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1.
Ecotoxicol Environ Saf ; 285: 117028, 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39276648

RESUMEN

Antiviral drugs have garnered considerable attention, particularly in the global battle against the COVID-19 pandemic, amid heightened concerns regarding environmentally acquired antiviral resistance. A comprehensive understanding of their transport in subsurface environments is imperative for accurately predicting their environmental fate and risks. This study investigated the mobility and retention characteristics of six COVID-19 antiviral drugs in saturated quartz sand columns. Results showed that the mobility of the drugs was primarily contingent on their hydrophobicity, with ribavirin and favipiravir exhibiting the highest transportability, while arbidol displaying the greatest retention. The transport characteristics of ribavirin and favipiravir remained largely unaffected by pH, whereas the retention of the other four antivirals remained consistently minimal under alkaline conditions. Elevating ionic strength marginally facilitated the transport of these antivirals, while the presence of Ca2+ notably enhanced their retention in quartz sand compared to Na+. Ribavirin and remdesivir warrant particular attention due to their relatively high transportability and propensity for environmentally acquired antiviral resistance. These findings contribute to an enhanced understanding of the leachate potential and transport of COVID-19-related antivirals in sandy porous media, furnishing fundamental data for predicting their environmental fate and associated risks.

2.
Anal Bioanal Chem ; 2024 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-39276213

RESUMEN

In this study, multiple particle binding-liposomes (MPB-Lips), encapsulating the luminophore tris(2',2-bipyridyl)ruthenium (II) complex ([Ru(bpy)3]2+), were developed as an electrochemiluminescence (ECL) signal amplifier and were applied to detect the model analyte streptavidin (SA) using the indirect competitive ECL method. The MPB-Lips were prepared by mixing various ratios of two different liposomes-one containing a phospholipid with a primary amine group and a biotinyl group (BIO/NH2-Lip) and one containing a phospholipid with an N-hydroxysuccinimide group (NHS-Lip) to allow binding between particles via amide bonds. Quartz crystal microbalance analysis using SA-modified gold-coated quartz crystals showed that the frequency shift values of MPB-Lips gradually decreased in the order BIO/NH2-Lip:NHS-Lip = 1:0 < 1:1 < 1:3 < 1:5. This indicated that MPB-Lips were successfully formed. The indirect competitive ECL method using SA-modified gold electrodes showed that the 1:5-Lip system had greater sensitivity than the 1:0-Lip system-the limit of detection and quantification values for the systems were 1.84 and 6.30 µg mL-1 for 1:0-Lip, and 1.20 and 1.74 µg mL-1 for 1:5-Lip. Finally, the recovery of SA spiked in fetal bovine serum samples using the 1:5-Lip system showed good accuracy and precision with a recovery rate of 83-106% and relative standard deviation of 4-14%. Our study demonstrated that the MPB-Lips system was an effective and useful ECL amplifier and the ECL method using MPB-Lips could be applied to detect an analyte in a real sample.

3.
Proc Natl Acad Sci U S A ; 121(40): e2407655121, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39284038

RESUMEN

As sand moves across Earth's landscapes, the shapes of individual grains evolve, and microscopic textures accumulate on their surfaces. Because transport processes vary between environments, the shape and suite of microtextures etched on sand grains provide insights into their transport histories. For example, previous efforts to link microtextures to transport environments have demonstrated that they can provide important information about the depositional environments of rocks with few other indicators. However, such analyses rely on 1) subjective human description of microtextures, which can yield biased, error-prone results; 2) nonstandard lists of microtextures; and 3) relatively large sample sizes (>20 grains) to obtain reliable results, the manual documentation of which is extremely labor intensive. These drawbacks have hindered broad adoption of the technique. We address these limitations by developing a deep neural network model, SandAI, that classifies scanning electron microscope images of modern sand grains by transport environment with high accuracy. The SandAI model was developed using images of sand grains from modern environments around the globe. Training data encompass the four most common terrestrial environments: fluvial, eolian, glacial, and beach. We validate the model on quartz grains from modern sites unknown to it, and Jurassic-Pliocene sandstones of known depositional environments. Next, the model is applied to two samples of the Cryogenian Bråvika Member (of contested origin), yielding insights into periglacial systems associated with Snowball Earth. Our results demonstrate the robustness and versatility of the model in quickly and automatically constraining the transport histories recorded in individual grains of quartz sand.

