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1.
Luminescence ; 39(1): e4668, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38286596

RESUMEN

Curcumin (Cur) is an acidic polyphenol with some effects on α-glucosidase (α-Glu), but Cur has disadvantages such as being a weak target, lacking passing the blood-brain barrier and having low bioavailability. To enhance the curative effect of Cur, the hybrid composed of ZnO nanoparticles decorated on rGO was used to load Cur (ZnO@rGO-Cur). The use of the multispectral method and enzyme inhibition kinetics analysis certify the inhibitory effect and interaction mechanism of ZnO@rGO-Cur with α-Glu. The static quenching of α-Glu with both Cur and ZnO@rGO-Cur is primarily driven by hydrogen bond and van der Waals interactions. The conformation-changing ability by binding to the neighbouring phenolic hydroxyl group of Cur increased their ability to alter the secondary structure of α-Glu, resulting in the inhibition of enzyme activity. The inhibition constant (Ki, Cur > Kis,ZnO@rGO-Cur ) showed that the inhibition effect of ZnO@rGO-Cur on α-Glu was larger than that of Cur. The CCK-8 experiments proved that ZnO@rGO nanocomposites have good biocompatibility. These results suggest that the therapeutic potential of ZnO@rGO-Cur composite is an emerging nanocarrier platform for drug delivery systems for the potential treatment of diabetes mellitus.


Asunto(s)
Curcumina , Diabetes Mellitus , Nanopartículas , Óxido de Zinc , Humanos , alfa-Glucosidasas/efectos de los fármacos , Curcumina/farmacología , Curcumina/química , Sistemas de Liberación de Medicamentos , Óxido de Zinc/farmacología , Óxido de Zinc/química , Inhibidores de Glicósido Hidrolasas/química , Inhibidores de Glicósido Hidrolasas/farmacología
2.
Anal Chem ; 95(12): 5176-5186, 2023 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-36917706

RESUMEN

Research on graphene-related two-dimensional (2D) materials (GR2Ms) in recent years is strongly moving from academia to industrial sectors with many new developed products and devices on the market. Characterization and quality control of the GR2Ms and their properties are critical for growing industrial translation, which requires the development of appropriate and reliable analytical methods. These challenges are recognized by International Organization for Standardization (ISO 229) and International Electrotechnical Commission (IEC 113) committees to facilitate the development of these methods and standards which are currently in progress. Toward these efforts, the aim of this study was to perform an international interlaboratory comparison (ILC), conducted under Versailles Project on Advanced Materials and Standards (VAMAS) Technical Working Area (TWA) 41 "Graphene and Related 2D Materials" to evaluate the performance (reproducibility and confidence) of the thermogravimetric analysis (TGA) method as a potential new method for chemical characterization of GR2Ms. Three different types of representative and industrially manufactured GR2Ms samples, namely, pristine few-layer graphene (FLG), graphene oxide (GO), and reduced graphene oxide (rGO), were used and supplied to ILC participants to complete the study. The TGA method performance was evaluated by a series of measurements of selected parameters of the chemical and physical properties of these GR2Ms including the number of mass loss steps, thermal stability, temperature of maximum mass change rate (Tp) for each decomposition step, and the mass contents (%) of moisture, oxygen groups, carbon, and impurities (organic and non-combustible residue). TGA measurements determining these parameters were performed using the provided optimized TGA protocol on the same GR2Ms by 12 participants across academia, industry stakeholders, and national metrology institutes. This paper presents these results with corresponding statistical analysis showing low standard deviation and statistical conformity across all participants that confirm that the TGA method can be satisfactorily used for characterization of these parameters and the chemical characterization and quality control of GR2Ms. The common measurement uncertainty for each parameter, key contribution factors were identified with explanations and recommendations for their elimination and improvements toward their implementation for the development of the ISO/IEC standard for chemical characterization of GR2Ms.

