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1.
ACS Appl Mater Interfaces ; 16(26): 33855-33864, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38900841

RESUMO

Near-infrared (NIR) phosphors have emerged as novel luminescent materials across various fields due to their unique advantages of high penetration and invisibility. However, there is currently a lack of intelligent NIR phosphors that can achieve multimode stimuli responsive for sensing applications. In this study, we employed a high-temperature solid-phase reaction to incorporate Pr3+ into Cr3+-doped gallate magnetite SrGa12O19 phosphor, yielding a multimode luminescent intelligent NIR phosphor. Also, due to the inherent cation vacancies and defects in the matrix, the material not only exhibits brighter photoluminescence but also exhibits distinct NIR mechanoluminescence at a lower load. Notably, Pr3+-doped SrGa12O19:Cr3+ also demonstrates extended persistent luminescence and thermoluminescence effects. Finally, we combined the phosphor with the blue LED chip to develop a new multifunctional NIR pc-LED. Leveraging NIR's unique penetrating ability, it can persist in biological tissues for prolonged periods, enabling optical inspection and offering a novel approach to password protection for anticounterfeiting measures. This intelligent NIR phosphor solution significantly expands the application potential of NIR light in food quality assessment and analysis.

2.
ACS Med Chem Lett ; 15(6): 950-957, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38894905

RESUMO

The main protease (MPro) of SARS-CoV-2 is crucial for the virus's replication and pathogenicity. Its active site is characterized by four distinct pockets (S1, S2, S4, and S1-3') and a solvent-exposed S3 site for accommodating a protein substrate. During X-ray crystallographic analyses of MPro bound with dipeptide inhibitors containing a flexible N-terminal group, we often observed an unexpected binding mode. Contrary to the anticipated engagement with the deeper S4 pocket, the N-terminal group frequently assumed a twisted conformation, positioning it for interactions with the S3 site and the inhibitor component bound at the S1 pocket. Capitalizing on this observation, we engineered novel inhibitors to engage both S3 and S4 sites or to adopt a rigid conformation for selective S3 site binding. Several new inhibitors demonstrated high efficacy in MPro inhibition. Our findings underscore the importance of the S3 site's unique interactions in the design of future MPro inhibitors as potential COVID-19 therapeutics.

3.
Opt Lett ; 49(11): 3251-3254, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38824376

RESUMO

Herein, by ball milling CsPb(Br/I)3 quantum dot glass powder with Sr2MgSi2O7:Eu2+, Dy3+ phosphor, multicolor tunable long persistent luminescence (LPL) in inorganic composites with more than 700 min attenuation time can be obtained via a radiation photon reabsorption process. Attractively, the wide color gamut of LPL spectra overlaps the National Television System Committee space 74%. Notably, the luminescence intensity remains stable when the inorganic composites are composed with UV light for 100 h. Finally, practical anticounterfeiting application is successfully realized based on the prepared LPL inorganic composites. This work provides a new, to the best of our knowledge, perspective to achieve polychromatic adjustment of LPL.

4.
ACS Sens ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38922626

RESUMO

The concept of simulating external mechanical stimuli to generate luminescence has been a long-standing aspiration in real-time dynamic visualization. However, creating self-power and self-restoring mechanoluminescent electronic skins for artificial sensors poses significant challenges. In this study, we introduce a cutting-edge triboelectric-mechanoluminescent electronic skin (TMES) that exhibits a remarkable response to multiple external stimuli. This advancement is achieved by integrating a mechanoluminescent intermediate layer within a triboelectric nanogenerator (TENG). When pressure is applied to TMES, the maximum detection voltage can reach hundreds of volts and the maximum correlation sensitivity is 11.76 V/N. Moreover, we incorporate luminescence materials into mechanoluminescence layer, and the maximum absolute sensitivity SR can reach 1.41%. The device can not only distinguish between external stimuli such as pressing and bending but also continuously track external mechanical stimuli. A 4 × 4 matrix and motion prediction of 8 different postures were established to further demonstrate the significant advantages of the developed device in spatial detection. The versatility and performance of the TMES hint at its vast potential in areas such as human-computer interaction and wearable electronics, paving the way for more intuitive and dynamic technological interfaces.

