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1.
Eur Spine J ; 33(3): 1120-1128, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38347273

RESUMO

OBJECTIVE: This research aims to compare the clinical outcomes of VBE-TLIF and MIS-TLIF for the treatment of patients with single-level degenerative lumbar diseases. METHODS: Ninety patients were enrolled in this study. The estimated blood loss, operation time, postoperative hospitalization days, time to functional exercise, amount of surgical drain and inflammatory index were recorded. The visual analog scale, Oswestry dysfunction index and modified MacNab criteria were used to assessed the patient's back and leg pain, functional status and clinical satisfaction rates. RESULTS: The average operation time of the VBE-TLIF group was longer than that of the MIS-TLIF group. The time for functional exercise, length of hospital stay, estimated blood loss and amount of surgical drain in the VBE-TLIF group were relative shorter than those in the MIS-TLIF group. Additionally, the levels of CRP, neutrophil, IL-6 and CPK in the VBE-TLIF group were significantly lower than those in the MIS-TLIF group at postoperative days 1 and 3, respectively (P < 0.001). Patients undergoing VBE-TLIF had significantly lower back VAS scores than those in the MIS-TLIF group on postoperative days 1 and 3 (P < 0.001). No significant differences were found in the clinical satisfaction rates (95.83 vs. 95.24%, P = 0.458) or interbody fusion rate (97.92 vs. 95.24%, P = 0.730) between these two surgical procedures. CONCLUSIONS: Both VBE-TLIF and MIS-TLIF are safe and effective surgical procedures for patients with lumbar diseases, but VBE-TLIF technique is a preferred surgical procedure with merits of reduced surgical trauma and quicker recovery.


Assuntos
Vértebras Lombares , Fusão Vertebral , Humanos , Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Resultado do Tratamento , Fusão Vertebral/métodos , Região Lombossacral/cirurgia , Estudos Retrospectivos
2.
J Cell Biochem ; 124(11): 1835-1847, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37882437

RESUMO

Excess glucocorticoids (GCs) have been reported as key factors that impair osteoblast (OB) differentiation and function. However, the role of RNA N6-methyladenosine (m6 A) in this process has not yet been elucidated. In this study, we report that both the mRNA and protein expression of fat mass and obesity-associated gene (FTO), a key m6 A demethylase, were dose-dependently downregulated during OB differentiation by dexamethasone (DEX) in bone marrow mesenchymal stem cells (BMSCs), and FTO was gradually increased during OB differentiation. Meanwhile, FTO knockdown suppressed OB differentiation and mineralization, whereas overexpression of wide-type FTO, but not mutant FTO (mutated m6 A demethylase active site), reversed DEX-induced osteogenesis impairment. Interfering with FTO inhibited proliferation and the expression of Ki67 and Pcna in BMSCs during OB differentiation, whereas forced expression of wide-type FTO improved DEX-induced inhibition of BMSCs proliferation. Moreover, FTO knockdown reduced the mRNA stability of the OB marker genes Alpl and Col1a1, and FTO-modulated OB differentiation via YTHDF1 and YTHDF2. In conclusion, our results suggest that FTO inhibits the GCs-induced OB differentiation and function of BMSCs.


Assuntos
Glucocorticoides , Células-Tronco Mesenquimais , Glucocorticoides/farmacologia , Osteogênese/genética , RNA/metabolismo , Diferenciação Celular , Adenosina/farmacologia , Adenosina/metabolismo , Células-Tronco Mesenquimais/metabolismo , Osteoblastos/metabolismo
3.
Eur Spine J ; 32(8): 2845-2852, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37160442