3.
Inorg Chem ; 61(37): 14684-14694, 2022 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-36050289

RESUMEN

Magnesium oxide and hydroxide nanomaterials comprise a class of promising advanced functional metal nanomaterials whose use in environmental and material applications is increasing. Several strategies to synthesize these nanomaterials have been described but are unsustainable and uneconomic. This work reports on a processing strategy that turns natural magnesium-rich chrysotile into magnesium oxide and hydroxide nanoparticles via nanoparticle hybridization and an alkaline process while enabling La-based nanoparticles to coat the chrysotile nanotube surfaces. The adsorbent's resulting hybrid nanostructure had an outstanding capacity for phosphate uptake (135.2 mg P g-1) and enhanced regeneration performance. Furthermore, the adsorbent featured wide applicability with respect to the coexistence of competitive anions and a broad range of pH conditions, and its high-performance phosphate removal from sewage effluent was also demonstrated. Spectroscopic and microscopic analyses revealed the scavenging ability of phosphate by the La-based and Mg-based nanoparticles and the multiple capture mechanisms involved, including surface complexation and ion exchange. This proposed approach expands chrysotile's potential use as a magnesium-rich nanomaterial and harbors great promise for the removal of pollutants in a variety of real-world settings.

4.
Anal Chem ; 93(34): 11859-11867, 2021 08 31.
Artículo en Inglés | MEDLINE | ID: mdl-34319694

RESUMEN

Counterfeits in the supply chain of high-value advanced materials such as graphene and their derivatives have become a concerning problem with a potential negative impact on this growing and emerging industry. Recent studies have revealed alarming facts that a large percentage of manufactured graphene materials on market are not graphene, raising considerable concerns for the end users. The common and recommended methods for the characterization of graphene materials, such as transmission electron microscopy (TEM), atomic force microscopy (AFM), and Raman spectroscopy based on spot analysis and probing properties of individual graphene particles, are limited to provide the determination of the properties of "bulk" graphene powders at a large scale and the identification of non-graphene components or purposely included additives. These limitations are creating counterfeit opportunities by adding low-cost black carbonaceous materials into manufactured graphene powders. To address this problem, it is critical to have reliable characterization methods, which can probe the specific properties of graphene powders at bulk scale, confirm their typical graphene signature, and detect the presence of unwanted additional compounds, where the thermogravimetric analysis (TGA) method is one of the most promising methods to perform this challenging task. This paper presents the evaluation of the TGA method and its ability to detect low-cost carbon additives such as graphite, carbon black, biochar, and activated carbon as potential counterfeiting materials to graphene materials and their derivatives such as graphene oxide (GO) and reduced GO. The superior performance of the TGA method is demonstrated here, showing its excellent capability to successfully detect these additives when mixed with graphene materials, which is not possible by two other comparative methods (Raman spectroscopy and powder X-ray diffraction (XRD)), which are used as the common characterization methods for graphene materials.


Asunto(s)
Grafito , Microscopía de Fuerza Atómica , Microscopía Electrónica de Transmisión , Espectrometría Raman , Difracción de Rayos X
5.
Biotechnol Bioeng ; 118(11): 4217-4230, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34264518

RESUMEN

Neural tissue engineering aims to restore the function of nervous system tissues using biocompatible cell-seeded scaffolds. Graphene-based scaffolds combined with stem cells deserve special attention to enhance tissue regeneration in a controlled manner. However, it is believed that minor changes in scaffold biomaterial composition, internal porous structure, and physicochemical properties can impact cellular growth and adhesion. The current work aims to investigate in vitro biological effects of three-dimensional (3D) graphene oxide (GO)/sodium alginate (GOSA) and reduced GOSA (RGOSA) scaffolds on dental pulp stem cells (DPSCs) in terms of cell viability and cytotoxicity. Herein, the effects of the 3D scaffolds, coating conditions, and serum supplementation on DPSCs functions are explored extensively. Biodegradation analysis revealed that the addition of GO enhanced the degradation rate of composite scaffolds. Compared to the 2D surface, the cell viability of 3D scaffolds was higher (p < 0.0001), highlighting the optimal initial cell adhesion to the scaffold surface and cell migration through pores. Moreover, the cytotoxicity study indicated that the incorporation of graphene supported higher DPSCs viability. It is also shown that when the mean pore size of the scaffold increases, DPSCs activity decreases. In terms of coating conditions, poly- l-lysine was the most robust coating reagent that improved cell-scaffold adherence and DPSCs metabolism activity. The cytotoxicity of GO-based scaffolds showed that DPSCs can be seeded in serum-free media without cytotoxic effects. This is critical for human translation as cellular transplants are typically serum-free. These findings suggest that proposed 3D GO-based scaffolds have favorable effects on the biological responses of DPSCs.


