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1.
Curr Issues Mol Biol ; 45(11): 9103-9116, 2023 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-37998748

RESUMEN

Although the efficiency of cloning remains very low, this technique has become the most reliable way to produce transgenic pigs. However, the high rate of abnormal offspring such as an enlarged tongue lowers the cloning efficiency by reducing the early survivability of piglets. Thus, the present study was conducted to identify the characteristics of the enlarged tongue from cloned piglets by histologic and transcriptomic analysis. As a result, it was observed that the tissues from enlarged tongues (n = 3) showed isolated and broken muscle bundles with wide spaces while the tissues from normal tongues (n = 3) showed the tight connection of muscle bundles without space by histological analysis. Additionally, transmission electron microscopy results also showed the formation of isolated and broken muscle bundles in enlarged tongues. The transcriptome analysis showed a total of 197 upregulated and 139 downregulated genes with more than 2-fold changes in enlarged tongues. Moreover, there was clear evidence for the difference between groups in the muscle system process with high relation in the biological process by gene ontology analysis. The analysis of the Kyoto Encyclopedia of Gene and Genomes pathway of differentially expressed genes indicated that the pentose phosphate pathway, glycolysis/gluconeogenesis, and glucagon signaling pathway were also involved. Conclusively, our results could suggest that the abnormal glycolytic regulation may result in the formation of an enlarged tongue. These findings might have the potential to understand the underlying mechanisms, abnormal development, and disease diagnosis in cloned pigs.

2.
Blood ; 138(16): 1465-1480, 2021 10 21.
Artículo en Inglés | MEDLINE | ID: mdl-34077953

RESUMEN

B- and T-cell acute lymphoblastic leukemia (B/T-ALL) may be refractory or recur after therapy by suppressing host anticancer immune surveillance mediated specifically by natural killer (NK) cells. We delineated the phenotypic and functional defects in NK cells from high-risk patients with B/T-ALL using mass cytometry, flow cytometry, and in silico cytometry, with the goal of further elucidating the role of NK cells in sustaining acute lymphoblastic leukemia (ALL) regression. We found that, compared with their normal counterparts, NK cells from patients with B/T-ALL are less cytotoxic but exhibit an activated signature that is characterized by high CD56, high CD69, production of activated NK cell-origin cytokines, and calcium (Ca2+) signaling. We demonstrated that defective maturation of NK cells into cytotoxic effectors prevents NK cells from ALL from lysing NK cell-sensitive targets as efficiently as do normal NK cells. Additionally, we showed that NK cells in ALL are exhausted, which is likely caused by their chronic activation. We found that increased frequencies of activated cytokine-producing NK cells are associated with increased disease severity and independently predict poor clinical outcome in patients with ALL. Our studies highlight the benefits of developing NK cell profiling as a diagnostic tool to predict clinical outcome in patients with ALL and underscore the clinical potential of allogeneic NK cell infusions to prevent ALL recurrence.


Asunto(s)
Células Asesinas Naturales/inmunología , Activación de Linfocitos , Leucemia-Linfoma Linfoblástico de Células Precursoras/inmunología , Antígenos CD/inmunología , Antígenos de Diferenciación de Linfocitos T/inmunología , Antígeno CD56/inmunología , Células Cultivadas , Citocinas/inmunología , Citotoxicidad Inmunológica , Humanos , Lectinas Tipo C/inmunología , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Pronóstico
3.
Inorg Chem ; 62(15): 6065-6075, 2023 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-37000130