RESUMO

PURPOSE: Our team designed a novel two-medium compatible bichannel endoscopy system for spinal surgery, V-shape bichannel endoscopy (VBE) system. Hereby, this study will introduce minimally invasive transforaminal lumbar interbody fusion (TLIF) with VBE system and report its preliminary clinical results. METHODS: Fifty-two participants, who accepted VBE-assisted TLIF surgery (VBE-TLIF) in our hospital were included in this study. The duration of operation, off-bed time, and days of hospitalization were recorded. Besides, the patient's preoperative and postoperative pain were evaluated via visual analog scale (VAS), the functional status was evaluated via Oswestry dysfunction index (ODI) and modified MacNab criteria. Patients were asked to follow-up in the outpatient department at the 3rd, 6th, 12th, and 24th month after surgery. X-ray or CT was examined to evaluate the internal fixation position and interbody fusion result. RESULTS: All patients received unilateral decompression with an average operation duration of 178.49 ± 27.49 min. After the surgery, their VAS score of leg pain and back pain reduced significantly. At the last follow-up, the VAS score of leg pain and back pain was 0.80 ± 0.69 and 0.86 ± 0.75 separately. The difference shows statistically significant with p < 0.05. At the last follow-up, the ODI was 15.20 ± 5.75. According to modified MacNab criteria, 39 patients rated their function as excellent, and 10 patients were good. The overall satisfaction rate reached 94%. CONCLUSION: The VBE system reported in the current study can complete TLIF surgery safely and effectively.


Assuntos
Procedimentos Cirúrgicos Minimamente Invasivos , Fusão Vertebral , Humanos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Fusão Vertebral/métodos , Endoscopia , Dor Pós-Operatória , Dor nas Costas , Estudos Retrospectivos , Resultado do Tratamento
4.
Phys Chem Chem Phys ; 24(47): 29034-29042, 2022 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36427044

RESUMO

Gold nanoclusters (AuNCs) are a unique class of materials that exhibit visible luminescence. Amorphous calcium phosphate (ACP) is a widely used biomaterial for a variety of purposes, such as drug delivery, bone cementing, and implant coatings. In this study, a nanocomposite of AuNCs and ACP is prepared by biomimetic mineralization in a Dulbecco's modified Eagle's medium (DMEM). The strong interaction between AuNCs and Ca2+ ions effectively induces aggregation of AuNCs. The as-formed nanocomposite, AuNCs@ACP, emits significantly enhanced luminescence compared to AuNCs alone. The luminescence enhancement mechanism is investigated using synchrotron X-ray absorption fine structure spectroscopy. In addition, the presence of AuNCs stabilizes ACP and also enhances the biocompatibility of ACP in promoting cell proliferation, and the nanocomposites are promising as nanoprobes for cancer therapy and/or bone tissue engineering.


Assuntos
Biomimética , Ouro , Fosfatos de Cálcio
5.
BMC Musculoskelet Disord ; 23(1): 840, 2022 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-36057594

RESUMO

PURPOSE: To describe the cervical spine morphology and explore its relationship to global sagittal alignment parameters in the asymptomatic adolescent population.  METHODS: A total of 111 adolescent subjects were included. Sagittal alignment parameters, including C7 Slope, C2-C7 Cobb, C2-7 plumb line (PL), C2-S1 Sagittal Vertical Axis (SVA), C7-S1 SVA, T5-12 Cobb, T10-L2 Cobb, L1-S1 Cobb, pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS), were obtained from lateral radiographs.  RESULTS: Forty-four males and sixty-seven females with a mean age of 16.12 ± 2.40 years were included in this study. The mean values of C7 Slope, C2-7 Cobb and C2-7PL were 20.45 ± 8.88°, -7.72 ± 12.10°, and 13.53 ± 11.63 mm, respectively. C2-7 Cobb, C7 Slope showed significant differences between the male and female groups. Correlation analysis showed that C7 slope was significantly correlated with C2-7 Cobb (r = -0.544, P < 0.001), C2-S1 SVA (r = 0.335, P < 0.001), and C7-S1 SVA (r = 0.310, P = 0.001), but not lumbosacral parameters(L5-S1 Cobb, PI, PT, SS). Using a modified method of Toyama to describe the cervical spine morphology, there were 37 cases (33.3%) in the Lordotic group, and C7 slope, C2-7 Cobb and C2-7PL showed significant differences between groups. According to C2-C7 Cobb, there were 80 Lordotic cases (72.1%). C7 slope and C2-7PL were significantly different between the two groups. CONCLUSION: The cervical spine morphology of asymptomatic adolescents varies widely, from lordotic to kyphotic. Combining different classification methods provides a better understanding of the morphology of the cervical spine. C7 slope is an important predictor of global sagittal balance and C2-7PL is a key parameter for restoring cervical lordosis, which should be considered pre-operatively and for conservative treatment. Cervical regional sagittal alignment parameters are not correlated with lumbosacral parameters, and C2-7 Cobb, C7 Slope showed significant differences between males and females.


