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1.
BMC Musculoskelet Disord ; 25(1): 20, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38167040

RESUMEN

BACKGROUND: Corticocancellous bone grafting from the iliac crest is acceptable treatment for unstable scaphoid nonunion with a viable proximal pole. However, harvesting graft from the iliac crest is associated with donor site morbidity and the requirement of general anesthesia. Thus, bone grafting from the anterolateral metaphysis of the distal radius (DR) can be a treatment option. However, no study has compared the clinical effect between the two grafting techniques. METHODS: From 2014 to 2019, patients with unstable scaphoid nonunion with humpback deformity underwent corticocancellous bone grafting from the anterolateral metaphysis of the DR (group DR) or iliac crest (group IC). Humpback deformity was determined by evaluating the scapholunate angle (SLA) ≥ 60°, intrascaphoid angle (ISA) ≥ 45°, and radiolunate angle (RLA) ≥ 15° from preoperative radiographs and computed tomography scans. The SLA, ISA, and RLA served to gauge carpal alignment. The operative time, grip strength, active range of motion (ROM), the Modified Mayo Wrist score (MMWS), and Disabilities of Arm, Shoulder, and Hand (DASH) score were assessed postoperatively. RESULTS: Thirty-eight patients qualified for the study (group DR, 15; group IC, 23). Union rates did not differ by patient subset (group DR, 100%; group IC, 95.7%; P = .827), and grip strength, ROM, MWS, and DASH score were similar between groups at the last follow-up. The operative time (minutes) was significantly shorter in group DR (median, 98; quartiles, 80, 114) than in group IC (median, 125; quartiles, 105, 150, P < .001). The ISA, RLA, and SLA improved postoperatively in both groups (P < 0.001). The degree of restoring carpal alignment, as evaluated by SLA, showed superior correction capability in group DR (median, 25.3% quartiles, 21.1, 35.3, P < 0.05). Donor site complications were not significantly different between the groups. CONCLUSIONS: Corticocancellous bone graft from the anterolateral metaphysis of the DR for unstable scaphoid nonunion is associated with a shorter operation time and comparable results with that from the iliac crest in regard to union, restoration of carpal alignment, and wrist function. LEVEL OF EVIDENCE: Level III.


Asunto(s)
Fracturas no Consolidadas , Hueso Escafoides , Humanos , Radio (Anatomía)/diagnóstico por imagen , Radio (Anatomía)/cirugía , Trasplante Óseo/métodos , Ilion/trasplante , Fracturas no Consolidadas/diagnóstico por imagen , Fracturas no Consolidadas/cirugía , Hueso Escafoides/diagnóstico por imagen , Hueso Escafoides/cirugía , Fijación Interna de Fracturas/métodos , Estudios Retrospectivos
2.
Adv Funct Mater ; 33(50)2023 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-38646474

RESUMEN

While the human body has many different examples of perfusable structures with complex geometries, biofabrication methods to replicate this complexity are still lacking. Specifically, the fabrication of self-supporting, branched networks with multiple channel diameters is particularly challenging. Here, we present the Gelation of Uniform Interfacial Diffusant in Embedded 3D Printing (GUIDE-3DP) approach for constructing perfusable networks of interconnected channels with precise control over branching geometries and vessel sizes. To achieve user-specified channel dimensions, this technique leverages the predictable diffusion of crosslinking reaction-initiators released from sacrificial inks printed within a hydrogel precursor. We demonstrate the versatility of GUIDE-3DP to be adapted for use with diverse physicochemical crosslinking mechanisms by designing seven printable material systems. Importantly, GUIDE-3DP allows for the independent tunability of both the inner and outer diameters of the printed channels and the ability to fabricate seamless junctions at branch points. This 3D bioprinting platform is uniquely suited for fabricating lumenized structures with complex shapes characteristic of multiple hollow vessels throughout the body. As an exemplary application, we demonstrate the fabrication of vasculature-like networks lined with endothelial cells. GUIDE-3DP represents an important advance toward the fabrication of self-supporting, physiologically relevant networks with intricate and perfusable geometries.

3.
Arthroscopy ; 38(4): 1146-1153.e1, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34906676

RESUMEN

PURPOSE: To investigate the longitudinal trend of symptomatic distal radioulnar joint (DRUJ) instability after plate fixation for distal radius fractures (DRFs), determine which factors are associated with persistent symptomatic DRUJ instability, and evaluate the postoperative outcomes of arthroscopic foveal repair of the triangular fibrocartilage complex (TFCC) in patients with persistent symptomatic DRUJ instability after plate fixation for DRF. METHODS: All consecutive patients who underwent plate fixation for DRF between January 2014 and December 2017 and were followed up for a minimum of 1 year were included in this retrospective study. DRUJ instability was evaluated by subjective ulnar wrist pain and physical examination that included foveal sign and ballottement testing every 2 months after surgery. In patients with persistent symptomatic DRUJ instability lasting >6 months, arthroscopic transosseous foveal repair was performed with consent. Clinical outcomes were evaluated at a minimum of 2 years after surgery. The Generalized Estimating Equation model was used to analyze the incidence rate trend of symptomatic DRUJ instability. RESULTS: Overall, 204 patients were included. The incidence of symptomatic DRUJ instability decreased gradually with time after fixation for DRF until 6 months and was maintained thereafter. Thirty-four of 204 patients (16.6%) had persistent symptomatic DRUJ instability. In multivariable analysis, only high-energy injury was an independent risk factor for persistent symptomatic DRUJ instability (P = .003; odds ratio = 3.599). Seventeen patients underwent arthroscopic foveal repair. The mean follow-up period thereafter was 28.6 months. All clinical outcomes improved significantly compared with preoperative values, and no patient had residual DRUJ instability. CONCLUSION: In patients who had persistent symptomatic DRUJ instability for >6 months after plate fixation for DRFs, arthroscopic foveal repair of the TFCC is considered as a treatment option. Arthroscopic foveal repair of the TFCC to stabilize the DRUJ provided satisfactory clinical and functional outcomes and decreased ulnar-side pain. LEVEL OF EVIDENCE: Level IV, retrospective case series.


Asunto(s)
Inestabilidad de la Articulación , Fracturas del Radio , