RESUMEN
Electrochemical approaches, along with miniaturization of electrodes, are increasingly being employed to detect and quantify nucleic acid biomarkers. Miniaturization of the electrodes is achieved through the use of screen-printed electrodes (SPEs), which consist of one to a few dozen sets of electrodes, or by utilizing printed circuit boards. Electrode materials used in SPEs include glassy carbon (Chiang H-C, Wang Y, Zhang Q, Levon K, Biosensors (Basel) 9:2-11, 2019), platinum, carbon, and graphene (Cheng FF, He TT, Miao HT, Shi JJ, Jiang LP, Zhu JJ, ACS Appl Mater Interfaces 7:2979-2985, 2015). There are numerous modifications to the electrode surfaces as well (Cheng FF, He TT, Miao HT, Shi JJ, Jiang LP, Zhu JJ, ACS Appl Mater Interfaces 7:2979-2985, 2015). These approaches offer distinct advantages, primarily due to their demonstrated superior limit of detection without amplification. Using the SPEs and potentiostats, we can detect cells, proteins, DNA, and RNA concentrations in the nanomolar (nM) to attomolar (aM) range. The focus of this chapter is to describe the basic approach adopted for the use of SPEs for nucleic acid measurement.
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Técnicas Biosensibles , Técnicas Electroquímicas , Electrodos , Grafito , Grafito/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Ácidos Nucleicos/análisis , Humanos , ADN/análisisRESUMEN
The contamination of mycotoxins poses a serious threat to global food security, hence the urgent need for simultaneous detection of multiple mycotoxins. Herein, two SERS nanoprobes were synthesized by embedded SERS tags (4-mercaptopyridine, 4MPy; 4-mercaptobenzonitrile, TBN) into the Au and Ag core-shell structure, and each was coupled with the aptamers specific to ochratoxin A (OTA) and zearalenone (ZEN). Meanwhile, a rigid enhanced substrate Indium tin oxide glass/AuNPs/Graphene oxide (ITO/AuNPs/GO) was combined with aptamer functionalized Au@AgNPs via π-π stacking interactions between the aptamer and GO to construct a surface-enhanced Raman spectroscopy (SERS) aptasensor, thereby inducing a SERS enhancement effect for the effective and swift simultaneous detection of both OTA and ZEN. The presence of OTA and ZEN caused signal probes dissociation, resulting in an inverse correlation between Raman signal intensity (1005 cm-1 and 2227 cm-1) and the concentrations of OTA and ZEN, respectively. The SERS aptasensor exhibited wide linear detection ranges of 0.001-20 ng/mL for OTA and 0.1-100 ng/mL for ZEN, with low detection limits (LOD) of 0.94 pg/mL for OTA and 59 pg/mL for ZEN. Furthermore, the developed SERS aptasensor demonstrated feasible applicability in the detection of OTA and ZEN in maize, showcasing its substantial potential for practical implementation.
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Aptámeros de Nucleótidos , Oro , Grafito , Límite de Detección , Nanopartículas del Metal , Ocratoxinas , Plata , Espectrometría Raman , Zearalenona , Ocratoxinas/análisis , Espectrometría Raman/métodos , Oro/química , Zearalenona/análisis , Nanopartículas del Metal/química , Aptámeros de Nucleótidos/química , Plata/química , Grafito/química , Compuestos de Estaño/química , Técnicas Biosensibles/métodos , Contaminación de Alimentos/análisisRESUMEN
While numerous methods exist for diagnosing tumors through the detection of miRNA within tumor cells, few can simultaneously achieve both tumor diagnosis and treatment. In this study, a novel graphene oxide (GO)-based DNA nanodevice (DND), initiated by miRNA, was developed for fluorescence signal amplification imaging and photodynamic therapy in tumor cells. After entering the cells, tumor-associated miRNA drives DND to Catalyzed hairpin self-assembly (CHA). The CHA reaction generated a multitude of DNA Y-type structures, resulting in a substantial amplification of Ce6 fluorescence release and the generation of numerous singlet oxygen (1O2) species induced by laser irradiation, consequently inducing cell apoptosis. In solution, DND exhibited high selectivity and sensitivity to miRNA-21, with a detection limit of 11.47 pM. Furthermore, DND discriminated between normal and tumor cells via fluorescence imaging and specifically generated O21 species in tumor cells upon laser irradiation, resulting in tumor cells apoptosis. The DND offer a new approach for the early diagnosis and timely treatment of malignant tumors.
