RESUMEN
Hepatitis B virus (HBV) infection significantly impacts Asian populations. The influences of continuous HBV antigen and inflammatory stimulation to T cells in chronic hepatitis B (CHB) remain unclear. In this study, we first conducted bioinformatics analysis to assess T-cell signaling pathways in CHB patients. In a Taiwanese cohort, we examined the phenotypic features of HBVcore -specific T cells and their correlation with clinical parameters. We used core protein overlapping peptides from the Taiwan prevalent genotype B HBV to investigate the antiviral response and the functional implication of HBV-specific T cells. In line with Taiwanese dominant HLA-alleles, we also evaluated ex vivo HBVcore -specific T cells by pMHC-tetramers targeting epitopes within HBV core protein. Compared to healthy subjects, we disclosed CD8 T cells from CHB patients had higher activation marker CD38 levels but showed an upregulation in the inhibitory receptor PD-1. Our parallel study showed HBV-specific CD8 T cells were more activated with greater PD-1 expression than CMV-specific subset and bulk CD8 T cells. Moreover, our longitudinal study demonstrated a correlation between the PD-1 fluctuation pattern of HBVcore -specific CD8 T cells and liver inflammation in CHB patients. Our research reveals the HBV core antigen-mediated immunopathologic profile of CD8 T cells in chronic HBV infection. Our findings suggest the PD-1 levels of HBVcore -specific CD8 T cells can be used as a valuable indicator of personal immune response for clinical application in hepatitis management.
Asunto(s)
Hepatitis B Crónica , Hepatitis B , Humanos , Virus de la Hepatitis B/genética , Receptor de Muerte Celular Programada 1/genética , Estudios Longitudinales , Antígenos del Núcleo de la Hepatitis B , Linfocitos T CD8-positivosRESUMEN
NK cells, which are highly enriched in the liver, are potent regulators of antiviral T cells and immunopathology in persistent viral infection. We investigated the role of the NKG2D axis in T cell/NK cell interactions in hepatitis B. Activated and hepatitis B virus (HBV)-specific T cells, particularly the CD4 fraction, expressed NKG2D ligands (NKG2DL), which were not found on T cells from healthy controls (p < 0.001). NKG2DL-expressing T cells were strikingly enriched within HBV-infected livers compared with the periphery or to healthy livers (p < 0.001). NKG2D+NK cells were also increased and preferentially activated in the HBV-infected liver (p < 0.001), in direct proportion to the percentage of MICA/B-expressing CD4 T cells colocated within freshly isolated liver tissue (p < 0.001). This suggests that NKG2DL induced on T cells within a diseased organ can calibrate NKG2D-dependent activation of local NK cells; furthermore, NKG2D blockade could rescue HBV-specific and MICA/B-expressing T cells from HBV-infected livers. To our knowledge, this is the first ex vivo demonstration that non-virally infected human T cells can express NKG2DL, with implications for stress surveillance by the large number of NKG2D-expressing NK cells sequestered in the liver.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Hepatitis B Crónica/inmunología , Células Asesinas Naturales/inmunología , Hígado/inmunología , Subfamilia K de Receptores Similares a Lectina de Células NK/fisiología , Adulto , Comunicación Celular , Células Cultivadas , Femenino , Humanos , Ligandos , Hígado/virología , Activación de Linfocitos , Masculino , Subfamilia K de Receptores Similares a Lectina de Células NK/antagonistas & inhibidoresRESUMEN
A graded fullerene derivative thin film was used as a dual-functional electron transport layer (ETL) in CH3NH3PbI3 (MAPbI3) solar cells, to improve the fill factor (FF) and device stability. The graded ETL was made by mixing phenyl-C61-butyric acid methyl ester (PCBM) molecules and C60-diphenylmethanofullerene-oligoether (C60-DPM-OE) molecules using the spin-coating method. The formation of the graded ETLs can be due to the phase separation between hydrophobic PCBM and hydrophilic C60-DPM-OE, which was confirmed by XPS depth-profile analysis and an electron energy-loss spectroscope. Comprehensive studies were carried out to explore the characteristics of the graded ETLs in MAPbI3 solar cells, including the surface properties, electronic energy levels, molecular packing properties and energy transfer dynamics. The elimination of the s-shape in the current density-voltage curves results in an increase in the FF, which originates from the smooth contact between the C60-DPM-OE and hydrophilic MAPbI3 and the formation of the more ordered ETL. There was an improvement in device stability mainly due to the decrease in the photothermal induced morphology change of the graded ETLs fabricated from two fullerene derivatives with distinct hydrophilicity. Consequently, such a graded ETL provides dual-functional capabilities for the realization of stable high-performance MAPbI3 solar cells.