Assuntos
Cifose , Lordose , Adolescente , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Feminino , Humanos , Cifose/cirurgia , Lordose/diagnóstico por imagem , Lordose/cirurgia , Vértebras Lombares/cirurgia , Masculino , Estudos Retrospectivos , Sacro
6.
BMC Cancer ; 21(1): 355, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33823834

RESUMO

BACKGROUND: The long non-coding (lnc) RNA activated by small nucleolar RNA host gene 16 (SNHG16), which has been reported to play a vital role in a number of different types of cancer, is a novel lncRNA. However, following an osteosarcoma (OS) study, the expression pattern, biological roles, clinical values and potential molecular mechanism of SNHG16 remain unclear. In the current study, we aimed to examine its expression and possible function in osteosarcoma (OS). METHOD: Cell proliferation was measured by colony formation assay and Cell Counting Kit-8 (CCK-8) in vitro, and xenograft transplantation assay in vivo. Meanwhile, we used transwell chambers to test cell migration and invasion was evaluated. Cell cycle and apoptosis was evaluated by flow cytometry assay. Immunoblotting and qPCR analysis was carried out to detect protein and gene expression, respectively. Luciferase reporter assay was used to predict the potential downstream genes. RESULTS: The present study demonstrated that SNHG16 is highly expressed in both the tissues of patients with OS, as well as OS cell lines, and its expression level was positively correlated with clinical stage and poor overall survival. Functional assays revealed that the depletion of SNHG16 inhibits OS growth, OS cell progression and promotes apoptosis both in vivo and in vitro. In addition, the present study revealed that microRNA-1285-3p expression levels can be decreased by SNHG16 acting as a 'sponge', and that this pathway takes part in OS tumor growth in vivo, and OS cell proliferation, invasion, migration and apoptosis in vitro. CONCLUSIONS: The results from the present study demonstrate the role of lncRNA SNHG16 in OS progression, which is SNHG16 might exert oncogenic role in osteosarcoma (OS) by acting as a ceRNA of miR-1285-3p, and it may become a novel target in OS therapy.


Assuntos
MicroRNAs/metabolismo , Osteossarcoma/genética , RNA Longo não Codificante/genética , Animais , Linhagem Celular Tumoral , Proliferação de Células , Progressão da Doença , Humanos , Masculino , Camundongos , Camundongos Nus , Transfecção
7.
Proc Natl Acad Sci U S A ; 115(23): 5878-5883, 2018 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-29784824

RESUMO

Nucleation and growth of hydrogen nanobubbles are key initial steps in electrochemical water splitting. These processes remain largely unexplored due to a lack of proper tools to probe the nanobubble's interfacial structure with sufficient spatial and temporal resolution. We report the use of superresolution microscopy to image transient formation and growth of single hydrogen nanobubbles at the electrode/solution interface during electrocatalytic water splitting. We found hydrogen nanobubbles can be generated even at very early stages in water electrolysis, i.e., ∼500 mV before reaching its thermodynamic reduction potential. The ability to image single nanobubbles on an electrode enabled us to observe in real time the process of hydrogen spillover from ultrathin gold nanocatalysts supported on indium-tin oxide.