RESUMEN

A silicoaluminophosphate molecular sieve, CIT-16P, is synthesized using butane-1,4-bis(quinuclidinium) [(C7H13N)-(CH2)4-(NC7H13)]2+ dihydroxide (DiQ-C4-(OH)2) as an organic structure-directing agent (OSDA). Upon the removal of the OSDA, either by thermal treatment in air at temperatures exceeding 490 °C or by extended ozone treatment at 150 °C, CIT-16P transforms to SAPO-17 (ERI topology). The structure solution of CIT-16P in its as-synthesized form is obtained using a Rietveld refinement of the powder X-ray diffraction pattern. The primary composite building units (CBUs) of CIT-16P are highly distorted cancrinite (can) CBUs that transform into stable can units of the ERI-type framework as a result of the OSDA removal. The distortion of can CBU is maintained without transformation by the presence of tightly bound DiQ-C4 dications in the as-synthesized form of CIT-16P. The transformed material is characterized and evaluated as a catalyst in the methanol-to-olefins (MTO) reaction. The catalytic behavior of the formed SAPO-17 (Si/T-atom = 0.022) (T = Si + Al + P) at 400 °C and WHSV of 1.3 h-1 produces elevated C3+ olefin products (i.e., propylene, butenes, and pentenes) in early stages of the reaction. However, as the reaction proceeds, the C3+ fraction decreases in favor of more ethylene.

4.
Zygote ; 31(4): 380-385, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37212055

RESUMEN

In this study, we built on our previous research that discovered that autophagy activated the metaphase I stage during porcine oocytes in vitro maturation. We investigated the relationship between autophagy and oocyte maturation. First, we confirmed whether autophagy was activated differently by different media (TCM199 and NCSU-23) during maturation. Then, we investigated whether oocyte maturation affected autophagic activation. In addition, we examined whether the inhibition of autophagy affected the nuclear maturation rate of porcine oocytes. As for the main experiment, we measured LC3-II levels using western blotting after inhibition of nuclear maturation via cAMP treatment in an in vitro culture to clarify whether nuclear maturation affected autophagy. After autophagy inhibition, we also counted matured oocytes by treating them with wortmannin or a E64d and pepstatin A mixture. Both groups, which had different treatment times of cAMP, showed the same levels of LC3-II, while the maturation rates were about four times higher after cAMP 22 h treatment than that of the 42 h treatment group. This indicated that neither cAMP nor nuclear status affected autophagy. Autophagy inhibition during in vitro oocyte maturation with wortmannin treatment reduced oocyte maturation rates by about half, while autophagy inhibition by the E64d and pepstatin A mixture treatment did not significantly affect the oocyte maturation. Therefore, wortmannin itself, or the autophagy induction step, but not the degradation step, is involved in the oocyte maturation of porcine oocytes. Overall, we propose that oocyte maturation does not stand upstream of autophagy activation, but autophagy may exist upstream of oocyte maturation.


Asunto(s)
Técnicas de Maduración In Vitro de los Oocitos , Oocitos , Animales , Porcinos , Wortmanina/farmacología , Wortmanina/metabolismo , Oocitos/fisiología , Metafase , Autofagia
5.
Analyst ; 147(19): 4285-4292, 2022 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-36000247

RESUMEN

Most spectral data, such as those obtained via infrared, Raman, and mass spectroscopy, have baseline drifts due to fluorescence or other reasons, which have an adverse impact on subsequent analyses. Therefore, several researchers have proposed the use of various baseline-correction methods to address the aforementioned issue. However, most baseline-correction methods require manual adjustment of the parameters to achieve desirable performance. In this study, we propose a baseline-correction method based on a deep-learning model that combines ResNet and UNet. The method uses a deep-learning model trained with simulated spectral data to perform baseline corrections and eliminates the need for manual parameter adjustments. Based on the results of the qualitative and quantitative analyses of the simulated spectral data and actual Raman spectra, the proposed method is easier to apply and has better performance compared to the existing methods. As the proposed method can be applied to Raman spectra and other spectra, it is expected to be widely used.