RESUMEN
Stimulus-responsive hydrogels make up an important class of programmable materials for a wide range of biomedical applications. Ultrasound (US) is a stimulus that offers utility because of its ability to permeate tissue and rapidly induce chemical alterations in aqueous media. Here we report on the synthesis and US-mediated disintegration of stimulus-responsive telechelic Dopa-modified polyethylene glycol-based hydrogels. Fe3+-[PEG-Dopa]4 hydrogels are formed through Fe3+-induced cross-linking of four-arm polyethylene glycol-dopamine precursors to produce networks. The relative amounts of H-bonds, coordination bonds, and covalent bonds can be controlled by the [Fe3+]:[Dopa] molar ratio in precursor solutions. Networks formed from precursors with high [Fe3+]:[Dopa] ratios create mechanically robust networks (G' = 6880 ± 240 Pa) that are largely impervious to US-mediated disintegration at intensities of ≤43 W/cm2. Conversely, lightly cross-linked networks formed through [Fe3+]:[Dopa] molar ratios of <0.73 are susceptible to rapid disintegration upon exposure to US. Pulsatile US exposure allows temporal control over hydrogel disintegration and programmable self-healing. Sustained US energy can also stabilize hydrogels through the formation of additional cross-links via free radical-mediated coupling of pendant catechols. Taken together, the diverse ranges of mechanical behavior, self-healing capability, and differential susceptibility to ultrasonic disintegration suggest that Fe3+-[PEG-Dopa]4 hydrogels yield a class of application-specific stimulus-responsive polymers as smart materials for applications ranging from transient medical implants to matrices for smart drug delivery.
Asunto(s)
Hidrogeles/química , Hierro/química , Ultrasonido , Dopamina/química , Sistemas de Liberación de Medicamentos , Polietilenglicoles/químicaRESUMEN
Proinflammatory cytokines are key inflammatory mediators in periodontitis. This study aimed to investigate the relationship between proinflammatory cytokines in saliva and periodontal status. To investigate the usefulness of cytokines in the therapeutic approach for periodontal disease, the relationship between stimulated cytokine changes and the periodontitis treatment outcome was investigated in this study. Saliva was obtained from 22 patients diagnosed by dentists as having chronic periodontitis. The proinflammatory cytokine (interleukin-1α (IL-1α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor α (TNF-α), and tumor necrosis factor ß (TNF-ß)) levels were determined using a commercially available kit. The IL-1ß and IL-6 levels increased, whereas the TNF-ß levels decreased with the severity of periodontitis (4 mm pocket percentage). Poststimulation IL-1α, IL-6, and IL-8 levels were higher in patients who had an improved treatment outcome. The differences of IL-6 levels (cut point: 0.05 µg/g) yielded a sensitivity and specificity of 90.0% and 81.82%, respectively, for predicting the periodontitis treatment outcome. Among the proinflammatory cytokines, stimulated IL-6 was an excellent marker for predicting the periodontitis treatment outcome.
