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1.
Biosens Bioelectron ; 249: 115984, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38219464

RESUMO

Immune checkpoint proteins (ICPs) play a major role in a patient's immune response against cancer. Tumour cells usually express those proteins to communicate with immune cells as a process of escaping the anti-cancer immune response. Detecting the major functional immune checkpoint proteins present on cancer cells (such as circulating tumor cells or CTCs) and examining the heterogeneity in their expression at the single-cell level could play a crucial role in both cancer diagnosis and the monitoring of therapy. In this study, we develop a mesoporous gold biosensor to precisely assess ICP heterogeneity in individual cancer cells within a lung cancer model. The platform utilizes a nanostructured mesoporous gold surface to capture CTCs and a Surface Enhanced Raman Scattering (SERS) readout to identify and monitor the expression of key ICP proteins (PD-L1, B7H4, CD276, CD80) in lung cancer cells. The homogeneous and abundant pores in mesoporous 3D gold nanostructures enable increased antibody loading on-chip and an enhanced SERS signal, which are key to our single cell capture, and accurate analysis of ICPs in cancer cells with high sensitivity. Our lung cancer cell line model data showed that our method can detect single cells and analyse the expression of four lung cancer associated ICPs on individual cell surfaces during treatment. To show the potential of our mesoporous gold biosensor in analysing clinical samples, we tested 9 longitudinal Peripheral Blood Mononuclear Cells (PBMC) samples from lung cancer patient before and after therapy. Our mesoporous biosensor successfully captured single CTCs and found that the expression of ICPs in CTCs is highly heterogeneous in both pre-treatment and treated PBMC samples isolated from lung cancer patient blood. We suggest that our findings will help clinicians in selecting the most appropriate therapy for patients.


Assuntos
Técnicas Biossensoriais , Neoplasias Pulmonares , Células Neoplásicas Circulantes , Humanos , Proteínas de Checkpoint Imunológico , Leucócitos Mononucleares , Ouro , Células Neoplásicas Circulantes/patologia , Antígenos B7
2.
ACS Nano ; 17(4): 3346-3357, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36744876

RESUMO

Construction of a well-defined mesoporous nanostructure is crucial for applying nonnoble metals in catalysis and biomedicine owing to their highly exposed active sites and accessible surfaces. However, it remains a great challenge to controllably synthesize superparamagnetic CoFe-based mesoporous nanospheres with tunable compositions and exposed large pores, which are sought for immobilization or adsorption of guest molecules for magnetic capture, isolation, preconcentration, and purification. Herein, a facile assembly strategy of a block copolymer was developed to fabricate a mesoporous CoFeB amorphous alloy with abundant metallic Co/Fe atoms, which served as an ideal scaffold for well-dispersed loading of Au nanoparticles (∼3.1 nm) via the galvanic replacement reaction. The prepared Au-CoFeB possessed high saturation magnetization as well as uniform and large open mesopores (∼12.5 nm), which provided ample accessibility to biomolecules, such as nucleic acids, enzymes, proteins, and antibodies. Through this distinctive combination of superparamagnetism (CoFeB) and biofavorability (Au), the resulting Au-CoFeB was employed as a dispersible nanovehicle for the direct capture and isolation of p53 autoantibody from serum samples. Highly sensitive detection of the autoantibody was achieved with a limit of detection of 0.006 U/mL, which was 50 times lower than that of the conventional p53-ELISA kit-based detection system. Our assay is capable of quantifying differential expression patterns for detecting p53 autoantibodies in ovarian cancer patients. This assay provides a rapid, inexpensive, and portable platform with the potential to detect a wide range of clinically relevant protein biomarkers.


