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This study introduces a novel electrochemical biosensor for detecting Matrix Metalloproteinase-2 (MMP-2), a key biomarker in cancer diagnostics and tissue remodeling. The biosensor is based on a dual-amplification strategy utilizing T7 RNA polymerase isothermal amplification and CRISPR-Cas12a technology. The principle involves the release of a DNA template in the presence of MMP-2, leading to RNA synthesis by T7 RNA polymerase. This RNA activates CRISPR-Cas12a, which cleaves a DNA probe on the electrode surface, resulting in a measurable electrochemical signal.The biosensor demonstrated exceptional sensitivity, with a detection limit of 2.62 fM for MMP-2. This high sensitivity was achieved through the combination of transcriptional amplification and the collateral cleavage activity of CRISPR-Cas12a, which amplifies the signal. The sensor was able to detect MMP-2 across a wide dynamic range from 2 fM to 1 nM, showing a strong linear correlation between MMP-2 concentration and the electrochemical signal. In practical applications, the biosensor accurately detected elevated levels of MMP-2 in cell culture supernatants from HepG2 liver cancer cells, distinguishing them from normal LO2 liver cells. The use of an MMP-2 inhibitor confirmed the specificity of the detection. These results underscore the biosensor's potential for clinical diagnostics, particularly in early cancer detection and monitoring of tissue remodeling activities. The biosensor's design allows for rapid, point-of-care testing without the need for complex laboratory equipment, making it a promising tool for personalized healthcare and diagnostic applications.
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BACKGROUND: MicroRNAs (miRNAs) are important non-coding RNA entities that affect gene expression and function by binding to target mRNAs, leading to degradation of the mRNAs or inhibiting their translation. MiRNAs are widely involved in a variety of biological processes, such as cell differentiation, development, metabolism, and apoptosis. In addition, miRNAs are associated with many diseases, including cancer. However, conventional detection techniques often suffer from shortcomings such as low sensitivity, so we need to develop a rapid and efficient detection strategy for accurate detection of miRNAs. RESULTS: We have developed an innovative homogeneous electrochemiluminescence (ECL) biosensor. This biosensor employs CRISPR/Cas12a gene editing technology for accurate and efficient detection of microRNA (miRNA). Compared to conventional technologies, this biosensor employs a unique homogeneous detection format that eliminates laborious probe fixation steps and greatly simplifies the detection process. By using two amplification techniques - isothermal amplification and T7 RNA polymerase amplification - the biosensor improves the sensitivity and specificity of the assay, providing excellent detection performance in the assay. This makes it possible to evaluate miRNA directly from a variety of biological samples such as cell lysates and diluted human serum. Experimental results convincingly demonstrate the extraordinary performance of this biosensor, including its extremely low detection limit of 1.27 aM, high sensitivity, reproducibility and stability. SIGNIFICANCE: The application of our constructed sensor in distinguishing between cancerous and non-cancerous cell lines highlights its potential for early cancer detection and monitoring. This innovative approach represents a major advancement in the field of miRNA detection, providing a user-friendly, cost-effective, and sensitive solution with broad implications for clinical diagnosis and patient care, especially in point-of-care settings.
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Técnicas Biosensibles , Sistemas CRISPR-Cas , Técnicas Electroquímicas , Mediciones Luminiscentes , MicroARNs , Humanos , Técnicas Biosensibles/métodos , MicroARNs/análisis , MicroARNs/sangre , MicroARNs/genética , Sistemas CRISPR-Cas/genética , Técnicas Electroquímicas/métodos , Límite de Detección , Proteínas Asociadas a CRISPR/genética , Proteínas Bacterianas , EndodesoxirribonucleasasRESUMEN
Tibial cortex transverse distraction is a surgical method for treating severe diabetic foot ulcers (DFUs), but the underlying mechanism is unclear. We show that antioxidant proteins and small extracellular vesicles (sEVs) with multiple-tissue regenerative potential are released during bone transport (BT) in humans and rats. These vesicles accumulate in diabetic wounds and are enriched with microRNAs (miRNAs) (e.g., miR-494-3p) that have high regenerative activities that improve the circulation of ischemic lower limbs while also promoting neovascularization, fibroblast migration, and nerve fiber regeneration. Deletion of miR-494-3p in rats reduces the beneficial effects of BT on diabetic wounds, while hydrogels containing miR-494-3p and reduced glutathione (GSH) effectively repair them. Importantly, the ginsenoside Rg1 can upregulate miR-494-3p, and a randomized controlled trial verifies that the regimen of oral Rg1 and GSH accelerates wound healing in refractory DFU patients. These findings identify potential functional factors for tissue regeneration and suggest a potential therapy for DFUs.