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ADN , Grafito , MicroARNs , Fotoquimioterapia , Nanomedicina Teranóstica , Fotoquimioterapia/métodos , Humanos , MicroARNs/análisis , Grafito/química , Nanomedicina Teranóstica/métodos , ADN/química , Apoptosis/efectos de los fármacos , Imagen Óptica , Línea Celular Tumoral , Oxígeno Singlete/metabolismo , Oxígeno Singlete/química , Neoplasias/tratamiento farmacológico , Neoplasias/diagnóstico por imagenRESUMEN
Low fluorescence under visible light excitation and catalytic activity limit many applications of graphene quantum dots in optical detection, biosensing, catalysis and biomedical. The paper reports design and synthesis of histidine, serine and folic acid-functionalized and boron and iron-doped graphene quantum dot (Fe/B-GQD-HSF). The Fe/B-GQD-HSF shows excellent fluorescence behavior and peroxidase-like activity. Excitation of 330 nm ultraviolet light produces the strongest blue fluorescence and excitation of 480 nm visible light produces the strongest yellow fluorescence. The specific activity reaches 92.67 U g-1, which is higher than that of other graphene quantum dots. The Fe/B-GQD-HSF can catalyze oxidation of 3,3',5,5'-tetramethylbenzidine with H2O2 to form blue compound. Based on this, it was used for colorimetric and fluorescence detection of H2O2. The absorbance at 652 nm linearly increases with the increase of H2O2 concentration between 0.5 and 100 µM with detection limit of 0.43 µM. The fluorescence signal linearly decreases with the increase of H2O2 concentration between 0.05 and 100 µM with detection limit of 0.035 µM. The analytical method has been satisfactorily applied in detection of H2O2 in food. The study also paves one way for design and synthesis of functional graphene quantum dots with ideal fluorescence behavior and catalytic activity.
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Boro , Colorimetría , Ácido Fólico , Grafito , Histidina , Peróxido de Hidrógeno , Hierro , Puntos Cuánticos , Serina , Puntos Cuánticos/química , Grafito/química , Peróxido de Hidrógeno/análisis , Peróxido de Hidrógeno/química , Colorimetría/métodos , Ácido Fólico/análisis , Ácido Fólico/química , Hierro/análisis , Hierro/química , Boro/química , Histidina/análisis , Histidina/química , Serina/análisis , Serina/química , Espectrometría de Fluorescencia/métodos , Límite de Detección , Análisis de los Alimentos/métodos , Peroxidasa/química , Peroxidasa/metabolismo , CatálisisRESUMEN
Photocatalytic disinfection is an eco-friendly strategy for countering bacterial pollution in aquatic environments. Numerous strategies have been devised to facilitate the generation of reactive oxygen species (ROS) within photocatalysts, ultimately leading to the eradication of bacteria. However, the significance of the physical morphology of photocatalysts in the context of sterilization is frequently obscured, and the progress in the development of physical-chemical synergistic sterilization photocatalysts has been relatively limited. Herein, graphitic carbon nitride (g-C3N4) is chemically protonated to expose more sharp edges. PL fluorescence and EIS results indicate that the protonation can accelerate photogenerated carrier separation and enhance ROS production. Meanwhile, the sharp edges on the protonated g-C3N4 facilitate the physical disruption of cell walls for further promoting oxidative damage. Protonated C3N4 demonstrated superior bactericidal performance than that of pristine g-C3N4, effectively eliminating Escherichia coli within 40 minutes under irradiation. This work highlights the significance of incorporating physical and chemical synergies in photocatalyst design to enhance the disinfection efficiency of photocatalysis.