Asunto(s)
Citocinas/metabolismo , Mediadores de Inflamación/metabolismo , Periodontitis/metabolismo , Periodontitis/terapia , Adulto , Anciano , Área Bajo la Curva , Demografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Curva ROC , Factores de Riesgo , Saliva/metabolismo , Resultado del TratamientoAsunto(s)
Acidosis Láctica/diagnóstico , Hipercalcemia/etiología , Linfoma de Células T/diagnóstico , Pancreatitis/etiología , Síndromes Paraneoplásicos/diagnóstico , Acidosis Láctica/sangre , Acidosis Láctica/etiología , Anciano , Humanos , Hipercalcemia/sangre , Linfoma de Células T/sangre , Linfoma de Células T/complicaciones , Masculino , Pancreatitis/sangre , Pancreatitis/diagnóstico , Síndromes Paraneoplásicos/sangre , Síndromes Paraneoplásicos/etiologíaRESUMEN
AIM: Our goal was to investigate associations among scaling-stimulated changes in salivary antioxidants, oral-health-related behaviors and attitudes, and periodontal treatment outcomes. MATERIALS AND METHODS: Thirty periodontitis patients with at least 6 pockets with pocket depths of >5 mm and more than 16 functional teeth were enrolled in the study. Patients were divided into three groups: an abandoned group (AB group), a nonprogress outcome group (NP group), and an effective treatment group (ET group). Nonstimulated saliva was collected before and after scaling were received to determine superoxide dismutase (SOD) and the total antioxidant capacity (TAOC). RESULTS: Salivary SOD following scaling significantly increased from 83.09 to 194.30 U/g protein in patients who had irregular dental visit patterns (<1 visit per year). After scaling, the TAOC was significantly higher in patients who had regular dental visits than in patients who had irregular dental visits (3.52 versus 0.70 mmole/g protein, P < 0.01). The scaling-stimulated increase in SOD was related to a higher severity of periodontitis in the NP group, while the scaling-stimulated increase in the TAOC was inversely related to the severity of periodontitis in the AB group. CONCLUSIONS: These results demonstrate the importance of scaling-stimulated salivary antioxidants as prognostic biomarkers of periodontal treatment.
Asunto(s)
Antioxidantes/metabolismo , Conductas Relacionadas con la Salud , Salud Bucal , Periodontitis/metabolismo , Saliva/metabolismo , Superóxido Dismutasa/metabolismo , Adulto , Biomarcadores/metabolismo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Periodontitis/terapiaRESUMEN
BACKGROUND & PROBLEMS: Our unit recorded 21 cases of pressure sores from January 2011 to June 2011. The resulting pressure-sore incidence density of 0.74% exceeded the Taiwan Clinical Performance Indicator (TCPI) for medical centers (0.62%) as well as the mean incidence density for our unit (0.55%) during the same period in 2010. PURPOSE: We developed this project to decrease the incidence density of pressure sores at our pediatric-surgical-intensive-care unit from 0.74% to 0.31%. RESOLUTIONS: Strategies implemented included: 1. providing on-the-job education; 2. providing bedside teaching; 3. developing a series of pictures to illustrate proper sitting, lying, and changing positions and the proper fixation of catheters; 4. implementing a reminder mechanism; 5. introducing pressure-preventing devices; 6. and establishing an audit team. RESULTS: Incidence density decreased from 0.74% (Jan. to Jun. 2011) to 0.18% (Mar. to Jul. 2012). CONCLUSIONS: We demonstrated that the developed improvement program effectively reduced the incidence density of pressure sores and increased the quality of nursing care.
