Electrochemical detection of 4(5)-methylimidazole in aqueous solutions.

4(5)-methylimidazole (4-MeI) is a potential carcinogen widely used in food colours. EU regulations specify a maximum allowable concentration of 200 ppm for 4-MeI in caramel colours. This study reports an electrochemical determination technique for 4-MeI in caramel colours for the first time.

Prunella vulgaris-phytosynthesized platinum nanoparticles: Insights into nanozymatic activity for HO and glutamate detection and antioxidant capacity.

Artificial nanozymes (enzyme-mimics), specifically metallic nanomaterials, have garnered significant attention recently due to their reduced preparation cost and enhanced stability in a wide range of environments. The present investigation highlights, for the first time, a straightforward green synthesis of biogenic platinum nanoparticles (PtNPs) from a natural resource, namely Prunella vulgaris (Pr). To demonstrate the effectiveness of the phytochemical extract as an effective reducing agent, the PtNPs were characterized by various techniques such as UV-vis spectroscopy, High-resolution Transmission electron microscopy (HR-TEM), zeta-potential analysis, Fourier-transform infrared spectroscopy (FTIR), and Energy dispersive spectroscopy (EDS).

Electrochemical assisted enhanced nanozymatic activity of functionalized borophene for HO and tetracycline detection.

This study unveils the electrochemically-enhanced nanozymatic activity exhibited by borophene during the reaction of 3,3',5,5'-tetramethylbenzidine (TMB) and HO. Herein, the surface of the pristine borophene was first modified with the addition of thiocyanate groups to improve hydroxyl radical (•OH) scavenging activity. Then, the oxidation reaction of TMB was accelerated under applied electrochemical potential.

Waste-Derived Sustainable Fluorescent Nanocarbon-Coated Breathable Functional Fabric for Antioxidant and Antimicrobial Applications.

Hospital-acquired (nosocomial) infections account for the majority of adverse health effects during care delivery, placing an immense financial strain on healthcare systems around the world. For the first time, the present article provides evidence of a straightforward pollution-free technique to fabricate a heteroatom-doped carbon dot immobilized fluorescent biopolymer composite for the development of functional textiles with antioxidant and antimicrobial properties. A simple, facile, and eco-friendly approach was devised to prepare heteroatom-doped carbon dots from waste green tea and a biopolymer.

Non-spherical gold nanoparticles enhanced fluorescence of carbon dots for norovirus-like particles detection.

Background: Norovirus is a common pathogen that causes foodborne outbreaks every year and the increasing number of deaths caused by it has become a substantial concern in both developed and underdeveloped countries. To date, no vaccines or drugs are able to control the outbreak, highlighting the importance of finding specific, and sensitive detection tools for the viral pathogen. Current diagnostic tests are limited to public health laboratories and/or clinical laboratories and are time-consuming.

Recent advancements of nanomodified electrodes - Towards point-of-care detection of cardiac biomarkers.

The increasing number of deaths from cardiovascular diseases has become a substantial concern in both developed and underdeveloped countries. Rapid and on-site monitoring of this disease is urgently important to control, prevent and make awareness of public health. Recently, a lot of focus has been placed on nanomaterials and modify these nanomaterials have been explored to detect cardiac biomarkers.

Positively Charged Gold Quantum Dots: An Nanozymatic "Off-On" Sensor for Thiocyanate Detection.

The concentration of thiocyanate (SCN) in bodily fluids is a good indicator of potential and severe health issues such as nasal bleeding, goiters, vertigo, unconsciousness, several inflammatory diseases, and cystic fibrosis. Herein, a visual SCN sensing method has been developed using the enzyme-like nature of positively charged gold quantum dots (Au QDs) mixed with 3,3',5,5'- (TMB) and hydrogen peroxide (HO. This research also reports a new method of synthesizing positively charged Au QDs directly from gold nanoparticles through a hydrothermal process.

Nanozymatic detection of thiocyanate through accelerating the growth of ultra-small gold nanoparticles/graphene quantum dots hybrids.

Thiocyanate (SCN) concentration monitoring in food is important to ensure the health and safety of the consumers.A colorimetric detection of thiocyanate (SCN) based on the nanozymatic activity of gold nanoparticle-graphene quantum dots (GQDs-Au NPs) hybrids in the presence of 3,3',5,5'-tetramethylbenzidine (TMB) and HO has been proposed. Here, a new synthesis method of GQDs directly from graphite was introduced.

A biomolecule-free electrochemical sensing approach based on a novel electrode modification technique: Detection of ultra-low concentration of Δ⁹-tetrahydrocannabinol in saliva by turning a sample analyte into a sensor analyte.