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Cicatrización de Heridas , Animales , Cicatrización de Heridas/efectos de los fármacos , Humanos , Ratas , Masculino , MicroARNs/metabolismo , MicroARNs/genética , Vesículas Extracelulares/metabolismo , Ratas Sprague-Dawley , Pie Diabético/metabolismo , Pie Diabético/patología , Diabetes Mellitus Experimental/metabolismo , Glutatión/metabolismo , Persona de Mediana Edad , Regeneración/efectos de los fármacos , Femenino , Huesos/metabolismoRESUMEN
The article details a groundbreaking platform for detecting microRNAs (miRNAs), crucial biomolecules involved in gene regulation and linked to various diseases. This innovative platform combines the CRISPR-Cas13a system's precise ability to specifically target and cleave RNA molecules with the amplification capabilities of the hybridization chain reaction (HCR). HCR aids in signal enhancement by creating branched DNA structures. Additionally, the platform employs electrochemiluminescence (ECL) for detection, noted for its high sensitivity and low background noise, making it particularly effective. A key application of this technology is in the detection of miR-17, a biomarker associated with multiple cancer types. It exhibits remarkable detection capabilities, characterized by low detection limits (14.38 aM) and high specificity. Furthermore, the platform's ability to distinguish between similar miRNA sequences and accurately quantify miR-17 in cell lysates underscores its significant potential in clinical and biomedical fields. This combination of precise targeting, signal amplification, and sensitive detection positions the platform as a powerful tool for miRNA analysis in medical diagnostics and research.
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Sistemas CRISPR-Cas , Técnicas Electroquímicas , Mediciones Luminiscentes , MicroARNs , Hibridación de Ácido Nucleico , MicroARNs/análisis , MicroARNs/genética , Humanos , Sistemas CRISPR-Cas/genética , Técnicas Electroquímicas/métodos , Técnicas Biosensibles/métodos , Límite de DetecciónRESUMEN
B-type natriuretic peptide (BNP) is a biomarker for heart failure, a serious and prevalent disease that requires rapid and accurate diagnosis. In this study, we developed a novel electrochemical biosensor for BNP detection based on CRISPR/Cas13a and chain substitution reaction. The biosensor consists of a DNA aptamer that specifically binds to BNP, a T7 RNA polymerase that amplifies the signal, a CRISPR/Cas13a system that cleaves the target RNA, and a two-dimensional DNA nanoprobe that generates an electrochemical signal. The biosensor exhibits high sensitivity, specificity, and stability, with a detection limit of 0.74 aM. The biosensor can also detect BNP in human serum samples with negligible interference, demonstrating its potential for clinical and point-of-care applications. This study presents a novel strategy for integrating CRISPR/Cas13a and chain substitution reaction into biosensor design, offering a versatile and effective platform for biomolecule detection.