Asunto(s)
Diferenciación Celular , Pulpa Dental/metabolismo , Grafito/química , Tejido Nervioso/metabolismo , Células Madre/metabolismo , Ingeniería de Tejidos , Andamios del Tejido/química , Materiales Biocompatibles/química , Pulpa Dental/citología , Humanos , Tejido Nervioso/citología , Células Madre/citología
6.
Nanotechnology ; 32(24)2021 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-33690186

RESUMEN

We report a flexible and highly efficient wideband slot antenna based on a highly conductive composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and N-doped reduced graphene oxide (N-doped rGO) for wearable applications. The high conductivity of this hybrid material with low sheet resistance of 0.56 Ω/square, substantial thickness of 55µm, and excellent mechanical resilience (<5.5% resistance change after 1000 bending cycles) confirmed this composite to be a suitable antenna conductor. The antenna achieved an estimated conduction efficiency close to 80% over a bandwidth from 3 to 8 GHz. Moreover, the successful operation of a realized antenna prototype has been demonstrated in free space and as part of a wearable camera system. The read range of the system was measured to be 271.2 m, which is 23 m longer than that of the original monopole antennas provided by the supplier. The synergistic effects between the dual conjugated structures of N-doped rGO and PEDOT in a single composite with fine distribution and interfacial interactions are critical to the demonstrated material performance. The N-doped rGO sheet reinforces the mechanical stability whereas the PEDOT functions as additive and/or binder, leading to an improved electrical and mechanical performance compared to that of the graphene and PEDOT alone. This high-performing nanocomposite material meets requirements for antenna design and opens the door for diverse future non-metallic flexible electronic device developments.

7.
Nanotechnology ; 32(40)2021 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-34102628

RESUMEN

Owing to many fascinating properties including high thermal and chemical stability, excellent electrical insulation, fire-retardant and antibacterial properties, hexagonal boron nitride (hBN) has emerged as a prominent 2D material for broad applications. However, the production of high quality of hBN by chemical exfoliation from its precursor is still challenging. This paper presents a high-yield (+83%), low-cost and energy-efficient wet chemical exfoliation strategy, which produces few-layers (FL, 3-6 layers) of edge-functionalized (OH) hBN nanosheets with uniform size (486 ± 51 nm). This optimized preparation is established based on a comprehensive investigation on the key exfoliation parameters such as exfoliation temperature, time and amount of the oxidant (potassium permanganate). High quality of FL-hBN was confirmed by various characterization techniques including scanning electron microscopy coupled with energy dispersive X-ray, transmission electron microscopy, Raman, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy analyses. The outcome of this study paves a promising pathway to effectively produce hBN through a cost-efficient exfoliation approach, which has a significant impact on industrial applications.

8.
Nanomedicine ; 14(7): 2365-2374, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-28648641

RESUMEN

Advances in molecular biology and nanomedicine based therapies hold promise to obviate the need of multiple surgical interventions (associated with current management) in craniosynostosis by preventing bone re-ossification. One such adjunctive therapy involves application of glypicans 1 and 3 (GPC1 and GPC3) that are BMP inhibitors implicated in downregulating the BMP2 activity in prematurely fusing sutures. Electrochemically anodized Titania nanotube (TNT) arrays have been recognized as a promising localized, long-term drug delivery platform for bone-related therapies. This study presents the application of nanoengineered TNT/Ti implants loaded with recombinant glypicans for craniosynostosis therapy. By using Dual luciferase Reporter assay, we tested the biofunctionality of eluted glypicans from the TNT/Ti implants for BMP2 bioactivity regulation in C2C12 murine myoblast cell line. BMP2 activity was inhibited significantly for up to 15days by the glypicans released from polymer-coated TNT/Ti implants, indicating their potential application in adjunctive craniosynostosis treatment.