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Desinfección , Nitrilos , Nitrilos/química , Desinfección/métodos , Catálisis , Escherichia coli/efectos de los fármacos , Especies Reactivas de Oxígeno , Grafito/química , Esterilización/métodos , Compuestos de Nitrógeno/químicaRESUMEN
Fischer-Tropsch synthesis (FTS) wastewater retaining low-carbon alcohols and acids are organic pollutants as a limiting factor for FTS industrialization. In this work, the structure-capacity relationships between alcohol-acid adsorption and surface species on graphene were reported, shedding light into their intricate interactions. The graphene oxide (GO) and reduced graphene oxide (rGO) were synthesized via improved Hummers method with flake graphite (G). The physicochemical properties of samples were characterized via SEM, XRD, XPS, FT-IR, and Raman. The alcohol-acid adsorption behaviors and adsorption quantities on G, GO, and rGO were measured via theoretical and experimental method. It was revealed that the presence of COOH, C=O and CO species on graphene occupy the adsorption sites and increase the interactions of water with graphene, which are unfavorable for alcohol-acid adsorption. The equilibrium adsorption quantities of alcohols and acids grow in pace with carbon number. The monolayer adsorption occurs on graphene was verified via model fitting. rGO has the highest FTS modeling wastewater adsorption quantity (110 mg/g) due to the reduction of oxygen species. These novel findings provide a foundation for the alcohol-acid wastewater treatment, as well as the design and development of high-performance carbon-based adsorbent materials.
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Alcoholes , Grafito , Aguas Residuales , Contaminantes Químicos del Agua , Grafito/química , Adsorción , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Alcoholes/química , Eliminación de Residuos Líquidos/métodos , Modelos Químicos , Ácidos/químicaRESUMEN
Herein, a modified screen printed carbon electrode (SPCE) based on a composite material, graphene oxide-gold nanoparticles (GO-AuNPs), and poly(3-aminobenzoic acid)(P3ABA) for the detection of paraquat (PQ) is introduced. The modified electrode was fabricated by drop casting of the GO-AuNPs, followed by electropolymerization of 3-aminobenzoic acid to achieve SPCE/GO-AuNPs/P3ABA. The morphology and microstructural characteristics of the modified electrodes were revealed by scanning electron microscopy (SEM) for each step of modification. The composite GO-AuNPs can provide high surface area and enhance electroconductivity of the electrode. In addition, the presence of negatively charged P3ABA notably improved PQ adsorption and electron transfer rate, which stimulate redox reaction on the modified electrode, thus improving the sensitivity of PQ analysis. The SPCE/GO-AuNPs/P3ABA offered a wide linear range of PQ determination (10-9-10-4 mol/L) and low limit of detection (LOD) of 0.45 × 10-9 mol/L or 0.116 µg/L, which is far below international safety regulations. The modified electrode showed minimum interference effect with percent recovery ranging from 96.5% to 116.1% after addition of other herbicides, pesticides, metal ions, and additives. The stability of the SPCE/GO-AuNPs/P3ABA was evaluated, and the results indicated negligible changes in the detection signal over 9 weeks. Moreover, this modified electrode was successfully implemented for PQ analysis in both natural and tapped water with high accuracy.
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Técnicas Electroquímicas , Electrodos , Oro , Grafito , Nanopartículas del Metal , Paraquat , Grafito/química , Paraquat/análisis , Oro/química , Nanopartículas del Metal/química , Técnicas Electroquímicas/métodos , Límite de Detección , Carbono/química , Contaminantes Químicos del Agua/análisis , Herbicidas/análisisRESUMEN
For environmental applications, it is crucial to rationally design and synthesize photocatalysts with positive exciton splitting and interfacial charge transfer. Here, a novel Ag-bridged dual Z-scheme Ag/g-C3N4/CoNi-LDH plasmonic heterojunction was successfully synthesized using a simple method, with the goal of overcoming the common drawbacks of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers, and unstable structure. These materials were characterized by XRD, FT-IR, SEM, TEM UV-Vis/DRS, and XPS to verify the structure and stability of the heterostructure. The pristine LDH, g-C3N4, and Ag/g-C3N4/CoNi-LDH composite were investigated as photocatalysts for water remediation, an environmentally motivated process. Specifically, the photocatalytic degradation of tetracycline was studied as a model reaction. The performance of the supports and composite catalyst were determined by evaluating both the degradation and adsorption phenomenon. The influence of several experimental parameters such as catalyst loading, pH, and tetracycline concentration were evaluated. The current study provides important data for water treatment and similar environmental protection applications.