6.
Nature ; 535(7610): 131-5, 2016 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-27362224

RESUMEN

Three-dimensional graphene architectures with periodic nanopores­reminiscent of zeolite frameworks­are of topical interest because of the possibility of combining the characteristics of graphene with a three-dimensional porous structure. Lately, the synthesis of such carbons has been approached by using zeolites as templates and small hydrocarbon molecules that can enter the narrow pore apertures. However, pyrolytic carbonization of the hydrocarbons (a necessary step in generating pure carbon) requires high temperatures and results in non-selective carbon deposition outside the pores. Here, we demonstrate that lanthanum ions embedded in zeolite pores can lower the temperature required for the carbonization of ethylene or acetylene. In this way, a graphene-like carbon structure can be selectively formed inside the zeolite template, without carbon being deposited at the external surfaces. X-ray diffraction data from zeolite single crystals after carbonization indicate that electron densities corresponding to carbon atoms are generated along the walls of the zeolite pores. After the zeolite template is removed, the carbon framework exhibits an electrical conductivity that is two orders of magnitude higher than that of amorphous mesoporous carbon. Lanthanum catalysis allows a carbon framework to form in zeolite pores with diameters of less than 1 nanometre; as such, microporous carbon nanostructures can be reproduced with various topologies corresponding to different zeolite pore sizes and shapes. We demonstrate carbon synthesis for large-pore zeolites (FAU, EMT and beta), a one-dimensional medium-pore zeolite (LTL), and even small-pore zeolites (MFI and LTA). The catalytic effect is a common feature of lanthanum, yttrium and calcium, which are all carbide-forming metal elements. We also show that the synthesis can be readily scaled up, which will be important for practical applications such as the production of lithium-ion batteries and zeolite-like catalyst supports.

7.
Sensors (Basel) ; 22(2)2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-35062462

RESUMEN

Spinal cord stimulation is a therapy to treat the severe neuropathic pain by suppressing the pain signal via electrical stimulation of the spinal cord. The conventional metal packaged and battery-operated implantable pulse generator (IPG) produces electrical pulses to stimulate the spinal cord. Despite its stable operation after implantation, the implantation site is limited due to its bulky size and heavy weight. Wireless communications including wireless power charging is also restricted, which is mainly attributed to the electromagnetic shielding of the metal package. To overcome these limitations, here, we developed a fully implantable miniaturized spinal cord stimulator based on a biocompatible liquid crystal polymer (LCP). The fabrication of electrode arrays in the LCP substrate and monolithically encapsulating the circuitries using LCP packaging reduces the weight (0.4 g) and the size (the width, length, and thickness are 25.3, 9.3, and 1.9 mm, respectively). An inductive link was utilized to wirelessly transfer the power and the data to implanted circuitries to generate the stimulus pulse. Prior to implantation of the device, operation of the pulse generator was evaluated, and characteristics of stimulation electrode such as an electrochemical impedance spectroscopy (EIS) were measured. The LCP-based spinal cord stimulator was implanted into the spared nerve injury rat model. The degree of pain suppression upon spinal cord stimulation was assessed via the Von Frey test where the mechanical stimulation threshold was evaluated by monitoring the paw withdrawal responses. With no spinal cord stimulation, the mechanical stimulation threshold was observed as 1.47 ± 0.623 g, whereas the stimulation threshold was increased to 12.7 ± 4.00 g after spinal cord stimulation, confirming the efficacy of pain suppression via electrical stimulation of the spinal cord. This LCP-based spinal cord stimulator opens new avenues for the development of a miniaturized but still effective spinal cord stimulator.


Asunto(s)
Terapia por Estimulación Eléctrica , Estimulación de la Médula Espinal , Animales , Electrodos Implantados , Dolor , Polímeros , Ratas , Médula Espinal
8.
Sensors (Basel) ; 22(12)2022 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-35746337