Asunto(s)
Proteína Morfogenética Ósea 2/metabolismo , Craneosinostosis/tratamiento farmacológico , Liberación de Fármacos , Glipicanos/administración & dosificación , Mioblastos/efectos de los fármacos , Prótesis e Implantes , Titanio/química , Animales , Células Cultivadas , Craneosinostosis/metabolismo , Craneosinostosis/patología , Sistemas de Liberación de Medicamentos , Regulación de la Expresión Génica/efectos de los fármacos , Glipicanos/química , Ratones , Mioblastos/citología , Mioblastos/metabolismo , Polímeros/química
9.
Sensors (Basel) ; 18(2)2018 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-29415436

RESUMEN

Herein, we present an innovative strategy for optimizing hierarchical structures of nanoporous anodic alumina (NAA) to advance their optical sensing performance toward multi-analyte biosensing. This approach is based on the fabrication of multilayered NAA and the formation of differential effective medium of their structure by controlling three fabrication parameters (i.e., anodization steps, anodization time, and pore widening time). The rationale of the proposed concept is that interferometric bilayered NAA (BL-NAA), which features two layers of different pore diameters, can provide distinct reflectometric interference spectroscopy (RIfS) signatures for each layer within the NAA structure and can therefore potentially be used for multi-point biosensing. This paper presents the structural fabrication of layered NAA structures, and the optimization and evaluation of their RIfS optical sensing performance through changes in the effective optical thickness (EOT) using quercetin as a model molecule. The bilayered or funnel-like NAA structures were designed with the aim of characterizing the sensitivity of both layers of quercetin molecules using RIfS and exploring the potential of these photonic structures, featuring different pore diameters, for simultaneous size-exclusion and multi-analyte optical biosensing. The sensing performance of the prepared NAA platforms was examined by real-time screening of binding reactions between human serum albumin (HSA)-modified NAA (i.e., sensing element) and quercetin (i.e., analyte). BL-NAAs display a complex optical interference spectrum, which can be resolved by fast Fourier transform (FFT) to monitor the EOT changes, where three distinctive peaks were revealed corresponding to the top, bottom, and total layer within the BL-NAA structures. The spectral shifts of these three characteristic peaks were used as sensing signals to monitor the binding events in each NAA pore in real-time upon exposure to different concentrations of quercetin. The multi-point sensing performance of BL-NAAs was determined for each pore layer, with an average sensitivity and low limit of detection of 600 nm (mg mL-1)-1 and 0.14 mg mL-1, respectively. BL-NAAs photonic structures have the capability to be used as platforms for multi-point RIfS sensing of biomolecules that can be further extended for simultaneous size-exclusion separation and multi-analyte sensing using these bilayered nanostructures.

10.
Sensors (Basel) ; 17(8)2017 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-28825646

RESUMEN

The early diagnosis of diseases, e.g., Parkinson's and Alzheimer's disease, diabetes, and various types of cancer, and monitoring the response of patients to the therapy plays a critical role in clinical treatment; therefore, there is an intensive research for the determination of many clinical analytes. In order to achieve point-of-care sensing in clinical practice, sensitive, selective, cost-effective, simple, reliable, and rapid analytical methods are required. Biosensors have become essential tools in biomarker sensing, in which electrode material and architecture play critical roles in achieving sensitive and stable detection. Carbon nanomaterials in the form of particle/dots, tube/wires, and sheets have recently become indispensable elements of biosensor platforms due to their excellent mechanical, electronic, and optical properties. This review summarizes developments in this lucrative field by presenting major biosensor types and variability of sensor platforms in biomedical applications.


Asunto(s)
Técnicas Biosensibles , Humanos , Nanoestructuras , Neoplasias , Sistemas de Atención de Punto
11.
Anal Chem ; 88(11): 5971-80, 2016 06 07.
Artículo en Inglés | MEDLINE | ID: mdl-27128744

RESUMEN

In this study, we report an innovative approach aiming to assess the binding affinity between drug molecules and human serum albumin by combining nanoporous anodic alumina rugate filters (NAA-RFs) modified with human serum albumin (HSA) and reflectometric interference spectroscopy (RIfS). NAA-RFs are photonic crystal structures produced by sinusoidal pulse anodization of aluminum that present two characteristic optical parameters, the characteristic reflection peak (λPeak), and the effective optical thickness of the film (OTeff), which can be readily used as sensing parameters. A design of experiments strategy and an ANOVA analysis are used to establish the effect of the anodization parameters (i.e., anodization period and anodization offset) on the sensitivity of HSA-modified NAA-RFs toward indomethacin, a model drug. To this end, two sensing parameters are used, that is, shifts in the characteristic reflection peak (ΔλPeak) and changes in the effective optical thickness of the film (ΔOTeff). Subsequently, optimized NAA-RFs are used as sensing platforms to determine the binding affinity between a set of drugs (i.e., indomethacin, coumarin, sulfadymethoxine, warfarin, and salicylic acid) and HSA molecules. Our results verify that the combination of HSA-modified NAA-RFs with RIfS can be used as a portable, low-cost, and simple system for establishing the binding affinity between drugs and plasma proteins, which is a critical factor to develop efficient medicines for treating a broad range of diseases and medical conditions.