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Técnicas Biosensibles , Sistemas CRISPR-Cas , Técnicas Electroquímicas , Péptido Natriurético Encefálico , Técnicas Biosensibles/métodos , Péptido Natriurético Encefálico/sangre , Péptido Natriurético Encefálico/química , Humanos , Sistemas CRISPR-Cas/genética , Límite de Detección , Aptámeros de Nucleótidos/químicaRESUMEN
A novel electrochemical biosensor that combines the CRISPR-Cas12a system with a gold electrode is reported for the rapid and sensitive detection of microphthalmia-associated transcription factor (MITF). The biosensor consists of a gold electrode modified with DNA1, which contains the target sequence of MITF and is labeled with ferrocene, an electroactive molecule. The biosensor also includes hairpin DNA, which has a binding site for MITF and can hybridize with helper DNA to form a double-stranded complex that activates CRISPR-Cas12a. When MITF is present, it binds to hairpin DNA and prevents its hybridization with helper DNA, thus inhibiting CRISPR-Cas12a activity and preserving the DPV signal of ferrocene. When MITF is absent, hairpin DNA hybridizes with helper DNA and activates CRISPR-Cas12a, which cleaves DNA1 and releases ferrocene, thus reducing the DPV signal. The biosensor can detect MITF with high sensitivity (with an LOD of 8.14 fM), specificity, and accuracy in various samples, such as cell nuclear extracts and human serum. The biosensor can also diagnose and monitor melanocyte-related diseases and melanin production. This work provides a simple, fast, sensitive, and cost-effective biosensor for MITF detection and a valuable tool for applications in genetic testing, disease diagnosis, and drug screening.
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Sistemas CRISPR-Cas , Factor de Transcripción Asociado a Microftalmía , Humanos , Factor de Transcripción Asociado a Microftalmía/genética , Metalocenos , Oro , ADN/genéticaRESUMEN
BACKGROUND: Escherichia coli (E.coli) is both a commensal and a foodborne pathogenic bacterium in the human gastrointestinal tract, posing significant potential risks to human health and food safety. However, one of the major challenges in E.coli detection lies in the preparation and storage of antibodies. In traditional detection methods, antibodies are indispensable, but their instability often leads to experimental complexity and increased false positives. This underscores the need for new technologies and novel sensors. Therefore, the development of a simple and sensitive method for analyzing E.coli would make significant contributions to human health and food safety. RESULTS: We constructed an electrochemical biosensor based on triple-helical DNA and entropy-driven amplification reaction (EDC) to inhibit the cleavage activity of Cas12a, enabling high-specificity detection of E.coli. Replacing antibodies with nucleic acid aptamers (Apt) as recognition elements, we utilized the triple-helical DNA generated by the binding of DNA2 and DNA5/DNA6 double-helical DNA through the entropy-driven amplification reaction to inhibit the collateral cleavage activity of clustered regularly interspaced short palindromic repeats gene editing system (CRISPR) and its associated proteins (Cas). By converting E.coli into electrical signals and recording signal changes in the form of square wave voltammetry (SWV), rapid detection of E.coli was achieved. Optimization of experimental conditions and data detection under the optimal conditions provided high sensitivity, low detection limits, and high specificity. SIGNIFICANCE: With a minimal detection limit of 5.02 CFU/mL and a linear range of 1 × 102 - 1 × 107 CFU/mL, the suggested approach was successfully verified to analyze E.coli at various concentrations. Additionally, after examining E.coli samples from pure water and pure milk, the recoveries ranged between 95.76 and 101.20%, demonstrating the method's applicability. Additionally, it provides a feasible research direction for the detection of pathogenic bacteria causing other diseases using the CRISPR/Cas gene editing system.
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Técnicas Biosensibles , Ácidos Nucleicos , Humanos , Sistemas CRISPR-Cas , Edición Génica , ADN/genética , Oligonucleótidos , Anticuerpos , Escherichia coli/genéticaRESUMEN
In the current study, a novel electrochemiluminescence biosensor based on the entropy-driven DNA tetrahedron for the detection of matrix metalloproteinase 2 (MMP2), an enzyme that regulates extracellular matrix remodeling and affects aging was reported. The biosensor utilizes an inverted DNA tetrahedron structure, which exposes three vertices to the solution, as molecular recognition units for capturing specific biomolecules. The biosensor also employs a ratiometric method and an entropy-driven reaction, which enhance the response rate and sensitivity of the detection. The biosensor can detect MMP2 with a detection limit of 55.2 fM, which is lower than that of conventional sensors. The biosensor also exhibits excellent stability and reproducibility, and can accurately measure MMP2 levels in complex samples, such as human serum. The paper demonstrates the feasibility and effectiveness of using the "inverted" DNA tetrahedron structure and the entropy-driven process to construct interfacial biosensors. The paper also discusses the potential applications of the biosensor in clinical diagnosis and anti-aging research, where MMP2 plays a crucial role in tissue damage and repair. The paper provides a valuable contribution to the field of biosensor development, and opens up new possibilities for using DNA nanotechnology for sensitive and reliable detection of various biomolecules.