RESUMEN

This paper presents an on-chip implementation of an analog processor-in-memory (PIM)-based convolutional neural network (CNN) in a biosensor. The operator was designed with low power to implement CNN as an on-chip device on the biosensor, which consists of plates of 32 × 32 material. In this paper, 10T SRAM-based analog PIM, which performs multiple and average (MAV) operations with multiplication and accumulation (MAC), is used as a filter to implement CNN at low power. PIM proceeds with MAV operations, with feature extraction as a filter, using an analog method. To prepare the input feature, an input matrix is formed by scanning a 32 × 32 biosensor based on a digital controller operating at 32 MHz frequency. Memory reuse techniques were applied to the analog SRAM filter, which is the core of low power implementation, and in order to accurately grasp the MAC operational efficiency and classification, we modeled and trained numerous input features based on biosignal data, confirming the classification. When the learned weight data was input, 19 mW of power was consumed during analog-based MAC operation. The implementation showed an energy efficiency of 5.38 TOPS/W and was differentiated through the implementation of 8 bits of high resolution in the 180 nm CMOS process.


Asunto(s)
Técnicas Biosensibles , Redes Neurales de la Computación , Aprendizaje
9.
J Am Chem Soc ; 143(2): 925-933, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33410693

RESUMEN

Electrocatalytic conversion of CO2 into value-added products offers a new paradigm for a sustainable carbon economy. For active CO2 electrolysis, the single-atom Ni catalyst has been proposed as promising from experiments, but an idealized Ni-N4 site shows an unfavorable energetics from theory, leading to many debates on the chemical nature responsible for high activity. To resolve this conundrum, here we investigated CO2 electrolysis of Ni sites with well-defined coordination, tetraphenylporphyrin (N4-TPP) and 21-oxatetraphenylporphyrin (N3O-TPP). Advanced spectroscopic and computational studies revealed that the broken ligand-field symmetry is the key for active CO2 electrolysis, which subordinates an increase in the Ni redox potential yielding NiI. Along with their importance in activity, ligand-field symmetry and strength are directly related to the stability of the Ni center. This suggests the next quest for an activity-stability map in the domain of ligand-field strength, toward a rational ligand-field engineering of single-atom Ni catalysts for efficient CO2 electrolysis.

10.
Arch Microbiol ; 203(2): 847-853, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33068123

RESUMEN

Probiotics are defined as live microorganisms that when administered in an appropriate amount, provide health benefits to the host. This study aimed to evaluate the effect of the oral administration of Lactobacillus salivarius (L. salivarius) on growth performance, immunological responses, fecal microbial flora and intestinal mucosal morphology in chickens. Chickens were fed with 109 colony-forming units (CFUs) of wild-type (WT) L. salivarius or phosphate-buffered saline (PBS) for 5 weeks. Chickens body weight was significantly increased by administration of L. salivarius groups compared than control group. The microbial taxonomy in the small intestine and cecum was identified via the chicken feces sample. A total of 286,331 bacterial species were obtained from the chicken fecal samples in overall experimental group. From these, 145,012 bacterial species were obtained from oral administration of L. salivarius treatment group, while 141,319 bacterial species were obtained from control group. Almost 98% of all 16S rRNA sequences from the chicken fecal sample of the two groups were classified into known phyla. Firmicutes, Cyanobacteria, Proteobacteria, Bacteroidetes and Actinobacteria were highly abundant in both groups. Compared with the control birds, the chickens orally administered L. salivarius showed no significant differences in villus length and crypt length. Serum concentrations of the cytokines IL-8, TNF-α, IFN-γ, and IL-4 were markedly reduced in the L. salivarius group. In summary, our findings reveal that L. salivarius can act as a potential probiotic to improve performance and overall gut health in of chickens.


Asunto(s)
Pollos , Heces/microbiología , Ligilactobacillus salivarius/inmunología , Animales , Bacterias/genética , Biodiversidad , Pollos/crecimiento & desarrollo , Pollos/inmunología , Pollos/microbiología , Citocinas/sangre , Mucosa Intestinal/citología , Microbiota , Probióticos/administración & dosificación , ARN Ribosómico 16S/genética
11.
Angew Chem Int Ed Engl ; 60(42): 22769-22775, 2021 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-34180114