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Nanocompuestos , Fotólisis , Plata , Contaminantes Químicos del Agua , Purificación del Agua , Nanocompuestos/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Plata/química , Catálisis , Nitrilos/química , Compuestos de Nitrógeno/química , Adsorción , GrafitoRESUMEN
The expandable graphite (EG) modified TiO2 nanocomposites were prepared by the high shear method using the TiO2 nanoparticles (NPs) and EG as precursors, in which the amount of EG doped in TiO2 was 10 wt.%. Followed by the impregnation method, adjusting the pH of the solution to 10, and using the electrostatic adsorption to achieve spatial confinement, the Pt elements were mainly distributed on the exposed TiO2, thus generating the Pt/10EG-TiO2-10 catalyst. The best CO oxidation activity with the excellent resistance to H2O and SO2 was obtained over the Pt/10EG-TiO2-10 catalyst: CO conversion after 36 hr of the reaction was ca. 85% under the harsh condition of 10 vol.% H2O and 100 ppm SO2 at a high gaseous hourly space velocity (GHSV) of 400,000 hr-1. Physicochemical properties of the catalysts were characterized by various techniques. The results showed that the electrostatic adsorption, which riveted the Pt elements mainly on the exposed TiO2 of the support surface, reduced the dispersion of Pt NPs on EG and achieved the effective dispersion of Pt NPs, hence significantly improving CO oxidation activity over the Pt/10EG-TiO2-10 catalyst. The 10 wt.% EG doped in TiO2 caused the TiO2 support to form a more hydrophobic surface, which reduced the adsorption of H2O and SO2 on the catalyst, greatly inhibited deposition of the TiOSO4 and formation of the PtSO4 species as well as suppressed the oxidation of SO2, thus resulting in an improvement in the resistance to H2O and SO2 of the Pt/10EG-TiO2-10 catalyst.
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Grafito , Oxidación-Reducción , Platino (Metal) , Dióxido de Azufre , Titanio , Titanio/química , Grafito/química , Dióxido de Azufre/química , Platino (Metal)/química , Catálisis , Monóxido de Carbono/química , Agua/química , Contaminantes Atmosféricos/química , Modelos QuímicosRESUMEN
The overuse of antibiotics and antitumor drugs has resulted in more and more extensive pollution of water bodies with organic drugs, causing detrimental ecological effects, which have attracted attention towards effective and sustainable methods for antibiotics and antitumor drug degradation. Here, the hybrid nanomaterial (g-C3N4@Fe/Pd) was synthesized and used to remove a kind of both an antibiotic and antitumor drug named mitoxantrone (MTX) with 92.0% removal efficiency, and the MTX removal capacity is 450 mg/g. After exposing to the hybrid material the MTX aqueous solution changed color from dark blue to lighter progressively, and LC-UV results of residual solutions show that a new peak at 3.0 min (MTX: 13.2 min) after removal by g-C3N4@Fe/Pd appears, with the simultaneous detection of intermediate products indicating that g-C3N4@Fe/Pd indeed degrades MTX. Detailed mass spectrometric analysis suggests that the nuclear mass ratio decreased from 445.2 (M+1H) to 126.0 (M+1H), 169.1 (M+1H), 239.2 (M+1H), 267.3 (M+1H), 285.2 (M+1H), 371.4 (M+1H) and 415.2 (M+1H), and the maximum proportion (5.63%) substance of all degradation products (126.0 (M+1H)) is 40-100 times less toxic than MTX. A mechanism for the removal and degradation of mitoxantrone was proposed. Besides, actual water experiments confirmed that the maximum removal capacity of MTX by g-C3N4@Fe/Pd is up to 492.4 mg/g (0.02 g/L, 10 ppm).
