehyde (FA). A nano-palladium grafted laser-induced graphene (nanoPd@LIG) composite was synthesized by one-step laser irradiation of a Pd-chitosan-polyimide precursor. The composite was synthesized in the form of a three-electrode sensor on a polymer substrate.

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.

Detection and discrimination of sedative-hypnotics in spiked beverage dry residues using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy combined with chemometrics.

Drugs-facilitated crimes (DFCs) involve the incapacitation of victims under the influence of drugs. Conventionally, a drug administration act is often determined through the examination of biological samples; however, dry residues from any surface, such as drinking glass if related to a DFC could be a potential source of evidence. This study was aimed to establish an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy coupled with chemometrics for the determination of spiked sedative-hypnotics from dry residues of a drug-spiked beverage.

A microplate spectrophotometric method for analysis of indole-3-carbinol in dietary supplements using -dimethylaminocinnamaldehyde (DMACA) as a chromogenic reagent.

This work presents the development of a microplate spectrophotometric method for determination of indole-3-carbinol in dietary supplements. The colorimetric procedure is based on the reaction of indole-3-carbinol with the -dimethylaminocinnamaldehyde (DMACA) reagent under acidic conditions. The absorbance of the colored product measured at 675 nm was used to determine the target analyte.

Flow Injection Amperometric Measurement of Formalin in Seafood.

Formalin is illegally used as an antibacterial and a preservative in seafood products. It is extremely important for public health reasons to be able to simply, rapidly, and accurately detect formalin in fresh seafood. In this work, we developed a flow injection amperometric (FI-Amp) formalin sensor based on a glassy carbon electrode modified with a composite of palladium particles and carbon microspheres (PdPs-CMs/GCE).

Vortex-assisted dispersive liquid-liquid microextraction-gas chromatography (VADLLME-GC) determination of residual ketamine, nimetazepam, and xylazine from drug-spiked beverages appearing in liquid, droplet, and dry forms.

Presently, investigations of drug-facilitated crimes (DFCs) rely on the detection of substances extracted from biological samples following intake by the victim. However, such detection requires rapid sampling and analysis prior to metabolism and elimination of the drugs from the body. In cases of suspected DFCs, drug-spiked beverage samples, whether in liquid, droplet, or even dried form, can be tested for the presence of spike drugs and used as evidence for the occurrence of DFCs.

Nanocoral-like Polyaniline-Modified Graphene-Based Electrochemical Paper-Based Analytical Device for a Portable Electrochemical Sensor for Xylazine Detection.

A portable electrochemical device for xylazine detection is presented for the first time. An electrochemical paper-based analytical device (ePAD) was integrated with a smartphone. The fabrication of the ePAD involved wax printing, low-tack transfer tape, and cutting and screen-printing techniques.