4.
Carbohydr Polym ; 345: 122556, 2024 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-39227119

RESUMEN

Cellulose nanofibrils (CNFs) from non-woody biomass, including citrus peel (CpCNFs), are promising naturally occurring nanomaterials; however, their properties depend on the composition of non-cellulosic components, including pectin. In this study, the effects of pectin modifications on CpCNFs were examined, including demethylesterification using alkaline treatment and enzymatic degradation of pectin using pectinase. CpCNFs could be redispersed in water with little aggregation after drying; however, the redispersibilities of both alkaline-treated (AT-CpCNFs) and pectinase-treated CpCNFs (PT-CpCNFs) were improved. Both AT-CpCNFs and PT-CpCNFs exhibited higher viscosity than untreated CpCNFs (UT-CpCNFs); redispersion in water after drying further increased the viscosity. A quartz crystal microbalance revealed that interactions between AT-CpCNFs were barely detectable, and interactions between PT-CpCNFs were stronger than those between UT-CpCNFs. The increase in the carboxylate groups of pectin due to demethylesterification in AT-CpCNF may have increased the viscosity and reduced the interactions between AT-CpCNFs, explaining the improved redispersibility. The increase in the viscosity of PT-CpCNFs may be attributed to the increased purity of CNFs, which is assumed to be more viscous than pectin. Our results show that the properties of CpCNFs are affected by the structure, properties, and content of pectin and can be controlled by pectin modification.

5.
J Hazard Mater ; 479: 135766, 2024 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-39244984

RESUMEN

Nanoplastics (NPs) pose great challenges to soil-groundwater systems. This study investigated the transport and retention of self-synthesized 0.5-µm polystyrene NPs with different shapes using column experiments. The regular NPs were with spherical shapes, while the irregular NPs were with toroid-like shapes. The toroid-like shapes were the irregular shapes (with low aspect ratio) which have not been studied yet. The explorations were carried out in both 5-25 mM NaNO3 and 1-10 mM Ca(NO3)2 solutions. Both breakthrough curves (BTCs) and retained profiles (RPs) were monitored. Our findings uncovered a clear disparity in the transport of irregular and regular NPs, with irregular particles exhibiting lower transport ability compared to the regular ones. For example, the average breakthrough plateaus of the regular and irregular NPs were ∼0.9 and ∼0.5, respectively, in 10 mM NaNO3. In-depth theoretical analysis indicated that the lower XDLVO interaction energy barrier between the irregular NPs and quartz sand was one factor, and the greater margination of irregular NPs on quartz sand, as verified by the numerical simulation, was another factor leading to the decreased transport and increased retention of the irregular NPs. The obtained results highlighted the significance of considering particle shape in future modelling and predicting the fate of NPs in real environmental circumstances.

6.
Anal Sci ; 2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39230826

RESUMEN

A reflective surface plasmon resonance (SPR) sensor was evaluated for real-time monitoring of scale deposition. The sensor consists of an optical fiber, only 5 mm at the gold-coated tip of the sensing area. The effect of silica growth on the sensor response was evaluated using a Na2SiO3 solution. The sensitivity of the sensor to silica was 1.6 ± 0.3 nm per one immersion in the solution of 1000 mg/L (as SiO2) at 85 °C and subsequnt air drying, as indicated by the SPR peak shift. The amount of silica deposited on the gold surface was measured by the quartz crystal microbalance method, and the SPR sensitivity of 0.089 nm/ng to silica mass was obtained. The detection limit (3σ) of the SPR sensor was 17 ng, corresponding to a thickness of 2.5 nm for amorphous silica. The SPR sensor was tested in geothermal brine sampled at the Sumikawa Geothermal Power Plant, where a clear SPR shift was observed, suggesting the effectiveness of the SPR sensor for scale monitoring.