8.
Anal Chem ; 92(5): 3682-3688, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32024359

RESUMO

In this work, we describe the preparation and use of a thin metal film modified Indium Tin Oxide (ITO) electrode as a highly conductive, transparent, and electrocatalytically active electrode material for studying nanobubbles generated at the electrode/solution interface. Hydrogen and oxygen nanobubbles were generated from water electrolysis on the surface of a Au/Pd alloy modified ITO electrode. The formation of single H2 and O2 nanobubbles was imaged in real time during a potential scan using single-molecule fluorescence microscopy. Our results show that while O2 nanobubbles can be detected at an early stage in the oxygen evolution reaction (OER), the formation of H2 nanobubbles requires a significant overpotential. Our study shows that thin-film-coated ITO electrodes are simple to make and can be useful electrode substrates for (single molecule) spectroelectrochemistry research.


Assuntos
Eletrólise , Hidrogênio/química , Microscopia de Fluorescência/métodos , Nanoestruturas/química , Oxigênio/química , Água/química , Eletrodos , Processamento de Imagem Assistida por Computador , Compostos de Estanho/química
9.
Med Sci Monit ; 26: e922777, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32506068

RESUMO

BACKGROUND Percutaneous endoscopic lumbar discectomy (PELD) has become one of the most popular minimally invasive surgeries for lumbar disc herniation (LDH), however, very highly migrated LDH is still a tricky issue for PELD. This study reported a new endoscopic discectomy strategy for the treatment of very highly migrated LDH between the L4/5 and L5/S1 level. MATERIAL AND METHODS The current study retrospectively analyzed 12 patients who accepted PELD for very highly migrated LDH between the L4/5 and L5/S1 level. Under local anesthesia, the transforaminal approach was chosen for the L4/5 level and the interlaminar approach was chosen for the L5/S1 level. The 10-point visual analogue scale (VAS) was used to assess back pain (VAS-Back) and leg pain (VAS-Leg). Oswestry disability index (ODI) and Modified Mac Nab Criteria were adopted as the functional evaluation methods. All patients were followed in the outpatient department for at least 12 months after their operation. RESULTS Our study showed that very highly migrated disc between L4/5 and L5/S1 level could be removed completely by this strategy. Except for 1 case of postoperative dysesthesia and 1 case of dural tear, no severe complication occurred. At the last follow-up, the average VAS-Back score of the study patients was reduced from 5.17±2.12 to 2.08±1.08 (P<0.05) and the average VAS-Leg score was reduced from 7.25±1.48 to 1.33±0.89 (P<0.05). The average ODI scores improved from 48.50±10.59 to 13.00±2.76 (P<0.05). According to the Modified Mac Nab Criteria, 83.33% of patients (10 out of 12 patients) received an excellent or good recovery and no poor result was reported. No recurrence was observed during follow up. CONCLUSIONS PELD via a transforaminal and interlaminar combined approach provides an alternative option for select patients with very highly migrated LDH between the L4/5 and L5/S1 level.


Assuntos
Discotomia Percutânea/métodos , Deslocamento do Disco Intervertebral/cirurgia , Adulto , Idoso , China , Discotomia/métodos , Endoscopia/métodos , Feminino , Humanos , Degeneração do Disco Intervertebral/cirurgia , Vértebras Lombares/cirurgia , Região Lombossacral/cirurgia , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos , Dor , Medição da Dor , Período Pós-Operatório , Recidiva , Estudos Retrospectivos , Escala Visual Analógica
10.
J Cell Mol Med ; 23(10): 6679-6689, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31338931

RESUMO

Disc degeneration is a common clinical condition in which damaged discs cause chronic pain; however, a laboratory diagnosis method for its detection is not available. As circulating miRNAs have potential as biomarkers, their application in disc degeneration has not been explored. Here, we prepared serum miRNAs from a mouse disc degeneration model and performed miRNA-Seq and quantitative PCR to characterize disc degeneration-associated miRNAs. We identified three miRNAs, including miR-26a-5p, miR-122-5p and miR-215-5p, undergoing perturbation during the pathogenesis of disc degeneration. Specifically, the levels of miR-26a-5p in the serum demonstrated steady increases in the model of disc degeneration, compared with those in the pre-injury samples of younger age or compared with normal controls of the same age but without disc degeneration, whereas the miRNAs miR-122-5p and miR-215-5p exhibited lower expression in post-injury samples than in their counterparts without the surgery. Moreover, we found that miR-26a-5p targets Smad1 expression, and Smad1 negatively regulates Vegfa expression in disc cells, and thus, miR-26a-5p promotes disc degeneration. In summary, we established a method that consistently profiles circulating miRNAs and identified multiple miRNAs as promising biomarkers for disc degeneration, among which miR-26a-5p enhances VEGF expression during disc degeneration through targeting Smad1 signalling.