Asunto(s)
Cumarinas/química , Indometacina/química , Ácido Salicílico/química , Albúmina Sérica Humana/química , Sulfadimetoxina/química , Warfarina/química , Óxido de Aluminio/química , Técnicas Biosensibles , Cristalización , Electrodos , Humanos , Nanoporos , Fenómenos Ópticos , Fotones
12.
Chemistry ; 22(18): 6148-78, 2016 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-26890404

RESUMEN

Computers have become smarter, smaller, and more efficient due to the downscaling of silicon-based components. Top-down miniaturisation of silicon-based computer components is fast reaching its limitations because of physical constraints and economical non-feasibility. Therefore, the possibility of a bottom-up approach that uses molecules to build nano-sized devices has been initiated. As a result, molecular logic gates based on chemical inputs and measurable optical outputs have captured significant attention very recently. In addition, it would be interesting if such molecular logic gates could be developed by making use of ion sensors, which can give significantly sensitive output information. This review provides a brief introduction to anion receptors, molecular logic gates, a comprehensive review on describing recent advances and progress on development of ion receptors for molecular logic gates, and a brief idea about the application of molecular logic gates.

13.
Biomacromolecules ; 17(4): 1261-71, 2016 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-26999291

RESUMEN

There is considerable interest in combining bioactive polymers such as chitosan with titanium bone implants to promote bone healing and address therapeutic needs. However, the fate of these biodegradable polymers especially on titanium implants is not fully explored. Here we report in situ formation of chitosan microtube (CMT) structures from chitosan films on the implant surface with titania nanotubes (TNTs) layer, based on phosphate buffer-induced transformation and precipitation process. We have comprehensively analyzed this phenomenon and the factors that influence CMT formation, including substrate topography, immersion solution and its pH, effect of coating thickness, and time of immersion. Significance of reported in situ formation of chitosan microtubes on the TNTs surface is possibly to tailor properties of implants with favorable micro and nano morphology using a self-ordering process after the implant's insertion.


Asunto(s)
Materiales Biocompatibles/síntesis química , Regeneración Ósea , Quitosano/química , Materiales Biocompatibles Revestidos/química , Prótesis e Implantes , Ingeniería de Tejidos/métodos , Titanio/química , Materiales Biocompatibles/química , Sistemas de Liberación de Medicamentos/métodos , Compuestos Férricos/química , Humanos , Nanopartículas del Metal/química , Polímeros/síntesis química , Polímeros/química , Propiedades de Superficie
14.
Biomacromolecules ; 17(8): 2726-36, 2016 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-27428076

RESUMEN

Iron oxide nanowires produced by bacteria (Mariprofundus ferrooxydans) are demonstrated as new multifunctional drug carriers for triggered therapeutics release and cancer hyperthmia applications. Iron oxide nanowires are obtained from biofilm waste in the bore system used to pump saline groundwater into the River Murray, South Australia (Australia) and processed into individual nanowires with extensive magnetic properties. The drug carrier capabilities of these iron oxide nanowires (Bac-FeOxNWs) are assessed by loading anticancer drug (doxorubicin, Dox) followed by measuring its elution under sustained and triggered release conditions using alternating magnetic field (AMF). The cytotoxicity of Bac-FeOxNWs assessed in 2D (96 well plate) and 3D (Matrigel) cell cultures using MDA-MB231-TXSA human breast cancer cells and mouse RAW 264.7 macrophage cells shows that these Bac-FeOxNWs are biocompatible even at concentrations as high as 250 µg/mL after 24 h of incubation. Finally, we demonstrate the capabilities of Bac-FeOxNWs as potential hyperthermia agent in 3D culture setup. Application of AMF increased the local temperature by 14 °C resulting in approximately 34% decrease in cell viability. Our results demonstrate that these naturally produced nanowires in the form of biofilm can efficiently act as drug carriers with triggered payload release and magnetothermal heating features for potential anticancer therapeutics applications.


