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1.
Stem Cells Int ; 2019: 2631024, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31772586

RESUMO

Adipose-derived stem cells (ASCs) have become one of the most promising stem cell populations for cell-based therapies in regenerative medicine and for autoimmune disorders owing to their multilineage differentiation and immunomodulatory capacities, respectively. One advantage of ASC-based therapy lies in their immunosuppressive potential. However, how to get ASCs to provide consistent immunosuppression remains unclear. In the current study, we found that miR-129-5p was induced in ASCs treated with inflammatory factors. ASCs with miR-129-5p knockdown exhibited enhanced immunosuppressive capacity, as evidenced by reduced expression of proinflammatory factors, with concurrent increased expression of inducible nitric oxide synthases (iNOS) and nitric oxide (NO) production. These cells also had an increased capacity to inhibit T cell proliferation in vitro. ASCs with miR-129-5p knockdown alleviated inflammatory bowel diseases and promoted tumor growth in vivo. Consistently, ASCs that overexpressed miR-129-5p exhibited reduced iNOS expression. Furthermore, we show that miR-129-5p knockdown in ASCs results in hyperphosphorylation of signal transducer and activator of transcription 1 (Stat1). When fludarabine, an inhibitor of Stat1 activation, was added to ASCs with miR-129-5p knockdown, iNOS mRNA and protein levels were significantly reduced. Collectively, these results reveal a new role for miR-129-5p in regulating the immunomodulatory activities of ASCs by targeting Stat1 activation. These novel insights into the mechanisms of ASC immunoregulation may lead to the consistent production of ASCs with strong immunosuppressive functions and thus better clinical utility of these cells.

2.
Biomater Sci ; 7(11): 4636-4650, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31455969

RESUMO

The use of engineered cardiac tissues (ECTs) is a new strategy for the repair and replacement of cardiac tissues in patients with myocardial infarction, particularly at late stages. However, the mechanisms underlying the development of ECTs, including cell-scaffold interactions, are not fully understood, although they are closely related to their therapeutic effect. In the present study, we aimed to determine the cellular fate of cardiomyocytes in a 3D scaffold microenvironment, as well as their role in generating the cellular diversity of ECTs by single-cell sequencing analysis. Consistent with the observed plasticity of cardiomyocytes during cardiac regeneration, cardiomyocytes in 3D scaffolds appeared to dedifferentiate, showing an initial loss of normal cytoskeleton organization in the adaptive response to the new scaffold microenvironment. Cardiomyocytes undergoing this process regained their proliferation potential and gradually developed into myocardial cells at different developmental stages, generating heterogeneous regenerative ECTs. To better characterize the remodeled ECTs, high-throughput single-cell sequencing was performed. The ECTs contained a wide diversity of cells related to endogenous classes in the heart, including myocardial cells at different developmental stages and different kinds of interstitial cells. Non-cardiac cells seemed to play important roles in cardiac reconstruction, especially Cajal-like interstitial cells and macrophages. Altogether, our results showed for the first time that cells underwent adaptive dedifferentiation for survival in a 3D scaffold microenvironment to generate heterogeneous tissues. These findings provide an important basis for an improved understanding of the development and assembly of engineered tissues.

3.
Med Eng Phys ; 71: 91-97, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31311692

RESUMO

Microelectrode arrays (MEAs) allow the investigation of the pharmacological and toxicological effects of chemicals on cultured neuronal networks. Understanding the functional connections between neurons and the resulting neuronal networks is important for evaluating drugs that affect synaptic transmission. Therefore, we acutely treated a mature cultured neuronal network on MEAs with accumulating amounts of glutamate and recorded their altered electrophysiology. Subsequently, a cross-covariance analysis was applied to process the spiking activity in the network and to evaluate the connections between neurons. Finally, graph theory was used to assess the functional network properties under acute glutamate treatment. Our data demonstrated that glutamate increased the similarity, connectivity weight, density, and largest-component size of the functional network. In addition, the small-world network topology was altered after glutamate treatment. Our results indicate that the graph theory can advance our understanding of the pharmacological significance of neurotransmitters on neuronal networks.