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Envejecimiento , Metaloproteinasa 2 de la Matriz , Humanos , Reproducibilidad de los Resultados , ADN , EntropíaRESUMEN
By merging DNA entropy-driven technology with triple-stranded nucleic acids in an electrochemical biosensor to detect the SARS-CoV-2 RdRp gene, we tackled the challenges of false negatives and the high cost of SARS-CoV-2 detection. The approach generates a CRISPR-Cas 13a-activated RNA activator, which then stimulates CRISPR-Cas 13a activity using an entropy-driven mechanism. The activated CRISPR-Cas 13a can cleave Hoogsteen DNA due to the insertion of two uracil (-U-U-) in Hoogsteen DNA. The DNA tetrahedra changed on the electrode surface and can therefore not construct a three-stranded structure after cleaving Hoogsteen DNA. Significantly, this DNA tetrahedron/Hoogsteen DNA-based biosensor can regenerate at pH = 10.0, which keeps Hoogsteen DNA away from the electrode surface, allowing the biosensor to function at pH = 7.0. We could use this technique to detect the SARS-CoV-2 RdRp gene with a detection limit of 89.86 aM. Furthermore, the detection method is very stable and repeatable. This technique offers the prospect of detecting SARS-CoV-2 at a reasonable cost. This work has potential applications in the dynamic assessment of the diagnostic and therapeutic efficacy of SARS-CoV-2 infection and in the screening of environmental samples.
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COVID-19 , Ácidos Nucleicos , Humanos , SARS-CoV-2/genética , Entropía , COVID-19/diagnóstico , ADN/genética , Tecnología , ARN Polimerasa Dependiente del ARNRESUMEN
In this study, we introduce an electrochemiluminescence (ECL) sensing platform based on the "Entropy-driven triggered T7 amplification-CRISPR/Cas13a system" (EDT-Cas). This platform combines a programmable entropy-driven cycling strategy, T7 RNA polymerase, and the CRISPR/Cas13a system to amplify the determination of the SARS-CoV-2 RdRp gene. The Ti3C2Tx-compliant ECL signaling molecule offers unique benefits when used with the ECL sensing platform to increase the assay sensitivity and the electrode surface modifiability. To obtain the T7 promoter, the SARS-CoV-2 RdRp gene may first initiate an entropy-driven cyclic amplification response. Then, after recognizing the T7 promoter sequence on the newly created dsDNA, T7 RNA polymerase starts transcription, resulting in the production of many single-stranded RNAs (ssRNAs), which in turn trigger the action of CRISPR/Cas13a. Finally, Cas13a/crRNA identifies the transcribed ssRNA. When it cleaves the ssRNA, many DNA reporter probes carrying -U-U- are cleaved on the electrode surface, increasing the ECL signal and allowing for the rapid and highly sensitive detection of SARS-CoV-2. With a detection limit of 7.39 aM, our method enables us to locate the SARS-CoV-2 RdRp gene in clinical samples. The detection method also demonstrates excellent repeatability and stability. The SARS-CoV-2 RdRp gene was discovered using the "Entropy-driven triggered T7 amplification-CRISPR/Cas13a system" (EDT-Cas). The developed ECL test had excellent recoveries in pharyngeal swabs and environmental samples. It is anticipated to offer an early clinical diagnosis of SARS-CoV-2 and further control the spread of the pandemic.