7.
Photoacoustics ; 38: 100629, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39100196

RESUMEN

Hydrogen cyanide (HCN) is a toxic industrial chemical, necessitating low-level detection capabilities for safety and environmental monitoring. This study introduces a novel approach for detecting hydrogen cyanide (HCN) using a clamp-type custom quartz tuning fork (QTF) integrated with a dual-tube acoustic micro-resonator (AmR) for enhanced photoacoustic gas sensing. The design and optimization of the AmR geometry were guided by theoretical simulation and experimental validation, resulting in a robust on-beam QEPAS (Quartz-Enhanced Photoacoustic Spectroscopy) configuration. To boost the QEPAS sensitivity, an Erbium-Doped Fiber Amplifier (EDFA) was incorporated, amplifying the laser power by approximately 286 times. Additionally, a transformer-based U-shaped neural network, a machine learning filter, was employed to refine the photoacoustic signal and reduce background noise effectively. This combination yielded a significantly low detection limit for HCN at 0.89 parts per billion (ppb) with a rapid response time of 1 second, marking a substantial advancement in optical gas sensing technologies. Key modifications to the QTF and innovative use of AmR lengths were validated under various experimental conditions, affirming the system's capabilities for real-time, high-sensitivity environmental monitoring and industrial safety applications. This work not only demonstrates significant enhancements in QEPAS but also highlights the potential for further technological advancements in portable gas detection systems.

8.
Ann Work Expo Health ; 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39102735

RESUMEN

Internationally, respirable crystalline silica (RCS) occupational exposure limits (OELs) are being reassessed and, in some jurisdictions, lowered, putting pressure on the capabilities of the analytical techniques used to achieve robust analyses and reliable detection limits. In preparation of a lower OEL, options for lowering the limit of detection (LoD) for RCS analysis have been assessed. Using a Direct-on-Filter X-Ray Diffraction (XRD) analysis under reduced scan speeds in combination with low-noise RCS sampling filters, an LoD of 0.25 µg/filter and a limit of quantification (LoQ) of 0.82 µg/filter can be achieved. Both limits would translate in an LoD of 0.24 µg/m3 and LoQ of 0.78 µg/m3 when sampling respirable dust for 8 h at 2.2 L/min, providing a technical solution to monitor exposures at the proposed OEL of 0.025 mg/m3 (25 µg /m3) and below, with general sampling conditions as typically applied in Australia. This is the first report showing that the OEL of 0.025 mg/m3 (25 µg /m3) is measurable by one of the standardized, direct-on-filter XRD methods.

9.
Photoacoustics ; 38: 100633, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39104762

RESUMEN

Quartz tuning fork (QTF)-based techniques of photoacoustic spectroscopy and thermoelastic spectroscopy play a significant role in trace gas sensing due to unique high sensitivity and compactness. However, the stability of both techniques remains plagued by the inevitable and unpredictable laser power variation and demodulation phase variation. Herein, we investigate the phase change of a QTF when integrating both techniques for enhanced gas sensing. By demonstrating harmonic phase-sensitive methane detection as an example, we achieve stable gas measurement at varying laser power (2.4-9.4 mW) and varying demodulation phase (-90-90°). Besides, this method shows more tolerance to resonant frequency drift, contributing to a small signal fluctuation of ≤ 6.4 % over a wide modulation range (>10 times of the QTF bandwidth). The realization of harmonic-phase detection allows strengthening the stability of QTF-based sensors in a simple manner, especially when stable parameters, such as laser power, demodulation phase, even resonant frequency, cannot always be maintained.