Assuntos
Degeneração do Disco Intervertebral/metabolismo , MicroRNAs/sangue , Proteína Smad1/metabolismo , Animais , Biomarcadores/sangue , Células Cultivadas , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Homeostase/genética , Degeneração do Disco Intervertebral/diagnóstico , Degeneração do Disco Intervertebral/diagnóstico por imagem , Degeneração do Disco Intervertebral/genética , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , RNA-Seq , Proteína Smad1/genética , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
11.
J Cell Physiol ; 234(5): 6679-6687, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30341902

RESUMO

Runx2 plays an essential role in embryonic disc tissue development in mice. However, the role of runt-related transcription factor 2 (Runx2) in postnatal disc tissue growth and development has not been defined. In the present studies, we generated Runx2 conditional knockout (KO) mice (Runx2Agc1ER ), in which Runx2 was deleted in Aggrecan-expressing cells in disc tissue at postnatal 2-weeks of age. We then analyzed changes in disc tissue growth and development using histology and immunohistochemical methods in 3-month-old mice. We found that large vacuolated notochordal cells were accumulated in the nucleus pulposus (NP) in Runx2 KO mice. The growth plate cartilage tissue in the disc was thicker in Runx2 KO mice. We also found a significant upregulation of Indian hedgehog (Ihh) expression in the cells in NP cells and in annulus fibrosus cells of Runx2 KO mice. These results demonstrated that Runx2 may play an important role in postnatal disc tissue development through interacting with Ihh signaling.


Assuntos
Anel Fibroso/crescimento & desenvolvimento , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Degeneração do Disco Intervertebral/patologia , Disco Intervertebral/crescimento & desenvolvimento , Animais , Diferenciação Celular/fisiologia , Células Cultivadas , Condrócitos/metabolismo , Lâmina de Crescimento/metabolismo , Proteínas Hedgehog/metabolismo , Disco Intervertebral/patologia , Camundongos Transgênicos , Núcleo Pulposo/patologia
12.
Ann Rheum Dis ; 78(5): 676-682, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30842121

RESUMO

OBJECTIVES: Osteoarthritis (OA) is a painful and debilitating disease and it is associated with aberrant upregulation of multiple factors, including matrix metalloproteinase 13 (MMP13), interleukin-1ß (IL-1ß) and nerve growth factor (NGF). In this study, we aimed to use the CRISPR/Cas9 technology, a highly efficient gene-editing tool, to study whether the ablation of OA-associated genes has OA-modifying effects. METHODS: We performed intra-articular injection of adeno-associated virus, which expressed CRISPR/Cas9 components to target each of the genes encoding MMP13, IL-1ß and NGF, in a surgically induced OA mouse model. We also tested triple ablations of NGF, MMP13 and IL-1ß. RESULTS: Loss-of-function of NGF palliates pain but worsens joint damage in the surgically induced OA model. Ablation of MMP13 or IL-1ß reduces the expression of cartilage-degrading enzymes and attenuates structural deterioration. Targeting both MMP13 and IL-1ß significantly mitigates the adverse effects of NGF blockade on the joints. CONCLUSIONS: CRISPR-mediated ablation of NGF alleviates OA pain, and deletion of MMP13-1ß or IL-1ß attenuates structural damage in a post-traumatic OA model. Multiplex ablations of NGF, MMP13 and IL-1ß provide benefits on both pain management and joint structure maintenance. Our results suggest that CRISPR-based gene editing is useful for the identification of promising drug targets and the development of feasible therapeutic strategies for OA treatment.