Asunto(s)
Unidades de Cuidado Intensivo Pediátrico , Úlcera por Presión/prevención & control , Niño , Humanos , Incidencia , Úlcera por Presión/epidemiologíaRESUMEN
Implantable electrodes have raised great interest over the last years with the increasing incidence of neurodegenerative disorders. For brain implant devices, some key factors resulting in the formation of glial scars, such as mechanical mismatch and acute injury-induced inflammation, should be considered for material design. Therefore, in this study, a new biocompatible flexible electrode (e-SgG) with arbitrary shapes on a positive electrode was developed via electrogelation by applying a direct electrical voltage on a silk fibroin/gelatin/reduced graphene oxide composite hydrogel. The implantable flexible e-SgG-2 film with 1.23% rGO content showed high Young's modulus (11-150 MPa), which was sufficient for penetration under dried conditions but subsequently became a biomimetic brain tissue with low Young's modulus (50-3200 kPa) after insertion in the brain. At the same time, an anti-inflammatory drug (DEX) incorporated into the e-SgG-2 film can be electrically stimulated to exhibit two-stage release to overcome tissue inflammation during cyclic voltammetry via degradation by applying an AC field. The results of cell response to the SF/gelatin/rGO/DEX composite film showed that the released DEX could interrupt astrocyte growth to reduce the inflammatory response but showed non-toxicity toward neurons, which demonstrated a great potential for the application of the biocompatible and degradable e-SgG-D electrodes in the improvement of nerve tissue repair.
Asunto(s)
Gelatina , Seda , Humanos , Electrodos Implantados , Encéfalo , Inflamación , AntiinflamatoriosRESUMEN
BACKGROUND: Approximately 10-40% of hepatocellular carcinoma (HCC) patients have definite vascular invasion at the time of diagnosis. Without curative treatment options, these patients have an abysmal prognosis with a median survival of only a few months following systemic therapy. However, supportive evidence of combining multiple locoregional treatments with systemic therapy is limited. This study compared the outcomes of sorafenib alone versus multimodality therapy with sorafenib, radiotherapy (RT), and transarterial chemoembolization (TACE) in advanced HCC patients with macrovascular invasion (MaVI). METHODS: The process took place over a nine-year period between March 2009 and October 2017, wherein 78 HCC patients with MaVI who underwent either sorafenib therapy alone (n = 49) or combined sorafenib/RT/TACE (n = 29) therapy were chosen for the retrospective study. We compared the overall survival (OS) between the two groups using the Cox regression hazard model and adjusted imbalances using propensity score matching (PSM). RESULTS: At the last follow-up, 76 patients had died, with a median follow-up time of 4.8 months for all patients and 31 months for those who were alive. Patients treated with sorafenib/RT/TACE had superior OS compared to those treated with sorafenib alone, showing a median survival of 9.3 vs. 2.7 months and a one-year survival of 37.1% vs. 6.1% (p < 0.001). In the multivariable analysis, new diagnosis or recurrence of HCC and treatment modalities (sorafenib alone vs. sorafenib/RT/TACE) were independent prognostic factors for OS. Compared to patients treated with sorafenib alone, significantly better OS was further verified using PSM (p < 0.001) in patients who received multiple therapeutic modalities. CONCLUSION: Multimodality therapy with sorafenib/RT/TACE increased OS threefold versus sorafenib therapy alone in HCC patients with MaVI. This study offers promising benefits of combined locoregional and systemic therapy for advanced HCC in current patient management and prospective clinical trials.
RESUMEN
.
Asunto(s)
Músculo Esquelético , Electromiografía , Humanos , Músculo Esquelético/diagnóstico por imagen , UltrasonografíaRESUMEN
Sintered silver paste is widely used as the die-attachment material for power semiconductors. However, sintered silver joints encounter problems, such as severe coarsening of sintered pores and oxidation issues, in harsh high-temperature environments. These lead to the deterioration of the die-attachment joints. In this paper, a novel method of sintering silver joints is demonstrated, where silver-indium alloy paste is used to improve the reliability of sintered Ag joints. The silver-indium (Ag-In) alloy paste was fabricated through mechanical alloying using the ball-milling technique. The well-bonded sintered Ag-In alloy joints inhibited pore coarsening better than pure sintered Ag joints and significantly enhanced the mechanical properties at high operating temperatures. Lastly, an oxidation mechanism for the sintered joint was proposed, and strategies to prevent such high-temperature oxidation were discussed.