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Técnicas Biosensibles , COVID-19 , Humanos , COVID-19/diagnóstico , Entropía , SARS-CoV-2/genética , ARN Polimerasa Dependiente del ARNRESUMEN
As a common technique for detecting AßO, the enzyme-linked immunosorbent assay (ELISA) method is time-consuming, high in cost, and poor in stability. Therefore, it is necessary to develop a highly sensitive, method-simple and low-cost method for the selective detection of AßO. Here, we created a novel signal-on and label-free electrochemical aptamer sensor for the detection of AßO based on a DNAzyme-driven DNA bipedal walking strategy. Compared with common DNA walkers, bipedal DNA walkers exhibit larger walking areas and faster walking kinetics, and provide higher amplification efficiency. The DNAwalker is powered by an Mg2+-dependent DNAzyme, and the binding-induced DNAwalker continuously clamps the MB, unlocking several active G-quadruplex-forming sequences. These G-quadruplexes can be further combined by hemin to generate a G-quadruplex/heme complex, resulting in an amperometric signal, resulting in a broad proportional band from 0.1 pM to 1 nM and an excellent detection range of 46 fM. A bipedal DNA walker aptamer sensor can detect human serum AßO with remarkable specificity, high reproducibility and practical application value.
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Aptámeros de Nucleótidos , Técnicas Biosensibles , ADN Catalítico , G-Cuádruplex , Humanos , ADN Catalítico/genética , Péptidos beta-Amiloides/genética , Reproducibilidad de los Resultados , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , ADN/genética , Hemina , Límite de DetecciónRESUMEN
A disintegrin and metalloprotease 10 (ADAM-10), a member of the ADAM protease family, has biological activities related to TNF-α activation, cell adhesion, and migration, among other functions. Macrophages are important immune cells that are involved in the inflammatory response of the body. ADAM-10 is involved in inflammatory responses, but the specific regulatory mechanisms are not fully understood. In this study, we investigated the regulatory mechanism of ADAM-10 in the lipopolysaccharide-promoted proliferation (LPS) of the macrophage inflammatory response. Differentially expressed or regulated proteins were identified in interfered ADAM-10 (sh ADAM-10) macrophages using tandem mass tag (TMT) proteomics. The changes and regulatory role of ADAM-10 during LPS-induced inflammatory response in normal, interfering, and overexpressing ADAM-10 (EX ADAM-10) cells were determined. Results indicated that ADAM-10 interference affected inflammation-related pathways and reduced matrix metalloproteinase 12 (MMP-12) protein levels, as identified by TMT proteomics. In normal cells, LPS decreased ADAM-10 gene expression, but promoted ADAM-10 secretion, MMP-12 and TNF-α gene expression, and MMP-12, iNOS, IL-10, and cyclinD1 protein expression. Additionally, ADAM-10 knockdown decreased macrophage viability in sh-ADAM-10 cells. Moreover, an MMP-12 inhibitor had no impact on the viability effect of LPS on cells or the expression of ADAM-10. iNOS expression decreased, whereas IL-10 expression increased after ADAM-10 depletion. ADAM-10 knockdown decreased MMP-12, iNOS, TNF-α, IL-1ß, and FKN, while overexpression had an opposite effect. ADAM-10 overexpression further increased MMP-12, iNOS, and TNF-α gene expression in response to LPS. Cell viability was increased in EX ADAM-10 cells, and ADAM-10 secretion was further increased in the EX and LPS groups. Flow cytometry and immunofluorescence staining revealed that EX-ADAM 10 cells had increased iNOS expression, which acted as an IL-6 expression driver. In summary, we found that ADAM-10 is activated by LPS and positively participates in LPS-stimulated macrophage inflammatory responses by positively regulating MMP-12 during the inflammatory process.