Assuntos
Proteína 9 Associada à CRISPR/genética , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , Osteoartrite/genética , Osteoartrite/terapia , Animais , Modelos Animais de Doenças , Interleucina-1beta/metabolismo , Metaloproteinase 13 da Matriz/metabolismo , Camundongos , Fator de Crescimento Neural/metabolismo , Osteoartrite/etiologia
13.
Bioconjug Chem ; 30(2): 284-292, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30543405

RESUMO

The rapid developments of gene therapy are benefit from the construction of efficient gene vectors, which help therapy genes efficiently overcome the barriers in the transport and transfection. Condensing DNA into nanoparticles is a crucial role in gene transfection, and the electrostatic interactions of synthetic cationic liposomes and cationic polymers with DNA are generally used for condensing DNA. Recent research has shown that the introduction of the hydrophobic interaction, hydrogen bonding, and coordinative interactions to the gene delivery vectors is also very important for DNA condensation, delivery, and transfection. This review focuses on the four types of interactions in condensed DNA nanoparticles, which could provide a new perspective for improving gene transfection efficacy.


Assuntos
DNA/administração & dosagem , DNA/química , Técnicas de Transferência de Genes , Animais , Cátions/química , DNA/genética , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Lipossomos/química , Nanopartículas/química , Conformação de Ácido Nucleico , Polímeros/química , Eletricidade Estática , Transfecção/métodos
14.
Langmuir ; 35(22): 7180-7190, 2019 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-31074628

RESUMO

We report the observation of transient bipolar electrochemical coupling on freely moving 40 nm silver nanoparticles. The use of an asymmetric nanoelectrochemical environment at the nanopore orifice, for example, an acid inside the pipette and halide ions in the bulk, enabled us to observe unusually large current blockages of single Ag nanoparticles. We attribute these current blockages to the formation of H2 nanobubbles on the surface of Ag nanoparticles due to the coupled faradaic reactions, in which the reduction of protons and water is coupled to the oxidation of Ag and water under potentials higher than 1 V. The appearance of large current blockages was strongly dependent on the applied voltage and the choice of anions in the bulk solution. The correlation between large current blockages with the oxidation of Ag nanoparticles and their nanopore translocation was further supported by simultaneous fluorescence and electric recordings. This study demonstrates that transient bipolar electrochemistry can take place on small metal nanoparticles below 50 nm when they pass through nanopores where the electric field is highly localized. The use of a nanopore and the resistive-pulse sensing method to study transient bipolar electrochemistry of nanoparticles may be extended to future studies in ultrafast electrochemistry, nanocatalyst screening, and gas nucleation on nanoparticles.

15.
Anal Chem ; 90(23): 13837-13841, 2018 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-30426745

RESUMO

We report the use of a Pt bipolar electrochemical nanocell and fluorescence to detect single redox molecules. A Pt nanocell is formed by depositing a Pt particle at a nanopipet orifice which separates the inside pipet volume from the bulk solution. Highly fluorescent resorufin molecules are generated on the inner Pt surface and optically detected and counted due to unique properties of the nanocell. First, the pipet is horizontally positioned on a microscope allowing one to examine a 6-µm distance from the electrode/solution interface. Second, the resazurin/resorufin molecules are confined inside a 100 nm pipet resulting in a very high signal/background ratio in fluorescence detection. Third, the small pipet size confines the motion of the redox molecules increasing the probability of transient molecular adsorption on the quartz walls. This, along with the longer diffusion distance increases the chance of fluorescence detection. The ability to count single redox molecules allows us to estimate the detection efficiency. This study shows the unique power of fluorescence-based electrochemical detection in studying single redox events. Future use of this method may enable one to study single redox events of conventional nonfluorogenic redox reactions on the outer surface of the bipolar nanoelectrode, such as oxidation of H2 catalyzed by a metal cluster electrocatalyst or a single enzyme.