RESUMEN
Although numerous strategies have been implemented to develop nerve guidance conduits (NGCs) to treat peripheral nerve injury (PNI), functionalization of an NGC to make it remotely controllable for providing spatiotemporal modulation on in situ nerve tissues remains a challenge. In this study, a gelatin/silk (GS) hydrogel was used to develop an NGC based on its self-owned reversible thermoresponsive sol-to-gel phase transformation ability that permitted rapid three-dimensional (3D) micropatterning of the incorporated nerve growth factor (NGF)-loaded magnetic poly(lactic-co-glycolic acid) (PLGA) microcapsules (called NGF@MPs) via multiple magnetic guidance. The thermally controllable viscosity of GS enabled the rapid formation of a 3D gradient and linearly aligned distribution of NGF@MPs, leading to magnetically controlled 3D gradient release of NGF to enhance topographical nerve guidance and wound healing in PNIs. Particularly, the as-formed micropatterned hydrogel, called NGF@MPs-GS, showed corrugation topography with a pattern height H of 15 µm, which resulted in the linear axon alignment of more than 90% of cells. In addition, by an external magnetic field, spatiotemporal controllability of NGF release was obtained and permitted neurite elongation that was almost 2-fold longer than that in the group with external addition of NGF. Finally, an NGC prototype was fabricated and implanted into the injured sciatic nerve. The patterned implant, assisted by magnetic stimulation, demonstrated accelerated restoration of motor function within 14 days after implantation. It further contributed to the enhancement of axon outgrowth and remyelination after 28 days. This NGC, with controllable mechanical, biochemical, and topographical cues, is a promising platform for the enhancement of nerve regeneration.
Asunto(s)
Gelatina , Factor de Crecimiento Nervioso , Factor de Crecimiento Nervioso/farmacología , Factor de Crecimiento Nervioso/metabolismo , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Cápsulas , Preparaciones de Acción Retardada/farmacología , Nervio Ciático/lesiones , Regeneración Nerviosa , Hidrogeles/farmacología , Seda , Fenómenos MagnéticosRESUMEN
The use of scaled-down micro-bumps in miniaturized consumer electronic products has led to the easy realization of full intermetallic solder bumps owing to the completion of the wetting layer. However, the direct contact of the intermetallic compounds (IMCs) with the adhesion layer may pose serious reliability concerns. In this study, the terminal reaction of the Ti adhesion layer with Cu-Sn IMCs was investigated by aging the micro-bumps at 200 °C. Although all of the micro-bumps transformed into intermetallic structures after aging, they exhibited a strong attachment to the Ti adhesion layer, which differs significantly from the Cr system where spalling of IMCs occurred during the solid-state reaction. Moreover, the difference in the diffusion rates between Cu and Sn might have induced void formation during aging. These voids progressed to the center of the bump through the depleting Cu layer. However, they neither affected the attachment between the IMCs and the adhesion layer nor reduced the strength of the bumps. In conclusion, the IMCs demonstrated better adhesive behavior with the Ti adhesion layer when compared to Cr, which has been used in previous studies.
