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With the increased demand for beef in emerging markets, the development of quality-control diagnostics that are fast, cheap and easy to handle is essential. Especially where beef must be free from pork residues, due to religious, cultural or allergic reasons, the availability of such diagnostic tools is crucial. In this work, we report a label-free impedimetric genosensor for the sensitive detection of pork residues in meat, by leveraging the biosensing capabilities of graphene acid - a densely and selectively functionalized graphene derivative. A single stranded DNA probe, specific for the pork mitochondrial genome, was immobilized onto carbon screen-printed electrodes modified with graphene acid. It was demonstrated that graphene acid improved the charge transport properties of the electrode, following a simple and rapid electrode modification and detection protocol. Using non-faradaic electrochemical impedance spectroscopy, which does not require any electrochemical indicators or redox pairs, the detection of pork residues in beef was achieved in less than 45 min (including sample preparation), with a limit of detection of 9% w/w pork content in beef samples. Importantly, the sample did not need to be purified or amplified, and the biosensor retained its performance properties unchanged for at least 4 weeks. This set of features places the present pork DNA sensor among the most attractive for further development and commercialization. Furthermore, it paves the way for the development of sensitive and selective point-of-need sensing devices for label-free, fast, simple and reliable monitoring of meat purity.
There is a huge interest in doped graphene and how doping can tune the material properties for the specific application. It was recently demonstrated that the effect of doping can have different influence on the electrochemical detection of electroactive probes, depending on the analysed probe, on the structural characteristics of the graphene materials and on the type and amount of heteroatom used for the doping. In this work we wanted to investigate the effect of doping on graphene materials used as platform for the detection of catechin, a standard probe which is commonly used for the measurement of polyphenols in food and beverages. To this aim we compared undoped graphene with boron-doped graphene and nitrogen doped graphene platforms for the electrochemical detection of standard catechin oxidation. Finally, the material providing the best electrochemical performance was employed for the analysis of real samples. We found that the undoped graphene, possessing lower amount of oxygen functionalities, higher density of defects and larger electroactive surface area provided the best electroanalytical performance for the determination of catechin in commercial beer samples. Our findings are important for the development of novel graphene platforms for the electrochemical assessment of food quality.
Our recent experience of the COVID-19 pandemic has highlighted the importance of easy-to-use, quick, cheap, sensitive and selective detection of virus pathogens for the efficient monitoring and treatment of virus diseases. Early detection of viruses provides essential information about possible efficient and targeted treatments, prolongs the therapeutic window and hence reduces morbidity. Graphene is a lightweight, chemically stable and conductive material that can be successfully utilized for the detection of various virus strains. The sensitivity and selectivity of graphene can be enhanced by its functionalization or combination with other materials. Introducing suitable functional groups and/or counterparts in the hybrid structure enables tuning of the optical and electrical properties, which is particularly attractive for rapid and easy-to-use virus detection. In this review, we cover all the different types of graphene-based sensors available for virus detection, including, e.g., photoluminescence and colorimetric sensors, and surface plasmon resonance biosensors. Various strategies of electrochemical detection of viruses based on, e.g., DNA hybridization or antigen-antibody interactions, are also discussed. We summarize the current state-of-the-art applications of graphene-based systems for sensing a variety of viruses, e.g., SARS-CoV-2, influenza, dengue fever, hepatitis C virus, HIV, rotavirus and Zika virus. General principles, mechanisms of action, advantages and drawbacks are presented to provide useful information for the further development and construction of advanced virus biosensors. We highlight that the unique and tunable physicochemical properties of graphene-based nanomaterials make them ideal candidates for engineering and miniaturization of biosensors.