RESUMEN

The analogy between single-atom catalysts (SACs) and molecular catalysts predicts that the specific catalytic activity of these systems is constant. We provide evidence that this prediction is not necessarily true. As a case in point, we show that the specific activity over ceria-supported single Pd atoms linearly increases with metal atom density, originating from the cumulative enhancement of CeO2 reducibility. The long-range electrostatic footprints (≈1.5 nm) around each Pd site overlap with each other as surface Pd density increases, resulting in an observed deviation from constant specific activity. These cooperative effects exhaust previously active O atoms above a certain Pd density, leading to their permanent removal and a consequent drop in reaction rate. The findings of our combined experimental and computational study show that the specific catalytic activity of reducible oxide-supported single-atom catalysts can be tuned by varying the surface density of single metal atoms.

12.
Anal Chem ; 92(15): 10291-10299, 2020 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-32493007

RESUMEN

The recognition capability of the identification system using Raman spectroscopy is increasing with the demands in the field. Among the various approaches that determine the identity of a target, signal correlation using a moving window is one of the most effective and intuitive methods. In this paper, we report a new correlation method that is robust to spectral intensity variations. Using the peak distribution of a given spectrum, this method adaptively determines meaningful spectral regions for the identification target. Three commercial Raman spectrometer and a 14 033 library were included in the study, which was used for a library-based chemical discrimination test and mixed material analysis experiments. According to the identification experimental results, the proposed method correctly identified all of the spectra and maintained a mean correlation score above 0.95 while maintaining the correlation score of nontarget materials as low as possible.

13.
J Org Chem ; 85(23): 15082-15091, 2020 12 04.
Artículo en Inglés | MEDLINE | ID: mdl-33151070

RESUMEN

A novel polyheterocyclic chemical space, 6H-furo[3,2-f]pyrrolo[1,2-d][1,4]diazepine, was generated by a one-pot four-component coupling reaction where multiple bonds (three C-C, one C-O, and one C-N) were formed through a domino sequence. Two heterocyclic rings (furan and diazepine) were sequentially constructed from the monocyclic pyrrole derivative under environment-friendly reaction conditions to furnish the tricyclic fused scaffold.

14.
BMC Vet Res ; 16(1): 273, 2020 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-32762754

RESUMEN

BACKGROUND: The 3D8 single chain variable fragment (scFv) is a mini-antibody sequence that exhibits independent nuclease activity against all types of nucleic acids. In this research, crossing a 3D8 scFv G1 transgenic rooster with wild-type hens produced 3D8 scFv G2 transgenic chickens to evaluate suppression of viral transmission. RESULT: The transgenic chickens were identified using genomic PCR and immunohistochemistry. To evaluate Newcastle disease virus (NDV) protection conferred by 3D8 scFv expression, transgenic, non-transgenic, and specific pathogen-free (SPF) chickens were challenged with virulent NDV by direct injection or aerosol exposure. The three groups of chickens showed no significant differences (p < 0.05) in mean death time after being directly challenged with NDV; however, in contrast to chickens in the non-transgenic and SPF groups, chickens in the transgenic group survived after aerosol exposure. Although the transgenic chickens did not survive after direct challenge, we found that the chickens expressing the 3D8 scFv survived aerosol exposure to NDV. CONCLUSIONS: Our finding suggest that the 3D8 scFv could be a useful tool to prevent chickens from spreading NDV and control virus transmission.


Asunto(s)
Pollos/genética , Enfermedad de Newcastle/transmisión , Virus de la Enfermedad de Newcastle/fisiología , Enfermedades de las Aves de Corral/virología , Animales , Animales Modificados Genéticamente , Pollos/inmunología , Femenino , Masculino , Enfermedad de Newcastle/virología , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/transmisión , Anticuerpos de Cadena Única , Organismos Libres de Patógenos Específicos
15.
J Artif Organs ; 23(3): 262-269, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32342231