5.
Insect Sci ; 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38769889

RESUMO

Disruption of the circadian clock can affect starvation resistance, but the molecular mechanism is still unclear. Here, we found that starvation resistance was significantly reduced in the core gene BmPer deficient mutant silkworms (Per-/-), but the mutant's starvation resistance increased with larval age. Under natural physiological conditions, the weight of mutant 5th instar larvae was significantly increased compared to wild type, and the accumulation ability of triglycerides and glycogen in the fat bodies was upregulated. However, under starvation conditions, the weight consumption of mutant larvae was increased and cholesterol utilization was intensified. Transcriptome analysis showed that beta-oxidation was significantly upregulated under starvation conditions, fatty acid synthesis was inhibited, and the expression levels of genes related to mitochondrial function were significantly changed. Further investigations revealed that the redox balance, which is closely related to mitochondrial metabolism, was altered in the fat bodies, the antioxidant level was increased, and the pentose phosphate pathway, the source of reducing power in cells, was activated. Our findings suggest that one of the reasons for the increased energy burden observed in mutants is the need to maintain a more robust redox balance in metabolic tissues. This necessitates the diversion of more glucose into the pentose phosphate pathway to ensure an adequate supply of reducing power.

6.
ACS Cent Sci ; 10(4): 782-792, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38680566

RESUMO

Epigenetic reader proteins interpret histone epigenetic marks to regulate gene expression. Given their vital roles and the link between their dysfunction and various diseases, these proteins present compelling targets for therapeutic interventions. Nevertheless, designing selective inhibitors for these proteins poses significant challenges, primarily due to their unique properties such as shallow binding sites and similarities with homologous proteins. To overcome these challenges, we propose an innovative strategy that uses phage display with a genetically encoded noncanonical amino acid (ncAA) containing an epigenetic mark. This ncAA guides binding to the reader protein's active site, allowing the identification of peptide inhibitors with enhanced affinity and selectivity. In this study, we demonstrate this novel approach's effectiveness by identifying potent inhibitors for the ENL YEATS domain that plays a critical role in leukemogenesis. Our strategy involved genetically incorporating Nε-butyryl-l-lysine (BuK), known for its binding to ENL YEATS, into a phage display library for enriching the pool of potent inhibitors. One resultant hit was further optimized by substituting BuK with other pharmacophores to exploit a unique π-π-π stacking interaction with ENL YEATS. This led to the creation of selective ENL YEATS inhibitors with a KD value of 2.0 nM and a selectivity 28 times higher for ENL YEATS than its close homologue AF9 YEATS. One such inhibitor, tENL-S1f, demonstrated robust cellular target engagement and on-target effects to inhibit leukemia cell growth and suppress the expression of ENL target genes. As a pioneering study, this work opens up extensive avenues for the development of potent and selective peptidyl inhibitors for a broad spectrum of epigenetic reader proteins.

7.
J Med Chem ; 67(8): 6495-6507, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38608245

RESUMO

We have witnessed three coronavirus (CoV) outbreaks in the past two decades, including the COVID-19 pandemic caused by SARS-CoV-2. Main protease (MPro), a highly conserved protease among various CoVs, is essential for viral replication and pathogenesis, making it a prime target for antiviral drug development. Here, we leverage proteolysis targeting chimera (PROTAC) technology to develop a new class of small-molecule antivirals that induce the degradation of SARS-CoV-2 MPro. Among them, MPD2 was demonstrated to effectively reduce MPro protein levels in 293T cells, relying on a time-dependent, CRBN-mediated, and proteasome-driven mechanism. Furthermore, MPD2 exhibited remarkable efficacy in diminishing MPro protein levels in SARS-CoV-2-infected A549-ACE2 cells. MPD2 also displayed potent antiviral activity against various SARS-CoV-2 strains and exhibited enhanced potency against nirmatrelvir-resistant viruses. Overall, this proof-of-concept study highlights the potential of targeted protein degradation of MPro as an innovative approach for developing antivirals that could fight against drug-resistant viral variants.