RESUMEN
Multimodal neural interfaces include combined functions of electrical neuromodulation and synchronic monitoring of neurochemical and physiological signals in one device. The remarkable biocompatibility and electrochemical performance of polystyrene sulfonate-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) have made it the most recommended conductive polymer neural electrode material. However, PEDOT:PSS formed by electrochemical deposition, called PEDOT/PSS, often need multiple doping to improve structural instability in moisture, resolve the difficulties of functionalization, and overcome the poor cellular affinity. In this work, inspired by the catechol-derived adhesion and semiconductive properties of polydopamine melanin (PDAM), we used electrochemical oxidation polymerization to develop PDAM-doped PEDOT (PEDOT/PDAM) as a bioactive multimodal neural interface that permits robust electrochemical performance, structural stability, analyte-trapping capacity, and neural stem cell affinity. The use of potentiodynamic scans resolved the problem of copolymerizing 3,4-ethylenedioxythiophene (EDOT) and dopamine (DA), enabling the formation of PEDOT/PDAM self-assembled nanodomains with an ideal doping state associated with remarkable current storage and charge transfer capacity. Owing to the richness of hydrogen bond donors/acceptors provided by the hydroxyl groups of PDAM, PEDOT/PDAM presented better electrochemical and mechanical stability than PEDOT/PSS. It has also enabled high sensitivity and selectivity in the electrochemical detection of DA. Different from PEDOT/PSS, which inhibited the survival of human induced pluripotent stem cell-derived neural progenitor cells, PEDOT/PDAM maintained cell proliferation and even promoted cell differentiation into neuronal networks. Finally, PEDOT/PDAM was modified on a commercialized microelectrode array system, which resulted in the reduction of impedance by more than one order of magnitude; this significantly improved the resolution and reduced the noise of neuronal signal recording. With these advantages, PEDOT/PDAM is anticipated to be an efficient bioactive multimodal neural electrode material with potential application to brain-machine interfaces.
Asunto(s)
Células Madre Pluripotentes Inducidas , Humanos , Melaninas , Polímeros/farmacología , Neuronas/fisiologíaRESUMEN
Aim: Approximately 66% of head and neck cancers are diagnosed at an advanced stage. This prospective study aimed to detect newly diagnosed head and neck cancers using regular upper gastrointestinal (UGI) endoscopy with oral-pharynx-larynx examination. Methods: A total of 2,849 patients underwent UGI endoscopy with an additional oral-pharynx-larynx examination. Patients aged < 20 years, those who were pregnant, had a history of head and neck cancers, were undergoing emergency endoscopy, and had a poor laryngopharyngeal view were excluded. The symptoms, incidence, location, pathology, and stage of malignant neoplasms were investigated. Results: A total of 2,720 patients were enrolled. Endoscopically observable 23 abnormal findings (0.85%) included 18 (0.66%) benign lesions and 5 (0.18%) newly diagnosed malignant neoplasms. Notably, 4 (80%) of 5 patients with malignant neoplasms were diagnosed at an early stage (Stage 0, I, and II). Conclusions: UGI endoscopy with oral-pharynx-larynx examination can achieve opportunistic head neck cancer screening and is recommended for every patient in endoscopy units.
RESUMEN
T lymphocyte infiltration with immunotherapy potentially suppresses most devastating brain tumors. However, local immune privilege and tumor heterogeneity usually limit the penetration of immune cells and therapeutic agents into brain tumors, leading to tumor recurrence after treatment. Here, a rabies virus glycoprotein (RVG)-camouflaged gold yarnball (RVG@GY) that can boost the targeting efficiency at a brain tumor via dual hierarchy- and RVG-mediated spinal cord transportation, facilitating the decrease of tumor heterogeneity for T cell infiltration, is developed. Upon magnetoelectric irradiation, the electron current generated on the GYs activates the electrolytic penetration of palbociclib-loaded dendrimer (Den[Pb]) deep into tumors. In addition, the high-density GYs at brain tumors also induces the disruption of cell-cell interactions and T cell infiltration. The integration of the electrolytic effects and T cell infiltration promoted by drug-loaded RVG@GYs deep in the brain tumor elicits sufficient T cell numbers and effectively prolongs the survival rate of mice with orthotopic brain tumors.