16.
J Am Chem Soc ; 139(35): 12274-12282, 2017 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-28799330

RESUMO

The electrochemical interface is an ultrathin interfacial region between the electrode surface and the electrolyte solution and is often characterized by numerous dynamic processes, such as solvation and desolvation, heterogeneous electron transfer, molecular adsorption and desorption, diffusion, and surface rearrangement. Many of these processes are driven and modulated by the presence of a large interfacial potential gradient. The study and better understanding of the electrochemical interface is important for designing better electrochemical systems where their applications may include batteries, fuel cells, electrocatalytic water splitting, corrosion protection, and electroplating. This, however, has proved to be a challenging analytical task due to the ultracompact and dynamic evolving nature of the electrochemical interface. Here, we describe the use of an electrochemical nanocell to image the dynamic collision and oxidation process of single silver nanoparticles at the surface of a platinum nanoelectrode. A nanocell is prepared by depositing a platinum nanoparticle at the tip of a quartz nanopipette forming a bipolar nanoelectrode. The compact size of the nanocell confines the motion of the silver nanoparticle in a 1-D space. The highly dynamic process of nanoparticle collision and oxidation is imaged by single-particle fluorescence microscopy. Our results demonstrate that silver nanoparticle collision and oxidation is highly dynamic and likely controlled by a strong electrostatic effect at the electrode/solution interface. We believe that the use of a platinum nanocell and single molecule/nanoparticle fluorescence microscopy can be extended to other systems to yield highly dynamic information about the electrochemical interface.


Assuntos
Eletrodos , Nanopartículas Metálicas/química , Prata/química , Soluções/química , Técnicas Eletroquímicas , Microscopia de Fluorescência
17.
J Am Chem Soc ; 139(8): 2964-2971, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28132499

RESUMO

Here we report the direct observation and quantitative analysis of single redox events on a modified indium-tin oxide (ITO) electrode. The key in the observation of single redox events are the use of a fluorogenic redox species and the nanoconfinement and hindered redox diffusion inside 3-nm-diameter silica nanochannels. A simple electrochemical process was used to grow an ultrathin silica film (∼100 nm) consisting of highly ordered parallel nanochannels exposing the electrode surface from the bottom. The electrode-supported 3-nm-diameter nanochannels temporally trap fluorescent resorufin molecules resulting in hindered molecular diffusion in the vicinity of the electrode surface. Adsorption, desorption, and heterogeneous redox events of individual resorufin molecules can be studied using total-internal reflection fluorescence (TIRF). The rate constants of adsorption and desorption processes of resorufin were characterized from single-molecule analysis to be (1.73 ± 0.08) × 10-4 cm·s-1 and 15.71 ± 0.76 s-1, respectively. The redox events of resorufin to the non-fluorescent dihydroresorufin were investigated by analyzing the change in surface population of single resorufin molecules with applied potential. The scan-rate-dependent molecular counting results (single-molecule fluorescence voltammetry) indicated a surface-controlled electrochemical kinetics of the resorufin reduction on the modified ITO electrode. This study demonstrates the great potential of mesoporous silica as a useful modification scheme for studying single redox events on a variety of transparent substrates such as ITO electrodes and gold or carbon film coated glass electrodes. The ability to electrochemically grow and transfer mesoporous silica films onto other substrates makes them an attractive material for future studies in spatial heterogeneity of electrocatalytic surfaces.


Assuntos
Técnicas Eletroquímicas , Índio/química , Dióxido de Silício/química , Compostos de Estanho/química , Eletrodos , Oxirredução , Tamanho da Partícula , Porosidade , Propriedades de Superfície
18.
Anal Chem ; 89(23): 12652-12658, 2017 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-29111678

RESUMO

In this Technical Note, we describe a method to fabricate nanopore-supported Pt nanoparticle electrodes and their use in bipolar electrochemistry. A Pt nanoparticle is deposited on the orifice of a solid-state nanopore inside a focused-ion beam (FIB) system. Complete blockage of the nanopore with Pt metal forms a closed bipolar nanoparticle electrode whose size and shape can be tunable in one simple step. Nanoparticle electrodes and their arrays can be prepared on different substrates such as the tip of a glass pipet, a double-barrel pipet, and a freestanding silicon nitride membrane. Steady-state voltammetry can be performed on such nanoparticle electrodes via bipolar electrochemistry. Moreover, an array of Pt nanoparticles can be used for fluorescence-enabled electrochemical microscopy. Future use of highly advanced FIB systems may allow nanoparticles of <10 nm to be fabricated which may enable coupled electrochemical reactions of single redox molecules. Pipette-supported single particle electrodes may also find useful applications in high resolution imaging with nanoscale scanning electrochemical microscopy (SECM) and neurochemical analysis inside single cells.