4.
Med Sci Monit ; 25: 5299-5305, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31311916

RESUMO

BACKGROUND Acute respiratory distress syndrome (ARDS) is a common acute and severe disease in clinic. Recent studies indicated that Cxc chemokine ligand 5 (CXCL5), an inflammatory chemokine, was associated with tumorigenesis. The present study investigated the role of the CXCL5/Cxc chemokine receptor 2 (CXCR2) bio-axis in ARDS, and explored the underlying molecular mechanism. MATERIAL AND METHODS The pathological morphology of lung tissue and degree of pulmonary edema were assessed by hematoxylin-eosin staining and pulmonary edema score, respectively. Real-time PCR and Western blot analysis were performed to detect the expression levels of CXCL5, CXCR2, Matrix metalloproteinases 2 (MMP2), and Matrix metalloproteinases 9 (MMP9) in lung tissues. Enzyme-linked immunosorbent assay (ELISA) was performed to determine the expression levels of CXCL5 and inflammatory factors (IL-1ß, IL-6, TNF-alpha, and IL-10) in serum. RESULTS The results demonstrated that diffuse alveolar damage and pulmonary edema appeared in lipopolysaccharide (LPS)-induced ARDS and were positively correlated with the severity of ARDS. In addition, CXCL5 and its receptor CXCR2 were overexpressed by upregulation of MMP2 and MMP9 in lung tissues of ARDS. In addition, CXCL5 neutralizing antibody effectively alleviated inflammatory response, diffuse alveolar damage, and pulmonary edema, and decreased the expression levels of MMP2 and MMP9 compared to LPS-induced ARDS. CONCLUSIONS We found that CXCL5/CXCR2 accelerated the progression of ARDS, partly by upregulation of MMP2 and MMP9 in lung tissues with the release of inflammatory factors.

6.
Neurosci Bull ; 35(5): 826-840, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31062334

RESUMO

Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixed-duration experiments (500 ms as the Short Group and 1500 ms as the Long Group) and random-duration experiments (500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from 15 Hz to 25 Hz. The beta power was higher during the hold period than the movement (reach and grasp) period. Further, in the fixed-duration experiments, the mean power as well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention.

7.
J Cell Mol Med ; 23(5): 3737-3746, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30895711

RESUMO

Adipose-derived stem cells (ASCs) are highly attractive for cell-based therapies in tissue repair and regeneration because they have multilineage differentiation capacity and are immunosuppressive. However, the detailed epigenetic mechanisms of their immunoregulatory capacity are not fully defined. In this study, we found that Mysm1 was induced in ASCs treated with inflammatory cytokines. Adipose-derived stem cells with Mysm1 knockdown exhibited attenuated immunosuppressive capacity, evidenced by less inhibition of T cell proliferation, more pro-inflammatory factor secretion and less nitric oxide (NO) production in vitro. Mysm1-deficient ASCs exacerbated inflammatory bowel diseases but inhibited tumour growth in vivo. Mysm1-deficient ASCs also showed depressed miR-150 expression. When transduced with Mysm1 overexpression lentivirus, ASCs exhibited enhanced miR-150 expression. Furthermore, Mysm1-deficient cells transduced with lentivirus containing miR-150 mimics produced less pro-inflammatory factors and more NO. Our study reveals a new role of Mysm1 in regulating the immunomodulatory activities of ASCs by targeting miR-150. These novel insights into the mechanisms through which ASCs regulate immune reactions may lead to better clinical utility of these cells.