Asunto(s)
Antibióticos Antineoplásicos/administración & dosificación , Neoplasias de la Mama/terapia , Doxorrubicina/administración & dosificación , Compuestos Férricos/química , Fiebre , Magnetismo , Nanocables , Animales , Antibióticos Antineoplásicos/farmacología , Bacterias/crecimiento & desarrollo , Biopelículas/crecimiento & desarrollo , Neoplasias de la Mama/patología , Técnicas de Cultivo de Célula , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Terapia Combinada , Doxorrubicina/farmacología , Portadores de Fármacos , Liberación de Fármacos , Femenino , Humanos , Macrófagos/citología , Macrófagos/efectos de los fármacos , Ratones
15.
Anal Chem ; 87(17): 9016-24, 2015 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-26259031

RESUMEN

Herein, we present an interferometric sensor based on the combination of chemically functionalized nanoporous anodic alumina photonic films (NAA-PFs) and reflectometric interference spectroscopy (RIfS) aimed to detect trace levels of enzymes by selective digestion of gelatin. The fabrication and sensing performance of the proposed sensor were characterized in real-time by estimating the changes in effective optical thickness (i.e., sensing principle) of gelatin-modified NAA-PFs (i.e., sensing element) during enzymatic digestion. The working range (WR), sensitivity (S), low limit of detection (LLoD), and linearity (R(2)) of this enzymatic sensor were established by a series of experiments with different concentrations of gelatin (i.e., specific chemical sensing element) and trypsin (i.e., analyte), a model protease enzyme with relevant implications as a biomarker in the diagnosis of several diseases. The chemical selectivity of the sensor was demonstrated by comparison of gelatin digestion by other nonspecific enzyme models such as chymotrypsin and horseradish peroxidase. Furthermore, the role of the chemical sensing element (i.e., gelatin) was assessed by using hemoglobin instead of gelatin. Finally, we demonstrated that this sensor can be readily used to establish the kinetic parameters of enzymatic reactions. The obtained results revealed that the presented sensor has a promising potential to be used as a point-of-care system for fast detection of gastrointestinal diseases at early stages.


Asunto(s)
Óxido de Aluminio/química , Gelatina/química , Nanoestructuras/química , Fotones , Tripsina/análisis , Electrodos , Interferometría , Tamaño de la Partícula , Porosidad , Propiedades de Superficie , Factores de Tiempo , Tripsina/metabolismo
16.
Anal Chem ; 86(3): 1837-44, 2014 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-24417182

RESUMEN

In this study, we report about the structural engineering and optical optimization of nanoporous anodic alumina rugate filters (NAA-RFs) for real-time and label-free biosensing applications. Structurally engineered NAA-RFs are combined with reflection spectroscopy (RfS) in order to develop a biosensing system based on the position shift of the characteristic peak in the reflection spectrum of NAA-RFs (Δλpeak). This system is optimized and assessed by measuring shifts in the characteristic peak position produced by small changes in the effective medium (i.e., refractive index). To this end, NAA-RFs are filled with different solutions of d-glucose, and the Δλpeak is measured in real time by RfS. These results are validated by a theoretical model (i.e., the Looyenga-Landau-Lifshitz model), demonstrating that the control over the nanoporous structure makes it possible to optimize optical signals in RfS for sensing purposes. The linear range of these optical sensors ranges from 0.01 to 1.00 M, with a low detection limit of 0.01 M of d-glucose (i.e., 1.80 ppm), a sensitivity of 4.93 nm M(-1) (i.e., 164 nm per refractive index units), and a linearity of 0.998. This proof-of-concept study demonstrates that the proposed system combining NAA-RFs with RfS has outstanding capabilities to develop ultrasensitive, portable, and cost-competitive optical sensors.


Asunto(s)
Óxido de Aluminio/química , Técnicas Biosensibles/instrumentación , Ingeniería/instrumentación , Filtración/instrumentación , Nanotecnología/instrumentación , Fenómenos Ópticos , Técnicas Biosensibles/economía , Análisis Costo-Beneficio , Electrodos , Porosidad , Factores de Tiempo
17.
Analyst ; 139(5): 1134-40, 2014 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-24416759

RESUMEN

Knowledge about electrochemical and electrical properties of nanopore structures and the influence of pore dimensions on these properties is important for the development of nanopore biosensing devices. The aim of this study was to explore the influence of nanopore dimensions (diameter and length) on biosensing performance using non-faradic electrochemical impedance spectroscopy (EIS). Nanoporous alumina membranes (NPAMs) prepared by self-ordered electrochemical anodization of aluminium were used as model nanopore sensing platforms. NPAMs with different pore diameters (25-65 nm) and lengths (4-18 µm) were prepared and the internal pore surface chemistry was modified by covalently attaching streptavidin and biotin. The performance of this antibody nanopore biosensing platform was evaluated using various concentrations of biotin as a model analyte. EIS measurements of pore resistivity and conductivity were carried out for pores with different diameters and lengths. The results showed that smaller pore dimensions of 25 nm and pore lengths up to 10 µm provide better biosensing performance.