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Grafito , Nanopartículas del Metal , Mitoxantrona , Paladio , Contaminantes Químicos del Agua , Mitoxantrona/química , Contaminantes Químicos del Agua/química , Grafito/química , Nanopartículas del Metal/química , Paladio/química , Hierro/química , Catálisis , Compuestos de Nitrógeno/química , Antineoplásicos/químicaRESUMEN
The present study elucidates the effectiveness of a molecularly imprinted polyacrylonitrile-imbued graphite-base electrode (MAN@G) for the selective detection of folic acid (FA) in food samples. The prime objective of the recognition and quantification of vitamin compounds like FA is the overall quality assessment of vegetables and fruits. The cost-effective, reproducible, and durable MAN@G electrode has been fabricated using acrylonitrile (AN) as the monomer and FA as the template over graphite-base. The characterization of the synthesized MAN@G electrode material has been accomplished by utilizing UV-visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). A tri-electrode system based on differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques was employed to explore the analytical performance of the synthesized electrode. Rigorous analyses divulged that a widespread linearity window could be exhibited by the electrode under an optimized experimental environment, ranging from 20 µM to 400 µM concentrations with an acceptable lower limit of detection (LOD) and limit of quantification (LOQ) of 18 nM, and 60 nM respectively. Additionally, this electrode exhibits high reproducibility, good stability, and high repeatability, with RSD values of 1.72 %, 1.32 %, and 1.19 %, respectively. The detection efficacy of the proposed electrode has been further examined in food extracts, namely orange, spinach, papaya, soybean, and cooked rice, which endorsed high accuracy compared to the high-performance liquid chromatography (HPLC) method. Moreover, the statistical results obtained from the t-test analysis were also satisfactory for the FA concentrations present in those five samples.
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Resinas Acrílicas , Técnicas Electroquímicas , Electrodos , Ácido Fólico , Grafito , Grafito/química , Resinas Acrílicas/química , Ácido Fólico/análisis , Impresión Molecular , Límite de Detección , Análisis de los Alimentos/métodos , Polímeros Impresos Molecularmente/química , Frutas/químicaRESUMEN
Detecting dopamine (DA) in biological samples is vital to understand its crucial role in numerous physiological processes, such as motion, cognition, and reward stimulus. In this work, p-type graphene on sapphire, synthesized via chemical vapor deposition, serves as substrate for the preparation of p-type Cu2-xS films through solid-phase sulfurization. The optimized Cu2-xS/graphene heterostructure, prepared at 250 °C using a 15-nm copper film sulfurized for 2 h, exhibits superior electron transfer performance, ideal for electrochemical sensing. It is confirmed that the spontaneous charge transfer from graphene to Cu2-xS, higher Cu(II)/Cu(I) ratio (~ 0.8), and the presence of well-defined nanocrystalline structures with an average size of ~ 35 nm in Cu2-xS significantly contribute to the improved electron transfer of the heterostructure. The electrochemical sensor based on Cu2-xS/graphene heterostructure demonstrates remarkable sensitivity towards DA, with a detection limit as low as 100 fM and a dynamic range greater than 109 from 100 fM to 100 µM. Additionally, it exhibits excellent selectivity even in the presence of uric acid and ascorbic acid 100 times higher, alongside notable storage and measurement stability and repeatability. Impressively, the sensor also proves capable of detecting DA concentrations as low as 100 pM in rat serum, showcasing its potential for clinically relevant analytes and promising applications in sensitive, selective, reliable, and efficient point-of-care diagnostics.
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Cobre , Dopamina , Técnicas Electroquímicas , Grafito , Límite de Detección , Dopamina/sangre , Dopamina/análisis , Cobre/química , Grafito/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Animales , Ratas , Técnicas Biosensibles/métodos , ElectrodosRESUMEN
To meet the needs of developing efficient extractive materials alongside the evolution of miniaturized sorbent-based sample preparation techniques, a mesoporous structure of g-C3N4 doped with sulfur as a heteroatom was achieved utilizing a bubble template approach while avoiding the severe conditions of other methods. In an effort to increase the number of adsorption sites, the resultant exfoliated structure was then modified with thymol-coumarin NADES as a natural sorbent modifier, followed by introduction into a nylon 6 polymer via an electrospinning process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis validated S-doped g-C3N4 and composite production. The prepared electrospun fiber nanocomposite, entailing satisfactory processability, was then successfully utilized as a sorbent in on-chip thin film micro-solid-phase extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from saliva samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Utilizing a chip device, a thin film µ-SPE coupled with LC-MS/MS analysis yielded promising outcomes with reduced sample solution and organic solvents while extending lifetime of a thin film sorbent. The DES-modified S-doped g-C3N4 amount in electrospun was optimized, along with adsorption and desorption variables. Under optimal conditions, selected NSAIDs were found to have a linear range of 0.05-100.0 ng mL-1 with an R2 ≥ 0.997. The detection limits were ranged between 0.02 and 0.2 ng mL-1. The intra-day and inter-day precisions obtained were less than 6.0%. Relative recoveries were between 93.3 and 111.4%.