8.
J Cardiothorac Surg ; 14(1): 46, 2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-30819240

RESUMO

BACKGROUND: Minimally invasive McKeown esophagectomy is an important surgical approach for esophageal cancer. Anastomotic leak is one of its common and serious complications. We assumed that the preoperative risk factors and postoperative indicators would predict or detect anastomotic leak. METHODS: Between December 2016 and July 2017, patients underwent minimally invasive McKeown esophagectomy were identified and their preoperative variables and postoperative test indicators were recorded. Fisher's exact test, 2-tailed unpaired t test, nonparametric test and logistic regression were used to compare these datum between patients with or without anastomotic leak (AL). Receiver Operator Characteristic (ROC) curve was used to identify the best cut-off value of drainage amylase concentration for distinguishing anastomotic leak. RESULTS: In all the 96 patients included, 12 patients were diagnosed as anastomotic leak by the esophagram. No differences in preoperative variables were observed between patients with and without AL. Patients in AL group appeared to have a lower prealbumin concentration in AL group on POD (postoperative day) 4(P = 0.05), POD 5(P = 0.04), POD 6 (P = 0.06). Prealbumin concentration cutoff value of 128 g/L on postoperative day 5 is 100.00% sensitive and 50.00% specific for predicting esophageal leaks. Drain amylases levels were higher in patients with anastomotic leak than those without anastomotic leak on POD 3(P = 0.03), POD 4(P = 0.01), POD 5(P < 0.001), POD 6(P < 0.001). The drain amylase cutoff value of 85 IU/L on postoperative day 4 was 75.00% sensitive and 84.00% specific for detecting esophageal leaks; the cutoff value of 65 IU/L on postoperative day 5 was 91.67% sensitive and 80.77% specific. The cutoff of 55/L on POD 6 is 100% sensitive and 86.96% specific. CONCLUSION: Drainage amylase concentration on postoperative days may help to discover anastomotic leak in early stage after minimally invasive McKeown esophagectomy. Prealbumin concentration below 128 g/L on POD 5 might be potential risk factor for anastomotic leak.


Assuntos
Fístula Anastomótica/diagnóstico , Neoplasias Esofágicas/cirurgia , Esofagectomia/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Amilases/análise , Anastomose Cirúrgica/efeitos adversos , Fístula Anastomótica/etiologia , Neoplasias Esofágicas/sangue , Esofagectomia/métodos , Esôfago , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos/efeitos adversos , Período Perioperatório , Pré-Albumina/análise , Valor Preditivo dos Testes , Prognóstico , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Estômago/cirurgia
9.
J Neural Eng ; 16(3): 036011, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30822756

RESUMO

OBJECTIVE: For intracortical neurophysiological studies, spike sorting is an important procedure to isolate single units for analyzing specific functions. However, whether spike sorting is necessary or not for neural decoding applications is controversial. Several studies showed that using threshold crossings (TC) instead of spike sorting could also achieve a similar satisfactory performance. However, such studies were limited in similar behavioral tasks, and the neural signal source mainly focused on the motor-related cortical regions. It is not certain if this conclusion is applicable to other situations. Therefore, we compared the performance of TC and spike sorting in neural decoding with more comprehensive paradigms and parameters. APPROACH: Two rhesus macaques implanted with Utah or floating microelectrode arrays (FMAs) in motor or sensory-related cortical regions were trained to perform a motor or a sensory task. Data from each monkey were preprocessed with three different schemes: TC, automatic sorting (AS), and manual sorting (MS). A support vector machine was used as the decoder, and the decoding accuracy was used for evaluating the performance of three preprocessing methods. Different neural signal sources, different decoders, and related parameters and decoding stability were further tested to systematically compare three preprocessing methods. MAIN RESULTS: TC could achieve a similar (-4.5 RMS threshold) or better (-3.0 RMS threshold) decoding performance compared to the other two sorting methods in the motor or sensory tasks even if the neural signal sources or decoder-related parameters were changed. Moreover, TC was much more stable in neural decoding across sessions and robust to changes of threshold. SIGNIFICANCE: Our results indicated that spike-firing patterns could be stably extracted through TC from multiple cortices in both motor and sensory neural decoding applications. Considering the stability of TC, it might be more suitable for neural decoding compared to sorting methods.