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Lipopolisacáridos , Metaloproteinasa 12 de la Matriz , Desintegrinas/metabolismo , Desintegrinas/farmacología , Interleucina-10/metabolismo , Interleucina-6/metabolismo , Lipopolisacáridos/farmacología , Macrófagos , Metaloproteinasa 12 de la Matriz/genética , Metaloproteinasa 12 de la Matriz/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Osteoarthritis (OA) is a degenerative disease characterized by articular cartilage and/or chondrocyte destruction, and although it has long been considered as a primary disease, the importance of meniscus endothelial cell modulation in the subchondral microenvironment has recently drawn attention. Previous studies have shown that apelin could potentially inhibit cellular apoptosis; however, it remains unclear whether apelin could play a protective role in protecting the endothelium in the OA meniscus. In this study, with the advantages of single-cell RNA sequencing (scRNA-seq) data, in combination with flow cytometry, we identified two endothelial subclusters in the meniscus, featured by high expression of Homeobox A13 (HOXA13) and Ras Protein-Specific Guanine Nucleotide Releasing Factor 2 (RASGRF2), respectively. Compared with control patients, both subclusters decreased in absolute cell numbers and exhibited downregulated APJ endogenous ligand (APLN, coding for apelin) and upregulated apelin receptor (APLNR, coding apelin receptor). Furthermore, we confirmed that in OA, decreased endothelial cell numbers, including both subclusters, were related to intrinsic apoptosis factors: one more relevant to caspase 3 (CASP3) and the other to BH3-Interacting Domain Death agonist (BID). In vitro culturing of meniscal endothelial cells purified from patients proved that apelin could significantly inhibit apoptosis by downregulating these two factors in endothelial cell subclusters, suggesting that apelin could potentially serve as a therapeutic target for patients with OA.
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Menisco , Osteoartritis , Apelina/genética , Apelina/farmacología , Apelina/uso terapéutico , Apoptosis , Células Endoteliales/metabolismo , Humanos , Menisco/metabolismo , Osteoartritis/metabolismoRESUMEN
Non-alcoholic fatty liver disease (NAFLD) has become prevalent worldwide, but sufficient pharmaceutical treatments for this condition are lacking. Previous literature suggests that vitexin offers beneficial effects in the treatment of NAFLD, but the underlying mechanisms are not well understood. In this study, the in vivo effects of vitexin were investigated in high-fat-diet (HFD)-induced NAFLD mice. Liver pathology, biochemical parameters, lipid levels, hepatocyte ultrastructure, and related regulatory proteins were measured at the end of treatment. Treatment consisted of four weeks of daily administration of vitexin at a dose of 6 mg/kg of body weight. This treatment markedly improved hepatic architecture, attenuated lipid accumulation, and regulated lipid abnormalities. In addition, the treatment reduced endoplasmic reticulum (ER) stress, restored mitochondrial biological proteins, and increased autophagy. Furthermore, the treatment increased peroxisome proliferator-activated receptor-γ (PPAR-γ) protein, which was inhibited by HFD. Thus, it was speculated that vitexin degraded lipids in HFD-induced NAFLD mice liver by inducing autophagy and restoring both ER and mitochondrial biological proteins.
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Enfermedad del Hígado Graso no Alcohólico , Animales , Apigenina , Autofagia , Dieta Alta en Grasa/efectos adversos , Estrés del Retículo Endoplásmico , Metabolismo de los Lípidos , Lípidos , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/patologíaRESUMEN
Background: The incidence of diabetes-related wounds is widespread, and the treatment is challenging. We found that Moist Exposed Burn Ointment (MEBO) promotes the healing of diabetes-related wounds, but the mechanism is not clear. Methods: This study aimed to explore the mechanism of MEBO on diabetic wound healing, which may be related to the promotion of re-epithelialization. A full-thickness skin resection model was established in streptozotocin (STZ)-induced diabetic mice. MEBO and Kangfuxin (KFX) were applied to the wound area, and the wound healing rate was analyzed by photographing. The granulation tissue and epidermal thickness, the collagen remodeling rate, and the expression of cytokeratin 10 (CK10), cytokeratin 14 (CK14), Ki67, Collagen I, and Collagen III in the regenerated skin were detected by H&E staining, Masson staining, and immunofluorescence staining, respectively. MEBO and KFX were applied to human immortalized keratinocytes (HaCaT), mouse dermal fibrolasts (MDF) cells, and cell viability, cell migration, and differentiation were determined by CCK-8, scratching assay, RT-qPCR, and Western blot (WB), respectively. Results: We found that MEBO significantly promoted the formation of wound granulation tissue and collagen remodeling in diabetic mice. The application of MEBO to diabetic wounds not only promoted the formation of hair follicles and sebaceous glands but also promoted the expression of Ki67, CK10, and CK14 in epidermal cells. MEBO had no significant effect on the differentiation process of keratinocytes. Conclusion: Our study further proved that MEBO plays a positive role in diabetic wound healing, and its excellent ability to promote re-epithelialization may be an important reason for promoting wound healing.