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Antiinflamatorios no Esteroideos , Disolventes Eutécticos Profundos , Grafito , Límite de Detección , Nanofibras , Saliva , Espectrometría de Masas en Tándem , Saliva/química , Espectrometría de Masas en Tándem/métodos , Grafito/química , Nanofibras/química , Humanos , Adsorción , Antiinflamatorios no Esteroideos/análisis , Porosidad , Disolventes Eutécticos Profundos/química , Cromatografía Liquida/métodos , Compuestos de Nitrógeno/química , Microextracción en Fase Sólida/métodos , Extracción en Fase Sólida/métodosRESUMEN
The review summarises the prospects in the application of graphene and graphene-based nanomaterials (GBNs) in nanomedicine, including drug delivery, photothermal and photodynamic therapy, and theranostics in cancer treatment. The application of GBNs in various areas of science and medicine is due to the unique properties of graphene allowing the development of novel ground-breaking biomedical applications. The review describes current approaches to the production of new targeting graphene-based biomedical agents for the chemotherapy, photothermal therapy, and photodynamic therapy of tumors. Analysis of publications and FDA databases showed that despite numerous clinical studies of graphene-based materials conducted worldwide, there is a lack of information on the clinical trials on the use of graphene-based conjugates for the targeted drug delivery and diagnostics. The review will be helpful for researchers working in development of carbon nanostructures, material science, medicinal chemistry, and nanobiomedicine.
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Grafito , Neoplasias , Nanomedicina Teranóstica , Grafito/química , Grafito/uso terapéutico , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/terapia , Nanomedicina Teranóstica/métodos , Fotoquimioterapia , Nanoestructuras/uso terapéutico , Nanoestructuras/química , Sistemas de Liberación de Medicamentos , Animales , Antineoplásicos/uso terapéutico , Antineoplásicos/química , Terapia Fototérmica/métodosRESUMEN
This review article explores the developments and applications in agar-based composites (ABCs), emphasizing various constituents such as metals, clay/ceramic, graphene, and polymers across diversified fields like wastewater treatment, drug delivery, food packaging, the energy sector, biomedical engineering, bioplastics, agriculture, and cosmetics. The focus is on agar as a sustainable and versatile biodegradable polysaccharide, highlighting research that has advanced the technology of ABCs. A bibliometric analysis is conducted using the Web of Science database, covering publications from January 2020 to March 2024, processed through VOSviewer Software Version 1.6.2. This analysis assesses evolving trends and scopes in the literature, visualizing co-words and themes that underscore the growing importance and potential of ABCs in various applications. This review paper contributes by showcasing the existing state-of-the-art knowledge and motivating further development in this promising field.
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Agar , Embalaje de Alimentos , Agar/química , Humanos , Sistemas de Liberación de Medicamentos , Arcilla/química , Materiales Biocompatibles/química , Grafito/química , Cerámica/químicaRESUMEN
BACKGROUND: Dental implants are increasingly favored as a therapeutic replacement option for edentulism. Titanium (Ti), due to its excellent biocompatibility and unique osseointegration properties, is commonly used in dental implants. Various surface modifications have been explored to improve osseointegration outcomes. Graphene oxide (GO) is a promising material with various applications. Chitosan, found in the exoskeleton of crustaceans and in marine algae, has several biomedical applications. Silver (Ag) is another promising antibacterial agent that increases permeability and damages the bacterial cell membrane upon binding. OBJECTIVES: The present study applied a novel implant surface coating of Ag-decorated GO and chitosan on Ti implants to promote bone formation. We further analyzed the physiochemical and antibacterial properties of this surface coating. MATERIAL AND METHODS: A solution was prepared by mixing 3 mL of 1% chitosan solution with 10 mg of Ag-GO nanoparticles (NPs). Titanium metal was heated to 70-80°C on a hotplate and the solution was applied onto Ti to obtain an adhesive surface coating. The coated implant was further analyzed for surface properties, using scanning electron microscopy (SEM), the energy dispersive X-ray (EDX) analysis, the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) technique, and the biocompatibility and corrosion analyses. RESULTS: The SEM analysis revealed a homogenously spread, rough, fibrillar and porous layer of coating on the metal surface. The EDX and ATR-FTIR analyses confirmed the successful coating of the implant surface with Ag-decorated GO and chitosan layers. The cell culture assay demonstrated excellent biocompatibility of the surface coating. The corrosion analysis showed improved corrosion resistance of the developed implant surface coating. CONCLUSIONS: The various analyses of the coating showed ideal properties for improved cell attachment, differentiation and proliferation while maintaining an antimicrobial environment on the implant surface.