RESUMEN

An active intraocular prosthesis is herein proposed as a new image acquisition device for a cortical visual prosthesis. A conventional intraocular prosthesis is a passive device that helps blind patients underwent eye enucleation to maintain the shape of an eyeball. In contrast, an active intraocular prosthesis, which works as an implantable wireless camera, can capture real-time images and transmit them to a cortical visual prosthesis to restore partial vision of the patients. This active device has distinct advantages in that it can garner a variety of image information while focusing on objects in accordance with natural eye movements, compared with a glasses-mounted camera and implanted micro-photodiodes in typical artificial vision systems. Coated with an epoxy and sealed by an elastomer for biocompatibility as well as durability, the active intraocular prosthesis was fabricated in a spherical form miniaturized enough to be inserted into the eye. Its operation was evaluated by wireless image acquisition displaying a processed gray-scale image. Furthermore, signal-to-noise ratio measurements were conducted to find a reliable communication range of the fabricated prosthesis, while it was covered by an 8-mm-thick biological medium that mimicked in vivo environments. In conclusion, the feasibility of the active intraocular prosthesis to cooperate with a cortical visual prosthesis is discussed.


Asunto(s)
Ceguera/terapia , Diseño de Prótesis , Prótesis Visuales , Humanos , Implantación de Prótesis
16.
Neurosurg Focus ; 49(1): E10, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32610289

RESUMEN

OBJECTIVE: The authors' goal was to study avian motor brain mapping via wireless stimulation to induce certain behaviors. In this paper, the authors propose an electrode design that is suitable for avian brain stimulation as well as a stereotactic implant procedure for the proposed electrode. METHODS: An appropriate breed for avian brain study was chosen. A fully implantable remote-controlled electrical stimulation system was inserted to minimize discomfort. A suitable electrode design and stereotactic surgery method based on the electrode design were investigated. RESULTS: Using a wireless stimulation system, flapping and rotation behaviors were induced by stimulating the ventral part of the nucleus intercollicularis and formatio reticularis medialis mesencephali both on the ground and during flight. CONCLUSIONS: The authors were able to implant the entire brain stimulation system inside the avian body without any surgical complications. Postoperative observations suggested that the bird did not find the implant uncomfortable.


Asunto(s)
Encéfalo/fisiología , Encéfalo/cirugía , Estimulación Encefálica Profunda , Técnicas Estereotáxicas , Animales , Aves , Mapeo Encefálico/métodos , Estimulación Encefálica Profunda/métodos , Estimulación Eléctrica/métodos , Electrodos Implantados , Humanos , Imagenología Tridimensional
17.
Bioconjug Chem ; 30(6): 1642-1648, 2019 06 19.
Artículo en Inglés | MEDLINE | ID: mdl-31180651

RESUMEN

Because mitochondria are essential organelles for regulating energy homeostasis and intrinsic apoptosis, the perturbation of mitochondrial functions has been considered as an anticancer treatment. In this study, a new near-infrared (NIR) fluorescent probe, SiR-Mito11 was developed as a theragnostic agent for brain tumor by targeting mitochondria. SiR-Mito11 exhibited potential anticancer activity against glioma cells but tolerance in normal neuronal cells. We further confirmed that the selective accumulation of SiR-Mito11 in glioma cells disrupted mitochondria membrane potential, followed by apoptotic cell death.


Asunto(s)
Neoplasias Encefálicas/metabolismo , Colorantes Fluorescentes/metabolismo , Glioma/metabolismo , Mitocondrias/metabolismo , Espectroscopía Infrarroja Corta/métodos , Nanomedicina Teranóstica , Apoptosis , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Glioma/patología , Humanos , Potencial de la Membrana Mitocondrial
18.
Bioconjug Chem ; 30(1): 210-217, 2019 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-30562008

RESUMEN

Herein, we developed a near-infrared (NIR) fluorescent probe for mitochondrial staining based on the NIR fluorochrome, silicon-rhodamine. The hydrophobicity of the fluorescent core was systematically modified by conjugation with 10 different commercial amines. The resulting fluorescent compounds exhibited similar photophysical properties but diverse hydrophobicity. We identified the optimal level of hydrophobicity associated with high mitochondrial targeting efficiency. In particular, the SiR-Mito 8 probe provided excellent mitochondrial staining and successfully differentiated the live Hep3B cancer cells from normal L02 cells in vitro.