Assuntos
Antivirais , Proteases 3C de Coronavírus , Proteólise , SARS-CoV-2 , Humanos , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , Antivirais/química , Antivirais/síntese química , Proteólise/efeitos dos fármacos , Proteases 3C de Coronavírus/metabolismo , Proteases 3C de Coronavírus/antagonistas & inibidores , Células HEK293 , Descoberta de Drogas , Tratamento Farmacológico da COVID-19 , Células A549
8.
Materials (Basel) ; 17(7)2024 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-38612109

RESUMO

Numerous sources have already demonstrated that varying annealing rates can result in distinct toughness and brittleness in glass. To determine the underlying mechanisms driving this phenomenon, molecular dynamic (MD) simulations were employed to investigate the microstructure of aluminosilicate glasses under different cooling rates, and then uniaxial stretching was performed on them under controlled conditions. Results indicated that compared with short-range structure, cooling rate has a greater influence on the medium-range structure in glass, and it remarkably affects the volume of voids. Both factors play a crucial role in determining the brittleness of the glass. The former adjusts network connectivity to influence force transmission by manipulating the levels of bridging oxygen (BO) and non-bridging oxygen (NBO), and the latter accomplishes the objective of influencing brittleness by modifying the environmental conditions that affect the changes in BO and NBO content. The variation in the void environment results in differences in the strategies of the changes in BO and NBO content during glass stress. These findings stem from the excellent response of BO and NBO to the characteristic points of stress-strain curves during stretching. This paper holds importance in understanding the reasons behind the effect of cooling rates on glass brittleness and in enhancing our understanding of the ductile/brittle transition (DTB) in glass.

9.
Chem Biol Interact ; 395: 110999, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38608999

RESUMO

Bruceantinol (BOL), isolated from the dried fruit of the Brucea javanica (L.) Merr., exhibits cytotoxic effects on breast cancer cells. However, the underlying mechanism remains to be fully addressed. In this paper, the MCF-7 and MDA-MB-231 human breast cancer cell lines were used as experimental models to uncover how BOL inhibits breast cancer cell growth. The effects of BOL on cell growth, proliferation, the cell cycle, and apoptosis were investigated using the MTT assays, EdU incorporation assays, and flow cytometry, respectively. Bioinformatics techniques were applied to predict the key targets of BOL in breast cancer. Subsequent validation of these targets and the anti-breast cancer mechanism of BOL was conducted through Western blotting, RT-PCR, siRNA transfection, and molecular docking analysis. The results demonstrated that BOL dose- and time-dependently reduced the growth of both cell lines, impeded cell proliferation, disrupted the cell cycle, and induced necrosis in MCF-7 cells and apoptosis in MDA-MB-231 cells. Furthermore, CDK2/4/6 were identified as BOL targets, and their knockdown reduced cell sensitivity to BOL. BOL was found to potentially bind with CDK2/4/6 to facilitate protein degradation through the proteasome pathway. Additionally, BOL activated ERK in MDA-MB-231 cells, and this activation was required for BOL's functions in these cells. Collectively, BOL may act as an inhibitor of CDK2/4/6 to exert anti-breast cancer effects. Its effects on cell growth and CDK2/4/6 expression may also depend on ERK activation in HRs-HER2- breast cancer cells. These results suggest the potential of using BOL for treating breast cancer.


Assuntos
Apoptose , Neoplasias da Mama , Proliferação de Células , Quinase 2 Dependente de Ciclina , Quinase 4 Dependente de Ciclina , Quinase 6 Dependente de Ciclina , Simulação de Acoplamento Molecular , Humanos , Neoplasias da Mama/patologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Proliferação de Células/efeitos dos fármacos , Quinase 2 Dependente de Ciclina/metabolismo , Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Feminino , Linhagem Celular Tumoral , Quinase 6 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Células MCF-7 , Lignanas/farmacologia , Lignanas/química , Ciclo Celular/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química
10.
Small ; : e2309780, 2024 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-38433392

RESUMO

The conventional sea water desalination technologies are not yet adopted worldwide, especially in the third world countries due to their high capital cost as well as large energy requirement. To solve this issue in a sustainable way an interfacial solar water evaporation device is designed and proposed in this article using the branches of Prunus serrulata (PB). The PB has abundant microchannels and shows excellent photothermal conversion capability after carbonization. Moreover, the easy access to raw materials and the facile fabrication process makes the solar water evaporating device very cost effective for seawater desalination application. Experiments show that in the presence of the fabricated evaporator the evaporation rate of water can reach 3.5 kg m-2  h-1 under 1 sun, which is superior to many similar experimental devices. In addition, its advantages, such as effective sewage purification capability, low cost, and environmental friendliness, make this evaporator highly competitive in the extensive promotion of this technology and can be considered as a new sustainable solution for seawater desalination with great application potential and prospects.