10.
Artigo em Inglês | MEDLINE | ID: mdl-30703024

RESUMO

Recent progress in semantic segmentation has been driven by improving the spatial resolution under Fully Convolutional Networks (FCNs). To address this problem, we propose a Stacked Deconvolutional Network (SDN) for semantic segmentation. In SDN, multiple shallow deconvolutional networks, which are called as SDN units, are stacked one by one to integrate contextual information and bring the fine recovery of localization information. Meanwhile, inter-unit and intra-unit connections are designed to assist network training and enhance feature fusion since the connections improve the flow of information and gradient propagation throughout the network. Besides, hierarchical supervision is applied during the upsampling process of each SDN unit, which enhances the discrimination of feature representations and benefits the network optimization. We carry out comprehensive experiments and achieve the new state-ofthe- art results on four datasets, including PASCAL VOC 2012, CamVid, GATECH, COCO Stuff. In particular, our best model without CRF post-processing achieves an intersection-over-union score of 86.6% in the test set.

11.
Cell Prolif ; 52(3): e12574, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30724402

RESUMO

Induced pluripotent stem cells (iPSCs) are reprogrammed somatic cells that gained self-renewal and differentiation capacity similar to embryonic stem cells. Taking the precious opportunity of the TianZhou-1 spacecraft mission, we studied the effect of space microgravity (µg) on the self-renewal capacity of iPSCs. Murine iPSCs carrying pluripotency reporter Oct4-GFP were used. The Oct4-EGFP-iPSCs clones were loaded into the bioreactor and exposed to µg in outer space for 14 days. The control experiment was performed in identical device but on the ground in earth gravity (1 g). iPSCs clones were compact and highly expressed Oct4 before launch. In µg condition, cells in iPSC clones spread out more rapidly than those in ground 1 g condition during the first 3 days after launch. However, in 1 g condition, as the cell density increases, the Oct4-GFP signal dropped significantly during the following 3 days. Interestingly, in µg condition, iPSCs originated from the spread-out clones during the first 3 days appeared to cluster together and reform colonies that activated strong Oct4 expression. On the other hand, iPSC clones in 1 g condition were not able to recover Oct4 expression after overgrown. Our study for the first time performed real-time imaging on the proliferation process of iPSCs in space and found that in µg condition, cell behaviour appeared to be more dynamic than on the ground.


Assuntos
Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Voo Espacial , Ausência de Peso , Animais , Reatores Biológicos , Proliferação de Células , Autorrenovação Celular , Células Clonais , Sistemas de Computação , Camundongos , Camundongos Transgênicos , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Regeneração
12.
Stem Cells Dev ; 28(6): 357-360, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30654722

RESUMO

During space travel, exposure to microgravity may have profound influence on the physiological function of mammalian cells. In this study, we took opportunity of the Tianzhou-1 (TZ-1) mission to investigate how spaceflight may affect cardiac differentiation of mouse induced pluripotent stem cells (iPSCs). A bioreactor was engineered to perform cell culturing and the time-lapse imaging experiments on-orbit. Transgenic iPSC lines with either Oct4 or α-myosin heavy chain (αMHC) promoter driving green fluorescent protein (GFP) expression were used to study cardiomyocyte (CM) differentiation in real microgravity. The differentiation status was monitored by GFP fluorescence intensity. Interestingly, compared with cells cultured in identical environment at ground gravity, embryoid bodies (EBs) derived from Oct4 reporter iPSC downregulated GFP significantly quicker in space. Meanwhile, EBs derived from αMHC reporter iPSC activated GFP strongly 4 days after launch (P < 0.05) and lasted for 10 days afterward, indicating robust CM formation. This is the first real-time imaging study of iPSC myocardial differentiation in space. Under our experimental condition, real microgravity enhanced the CM differentiation process of iPSCs. Our study provided rare information about iPSC cardiac differentiation in space. In the future, similar automated stem cell experiments may help to realize personalized cardiac tissue biomanufacturing and drug test during space travel.