Asunto(s)
Colorantes Fluorescentes/farmacología , Mitocondrias/efectos de los fármacos , Animales , Línea Celular , Línea Celular Tumoral , Colorantes Fluorescentes/química , Células HeLa , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Ratones , Imagen Óptica , Células RAW 264.7 , Rodaminas/química
19.
Biomed Microdevices ; 21(1): 27, 2019 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-30847585

RESUMEN

OBJECTIVE: It is known that the insertion of the intracochlear electrode is critical procedure because the damage around cochlear structures can deteriorate hearing restoration. To reduce the trauma during the electrode insertion surgery, we developed a thin and flexible intracochlear electrode array constructed with carbon nanotube (CNT) bundles. METHODS: Each CNT bundle was used for an individual electrode channel after coated with parylene C for insulation. By encapsulating eight CNT bundles with silicone elastomer, an 8-channel intracochlear electrode array was fabricated. The mechanical and electrochemical characteristics were assessed to evaluate the flexibility and feasibility of the electrode as a stimulation electrode. The functionality of the electrode was confirmed by electrically evoked auditory brainstem responses (eABR) recorded from a rat. RESULTS: The proposed electrode has a thickness of 135 µm at the apex and 395 µm at the base. It was demonstrated that the CNT bundle-based electrodes require 6-fold the lower insertion force than metal wire-based electrodes. The electrode impedance and the cathodic charge storage capacitance (CSCc) were 2.70 kΩ âˆ -20.4° at 1 kHz and - 708 mC/cm2, respectively. The eABR waves III and V were observed when stimulation current is greater than 50 µA. CONCLUSION: A thin and flexible CNT bundle-based intracochlear electrode array was successfully developed. The feasibility of the proposed electrode was shown in terms of mechanical and electrochemical characteristics. A proposed CNT bundle-based intracochlear electrode may reduce the risk of trauma during electrode insertion surgery.


Asunto(s)
Implantes Cocleares , Diseño de Equipo , Potenciales Evocados Auditivos del Tronco Encefálico , Nanotubos de Carbono , Animales , Implantación Coclear , Ratas , Ratas Sprague-Dawley
20.
Sensors (Basel) ; 19(5)2019 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-30832357

RESUMEN

Microfabrication technology for cortical interfaces has advanced rapidly over the past few decades for electrophysiological studies and neuroprosthetic devices offering the precise recording and stimulation of neural activity in the cortex. While various cortical microelectrode arrays have been extensively and successfully demonstrated in animal and clinical studies, there remains room for further improvement of the probe structure, materials, and fabrication technology, particularly for high-fidelity recording in chronic implantation. A variety of non-conventional probes featuring unique characteristics in their designs, materials and fabrication methods have been proposed to address the limitations of the conventional standard shank-type ("Utah-" or "Michigan-" type) devices. Such non-conventional probes include multi-sided arrays to avoid shielding and increase recording volumes, mesh- or thread-like arrays for minimized glial scarring and immune response, tube-type or cylindrical probes for three-dimensional (3D) recording and multi-modality, folded arrays for high conformability and 3D recording, self-softening or self-deployable probes for minimized tissue damage and extensions of the recording sites beyond gliosis, nanostructured probes to reduce the immune response, and cone-shaped electrodes for promoting tissue ingrowth and long-term recording stability. Herein, the recent progress with reference to the many different types of non-conventional arrays is reviewed while highlighting the challenges to be addressed and the microfabrication techniques necessary to implement such features.


Asunto(s)
Microelectrodos , Microtecnología/métodos , Neuronas/metabolismo , Animales , Diseño de Equipo , Humanos
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