10.
Front Chem ; 12: 1435562, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39108353

RESUMEN

The continuous development and application of laser technology, and the increasing energy and power of laser output have promoted the development of various types of laser optical systems. The optical components based on quartz materials are key components of high-power laser systems, and their quality directly affects the load capacity of the system. Due to the photothermal effect when the laser interacts with the quartz material and generates extremely high temperatures in a short period of time, it is impossible to experimentally solve the phenomena and physical mechanisms under extreme conditions. Therefore, it is very important to select a suitable method to investigate the thermal effect of intense laser interaction with quartz materials and explain the related physical mechanism. In this study, a three-dimensional quarter-symmetric laser heating quartz material geometry model by using nonlinear transient finite element method was established, and its transient temperature field distribution of the quartz material after being heated by a 1,064 nm continuous laser was investigated. In addition, the influence of different laser parameters (laser spot radius, heat flux and irradiation time), material parameters (material thickness, material absorption rate of laser) on the thermal effect of heating quartz material were also studied. When the laser heat flux is 20 W/cm2, the diameter of the laser spot is 10 cm, the irradiation time is 600 s and the thickness is 4 cm, the temperature after laser heating can reach 940.18°C, which is far lower than the melting point. In addition, the temperature maximum probes were set at the overall model, spot edge and rear surface respectively, and their temperature rise curves with time were obtained. It is also found that there is a significant hysteresis period for the rear surface temperature change of the quartz material compared with the overall temperature change due to heat conduction. Finally, the method proposed can also be applied to the laser heating of other non-transparent materials.

11.
Biosensors (Basel) ; 14(8)2024 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-39194595

RESUMEN

This study presents and compares two methods for identifying the types of extracellular vesicles (EVs) from different cell lines. Through SDS-PAGE analysis, we discovered that the ratio of CD63 to CD81 in different EVs is consistent and distinct, making it a reliable characteristic for recognizing EVs secreted by cancer cells. However, the electrophoresis and imaging processes may introduce errors in the concentration values, especially at lower concentrations, rendering this method potentially less effective. An alternative approach involves the use of quartz crystal microbalance (QCM) and electroanalytical interdigitated electrode (IDT) biosensors for EV type identification and quantification. The QCM frequency shift caused by EVs is directly proportional to their concentration, while electroanalysis relies on measuring the curvature of the I-V curve as a distinguishing feature, which is also proportional to EV concentration. Linear regression lines for the QCM frequency shift and the electroanalysis curvature of various EV types are plotted separately, enabling the estimation of the corresponding concentration for an unknown EV type on the graphs. By intersecting the results from both biosensors, the unknown EV type can be identified. The biosensor analysis method proves to be an effective means of analyzing both the type and concentration of EVs from different cell lines.


Asunto(s)
Técnicas Biosensibles , Vesículas Extracelulares , Tecnicas de Microbalanza del Cristal de Cuarzo , Humanos , Electroforesis en Gel de Poliacrilamida , Línea Celular Tumoral , Electrodos
12.
Sci Total Environ ; 951: 175640, 2024 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-39168322

RESUMEN

Silicon within Si-rich biochars (sichar) plays a crucial role in immobilizing heavy metals and providing slow-releasing bioavailable silicon for silicophilic plants. However, the impact of heating rate on the silicon properties and carbon­silicon interactions in sichars remains unclear. In this study, rice husk was used as a silicon-rich biomass to prepare sichars at different heating rates (10, 30 and 60 °C per minute, and ultra-fast-pyrolysis), then experiments such as silicon concentration measurement, Raman and XRD characterization were conducted. The results showed that a faster heating rate reduced the carbon content during pyrolysis while promoted the formation of amorphous silica, resulting in a threefold increase in dissolved silicon in sichars prepared at 400 °C. Additionally, we observed the formation of a meta-stable SiO2 polymorph (tridymite) in rice husk-derived biochars under fast heating, differing from the previously observed quartz generated at slow heating rates. Regarding the CSi relationship, a faster heating rate facilitated the removal of the surface carbon layer, exposing the underlying silicon layer. This led to more soluble silicon species and less encapsulated silicon, resulting in a continuous release and cumulative silicon dissolution amount 1.2 times and 1.6-1.9 times higher, respectively, than those in slow heating rate-derived sichars. Consequently, this enhanced silicon uptake in rice seedlings. Our findings indicate that beyond pyrolysis temperature, the heating rate significantly affects the silicon species, silicon dissolution behavior, and carbon­silicon relationships of biochar, ultimately determines the properties and applications of sichars.