11.
Antiviral Res ; 225: 105874, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38555023

RESUMO

The main protease (MPro) of SARS-CoV-2, the causative agent of COVID-19, is a pivotal nonstructural protein critical for viral replication and pathogenesis. Its protease function relies on three active site pockets for substrate recognition and a catalytic cysteine for enzymatic activity. To develop potential SARS-CoV-2 antivirals, we successfully synthesized a diverse range of azapeptide inhibitors with various covalent warheads to target MPro's catalytic cysteine. Our characterization identified potent MPro inhibitors, including MPI89 that features an aza-2,2-dichloroacetyl warhead with a remarkable EC50 value of 10 nM against SARS-CoV-2 infection in ACE2+ A549 cells and a selective index of 875. MPI89 is also remarkably selective and shows no potency against SARS-CoV-2 papain-like protease and several human proteases. Crystallography analyses demonstrated that these inhibitors covalently engaged the catalytic cysteine and used the aza-amide carbonyl oxygen to bind to the oxyanion hole. MPI89 stands as one of the most potent MPro inhibitors, suggesting the potential for further exploration of azapeptides and the aza-2,2-dichloroacetyl warhead for developing effective therapeutics against COVID-19.


Assuntos
COVID-19 , Proteases 3C de Coronavírus , SARS-CoV-2 , Humanos , SARS-CoV-2/metabolismo , Cisteína , Cisteína Endopeptidases/metabolismo , Proteínas não Estruturais Virais , Inibidores de Proteases/farmacologia , Antivirais/farmacologia
12.
Biochemistry ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38329238

RESUMO

Numerous organic molecules are known to inhibit the main protease (MPro) of SARS-CoV-2, the pathogen of Coronavirus Disease 2019 (COVID-19). Guided by previous research on zinc-ligand inhibitors of MPro and zinc-dependent histone deacetylases (HDACs), we identified BRD4354 as a potent inhibitor of MPro. The in vitro protease activity assays show that BRD4354 displays time-dependent inhibition against MPro with an IC50 (concentration that inhibits activity by 50%) of 0.72 ± 0.04 µM after 60 min of incubation. Inactivation follows a two-step process with an initial rapid binding step with a KI of 1.9 ± 0.5 µM followed by a second slow inactivation step, kinact,max of 0.040 ± 0.002 min-1. Native mass spectrometry studies indicate that a covalent intermediate is formed where the ortho-quinone methide fragment of BRD4354 forms a covalent bond with the catalytic cysteine C145 of MPro. Based on these data, a Michael-addition reaction mechanism between MPro C145 and BRD4354 was proposed. These results suggest that both preclinical testing of BRD4354 and structure-activity relationship studies based on BRD4354 are warranted to develop more effective anti-COVID therapeutics.

13.
Int J Mol Sci ; 25(3)2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38339000

RESUMO

Diet plays a crucial role in shaping the gut microbiota and overall health of animals. Traditionally, silkworms are fed fresh mulberry leaves, and artificial diets do not support good health. The aim of this study was to explore the relationship between the dietary transition from artificial diets to mulberry leaves and the effects on the gut microbiota and physiological changes in silkworms as a model organism. With the transition from artificial diets to mulberry leaves, the diversity of the silkworm gut microbiota increased, and the proportion of Enterococcus and Weissella, the dominant gut bacterial species in silkworms reared on artificial diets, decreased, whereas the abundance of Achromobacter and Rhodococcus increased. Dietary transition at different times, including the third or fifth instar larval stages, resulted in significant differences in the growth and development, immune resistance, and silk production capacity of silkworms. These changes might have been associated with the rapid adaptation of the intestinal microbiota of silkworms to dietary transition. This study preliminarily established a dietary transition-gut microbial model in silkworms based on the conversion from artificial diets to mulberry leaves, thus providing an important reference for future studies on the mechanisms through which habitual dietary changes affect host physiology through the gut microbiome.