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Quitosano , Materiales Biocompatibles Revestidos , Implantes Dentales , Grafito , Ensayo de Materiales , Plata , Propiedades de Superficie , Titanio , Quitosano/farmacología , Quitosano/química , Plata/farmacología , Corrosión , Antibacterianos/farmacología , Microscopía Electrónica de Rastreo , HumanosRESUMEN
Easy, economical, and swift detecting tools are very demanded for assaying various chemical species. The introduction of label-free paper-based read-out devices has significantly reached the demand of analytical science for target analytes assays. Herein, a facile, and disposable inexpensive paper-based sensing tool was fabricated for sensing As3+ ion using graphene quantum dots (GQDs) as a fluorescent reader. The CA-GQDs were synthesized using citric acid (CA) as a precursor via the pyrolysis method, further physisorbed on the cellulose substrate for sensing of As3+ via aggregation-based fluorescence "turn-off" mechanism. The linear range for quantitating As3+ ion is in the range of 0.05-50 µM with a detection limit of 10 nM. The practical application of the CA-GQDs-based analytical platform was verified by assaying As3+ ion in water samples. The CA-GQDs-embedded paper strip can be easily extended for assaying of As3+ ion, which meets the demand for monitoring of As3+ ion in real samples.
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Celulosa , Grafito , Papel , Puntos Cuánticos , Grafito/química , Puntos Cuánticos/química , Celulosa/química , Colorantes Fluorescentes/química , Colorantes Fluorescentes/síntesis química , Espectrometría de Fluorescencia , Iones/análisis , Iones/química , Límite de Detección , FluorescenciaRESUMEN
CONTEXT: Airborne pathogens, defined as microscopic organisms, pose significant health risks and can potentially cause a variety of diseases. Given their ability to spread through diverse transmission routes from infected hosts, there is a critical need for accurate monitoring of these pathogens. This study aims to develop a sensor by investigating the vibrational responses of cantilever and bridged boundary-conditioned single-layer graphene (SLG) sheets with microorganisms, specifically SARS-CoV-2, attached at various positions on the sheet. The dynamic analysis of SLG with different boundary conditions and lengths was conducted using the atomistic finite element method (AFEM). Simulations were performed to evaluate SLG's performance as a sensor for biological entities. Altering the sheet's length and the mass of the attached biological object revealed observable frequency differences. This sensor design shows promise for enhancing the detection capabilities of graphene-based technologies for viruses. METHODS: Finite element method (FEM) analysis is employed to model the sensor's performance and optimize its design parameters. The simulation results highlight the sensor's potential for achieving high sensitivity and rapid detection of SARS-CoV-2. Bridged and cantilever boundary conditions are applied at the ends of the SLG structure by using ANSYS software. Simulations have been conducted to observe how SLG behaves when used as sensors. In armchair graphene, under both boundary conditions, an SLG (5, 5) structure with a length of 50 nm displayed the highest frequency when a SARS-CoV-2 molecule with a mass of 2.6594 × 10-18 g was attached. Conversely, the chiral SLG (17, 1) structure exhibited its lowest frequency at a length of 10 nm. This insight is crucial for grasping detection limits and how factors such as size and boundary conditions influence sensor efficacy. These biosensors hold immense promise in biological sciences and medical applications, revolutionizing patient care by enabling early detection and accurate pathogen identification in clinical settings.