Assuntos
Eletroquímica/instrumentação , Eletrodos , Nanopartículas Metálicas/química , Platina/química , Eletroquímica/métodos , Fluorescência , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Nanoporos , Oxazinas/química
19.
Int Orthop ; 41(2): 323-332, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27591770

RESUMO

PURPOSE: Beginners usually need increased punctures and dozens of fluoroscopy in learning transforamimal percutaneous endoscopic lumbar discectomy (tPELD). Navigator-assisted spinal surgery (NASS) is a novel technique that could induce a definite trajectory. The retrospective study aimed to investigate the impact of a definite trajectory on the learning curve of tPELD. METHODS: A total of 120 patients with symptomatic lumbar disc herniation who received tPELD between 2012 and 2014. Patients receiving tPELD with NASS technique by one surgeon were regarded as group A, and those receiving conventional methods by another surgeon were regarded as group B. Each group was divided into three subgroups (case 1-20, case 21-40, case 41-60). RESULTS: The fluoroscopy times were 22.62 ± 3.80 in group A and 34.32 ± 4.78 in group B (P < 0.001). The pre-operative location time was 3.56 ± 0.60 minutes in group A and 5.49 ± 1.48 minutes in group B (P < 0.001). The puncture-channel time was 21.85 ± 4.31 minutes in group A and 34.20 ± 8.88 minutes in group B (P < 0.001). The operation time was 84.62 ± 9.20 minutes in group A and 101.97 ± 14.92 minutes in group B (P < 0.001), and the learning curve of tPELD in group A was steeper than that in group B. No significant differences were detected in patient-reported outcomes, hospital stay, patient satisfaction, and complication rate between the two groups (p > 0.05). CONCLUSIONS: Definite trajectory significantly reduced the operation time, preoperative location time, puncture-channel time, and fluoroscopy times of tPELD by beginners, and thus reshaped the learning curve of tPELD and minimized the radiation exposure.


Assuntos
Discotomia Percutânea/métodos , Deslocamento do Disco Intervertebral/cirurgia , Curva de Aprendizado , Vértebras Lombares/cirurgia , Adulto , Discotomia Percutânea/estatística & dados numéricos , Endoscopia/métodos , Endoscopia/estatística & dados numéricos , Feminino , Fluoroscopia/estatística & dados numéricos , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Estudos Retrospectivos
20.
Analyst ; 141(19): 5474-87, 2016 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-27510555

RESUMO

Nanoelectrodes have key advantages compared to electrodes of conventional size and are the tool of choice for numerous applications in both fundamental electrochemistry research and bioelectrochemical analysis. This Minireview summarizes recent advances in the development, characterization, and use of nanoelectrodes in nanoscale electroanalytical chemistry. Methods of nanoelectrode preparation include laser-pulled glass-sealed metal nanoelectrodes, mass-produced nanoelectrodes, carbon nanotube based and carbon-filled nanopipettes, and tunneling nanoelectrodes. Several new topics of their recent application are covered, which include the use of nanoelectrodes for electrochemical imaging at ultrahigh spatial resolution, imaging with nanoelectrodes and nanopipettes, electrochemical analysis of single cells, single enzymes, and single nanoparticles, and the use of nanoelectrodes to understand single nanobubbles.


Assuntos
Técnicas Eletroquímicas , Eletrodos , Nanotecnologia , Enzimas/análise , Vidro , Nanopartículas , Nanotubos de Carbono , Análise de Célula Única
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