Assuntos
Bombyx , Microbioma Gastrointestinal , Morus , Animais , Seda , Larva
14.
Nat Commun ; 15(1): 1140, 2024 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-38326310

RESUMO

Lanthanide-doped fluoride nanoparticles (NPs) showcase adjustable X-ray-excited persistent luminescence (XEPL), holding significant promise for applications in three-dimensional (3D) imaging through the creation of flexible X-ray detectors. However, a dangerous high X-ray irradiation dose rate and complicated heating procedure are required to generate efficient XEPL for high-resolution 3D imaging, which is attributed to a lack of strategies to significantly enhance the XEPL intensity. Here we report that the XEPL intensity of a series of lanthanide activators (Dy, Pr, Er, Tm, Gd, Tb) is greatly improved by constructing dual heterogeneous interfaces in a double-shell nanostructure. Mechanistic studies indicate that the employed core@shell@shell structure could not only passivate the surface quenchers to lower the non-radiative relaxation possibility, but also reduce the interfacial Frenkel defect formation energy leading to increase the trap concentration. By employing a NPs containing flexible film as the scintillation screen, the inside 3D electrical structure of a watch was clearly achieved based on the delayed XEPL imaging and 3D reconstruction procedure. We foresee that these findings will promote the development of advanced X-ray activated persistent fluoride NPs and offer opportunities for safer and more efficient X-ray imaging techniques in a number of scientific and practical areas.

15.
Opt Lett ; 49(2): 294-297, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38194551

RESUMO

In the emerging field of high-capacity information encryption, multicolor, multitemporal, and multimodal luminescence inorganic materials are of great significance. However, conventional inorganic materials lack the flexibility to dynamically adjust the photon transition path, resulting in unicolor luminescence of the sample and reducing the reading and decoding levels. Herein, we elaborately designed the components for constructing dual-phase crystal fields for Eu2+ in phosphors based on a high temperature solid-state method. Specifically, SrAl2O4:Eu2+ crystal with a bright green afterglow and CaAl2O4:Eu2+ crystal with a blue afterglow were obtained in phosphors at the same time. As a result, a tunable afterglow behavior from blue to white was achieved due to the 4f65d1 → 4f7 transition of Eu2+ at different crystal field sites. Finally, the color tunable afterglow sample was used to explore the encryption and decryption processes of information, and the results showed that the prepared material has a good anti-counterfeiting performance, which is promising for the development of long persistent luminescent materials.

16.
J Econ Entomol ; 117(2): 388-400, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38266252

RESUMO

Artificial diets for silkworms overcome the seasonal limitations of traditional rearing methods with fresh mulberry leaves. However, the current wet artificial diets, steamed at high temperatures, are not favored by silkworms, and they are cumbersome and challenging to preserve. These conditions adversely affected the development of artificial diet-based sericulture production. In this study, we disinfected dry powder diets with radiation and added distilled water without steaming before use. Then, the nutritional value of finished diets and their impact on silkworm development was assessed. Compared with steamed diets, nonsteamed diets were more attractive to silkworms. Chemical assays showed significantly more essential nutrients for silkworms, including l-ascorbic acid, vitamin B1, vitamin B2, and urease in nonsteamed diets than in steamed diets. Feeding fifth-instar silkworm larvae with nonsteamed diets significantly improved the ammonia utilization efficiency of the diet and increased the cocoon shell rate and diet/silk protein conversion efficiency by 5.9% and 13.3%, respectively. When fed with nonsteamed diets, the abundance of aerobic microorganisms in silkworm intestines increased and the abundance of pathogenic bacteria decreased. Furthermore, the vitality of the silkworm, measured by the dead worm cocoon rate, significantly improved by 16.90%. In summary, preparing sterile wet diets without high-temperature steaming effectively improved the nutritional value of the diet and enhanced silkworm growth.


Assuntos
Bombyx , Morus , Animais , Seda/metabolismo , Dieta , Larva , Valor Nutritivo
17.
Int J Biol Macromol ; 258(Pt 1): 128809, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38128801

RESUMO

Hyperproteinemia is a serious metabolic disease of both humans and animals characterized by an abnormally high plasma protein concentration (HPPC). Although hyperproteinemia can cause an imbalance in blood cell homeostasis, the functional changes to blood cells remain unclear. Here, a HPPC silkworm model was used to assess changes to the chromatin accessibility and transcript levels of genes related to blood cell metabolism and immune function. The results showed that HPPC enhanced phagocytosis of blood cells, increased chromatin accessibility and transcript levels of genes involved in cell phagocytosis, proliferation, stress, and programmed death, while genes associated with aromatic amino acid metabolism, and antibacterial peptide synthesis were inhibited in blood cells. Further analysis of the chromatin accessibility of the promoter region found that the high chromatin accessibility of genes sensitive to HPPC, was related to histone modifications, including tri-methylation of lysine residue 4 of histone H3 and acetylation of lysine residue 27 of histone H3. Changes to the chromatin accessibility and transcript levels of genes related to immune function and amino acid metabolism in the blood cells of the HPPC silkworm model provided useful references for future studies of the mechanisms underlying epigenomic regulation mediated by hyperproteinemia.