Assuntos
Nanopartículas Metálicas , Feminino , Humanos , Nanopartículas Metálicas/química , Autoanticorpos , Ouro/química , Proteína Supressora de Tumor p53 , Nanopartículas Magnéticas de Óxido de Ferro
3.
Polymers (Basel) ; 14(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36501469

RESUMO

Nanocomposite hydrogels are highly porous colloidal structures with a high adsorption capacity, making them promising materials for wastewater treatment. In particular, magnetic nanoparticle (MNP) incorporated hydrogels are an excellent adsorbent for aquatic pollutants. An added advantage is that, with the application of an external magnetic field, magnetic hydrogels can be collected back from the wastewater system. However, magnetic hydrogels are quite brittle and structurally unstable under compact conditions such as in fixed-bed adsorption columns. To address this issue, this study demonstrates a unique hydrogel composite bead structure, providing a good adsorption capacity and superior compressive stress tolerance due to the presence of hollow cores within the beads. The gel beads contain alginate polymer as the matrix and MNP-decorated cellulose nanofibres (CNF) as the reinforcing agent. The MNPs within the gel provide active adsorption functionality, while CNF provide a good stress transfer phenomenon when the beads are under compressive stress. Their adsorption performance is evaluated in a red mud solution for pollutant adsorption. Composite gel beads have shown high performance in adsorbing metal (aluminium, potassium, selenium, sodium, and vanadium) and non-metal (sulphur) contaminations. This novel hybrid hydrogel could be a promising alternative to the conventionally used toxic adsorbent, providing environmentally friendly operational benefits.

4.
Small ; 18(26): e2107571, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35620959

RESUMO

The integration of nanoarchitectonics and hydrogel into conventional biosensing platforms offers the opportunities to design physically and chemically controlled and optimized soft structures with superior biocompatibility, better immobilization of biomolecules, and specific and sensitive biosensor design. The physical and chemical properties of 3D hydrogel structures can be modified by integrating with nanostructures. Such modifications can enhance their responsiveness to mechanical, optical, thermal, magnetic, and electric stimuli, which in turn can enhance the practicality of biosensors in clinical settings. This review describes the synthesis and kinetics of gel networks and exploitation of nanostructure-integrated hydrogels in biosensing. With an emphasis on different integration strategies of hydrogel with nanostructures, this review highlights the importance of hydrogel nanostructures as one of the most favorable candidates for developing ultrasensitive biosensors. Moreover, hydrogel nanoarchitectonics are also portrayed as a promising candidate for fabricating next-generation robust biosensors.


Assuntos
Técnicas Biossensoriais , Nanoestruturas , Hidrogéis/química , Nanoestruturas/química
5.
Environ Res ; 211: 112956, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35218711

RESUMO

Human health is being threatened by the ever-increasing water pollution. Sulfate radical (SO4•-)-based advanced oxidation processes (SR-AOPs) are rapidly being developed and gaining considerable attention due to their high oxidation potential and selectivity as a way to purify water by degrading organic contaminants in it. Among the catalytic materials that can activate the precursor to generate SO4•-, metal-organic frameworks (MOFs) are the most promising heterogeneous catalytic material in SR-AOPs because of their various structure possibilities, large surface area, ordered porous structure, and regular activation sites. Herein, an in-depth overview of MOFs and their derivatives for water purification with SR-AOPs is provided. The latest studies on pristine MOFs, MOF composites, and MOF derivatives (metal oxides, metal-carbon hybrids, and carbon materials) are summarized. The mechanisms of decomposition of pollutants in water via radical and non-radical pathways are also discussed. This review suggests future research directions for water purification through MOF-based SR-AOP.


Assuntos
Estruturas Metalorgânicas , Purificação da Água , Carbono , Humanos , Sulfatos
6.
Environ Res ; 210: 112909, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35157915