Asunto(s)
Técnicas Biosensibles/métodos , Técnicas Biosensibles/normas , Nanoporos/ultraestructura , Impedancia Eléctrica , Propiedades de Superficie
18.
Sensors (Basel) ; 14(7): 11878-918, 2014 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-25004150

RESUMEN

Electrochemical anodization of pure aluminum enables the growth of highly ordered nanoporous anodic alumina (NAA) structures. This has made NAA one of the most popular nanomaterials with applications including molecular separation, catalysis, photonics, optoelectronics, sensing, drug delivery, and template synthesis. Over the past decades, the ability to engineer the structure and surface chemistry of NAA and its optical properties has led to the establishment of distinctive photonic structures that can be explored for developing low-cost, portable, rapid-response and highly sensitive sensing devices in combination with surface plasmon resonance (SPR) and reflective interference spectroscopy (RIfS) techniques. This review article highlights the recent advances on fabrication, surface modification and structural engineering of NAA and its application and performance as a platform for SPR- and RIfS-based sensing and biosensing devices.


Asunto(s)
Óxido de Aluminio/química , Técnicas Biosensibles/instrumentación , Interferometría/instrumentación , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , Nanoporos/ultraestructura , Resonancia por Plasmón de Superficie/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo , Propiedades de Superficie , Transductores
19.
Sensors (Basel) ; 14(11): 21316-28, 2014 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-25393785

RESUMEN

The understanding of the electrochemical properties of nanopores is the key factor for better understanding their performance and applications for nanopore-based sensing devices. In this study, the influence of pore dimensions of nanoporous alumina (NPA) membranes prepared by an anodization process and their electrochemical properties as a sensing platform using impedance spectroscopy was explored. NPA with four different pore diameters (25 nm, 45 nm and 65 nm) and lengths (5 µm to 20 µm) was used and their electrochemical properties were explored using different concentration of electrolyte solution (NaCl) ranging from 1 to 100 µM. Our results show that the impedance and resistance of nanopores are influenced by the concentration and ion species of electrolytes, while the capacitance is independent of them. It was found that nanopore diameters also have a significant influence on impedance due to changes in the thickness of the double layer inside the pores.


Asunto(s)
Óxido de Aluminio/química , Conductometría/instrumentación , Espectroscopía Dieléctrica/instrumentación , Nanopartículas del Metal/química , Nanopartículas del Metal/ultraestructura , Análisis por Micromatrices/instrumentación , Nanoporos/ultraestructura , Conductividad Eléctrica , Diseño de Equipo , Análisis de Falla de Equipo , Ensayo de Materiales , Tamaño de la Partícula , Porosidad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Transductores
20.
ChemSusChem ; 17(5): e202301242, 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-37897222

RESUMEN

Poor interfacial contact between solid-state electrolytes and electrodes limits high-voltage performance of solid-state lithium batteries. A new gel electrolyte is proposed via in-situ polymerization, incorporating fluoroethylene carbonate (FEC) solvent and ionic liquid1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide (PP14 TFSI). This combination synergistically enhances Li ion transport, achieving a transfer number of 0.58 and improved electrochemical performance. FEC protects the Al current collectors from LiPF6 corrosion and promotes a protective interfacial layer formation. PP14 TFSI improves interfacial contact and provides stable components. An interface layer of fluorine and nitrogen composites forms, preventing side reactions. LiCoO2 ||PPE||Li cell exhibits robust cycling stability at 4.45 V, retaining ~80 % capacity after 200 cycles at room temperature with 0.2 C and 1 C rates, showing increased coulombic efficiency. NCM811||PPE||Li cell also displays exceptional cycling. In-situ polymerization and FEC-ionic liquid coordination enable high-voltage solid-state lithium metal batteries for practical use.

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