Assuntos
Bombyx , Doenças Metabólicas , Humanos , Animais , Histonas/metabolismo , Bombyx/metabolismo , Lisina/metabolismo , Multiômica , Cromatina , Proteínas Sanguíneas/metabolismo , Células Sanguíneas/metabolismo , Acetilação
18.
Opt Lett ; 48(21): 5739-5742, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37910747

RESUMO

The alkali metal Na+ is commonly applied as a charge compensator to optimize afterglow performance but rarely reported as a structural regulator to modify afterglow behavior in long afterglow glass materials. In this paper, by preparing the Na + -modified Ce-doped boroaluminate glasses under a high-temperature reducing atmosphere, super-five times brighter blue-violet afterglow lasting up to 30 min was obtained. Results show that appropriate Na+ doping loosens the glass structure and widens the bandgap, thereby regulating most of the electron capture-release modes. This work provides new insights into the behavior of afterglow enhancement in alkali metal-doped glasses.

19.
Nanoscale ; 15(44): 17850-17860, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37882702

RESUMO

Crystal facet engineering is an effective strategy for precisely regulating the orientations and electrochemical properties of metal oxides. However, the contribution of each crystal facet to pseudocapacitance is still puzzling, which is a bottleneck that restricts the specific capacitance of metal oxides. Herein, α-MnO2 nanorods with different exposed facets were synthesized through a hydrothermal route and applied to pseudocapacitors. XRD and TEM results verified that the exposure ratio of active crystal facets was significantly increased with the assistance of the structure-directing agents. XPS analysis showed that there was more adsorbed oxygen and Mn3+ on the active crystal facets, which can provide strong kinetics for the electrochemical reaction. Consequently, the α-MnO2 nanorods with {110} and {310} facets exhibited much higher pseudocapacitances of 120.0 F g-1 and 133.0 F g-1 than their α-MnO2-200 counterparts (67.5 F g-1). The theoretical calculations proved that the {310} and {110} facets have stronger adsorption capacity and lower diffusion barriers for sodium ions, which is responsible for the enhanced pseudocapacitance of MnO2. This study provides a strategy to enhance the electrochemical performance of metal oxide, based on facet engineering.

20.
Biosens Bioelectron ; 242: 115719, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37797532

RESUMO

Nucleic acid (NA) is a widely-used biomarker for viruses. Accurate quantification of NA can provide a reliable basis for point-of-care diagnosis and treatment. Here, we propose a tilted fiber Bragg grating (TFBG)-based plasmonic fiber-optic spectral comb for fast response and ultralow limit NA detection. The TFBG is coated with a gold film which enables excitation of surface plasmon resonance (SPR), and single-stranded probe NAs with known base sequences are assembled on the gold film. To enhance sensitivity of refractive index (RI) for sensing a chosen combination of probe and target NAs around the TFBG surface, gold nanoparticles (AuNPs) are bonded to the target NA molecules as "RI-labels". The NA combination-induced aggregation of AuNPs induces significant spectral responses in the TFBG that would be below the detection threshold for the NAs in the absence of the AuNPs. The proposed TFBG-SPR NA sensor shows a fast response time of 30 s and an ultra-wide NA detection range from 1 × 10-18 mol/L to 1 × 10-7 mol/L. In the NA concentration range of 1 × 10-12 mol/L (1 pM) to 105 pM, an ultra-high sensitivity of 1.534 dB/lg(pM) is obtained. The sensor achieves an ultra-low limit of detection down to 1.0 × 10-18 mol/L (1 aM), which is more than an order of magnitude lower than the previous reports. The proposed sensor not only shows potentials in practical applications of NA detection, but also provides a new way for TFBG-SPR biochemical sensors to achieve higher RI sensitivity.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Ouro/química , Nanopartículas Metálicas/química , Tecnologia de Fibra Óptica , Ressonância de Plasmônio de Superfície
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