RESUMO

The design of high-performance electrode materials with excellent desalination ability has always been a research goal for efficient capacitive deionization (CDI). Herein, a hybrid architecture with Cu/Cu2O nanospheres anchored on porous carbon nanosheets (Cu/Cu2O/C) was first synthesized by pyrolyzing a two-dimensional (2D) Cu-based metal-organic framework and then evaluated as a cathode for hybrid CDI. The as-prepared Cu/Cu2O/C exhibits a hierarchically porous structure with a high specific surface area of 305 m2 g-1 and large pore volume of 0.55 cm3 g-1, which is favorable to accelerating ion migration and diffusion. The porous carbon nanosheet matrix with enhanced conductivity will facilitate the Faradaic reactions of Cu/Cu2O nanospheres during the desalination process. The Cu/Cu2O/C hybrid architecture displays a high specific capacitance of 142.5 F g-1 at a scan rate of 2 mV s-1 in 1 M NaCl solution. The hybrid CDI constructed using the Cu/Cu2O/C cathode and a commercial activated carbon anode exhibits a high desalination capacity of 16.4 mg g-1 at an operation voltage of 1.2 V in 500 mg L-1 NaCl solution. Additionally, the hybrid CDI exhibits a good cycling stability with 18.3% decay in the desalination capacity after 20 electrosorption-desorption cycles. Thus, the Cu/Cu2O/C composite is expected to be a promising cathode material for hybrid CDI.

7.
ACS Appl Mater Interfaces ; 14(2): 3418-3426, 2022 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-34985245

RESUMO

A superconducting joint architecture to join unreacted carbon-doped multifilament magnesium diboride (MgB2) wires with the functionality to screen external magnetic fields for magnetic resonance imaging (MRI) magnet applications is proposed. The intrinsic diamagnetic property of a superconducting MgB2 bulk was exploited to produce a magnetic field screening effect around the current transfer path within the joint. Unprecedentedly, the joint fabricated using this novel architecture was able to screen magnetic fields up to 1.5 T at 20 K and up to 2 T at 15 K and thereby almost nullified the effect of the applied magnetic field by maintaining a constant critical current (Ic). The joint showed an Ic of 30.8 A in 1.5 T at 20 K and an ultralow resistance of about 3.32 × 10-14 Ω at 20 K in a self-field. The magnetic field screening effect shown by the MgB2 joint is expected to be extremely valuable for MRI magnet applications, where the Ic of the joints is lower than the Ic of the connected MgB2 wires in a given magnetic field and temperature.

8.
Chem Commun (Camb) ; 58(6): 863-866, 2022 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-34935790

RESUMO

A heterostructured porous carbon framework (PCF) composed of reduced graphene oxide (rGO) nanosheets and metal organic framework (MOF)-derived microporous carbon is prepared to investigate its potential use in a lithium-ion battery. As an anode material, the PCF exhibits efficient lithium-ion storage performance with a high reversible specific capacity (771 mA h g-1 at 50 mA g-1), an excellent rate capability (448 mA h g-1 at 1000 mA g-1), and a long lifespan (75% retention after 400 cycles). The in situ transmission electron microscopy (TEM) study demonstrates that its unique three-dimensional (3D) heterostructure can largely tolerate the volume expansion. We envisage that this work may offer a deeper understanding of the importance of tailored design of anode materials for future lithium-ion batteries.

9.
ACS Nano ; 15(12): 18931-18973, 2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-34860483

RESUMO

Potassium ion energy storage devices are competitive candidates for grid-scale energy storage applications owing to the abundancy and cost-effectiveness of potassium (K) resources, the low standard redox potential of K/K+, and the high ionic conductivity in K-salt-containing electrolytes. However, the sluggish reaction dynamics and poor structural instability of battery-type anodes caused by the insertion/extraction of large K+ ions inhibit the full potential of K ion energy storage systems. Extensive efforts have been devoted to the exploration of promising anode materials. This Review begins with a brief introduction of the operation principles and performance indicators of typical K ion energy storage systems and significant advances in different types of battery-type anode materials, including intercalation-, mixed surface-capacitive-/intercalation-, conversion-, alloy-, mixed conversion-/alloy-, and organic-type materials. Subsequently, host-guest relationships are discussed in correlation with the electrochemical properties, underlying mechanisms, and critical issues faced by each type of anode material concerning their implementation in K ion energy storage systems. Several promising optimization strategies to improve the K+ storage performance are highlighted. Finally, perspectives on future trends are provided, which are aimed at accelerating the development of K ion energy storage systems.