13.
ACS Sens ; 9(8): 3967-3978, 2024 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-39079008

RESUMEN

This article reports on a bioanalytical sensor device that hosts three different transducer principles: impedance spectroscopy, quartz-crystal microbalance with dissipation monitoring, and the thermal-current-based heat-transfer method. These principles utilize a single chip, allowing one to perform either microbalance and heat transfer measurements in parallel or heat transfer and impedance measurements. When taking specific precautions, the three measurement modalities can even be used truly simultaneously. The probed parameters are distinctly different, so that one may speak about multiparametric or "orthogonal" sensing without crosstalk between the sensing circuits. Hence, this sensor allows one to identify which of these label-free sensing principles performs best for a given bioanalytical application in terms of a high signal amplitude and signal-to-noise ratio. As a proof-of-concept, the three-parameter sensor was validated by studying the spontaneous, collective detachment of eukaryotic cells in the presence of a temperature gradient between the QCM chip and the supernatant liquid. In addition to heat transfer, detachment can also be monitored by the impedance- and QCM-related signals. These features allow for the distinguishing between different yeast strains that differ in their flocculation genes, and the sensor device enables proliferation monitoring of yeast colonies over time.


Asunto(s)
Técnicas Biosensibles , Tecnicas de Microbalanza del Cristal de Cuarzo , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Tecnicas de Microbalanza del Cristal de Cuarzo/métodos , Temperatura , Espectroscopía Dieléctrica/métodos , Diseño de Equipo , Saccharomyces cerevisiae , Adhesión Celular
14.
Molecules ; 29(14)2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39064983

RESUMEN

Human serum albumin (HSA) corona formation on polymer microparticles of a spheroidal shape was studied using dynamic light scattering and Laser Doppler Velocimetry (LDV). Physicochemical characteristics of the albumin comprising the zeta potential and the isoelectric point were determined as a function of pH for various ionic strengths. Analogous characteristics of the polymer particles were analyzed. The adsorption of albumin on the particles was in situ monitored by LDV. The stability of the HSA-functionalized particle suspensions under various pHs and their electrokinetic properties were also determined. The deposition kinetics of the particles on mica, silica and gold sensors were investigated by optical microscopy, AFM and quartz microbalance (QCM) under diffusion and flow conditions. The obtained results were interpreted in terms of the random sequential adsorption model that allowed to estimate the range of applicability of QCM for determining the deposition kinetics of viruses and bacteria at abiotic surfaces.


Asunto(s)
Albúmina Sérica Humana , Humanos , Cinética , Albúmina Sérica Humana/química , Adsorción , Concentración de Iones de Hidrógeno , Tecnicas de Microbalanza del Cristal de Cuarzo , Propiedades de Superficie , Tamaño de la Partícula , Oro/química , Concentración Osmolar , Dióxido de Silicio/química
15.
Materials (Basel) ; 17(14)2024 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-39063774

RESUMEN

The quartz sand-enhanced coagulation (QSEC) is an improved coagulation method for treating water, which uses quartz sand as a heavy medium to accelerate the sedimentation rate of flocs and reduce the sedimentation time. The factors that influence the QSEC effect and can be controlled manually include the quartz sand dosage, coagulant dosage, sewage pH, stirring time, settling time, etc., and their reasonable setting is critical to the result of water treatment. This paper aimed to study the optimal conditions of QSEC; first, single-factor tests were conducted to explore the optimal range of influencing factors, followed by response surface methodology (RSM) tests to accurately determine the optimum values of significant factors. The results show that the addition of quartz sand did not improve the water quality of the coagulation treatment, it took only 140 s for the floc to sink to the bottom, and the sediment volume only accounted for 12.2% of the total sewage. The quartz sand dosage, the coagulant dosage, and sewage pH all had a significant impact on the coagulation effect, and resulted in inflection points. A QSEC-guiding model was derived through RSM tests, and subsequent model optimization and experimental validation revealed the optimal conditions for treating domestic sewage as follows: the polyaluminum chloride (PAC) dosage, cationic polyacrylamide (CPAM) dosage, the sewage pH, quartz sand dosage, stirring time, and settling time were 0.97 g/L, 2.25 mg/L, 7.22, 2 g/L, 5 min, and 30 min, respectively, and the turbidity of the treated sewage was reduced to 1.15 NTU.