Cannabis is currently one of the most consumed drugs in many countries. Δ⁹-tetrahydrocannabinol (THC) is the principal psychoactive component of this drug and is present in saliva after consumption. This paper reports a novel biomolecule-free electrochemical approach to detect an ultra-low level of THC in saliva using modified electrodes with molecules of the same analyte (THC) that are detected later via square wave voltammetry.

Target specific aptamer-induced self-assembly of fluorescent graphene quantum dots on palladium nanoparticles for sensitive detection of tetracycline in raw milk.

The excessive use of tetracyclines (TCs), a bacteriostaticantibiotic, in food products, has led to the accumulation of TCs residues in the human body, affecting human health seriously. Therefore, the development of a highly sensitive method to detect TCs in food is of utmost importance. This study reports a novel sensing strategy using aptamer-induced fluorescence fluctuation of graphene quantum dots (GQDs) and palladium nanoparticles (Pd NPs) for the rapid and label-free detection of tetracycline with a limit of detection of 45 ng.

Chiral zirconium quantum dots: A new class of nanocrystals for optical detection of coronavirus.

A synthetic way of chiral zirconium quantum dots (Zr QDs) was presented for the first time using L(+)-ascorbic acid acts as a surface as well as chiral ligands. Different spectroscopic and microscopic analysis was performed for thorough characterization of Zr QDs. As-synthesized QDs exhibited fluorescence and circular dichroism properties, and the peaks were located at 412 nm and 352 nm, respectively.

Magnetic Nanozyme-Linked Immunosorbent Assay for Ultrasensitive Influenza A Virus Detection.

Rapid and sensitive detection of influenza virus is of soaring importance to prevent further spread of infections and adequate clinical treatment. Herein, an ultrasensitive colorimetric assay called magnetic nano(e)zyme-linked immunosorbent assay (MagLISA) is suggested, in which silica-shelled magnetic nanobeads (MagNBs) and gold nanoparticles are combined to monitor influenza A virus up to femtogram per milliliter concentration. Two essential strategies for ultrasensitive sensing are designed, i.

Chiral MoS Quantum Dots: Dual-Mode Detection Approaches for Avian Influenza Viruses.

Molybdenum disulfide (MoS), a type of transition metal dichalcogenide material, has emerged as an important class among 2D systems. When 2D MoS materials are reduced to 0D quantum dots (QDs), they introduce new optical properties that point to several potential technological advantages in electronic, magnetic, optical, and catalytic properties. In this study, a simple way to produce chiral MoS QDs from MoS nanopowder is presented using l(+)-ascorbic acid as a reducing agent.

Optoelectronic fowl adenovirus detection based on local electric field enhancement on graphene quantum dots and gold nanobundle hybrid.

An optoelectronic sensor is a rapid diagnostic tool that allows for an accurate, reliable, field-portable, low-cost device for practical applications. In this study, template-free In situ gold nanobundles (Au NBs) were fabricated on an electrode for optoelectronic sensing of fowl adenoviruses (FAdVs). Au NB film was fabricated on carbon electrodes working area using L(+) ascorbic acid, gold chroloauric acid and poly-l-lysine (PLL) through modified layer-by-layer (LbL) method.

Amplified visual immunosensor integrated with nanozyme for ultrasensitive detection of avian influenza virus.

Nanomaterial-based artificial enzymes or nanozymes exhibit superior properties such as stability, cost effectiveness and ease of preparation in comparison to conventional enzymes. However, the lower catalytic activity of nanozymes limits their sensitivity and thereby practical applications in the bioanalytical field. To overcome this drawback, herein we propose a very simple but highly sensitive, specific and low-cost dual enhanced colorimetric immunoassay for avian influenza A (H5N1) virus.

Recent Advances in Biosensor Development for Foodborne Virus Detection.

Outbreaks of foodborne diseases related to fresh produce have been increasing in North America and Europe. Viral foodborne pathogens are poorly understood, suffering from insufficient awareness and surveillance due to the limits on knowledge, availability, and costs of related technologies and devices. Current foodborne viruses are emphasized and newly emerging foodborne viruses are beginning to attract interest.

GryphSens: A Smartphone-Based Portable Diagnostic Reader for the Rapid Detection of Progesterone in Milk.

Enzyme-linked immunosorbent assay (ELISA) is a popular assay technique for the detection and quantification of various biological substances due its high sensitivity and specificity. More often, it requires large and expensive laboratory instruments, which makes it difficult to conduct when the tests must be performed quickly at the point-of-care (POC). To increase portability and ease of use, we propose a portable diagnostic system based on a Raspberry Pi imaging sensor for the rapid detection of progesterone in milk samples.