10.
Materials (Basel) ; 14(18)2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34576377

RESUMO

Annealing undoped MgB2 wires under high isostatic pressure (HIP) increases transport critical current density (Jtc) by 10% at 4.2 K in range magnetic fields from 4 T to 12 T and significantly increases Jtc by 25% in range magnetic fields from 2 T to 4 T and does not increase Jtc above 4 T at 20 K. Further research shows that a large amount of 10% SiC admixture and thermal treatment under a high isostatic pressure of 1 GPa significantly increases the Jtc by 40% at 4.2 K in magnetic fields above 6 T and reduces Jtc by one order at 20 K in MgB2 wires. Additionally, our research showed that heat treatment under high isostatic pressure is more evident in wires with smaller diameters, as it greatly increases the density of MgB2 material and the number of connections between grains compared to MgB2 wires with larger diameters, but only during the Mg solid-state reaction. In addition, our study indicates that smaller wire diameters and high isostatic pressure do not lead to a higher density of MgB2 material and more connections between grains during the liquid-state Mg reaction.

11.
Small ; 17(42): e2102220, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34216426

RESUMO

Extracellular vesicles (EVs) can transfer intercellular messages in various (patho)physiological processes and transport biomolecules to recipient cells. EVs possess the capacity to evade the immune system and remain stable over long periods, identifying them as natural carriers for drugs and biologics. However, the challenges associated with EVs isolation, heterogeneity, coexistence with homologous biomolecules, and lack of site-specific delivery, have impeded their potential. In recent years, the amalgamation of EVs with rationally engineered nanostructures has been proposed for achieving effective drug loading and site-specific delivery. With the advancement of nanotechnology and nanoarchitectonics, different nanostructures with tunable size, shapes, and surface properties can be integrated with EVs for drug loading, target binding, efficient delivery, and therapeutics. Such integration may enable improved cellular targeting and the protection of encapsulated drugs for enhanced and specific delivery to target cells. This review summarizes the recent development of nanostructure amalgamated EVs for drug delivery, therapeutics, and real-time monitoring of disease progression. With a specific focus on the exosomal cargo, diverse drug delivery system, and biomimetic nanostructures based on EVs for selective drug delivery, this review also chronicles the needs and challenges of EV-based biomimetic nanostructures and provides a future outlook on the strategies posed.


Assuntos
Produtos Biológicos , Vesículas Extracelulares , Preparações Farmacêuticas , Sistemas de Liberação de Medicamentos
12.
Nanoscale ; 13(25): 11086-11092, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34143172

RESUMO

Lithium-sulfur batteries (LSBs) have a high theoretical energy density and are low cost. However, the undesirable shuttle effect with the solid discharge product, Li2S, greatly impedes their market penetration. Conductive carbon materials with functional elements are beneficial in controlling the shuttle effect and can reactivate the Li2S, leading to improved long term cycling performance of LSBs. Herein, we report zinc (Zn) and nitrogen (N) co-doped ZIF-8 derived hollow carbon (ZHC) as a promising separator coating for LSBs to control the shuttle effect. The hollow area in the ZHC is identified to be around 250 nm with a carbonized outer surface thickness of approximately 50 nm. The presence of Zn and N in the nanohollow carbon structure helps to mitigate polysulfide (PS) diffusion in LSBs. Furthermore, the hollow interior of the carbon acts as a PS pocket to physically capture the PS and in addition Zn and N chemically attract the PS through polar-polar and metal sulfide interactions. The ZHC with its unique architecture and functional groups shows a promising performance with an initial specific capacity (S.cap) of 842 mA h g-1 at 4.80 mg cm-2 and cycling stability until 400 cycles, which is considerably higher in comparison with the cycling performance of parent ZIF-8.