16.
Materials (Basel) ; 17(14)2024 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-39063893

RESUMEN

With the increasing depletion of high-quality raw materials, siliceous limestone, sandstone and other hard-to-burn raw materials containing crystalline SiO2 are gradually being used to produce clinker. This study investigates the influence of the quartz content and particle size in siliceous limestone on the calcination process and the resultant quality of cement clinker. Two different siliceous limestones were grinded to different fineness, and calcinated with some other materials. The content of the clinkers was analyzed with the XRD-Rietveld method and the microstructure of the clinkers was observed with laser scanning confocal microscopy (LSCM) and field emission scanning electron microscopy (FESEM). Three key outcomes of this study provide new insights on the use of siliceous limestone in cement production, namely that (i) reducing the fineness values of siliceous limestone from 15% to 0% of residue on a 0.08 mm sieve decreases the quantity of these larger quartz particles, resulting in an increase in C3S content by up to 8% and an increase in 28d compressive strength by up to 4.4 Mpa, which is 62.30 Mpa; (ii) the morphology of quartz-either as chert nodules or single crystals-affects the microstructure of C2S clusters in clinker, finding that chert nodules result in clusters with more intermediate phases, whereas large single crystals lead to denser clusters; (iii) the sufficient fineness values of siliceous limestone SL1 and SL2 are 5% and 7% of residue on a 0.08 mm sieve, respectively, which can produce a clinker with a 28d compressive strength greater than 60 Mpa, indicating that for different kinds of quartz in siliceous limestone, there is an optimum grinding solution that can achieve a balance between clinker quality and energy consumption without having to grind siliceous limestone to very fine grades.

17.
J Forensic Leg Med ; 105: 102717, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38996743

RESUMEN

The primary objective of forensic investigation of a case is to recognize, identify, locate, and examine the evidence. Microscopy is a technique that provides crucial information for resolving a case or advancing the investigation process by analyzing the evidence obtained from a crime scene. It is often used in conjunction with suitable analytical techniques. Various microscopes are employed; scanning probe microscopes are available in diverse forensic analyses and studies. Among these, the atomic force microscope (AFM) is the most commonly used scanning probe technology, offering a unique morphological and physico-chemical perspective for analyzing multiple pieces of evidence in forensic investigations. Notably, it is a non-destructive technique capable of operating in liquid or air without complex sample preparation. The article delves into a detailed exploration of the applications of AFM in the realms of nanomechanical forensics and nanoscale characterization of forensically significant samples.


Asunto(s)
Ciencias Forenses , Microscopía de Fuerza Atómica , Humanos , Ciencias Forenses/métodos
18.
Sensors (Basel) ; 24(13)2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-39001098

RESUMEN

The quartz tuning fork (QTF) is a promising instrument for biosensor applications due to its advanced properties such as high sensitivity to physical quantities, cost-effectiveness, frequency stability, and high-quality factor. Nevertheless, the fork's small size and difficulty in modifying the prongs' surfaces limit its wide use in experimental research. Our study presents the development of a QTF immunosensor composed of three active layers: biocompatible natural melanin nanoparticles (MNPs), glutaraldehyde (GLU), and anti-IgG layers, for the detection of immunoglobulin G (IgG). Frequency shifts of QTFs after MNP functionalization, GLU activation, and anti-IgG immobilization were measured with an Asensis QTF F-master device. Using QTF immunosensors that had been modified under optimum conditions, the performance of QTF immunosensors for IgG detection was evaluated. Accordingly, a finite element method (FEM)-based model was produced using the COMSOL Multiphysics software program (COMSOL License No. 2102058) to simulate the effect of deposited layers on the QTF resonance frequency. The experimental results, which demonstrated shifts in frequency with each layer during QTF surface functionalization, corroborated the simulation model predictions. A modelling error of 0.05% was observed for the MNP-functionalized QTF biosensor compared to experimental findings. This study validated a simulation model that demonstrates the advantages of a simulation-based approach to optimize QTF biosensors, thereby reducing the need for extensive laboratory work.