13.
Biomacromolecules ; 20(2): 1007-1017, 2019 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-30616345

RESUMO

Understanding the fundamental cell-material interactions is essential to designing functional materials for biomedical applications. Although mesenchymal stromal cells (MSCs) are known to secrete cytokines and exosomes that are effective to treat degenerative diseases, the inherent property of biomaterials to modulate the therapeutic function of MSCs remains to be investigated. Here, a multivalent cell-membrane adhesive conjugate was generated through polyamindoamine (PAMAM) and an oligopeptide, IKVAV, and the conjugate was further complexed with hyaluronic acid (HA). The adhesive particulates were used to coat the surface of adipose-derived mesenchymal stromal cells (Ad-MSCs) and studied in the MSC spheroid culture. The analysis showed that the adhesive complexes formed via PAMAM conjugates and HA significantly promoted the proliferation and the gene expression of pro-angiogenesis cytokines in MSCs; the production of anti-inflammatory miRNAs in exosomes could also be elevated. The transplantation of the Ad-MSCs primed with PAMAM-IKVAV/HA composite particulates in a rat myocardial infarction model further demonstrated the beneficial effects of membrane-binding materials on improving the cell retention and tissue angiogenesis. The new function of membrane-binding adhesive materials potentially provides useful ways to improve cell-based therapy.

14.
Mol Biol Rep ; 45(6): 2393-2401, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30386973

RESUMO

Macrophages play pivotal roles in innate and adaptive immune response, tissue homeostasis and cancer development. Their development and heterogeneity are tightly controlled by epigenetic program and transcription factors. Deubiquitinase Mysm1 plays crucial roles in regulating stem cell maintenance and immune cell development. Here we show that Mysm1 expression is up regulated during bone marrow macrophage development. Mysm1 deficient cells exhibit accelerating proliferation with more cells going to S phase and higher cyclin D1, cyclin D2 and c-Myc expression. However, compared to WT counterparts, more cell death is also detected in Mysm1 deficient cells no matter M-CSF deprived or not. In LPS-condition medium, Mysm1-/- macrophages show more pro-inflammatory factors IL-1ß, TNFα and iNOS production. In addition, much higher expression of surface marker CD86 is detected in Mysm1-/- macrophages. In vivo tumor model data demonstrate that in contrast to WT macrophages promoting tumor growth, Mysm1-/- macrophages inhibit tumor growth, showing the properties of M1 macrophages. Collectively, these data indicate that Mysm1 is essential for macrophage survival and plays an important role in macrophage polarization and might be a target for cell therapy.


Assuntos
Endopeptidases/metabolismo , Macrófagos/metabolismo , Animais , Apoptose , Ciclo Celular/fisiologia , Diferenciação Celular , Células Cultivadas , Enzimas Desubiquitinantes/metabolismo , Endopeptidases/fisiologia , Regulação da Expressão Gênica/genética , Camundongos Knockout , Células-Tronco , Fatores de Transcrição , Ubiquitinação/fisiologia
18.
Front Neurosci ; 12: 272, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29867307

RESUMO

Multichannel electroencephalography (EEG) is widely used in typical brain-computer interface (BCI) systems. In general, a number of parameters are essential for a EEG classification algorithm due to redundant features involved in EEG signals. However, the generalization of the EEG method is often adversely affected by the model complexity, considerably coherent with its number of undetermined parameters, further leading to heavy overfitting. To decrease the complexity and improve the generalization of EEG method, we present a novel l1-norm-based approach to combine the decision value obtained from each EEG channel directly. By extracting the information from different channels on independent frequency bands (FB) with l1-norm regularization, the method proposed fits the training data with much less parameters compared to common spatial pattern (CSP) methods in order to reduce overfitting. Moreover, an effective and efficient solution to minimize the optimization object is proposed. The experimental results on dataset IVa of BCI competition III and dataset I of BCI competition IV show that, the proposed method contributes to high classification accuracy and increases generalization performance for the classification of MI EEG. As the training set ratio decreases from 80 to 20%, the average classification accuracy on the two datasets changes from 85.86 and 86.13% to 84.81 and 76.59%, respectively. The classification performance and generalization of the proposed method contribute to the practical application of MI based BCI systems.