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SiO2 and TiO2, as conventional dielectric shells of ferromagnetic/dielectric composite particles, can protect ferromagnetic particles from aggregation and oxidation, but contribute little to electromagnetic loss. In this work, we designed nano-assembled CoFe-CoFe2O4@C composite particles, in which ferrites with high permeability were dielectric elements and carbon was introduced as protective layers, aiming for high-efficiency microwave absorption. These assembled particles with different CoFe contents were prepared through solvothermal methods and subsequent hydrogen-thermal reduction. CoFe nanoparticles were dispersed on a CoFe2O4 matrix via an in situ reduction transformation from CoFe2O4 to CoFe. The microstructure evolution of composite particles and corresponding electromagnetic properties tailoring were investigated. The content and size of CoFe as well as the porosity of composite particles increase gradually as the annealing temperature increases. A maximum reflection loss (RL max) of -71.73 dB is observed at 4.78 GHz in 3.4 mm thick coating using particles annealed at 500 °C as fillers. The coating presents double-band absorbing characteristics, as broad effective absorption bandwidth with RL > 5 (ERL 5) and high RL max are observed in both S-C and X-Ku bands. The tunability as well as the assembled characteristic of the electromagnetic property that endued from the composite structure contributes to the excellent electromagnetic wave absorbing performances.
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Ferromagnetic metal/alloy nanoparticles have attracted extensive interest for electromagnetic wave-absorbing applications. However, ferromagnetic nanoparticles are prone to oxidization and producing eddy currents, leading to the deterioration of electromagnetic properties. In this work, a simple and scalable liquid-phase reduction method was employed to synthesize uniform Co7Fe3 nanospheres with diameters ranging from 350 to 650 nm for high-performance microwave absorption application. Co7Fe3@SiO2 core-shell nanospheres with SiO2 shell thicknesses of 30 nm were then fabricated via a modified Stöber method. When tested as microwave absorbers, bare Co7Fe3 nanospheres with a diameter of 350 nm have a maximum reflection loss (RL) of 78.4 dB and an effective absorption with RL > 10 dB from 10 to 16.7 GHz at a small thickness of 1.59 mm. Co7Fe3@SiO2 nanospheres showed a significantly enhanced microwave absorption capability for an effective absorption bandwidth and a shift toward a lower frequency, which is ascribed to the protection of the SiO2 shell from direct contact among Co7Fe3 nanospheres, as well as improved crystallinity and decreased defects upon annealing. This work illustrates a simple and effective method to fabricate Co7Fe3 and Co7Fe3@SiO2 nanospheres as promising microwave absorbers, and the design concept can also be extended to other ferromagnetic alloy particles.