13.
J Hazard Mater ; 408: 124843, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33421849

RESUMO

We report the nanoconfinement-mediated graphitic nanoporous carbon nitride (gNPCN) adsorbents with a high content of inbuilt basic nitrogen (N) (48%) by X-ray photoelectron spectroscopy (XPS) for efficient CO2 adsorption. The gNPCNs (gNPCN-150 and gNPCN-130) are synthesized using the mesoporous SBA-15 silica template and a single carbon-nitrogen (C-N) precursor (guanidine hydrochloride). The various adsorbents were utilized for investigating the influence of pore size (PS), surface area (SA), and type of adsorbent for CO2 adsorption performance. The capacity for CO2 capturing of gNPCN-150 reached 23.1 mmol/g at 0 °C under 30 bar pressure. This CO2 capturing capacity value was higher than the capacity gNPCN-130, SBA15, activated carbon (AC), and multiwalled carbon nanotube (MWCN) under identical conditions. The gNPCN materials exhibited superior CO2 adsorption ability that is ascribed to the presence of the highly organized mesoporosity, inbuilt high content of basic N site for adsorbing more CO2 through acid-base interaction, and tunable surface-structural properties. Moreover, the synthesis strategy is remarkably flexible in selecting C-N sources. This study features graphitic high-ordered nanoporous CN materials as a resourceful platform towards the efficient CO2 capture.

14.
ACS Appl Mater Interfaces ; 13(2): 3349-3357, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33400882

RESUMO

A superconducting joint of unreacted monofilament internal magnesium diffusion-processed magnesium diboride (MgB2) wires was fabricated by exploiting the phenomenon of magnesium diffusion into the boron layer inside the superconducting joint. Unprecedentedly, the joint was able to carry an almost identical transport current compared to the bare wire in a 2-7 T magnetic field at 20 K. The joint also exhibited very low joint resistance of 2.01 × 10-13 Ω in self-field at 20 K. Among commercially available superconductors, this work is the first to successfully realize a superconducting joint that is capable of transferring current from one conductor to another without any notable degradation under strong magnetic fields. This work demonstrates great potential to apply MgB2 in a range of practical applications, where superconducting joints are essential.

15.
J Hazard Mater ; 408: 124919, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33388627

RESUMO

Graphitic carbon nitride with suitably incorporated functionality has attracted much interest in the areas of environmental treatments, clean energy, sensing, and photocatalyst. However, the role of graphitic nanoporous carbon nitride (NCN) matrix from single carbon-nitrogen (C-N) source, aminoguanidine HCl as a precursor and close intimate contact between silver nanoparticles (Ag NPs) dispersed in NCN and bacteria has rarely been demonstrated. Herein, we demonstrate a nanostructure of Ag NPs-incorporated NCN sample (NCN@Ag) as an antibacterial agent against both wild type and the multidrug-resistant Escherichia coli (E. coli) pathogens. In-situ ultrasonication method was used to ensure the homogeneous mixing of the Ag NPs and a single C-N precursor at the molecular level so that pore size (PS) (9.17 nm) of SBA15 silica could be impregnated with ultrasonicated Ag NPs and a single C-N precursor. The porous structure, compositions, and structural information of the final nanocomposites were confirmed by using various analytical techniques such as XRD, TEM, BET surface area (SA) measurements, XPS, and UV. Then, the antibacterial activities of the NCN and NCN@Ag against both wild type and the multidrug-resistant Escherichia coli (E. coli) pathogens were also carried out and results from the in-vitro studies have shown the excellent bactericidal effect of the highly dispersed Ag NPs containing NCN@Ag sample against both E. coli strains. Results have confirmed that the antibacterial activity of the NCN@Ag sample is found to be higher than pure NCN, indicating that in-situ incorporated Ag NPs in NCN matrix have played significant role for enhancing antibacterial activities. Surprisingly, in the presence of NCN@Ag, the reduction in minimum inhibitory concentration (MIC) was higher (64-fold reduction) compared to its susceptible wild type (32-fold reduction) E. coli. These results indicate the potential application of NCN@Ag for inactivating infectious bacterial pathogens implicated in multidrug resistance.