19.
Theranostics ; 8(12): 3317-3330, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29930732

RESUMO

After myocardial infarction (MI), the scar tissue contributes to ventricular dysfunction by electrically uncoupling viable cardiomyocytes in the infarct region. Injection of a conductive hydrogel could not only provide mechanical support to the infarcted region, but also synchronize contraction and restore ventricular function by electrically connecting isolated cardiomyocytes to intact tissue. Methods: We created a conductive hydrogel by introducing graphene oxide (GO) nanoparticles into oligo(poly(ethylene glycol) fumarate) (OPF) hydrogels. The hydrogels were characterized by AFM and electrochemistry workstation. A rat model of myocardial infarction was used to investigate the ability of OPF/GO to improve cardiac electrical propagation in the injured heart in vivo. Echocardiography (ECHO) was used to evaluate heart function 4 weeks after MI. Ca2+ imaging was used to visualize beating cardiomyocytes (CMs). Immunofluorescence staining was used to visualize the expression of cardiac-specific markers. Results: OPF/GO hydrogels had semiconductive properties that were lacking in pure OPF. In addition, the incorporation of GO into OPF hydrogels could improve cell attachment in vitro. Injection of OPF/GO 4 weeks after myocardial infarction in rats enhanced the Ca2+ signal conduction of cardiomyocytes in the infarcted region in comparison with PBS or OPF alone. Moreover, the injection of OPF/GO hydrogel into the infarct region enhanced the generation of cytoskeletal structure and intercalated disc assembly. Echocardiography analysis showed improvement in load-dependent ejection fraction/fractional shortening of heart function 4 weeks after injection. Conclusions: We prepared a conductive hydrogel (OPF/GO) that provide mechanical support and biological conduction in vitro and in vivo. We found that injected OPF/GO hydrogels can provide mechanical support and electric connection between healthy myocardium and the cardiomyocytes in the scar via activating the canonical Wnt signal pathway, thus upregulating the generation of Cx43 and gap junction associated proteins. Injection of OPF/GO hydrogel maintained better heart function after myocardial infarction than the injection of a nonconductive polymer.


Assuntos
Condutividade Elétrica , Grafite/administração & dosagem , Hidrogel de Polietilenoglicol-Dimetacrilato/administração & dosagem , Infarto do Miocárdio/tratamento farmacológico , Poliésteres/administração & dosagem , Polietilenoglicóis/administração & dosagem , Animais , Modelos Animais de Doenças , Ecocardiografia , Imunofluorescência , Injeções , Infarto do Miocárdio/patologia , Imagem Óptica , Ratos , Resultado do Tratamento
20.
J Biomed Nanotechnol ; 14(6): 1099-1106, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29843874

RESUMO

Optical electrodes are important tools for optogenetic research. Flexible optical electrodes represent a refinement over traditional fiber-based electrodes because they contact with target cells gently by reducing mechanical mismatch, thereby enhancing their long-term, stable signal acquisition capability. Until now, little attention has been paid to flexible intracortical optical electrodes. Here, we reported a novel flexible penetrating optical electrode with a probe made of composite hydrogels. We used polydimethylsiloxane (PDMS), a kind of transparent material, to fabricate waveguide by capillary assembly method with two tungsten wires inside providing mechanic support. Then one tungsten wire was withdrawn out and the microchannel was filled with hydrogel composed of polyvinyl alcohol (PVA), multi-walled carbon nanotubes (MWCNT), poly(3,4-ethylenedioxythiophene) (PEDOT), and polystyrene sulfonate (PSS) as an electrical recording and stimulation probe. With PDMS as the waveguide and PVA/MWCNT/PEDOT/PSS hydrogel as the electroprobe, the optical electrode becomes a flexible package. The morphology observed by scanning electron microscopy showed that the PVA/MWCNT/PEDOT/PSS hydrogel had a loose surface structure, which would allow the effective adhesion to target neurons. A buckling test showed that our electrode maintained bending strength comparable to that of previously reported flexible penetrating electrodes. Finally, the electrical properties showed a lower impedance and higher charge capacity after PEDOT/PSS modification. The flexible penetrating optical electrode we developed may be used for long-term in vivo optogenetics studies.


Assuntos
Optogenética , Dimetilpolisiloxanos , Eletrodos , Hidrogéis , Nanotubos de Carbono
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