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OBJECTIVE: To observe the effect of electroacupuncture(EA) on phosphalized extracellular regulated protein kinases(p-ERK) 1/2 signaling pathway and tumor necrosis factor (TNF)-α and IL-1ß protein levels in the substantia nigra (SN) in rats with Parkinson's disease (PD), so as to explore its mechanism underlying improvement of PD. METHODS: 32 male SD rats were randomly and averagely divided into normal control group, sham-operation group, model group and EA group. PD model was established by intra-dermal-injection of rotenone(1 mg/kg, dissolved in DMSO and saline, concentration: 0. 25 mg/mL) at the nape, once daily for 14 days. EA (2 Hz, 2 mA) was applied to "Fengfu"(GV 16)and "Taichong"(LR 3) for 20 min, once daily for 14 days. For sham-operation group, subcutaneous injection of the same dose of DMSO and saline was given in the same way. The expression levels of tyrosine hydroxylase (TH), p-ERK 1/2, inflammatory cytokines TNF-α and IL-1P proteins of the SN tissue were detected using Western blot. The rat's horizontal and vertical movement ability was assessed using open-field tests. RESULTS: The horizontal and vertical movement scores were significantly lower in the model group than in the normal control group, and markedly higher in the EA group than in the model group (P<0. 05). Compared with the normal control group, the expression level of TH protein in the SN was significantly reduced in the model group( P<0. 05 ),while the expression levels of p-ERK 1/2, TNF-α and IL-1ß proteins were significantly increased in the model group(P<0. 05). After EA intervention, the expression level of TH protein was significantly increased(P<0.05),and those of p-ERK 1/2, TNF-α and IL-1ß proteins were significantly down-regulated(P<0. 05) in the EA group compared to the model group. CONCLUSION: EA therapy may improve PD rats' movement ability, which may be associated with its effects in down-regulating the expression levels of p-ERK 1/2, TNF-α and IL-1ß proteins and up-regulating the expression of TH protein in the SN.
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Electroacupuntura , Quinasas MAP Reguladas por Señal Extracelular/fisiología , Interleucina-1beta/análisis , Sistema de Señalización de MAP Quinasas/fisiología , Enfermedad de Parkinson/terapia , Sustancia Negra/metabolismo , Factor de Necrosis Tumoral alfa/análisis , Animales , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
OBJECTIVE: To explore action mechanism of electroacupuncture (EA) on treatment and prevention of Parkinson's disease (PD). METHODS: Fifty clean-grade SD rats were randomly divided into a normal group, a control group, a model group, a pretreatment group and a treatment group, ten rats in each one. The PD model was established by subcutaneous injection of rotenone in neck-back skin (2 mg/kg, dissolved in sun-flower oil, 2 mg/mL in density). The equal-volume sun-flower oil that didn't include rotenone was applied in the control group at the same area as the model group. EA was applied in the treatment group at "Fengfu" (GV 16) and "Taichong" (LR 3) with interrupted wave, 2 Hz in frequency, 1 mA in density, for 20 min. The treatment was given once day for conti-nuous 28 days. Rats in the pretreatment group received the same EA as the treatment group for 7 days, and then put into model establishment. After the model establishment, the rats received no treatment and were sacrificed after 28 days. No EA was given in the normal group, model group and control group. The ethology changes were observed and scored. The expression of Parkin, ubiquitin C terminal hydrolase-L1 (UCH-L1) and ubiquitin activating enzyme-1 (UBE1) in substantia nigra was tested by Western-blot method. The positive cell numbers of alpha-synuclein, ubiquitin (UB) and tyrosine hydroxylase (TH) in substantia nigra was tested by immunohistochemical method. RESULTS: There were abnormal ethology manifestation such as yellow and coarse hair, arched back, weaken behavior of resisting arrest and slow movement, which was more relieved in the treatment group and pretreatment group. Compared with normal group and control group, the expression of Parkin, UCH-L1, UBE1, UB, TH in the model group was obviously decreased while alpha-synuclein was obviously increased (all P<0.01). After EA or pretreatment, the expression of Parkin, UCH-L1, UBE1, UB, TH in the treatment group and pretreatment group was higher than that in the model group while expression of alpha-synuclein in the treatment group and pretreatment group was lower than that in the model group (all P<0.01). CONCLUSION: EA or pretreatment could not only have protective effect for rats with PD, but also increase function of ubiquitin-proteasome system, indicating action mechanism of EA on treatment and prevention of PD may be related with ubiquitin-proteasome system.