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Técnicas Biosensibles , COVID-19 , Análisis de Elementos Finitos , Grafito , SARS-CoV-2 , Grafito/química , SARS-CoV-2/aislamiento & purificación , Técnicas Biosensibles/métodos , COVID-19/virología , Humanos , Simulación por ComputadorRESUMEN
Graphene oxide (GO) is a novel nanomaterial being applied in different fields, but was less used as foliar fertilizer in agriculture. We conducted a pot experiment to analyze the effects of foliar spraying GO from 0 (control), 50 (T1), 100 (T2), 150 (T3) and 200 mg·L-1 (T4) on the morphogenesis and carbon and nitrogen metabolism of kidney bean plants during the initiation of flowering to clarify the physiological effects of foliar spraying GO. The results showed that dry matter accumulation, the content of photosynthetic pigments, soluble sugars of T1 to T4 treatments, were significantly increased by 40.7%-43.4%, 10.4%-80.7%, 6.4%-9.1% in kidney bean plants compared with CK treatment, respectively. T3 treatment performed the best. Meanwhile, the activities of sucrose phosphate synthase, acid converting enzyme and neutral converting enzyme of T3 and T4 treatments were increased by 25.7%-45.5%, 17.4%-28.6%, and 14.7%-20.1%, and the activities of nitrate reductase, glutamine synthetase, and glutamate synthetase of T2 and T3 treatments were increased by 8.1%-15.2%, 11.5%-25.0%, and 89.7%-93.1%, respectively. In conclusion, foliar spraying of appropriate GO in early flowering stage of kidney bean could increase the content of photosynthetic pigments, improve the level of photosynthetic carbon and nitrogen metabolism, and increase dry matter accumulation. T3 treatment (150 mg·L-1) was the most effective in this study.
Asunto(s)
Carbono , Flores , Grafito , Nitrógeno , Phaseolus , Nitrógeno/metabolismo , Grafito/metabolismo , Carbono/metabolismo , Phaseolus/crecimiento & desarrollo , Phaseolus/metabolismo , Phaseolus/efectos de los fármacos , Flores/metabolismo , Flores/crecimiento & desarrollo , Flores/efectos de los fármacos , Fertilizantes , Fotosíntesis/efectos de los fármacosRESUMEN
Background: The high infectivity of coronaviruses has led to increased interest in developing new strategies to prevent virus spread. Silver nanoparticles (AgNPs) and graphene oxide (GO) have attracted much attention in the antiviral field. We investigated the potential antiviral activity of GO and AgNPs combined in the nanocomposite GO-Ag against murine betacoronavirus MHV using an in vitro model. Methods: GO, AgNPs, and GO-Ag characterization (size distribution, zeta potential, TEM visualization, FT-IR, and EDX analysis) and XTT assay were performed. The antiviral activity of GO-Ag nanocomposites was evaluated by RT-qPCR and TCID50 assays. The results were compared with free AgNPs and pure GO. Cell growth and morphology of MHV-infected hepatocytes treated with GO-Ag composites were analyzed by JuLI™Br. Immunofluorescence was used to visualize the cell receptor used by MHV. Ultrastructural SEM analysis was performed to examine cell morphology after MHV infection and GO-Ag composite treatment. Results: A significant reduction in virus titer was observed for all nanocomposites tested, ranging from 3.2 to 7.3 log10 TCID50. The highest titer reduction was obtained for GO 5 µg/mL - Ag 25 µg/mL in the post-treatment method. These results were confirmed by RT-qPCR analysis. The results indicate that GO-Ag nanocomposites exhibited better antiviral activity compared to AgNPs and GO. Moreover, the attachment of AgNPs to the GO flake platform reduced their cytotoxicity. In addition, the GO-Ag composite modulates the distribution of the Ceacam1 cell receptor and can modulate cell morphology. Conclusion: Graphene oxide sheets act as a stabilizing agent, inhibiting the accumulation of AgNPs and reducing their cellular toxicity. The GO-Ag composite can physically bind and inhibit murine betacoronavirus from entering cells. Furthermore, the constant presence of GO-Ag can inhibit MHV replication and significantly limit its extracellular release. In conclusion, GO-Ag shows promise as an antiviral coating on solid surfaces to minimize virus transmission and spread.