- MeSH
- Betacoronavirus genetika izolace a purifikace patogenita MeSH
- biosenzitivní techniky * přístrojové vybavení metody trendy MeSH
- design vybavení MeSH
- DNA virů analýza genetika MeSH
- elektrochemické techniky MeSH
- grafit * chemie MeSH
- hybridizace nukleových kyselin MeSH
- klinické laboratorní techniky * přístrojové vybavení metody statistika a číselné údaje MeSH
- kolorimetrie MeSH
- koronavirové infekce diagnóza epidemiologie virologie MeSH
- kvantové tečky chemie MeSH
- lidé MeSH
- luminiscence MeSH
- nanostruktury chemie MeSH
- pandemie MeSH
- povrchová plasmonová rezonance MeSH
- Ramanova spektroskopie MeSH
- reakce antigenu s protilátkou MeSH
- virologie metody MeSH
- virová pneumonie diagnóza epidemiologie virologie MeSH
- viry genetika izolace a purifikace patogenita MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Doping graphene with heteroatoms can alter the electronic and electrochemical properties of the starting material. Contrasting properties should be expected when the doping is carried out with electron donating species (n-type dopants) or with electron withdrawing species (p-type dopants). This in turn can have a profound influence on the electroanalytical performance of the doped material being used for the detection of specific probes. Here we investigate the electrochemical oxidation of DNA bases adenine, guanine, thymine and cytosine on two heteroatom-doped graphene platforms namely boron-doped graphene (p-type dopant) and nitrogen-doped graphene (n-type dopant). We found that overall, boron-doped graphene provided the best response in terms of electrochemical signal sensitivity for all bases. This is due to the electron deficiency of boron-doped graphene, which can promote the oxidation of DNA bases, as opposed to nitrogen-doped graphene which possesses an excess of electrons. Moreover, also the structure of the nucleobase was found to have significant influence on the obtained signal. Our study may open new frontiers in the electrochemical detection of DNA bases which is the first step for label-free DNA analysis.
Graphene-based bionanocomposites are employed in several ailments, such as cancers and infectious diseases, due to their large surface area (to carry drugs), photothermal properties, and ease of their functionalization (owing to their active groups). Modification of graphene-derivatives with polysaccharides is a promising strategy to decrease their toxicity and improve target ability, which consequently enhances their biotherapeutic efficacy. Herein, functionalization of graphene-based materials with carbohydrate polymers (e.g., chitosan, starch, alginate, hyaluronic acid, and cellulose) are presented. Subsequently, recent advances in graphene nanomaterial/polysaccharide-based bionanocomposites in infection treatment and cancer therapy are comprehensively discussed. Pharmacogenomic and toxicity assessments for these bionanocomposites are also highlighted to provide insight for future optimized and smart investigations and researches.
- MeSH
- antitumorózní látky chemie farmakologie MeSH
- farmakogenetika * MeSH
- grafit chemie MeSH
- lidé MeSH
- nádory farmakoterapie genetika patologie MeSH
- nanokompozity aplikace a dávkování chemie MeSH
- nežádoucí účinky léčiv etiologie patologie MeSH
- polysacharidy chemie farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Understanding the interaction between graphene oxide (GO) and the biomolecules is fundamentally essential, especially for disease- and drug-related peptides and proteins. In this study, the interaction between GO and albumins (bovine serum albumin, human serum albumin, and bovine alpha-lactalbumin) has been performed by fluorescence and UV-Vis spectroscopic techniques. The fluorescence quenching mechanism between GO and aromatic acids residues with intrinsic fluorescence was determined as mainly static quenching in combination with dynamic quenching. The optimal conditions for the most effective affinity between albumins and GO have been estimated at neutral pH and room temperature. The strong impact of the size of graphene oxide on the interaction between proteins and graphene oxide has been confirmed, as well. The interaction between GO and albumins has been examined as electrostatic and hydrophobic. The electrostatic interaction was confirmed by pH effect, while the hydrophobic interaction was proved by the presence of Poloxamer188. The CD spectra of albumins exhibit decreasing helicity in the secondary structure of albumins upon the addition of GO. However, no significant changes in position and shape of characteristic negative bands have been noted. Mentioned changes indicate the successful interaction between GO and proteins, the predominantly α-helical structure of albumins has been preserved.