Asunto(s)
Técnicas Biosensibles , Inmunoglobulina G , Melaninas , Nanopartículas , Cuarzo , Inmunoglobulina G/química , Inmunoglobulina G/inmunología , Técnicas Biosensibles/métodos , Técnicas Biosensibles/instrumentación , Nanopartículas/química , Melaninas/química , Cuarzo/química , Inmunoensayo/métodos , Inmunoensayo/instrumentación , Simulación por Computador , Anticuerpos Antiidiotipos/inmunología , Anticuerpos Antiidiotipos/química , Humanos
19.
J Biomol NMR ; 2024 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-39066955

RESUMEN

Fluorine (19F) NMR is emerging as an invaluable analytical technique in chemistry, biochemistry, structural biology, material science, drug discovery, and medicine, especially due to the inherent rarity of naturally occurring fluorine in biological, organic, and inorganic compounds. Here, we revisit the under-reported problem of fluoride leaching from new and unused glass NMR tubes. We characterised the leaching of free fluoride from various types of new and unused glass NMR tubes over the course of several hours and quantify this contaminant to be at micromolar concentrations for typical NMR sample volumes across multiple glass types and brands. We find that this artefact is undetectable for samples prepared in quartz NMR tubes within the timeframes of our experiments. We also observed that pre-soaking new glass NMR tubes combined with rinsing removes this contamination below micromolar levels. Given the increasing popularity of 19F NMR across a wide range of fields, increasing popularity of single-use screening tubes, the long collection times required for relaxation studies and samples of low concentrations, and the importance of avoiding contamination in all NMR experiments, we anticipate that our simple solution will be useful to biomolecular NMR spectroscopists.

20.
Talanta ; 277: 126376, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-38852341

RESUMEN

In this study, a quartz crystal microbalance (QCM) aptasensor for carcinoembryonic antigen (CEA), a well-known biomarker for various cancer types, was reported, utilizing two different aptamers. To achieve this, a nanofilm of 4-mercaptophenyl was electrochemically attached to gold-coated QCM crystal surfaces via the reduction of 4-mercaptobenzenediazonium salt (4 MB-DAT) using cyclic voltammetry. Subsequently, gold nanoparticles (AuNP) were affixed to this structure, and then aptamers (antiCEA1 and antiCEA2) modified with SH-functional ends bound to AuNPs completed the modification. The analytical performance of the CEA sensor was evaluated through simultaneous QCM measurements employing CEA solutions ranging from 0.1 ng/mL to 25 ng/mL. The detection limit (LOD) for CEA was determined to be 102 pg/mL for antiCEA1 and 108 pg/mL for antiCEA2 aptamers. Interday and intraday precision and accuracy tests yielded maximum results of 4.3 and + 3.8, respectively, for both aptasensors, as measured by relative standard deviation (RSD%) and relative error (RE%). The kinetic data of the aptasensors resulted in affinity values (KD) of 0.43 ± 0.14 nM for antiCEA1 and 0.75 ± 0.42 nM for antiCEA2. These values were lower than the reported values of 3.9 nM and 37.8 nM for both aptamers, respectively. The selectivity of the aptasensor was evaluated by measuring the signal changes caused by alpha-fetoprotein (AFP), cancer antigen (CA-125), and vascular endothelial growth factor (VEGF-165) individually and together at a concentration of 500 ng/mL, resulting in a maximum 4.1 % change, which was comparable to precision and accuracy values reported in the literature. After confirming the selectivity of the aptamers, recovery experiments were conducted using spiked commercial serum samples to simulate real samples, and the lowest recovery value obtained was 95.4 %. It was determined that two different aptasensors could be successfully used for the QCM-based detection of CEA in this study.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Antígeno Carcinoembrionario , Oro , Nanopartículas del Metal , Tecnicas de Microbalanza del Cristal de Cuarzo , Antígeno Carcinoembrionario/sangre , Antígeno Carcinoembrionario/análisis , Aptámeros de Nucleótidos/química , Humanos , Oro/química , Nanopartículas del Metal/química , Técnicas Biosensibles/métodos , Límite de Detección
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