Assuntos
Nanopartículas Metálicas , Nanoporos , Antibacterianos/farmacologia , Escherichia coli , Testes de Sensibilidade Microbiana , Nitrilas , Prata
16.
J Hazard Mater ; 408: 124896, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33387722

RESUMO

Herein, we report the fabrication of highly oxidized silver oxide/silver/tin(IV) oxide (HOSBTO or Ag3+-enriched AgO/Ag/SnO2) nanocomposite under a robust oxidative environment created with the use of concentrated nitric acid. Tin(IV) hydroxide nanofluid is added to the reaction mixture as a stabilizer for the Ag3+-enriched silver oxide in the nanocomposite. The formation of Ag nanoparticles in this nanocomposite originates from the decomposition of silver oxides during calcination at 600 °C. For comparison, poorly oxidized silver oxide/silver/tin(IV) oxide (POSBTO with formula AgO/Ag/SnO2) nanocomposite has also been prepared by following the same synthetic procedures, except for the use of concentrated nitric acid. Finally, we studied in detail the anti-pathogenic capabilities of both nanocomposites against four hazardous pathogens, including pathogenic fish bacterium (Stenotrophomonas maltophilia stain EP10), oomycete (Phytophthora cactorum strain P-25), and two different strains of pathogenic strawberry fungus, BRSP08 and BRSP09 (Collectotrichum siamense). The bioassays reveal that the as-prepared HOSBTO and POSBTO nanocomposites exhibit significant inhibitory activities against the tested pathogenic bacterium, oomycete, and fungus in a dose-dependent manner. However, the degree of dose-dependent effectiveness of the two nanocomposites against each pathogen largely varies.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Animais , Antibacterianos , Óxidos , Prata , Compostos de Prata , Estanho
17.
J Mater Chem B ; 8(41): 9512-9523, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-32996976

RESUMO

Herein, we report the preparation of mesoporous gold (Au)-silver (Ag) alloy films through the electrochemical micelle assembly process and their applications as microRNA (miRNA) sensors. Following electrochemical deposition and subsequent removal of the templates, the polymeric micelles can create uniformly sized mesoporous architectures with high surface areas. The resulting mesoporous Au-Ag alloy films show high current densities (electrocatalytic activities) towards the redox reaction between potassium ferrocyanide and potassium ferricyanide. Following magnetic isolation and purification, the target miRNA is adsorbed directly on the mesoporous Au-Ag film. Electrochemical detection is then enabled by differential pulse voltammetry (DPV) using the [Fe(CN)6]3-/4- redox system (the faradaic current for the miRNA-adsorbed Au-Ag film decreases compared to the bare film). The films demonstrate great advantages towards miRNA sensing platforms to enhance the detection limit down to attomolar levels of miR-21 (limit of detection (LOD) = 100 aM, s/n = 3). The developed enzymatic amplification-free miniaturized analytical sensor has promising potential for RNA-based diagnosis of diseases.


Assuntos
Ligas de Ouro/química , MicroRNAs/análise , Prata/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Desenho de Equipamento , Ferrocianetos/química , Humanos , Micelas , Oxirredução , Porosidade
18.
Biosens Bioelectron ; 168: 112429, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32942183

RESUMO

Advances in nanoarchitectonics enable a wide variety of nanostructured electrodes with tunable shapes and surface for constructing sensitive biosensors. Herein we demonstrate the fabrication of a mesoporous gold (Au) biosensor for the specific and sensitive detection of miRNA in a relatively simple and portable manner. The electrocatalytic activity of the mesoporous Au electrode (MPGE) towards the redox reaction of Fe(CN)6]3-/4- expansively examined. Leveraging the electrocatalytic activity and signal enhancement capacity of the MPGE, an ultrasensitive and specific electrochemical sensor was developed for the detection of microRNA (miRNA). The target miRNA from spiked samples is selectively isolated and purified using magnetic bead-capture probe followed by the direct adsorption on the MPGE through direct affinity interaction between miRNA and mesoporous Au surface. The MPGE-bound miRNA is then quantified by differential pulse voltammetry (DPV) using [Fe(CN)6]4-/3- redox system (Faradaic current decrease with reference to the bare MPGE). This method evades the cumbersome PCR (polymerase chain reaction) and enzymatic amplification steps. This is a single-step assay building which can detect a wide dynamic linear range (100 aM to 1 nM) of miRNA with an ultra-low limit detection of 100 aM and present high translational potentiality for the development of high-performance detection tools for clinics.