- MeSH
- cirkulární dichroismus MeSH
- grafit chemie MeSH
- koncentrace vodíkových iontů MeSH
- laktalbumin chemie MeSH
- lidé středního věku MeSH
- lidé MeSH
- oxidy chemie MeSH
- sérový albumin hovězí chemie MeSH
- sérový albumin chemie MeSH
- skot MeSH
- teplota MeSH
- velikost částic MeSH
- zvířata MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Environmental pollutants, including antibiotics (ATBs), have become an increasingly common health hazard in the last several decades. Overdose and abuse of ATBs led to the emergence of antibiotic-resistant genes (ARGs), which represent a serious health threat. Moreover, water bodies and reservoirs are places where a wide range of bacterial species with ARGs originate, owing to the strong selective pressure from presence of ATB residues. In this regard, graphene oxide (GO) has been utilised in several fields including remediation of the environment. In this review, we present a brief overview of resistant genes of frequently used ATBs, their occurrence in the environment and their behaviour. Further, we discussed the factors influencing the binding of nucleic acids and the response of ARGs to GO, including the presence of salts in the water environment or water pH, because of intrinsic properties of GO of not only binding to nucleic acids but also catalysing their decomposition. This would be helpful in designing new types of water treatment facilities.
Addition of high-aspect-ratio (AR) nanofillers can markedly influence flow behavior of polymer systems. As a result, application of graphite nanoplatelets (GNP) allows preparation of microfibrillar composites (MFC) based on PCL matrix reinforced with in-situ generated PLA fibrils. This work deals, for the first time, with preparation of analogous melt-drawn fibers. Unlike other blend-based fibers, the spinning and melt drawing leads to structure of deformed inclusions due to unfavorable ratio of rheological parameters of components. Subsequent moderate cold drawing of the system with dissimilar deformability of components causes strengthening with PLA fibrils. Unexpectedly, high velocity and extent of cold drawing leads to structure with low-AR inclusions, similar to the original melt-drawn blend. Extensive fast deformation of the soft PCL matrix does not allow sufficient stress transfer to rigid PLA. In spite of peculiarities found, the GNP-aided melt spinning allows facile preparation of biodegradable biocompatible fibers with wide range of diameters (80-400 μm) and parameters (2.35-18 cN/tex).
Graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) were added to furcellaran films (FUR). Silver nanoparticles (AgNPs) were prepared by reducing AgNO3 using a FUR matrix as the stabilising agent. The structure and surface morphology of nanocomposite films were obtained using FTIR, SEM and XRD. The molecular weights of furcellaran chains were estimated using HPSEC-MALLS-RI. Characterisation of the films was undertaken to analyse their physical, mechanical and structural properties. SEM analysis revealed that GO, MWCNTs and AgNPs were evenly distributed throughout the FUR surface. FUR + AgNP films showed antimicrobial activity against bacteria and fungi. P. aeruginosa, E. faecalis and S. aureus were the most affected with effective growth inhibition using the disc diffusion method. In the study, the effect of nanofillers on the structural, thermal, mechanical and antimicrobial properties of furcellaran films as potential materials for food packaging is presented.
- MeSH
- algináty chemie MeSH
- antibakteriální látky chemie farmakologie MeSH
- Bacteria účinky léků MeSH
- biopolymery chemie MeSH
- grafit chemie MeSH
- kovové nanočástice chemie MeSH
- nanokompozity chemie MeSH
- nanotrubičky uhlíkové chemie MeSH
- rostlinné gumy chemie MeSH
- stříbro chemie MeSH
- Publikační typ
- časopisecké články MeSH
Structure and properties of poly(lactic acid) (PLA)/poly (ɛ-caprolactone) (PCL) influenced by graphite nanoplatelets (GNP) were studied in dependence on blend composition. Electron microscopy indicates predominant localization of GNP in PCL. GNP-induced changes in viscosity hinder refinement of PCL inclusions, support PCL continuity in the co-continuous system, and lead to reduction of PLA inclusions size without GNP being present at the interface in the PCL-matrix blend. Negligible differences in crystallinity of both phases indicate that mechanical behaviour is mainly influenced by reinforcement and GNP-induced changes in morphology. Addition of 5 parts of GNP leads to ~40% and ~25% increase of stiffness in the PCL- and PLA-matrix systems, respectively, whereas the reinforcing effect is practically eliminated in the co-continuous systems due to GNP-induced lower continuity of PLA which enhances toughness. Impact resistance of the 80/20 blend shows increase with 5 parts content due to synergistic effect of PCL/GNP stacks, whereas minor increase in the blend of the ductile PCL matrix with brittle PLA inclusions is caused by GNP-modification of the component parameters. Results indicate high potential of GNP in preparing biocompatible systems with wide range of structure and properties.