Asunto(s)
Neoplasias Encefálicas , Virus de la Rabia , Animales , Neoplasias Encefálicas/tratamiento farmacológico , Glicoproteínas , Oro/uso terapéutico , Ratones , Linfocitos T/patologíaRESUMEN
Patients with a long-term PEG may suffer from complications and received physical and endoscopic examinations. However, these examinations do not provide information between skin and stomach. We present the findings of computed tomography (CT) for patients with long-term percutaneous endoscopic gastrostomy (PEG). After 1 year PEG (183 patients), 57 patients had received CT examinations. Skin indentation, soft-tissue thickening, peritoneal gap, internal bumper migration, and clinical abnormalities detected by CT examination were recorded. Thickness of subcutaneous fat, muscle, and abdominal wall along the tract were measured. The same parameters at 3 cm away from the tract were obtained for comparison. CT demonstrated that 28 (49.1%) patients present soft-tissue thickening, 19 (33.3%) patients present skin indentation, and 24 (42.1%) patients present a peritoneal gap. One patient with internal bumper migration, 3 patients had buried bumper syndrome, 2 patients had gastric herniation, and 1 patient had esophageal cancer metastasizes to the PEG site. Thickness of subcutaneous fat, muscle, and abdominal wall decreased significant. CT can provide detailed anatomy and orientation along the PEG tube. Familiarity of the CT appearance can minimize potential complications before PEG tube replacement.
Asunto(s)
Gastroscopía , Gastrostomía/métodos , Complicaciones Posoperatorias/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Migración de Cuerpo Extraño/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Siembra NeoplásicaRESUMEN
Hydrogels are the ideal materials in the development of implanted bioactive neural interfaces because of the nerve tissue-mimicked physical and biological properties that can enhance neural interfacing compatibility. However, the integration of hydrogels and rigid/dehydrated electronic microstructure is challenging due to the non-reliable interfacial bonding, whereas hydrogels are not compatible with most conditions required for the micromachined fabrication process. Herein, we propose a new enzyme-mediated transfer printing process to design an adhesive biological hydrogel neural interface. The donor substrate was fabricated via photo-crosslinking of gelatin methacryloyl (GelMA) containing various conductive nanoparticles (NPs), including Ag nanowires (NWs), Pt NWs, and PEDOT:PSS, to form a stretchable conductive bioelectrode, called NP-doped GelMA. On the other hand, a receiver substrate composed of microbial transglutaminase-incorporated gelatin (mTG-Gln) enabled simultaneous temporally controlled gelation and covalent bond-enhanced adhesion to achieve one-step transfer printing of the prefabricated NP-doped GelMA features. The integrated hydrogel microelectrode arrays (MEA) were adhesive, and mechanically/structurally bio-compliant with stable conductivity. The devices were structurally stable in moisture to support the growth of neuronal cells. Despite that the introduction of AgNW and PEDOT:PSS NPs in the hydrogels needed further study to avoid cell toxicity, the PtNW-doped GelMA exhibited a comparable live cell density. This Gln-based MEA is expected to be the next-generation bioactive neural interface.
RESUMEN
Although traditional 3D scaffolds or biomimetic hydrogels have been used for tissue engineering and regenerative medicine, soft tissue microenvironment usually has a highly anisotropic structure and a dynamically controllable deformation with various biomolecule distribution. In this study, we developed a hierarchical hybrid gelatin methacrylate-microcapsule hydrogel (HGMH) with Neurotrophin-3(NT-3)-loaded PLGA microcapsules to fabricate anisotropic structure with patterned NT-3 distribution (demonstrated as striped and triangular patterns) by dielectrophoresis (DEP). The HGMH provides a dynamic biomimetic sinuate-microwrinkles change with NT-3 spatial gradient and 2-stage time-dependent distribution, which was further simulated using a 3D finite element model. As demonstrated, in comparison with striped-patterned hydrogel, the triangular-patterned HGMH with highly anisotropic array of microcapsules exhibits remarkably spatial NT-3 gradient distributions that can not only guide neural stem cells (NSCs) migration but also facilitate spinal cord injury regeneration. This approach to construct hierarchical 4D hydrogel system via an electromicrofluidic platform demonstrates the potential for building various biomimetic soft scaffolds in vitro tailed to real soft tissues.