Assuntos
Técnicas Biossensoriais , MicroRNAs , Nanoestruturas , Técnicas Eletroquímicas , Eletrodos , Ouro , Limite de Detecção
19.
Analyst ; 145(20): 6639-6648, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-32797121

RESUMO

Protein phosphorylation is a post-translational modification of kinase proteins that changes a protein's conformation to regulate crucial biological functions. However, the phosphorylation of protein is significantly altered during cancer progression which triggers abnormal cellular pathways and this phosphorylation can serve as an emergent diagnostic and prognostic biomarker for cancer. Herein, we develop a nanostructured mesoporous gold electrode (NMGE)-based biosensor that enables a highly sensitive detection of protein phosphorylation with electrochemical signal amplification. The biosensor comprises nanostructured mesoporous gold electrodes whose electro-conductive framework is superior to that of the nonporous electrodes. We characterize our developed nano/mesoporous gold electrode with various electrochemical methods in the presence of the [Fe(CN)6]3-/4- redox system. We find that the mesoporous gold electrode catalyzes both the oxidation and reduction processes of the [Fe(CN)6]3-/4- system and generates a current signal that is 3 times higher than that of the nonporous gold electrode. This superior signal transduction of our nano/mesoporous gold electrode is enabled through a pore-induced (i) high electrochemically active surface area and (ii) reduced impedance with a high signal to noise ratio. The assay utilizes direct adsorption of an immunoprecipitated purified BRAF protein towards the mesoporous gold electrode and thus avoids the cumbersome sensor surface functionalization. Our developed biosensor detects the phosphorylated BRAF protein with a 2.5-fold increase in sensitivity and an ≈10-fold increase in the limit of detection (LOD) in comparison with the nonporous gold electrodes. The assay also works on a wide dynamic range from 0.5 to 20 ng µL-1 of the protein which further shows its potential for clinical application. We envisage that this nanostructured mesoporous gold biosensor will be of high interest for clinical application.


Assuntos
Técnicas Biossensoriais , Neoplasias , Técnicas Eletroquímicas , Eletrodos , Ouro , Humanos , Limite de Detecção , Fosforilação
20.
Nat Protoc ; 15(9): 2980-3008, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32839575

RESUMO

High-surface-area mesoporous materials expose abundant functional sites for improved performance in applications such as gas storage/separation, catalysis, and sensing. Recently, soft templates composed of amphiphilic surfactants and block copolymers have been used to introduce mesoporosity in various materials, including metals, metal oxides and carbonaceous compounds. In particular, mesoporous metals are attractive in electrocatalysis because their porous networks expose numerous unsaturated atoms on high-index facets that are highly active in catalysis. In this protocol, we describe how to create mesoporous metal films composed of gold, palladium, or platinum using block copolymer micelle templates. The amphiphilic block copolymer micelles are the sacrificial templates and generate uniform structures with tunable pore sizes in electrodeposited metal films. The procedure describes the electrodeposition in detail, including parameters such as micelle diameters, deposition potentials, and deposition times to ensure reproducibility. The micelle diameters can be controlled by swelling the micelles with different solvent mixtures or by using block copolymer micelles with different molecular weights. The deposition potentials and deposition times allow further control of the mesoporous structure and its thickness, respectively. Procedures for example applications are included: glucose oxidation, ethanol oxidation and methanol oxidation reactions. The synthetic methods for preparation of mesoporous metal films will take ~4 h; the subsequent electrochemical tests will take ~5 h for glucose sensing and ~3 h for alcohol oxidation reaction.


Assuntos
Ouro/química , Paládio/química , Platina/química , Álcoois/química , Catálise , Técnicas de Química Sintética , Eletroquímica , Interações Hidrofóbicas e Hidrofílicas , Micelas , Modelos Moleculares , Conformação Molecular , Oxirredução , Polímeros/química
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