In situ self-assembly of gold nanoparticles on hydrophilic and hydrophobic substrates for influenza virus-sensing platform.

Nanomaterials without chemical linkers or physical interactions that reside on a two-dimensional surface are attractive because of their electronic, optical and catalytic properties. An in situ method has been developed to fabricate gold nanoparticle (Au NP) films on different substrates, regardless of whether they are hydrophilic or hydrophobic surfaces, including glass, 96-well polystyrene plates, and polydimethylsiloxane (PDMS). A mixture of sodium formate (HCOONa) and chloroauric acid (HAuCl) solution was used to prepare Au NP films at room temperature.

Size-controlled preparation of peroxidase-like graphene-gold nanoparticle hybrids for the visible detection of norovirus-like particles.

A hybrid structure of graphene-gold nanoparticles (Grp-Au NPs) was designed as a new nanoprobe for colorimetric immunoassays. This hybrid structure was prepared using chloroauric acid, sodium formate and Grp flakes at room temperature. Au NPs attached strongly onto the Grp surface, and their size was controlled by varying the sodium formate concentration.

Enhanced catalytic activity of gold nanoparticle-carbon nanotube hybrids for influenza virus detection.

Multifunctional nanohybrids have created new and valuable opportunities for a wide range of catalysis and biotechnology applications. Here, we present a relatively simple method for producing nanohybrids composed of gold nanoparticles (Au NPs) and carbon nanotubes (CNTs) that does not require an acidic pre-treatment of the CNTs. Transmission electron microscopy (TEM) images and ultraviolet-visible (UV-vis) spectra revealed that Au NPs bonded to the CNT surface.

Detection of influenza virus using peroxidase-mimic of gold nanoparticles.

A modified enzyme-linked immunosorbent assay (ELISA) with nanomaterials is an effective and powerful method to amplify the signal and reduce the cost of detecting and measuring trace biomarkers or proteins. In this study, an ultra-sensitive colorimetric immunoassay was designed, and its ability to detect influenza viruses using positively charged gold nanoparticles ((+)Au NPs) was assessed as a possible role for peroxidase-mimic inorganic enzymes. This method detected influenza virus A (H1N1) with a linear range up to 10 pg mL(-1) and clinically isolated influenza virus A (H3N2) up to 10 plaque forming units (PFU) mL(-1) , where its sensitivity improved to 500-fold higher than that of commercial virus kits.

Synthesis of Gold Nanoparticles with Buffer-Dependent Variations of Size and Morphology in Biological Buffers.

The demand for biologically compatible and stable noble metal nanoparticles (NPs) has increased in recent years due to their inert nature and unique optical properties. In this article, we present 11 different synthetic methods for obtaining gold nanoparticles (Au NPs) through the use of common biological buffers. The results demonstrate that the sizes, shapes, and monodispersity of the NPs could be varied depending on the type of buffer used, as these buffers acted as both a reducing agent and a stabilizer in each synthesis.

Plasmon-induced photoluminescence immunoassay for tuberculosis monitoring using gold-nanoparticle-decorated graphene.

Metal-nanoparticle-functionalized graphene, in particular, graphene sheets containing Au nanoparticles (Au NPs), have generated considerable interest because of their unique optical and electrical characteristics. In this study, we successfully produced graphene sheets decorated with Au NPs (AuGrp) using phytochemicals as reducing agents. During this reaction, Au ions intercalated into the layered graphene flakes and were then reduced into NPs, exfoliating the graphene sheets.

A plasmon-assisted fluoro-immunoassay using gold nanoparticle-decorated carbon nanotubes for monitoring the influenza virus.

A plasmon-assisted fluoro-immunoassay (PAFI) was developed for the detection of the influenza virus by using Au nanoparticle (Au NP)-decorated carbon nanotubes (AuCNTs) that were synthesized using phytochemical composites at room temperature in deionized water. Specific antibodies (Abs) against the influenza virus were conjugated onto the surface of AuCNTs and cadmium telluride quantum dots (QDs), which had a photoluminescence intensity that varied as a function of virus concentration and a detection limit of 0.1 pg/mL for all three types of influenza viruses examined.

Metal enhanced fluorescence on nanoporous gold leaf-based assay platform for virus detection.

In the present study, a rapid, sensitive and quantitative detection of influenza A virus targeting hemagglutinin (HA) was developed using hybrid structure of quantum dots (QDs) and nanoporous gold leaf (NPGL). NPGL film was prepared by dealloying bimetallic film where its surface morphology and roughness were fairly controlled. Anti-influenza A virus HA antibody (ab66189) was bound with NPGL and amine (-NH2) terminated QDs.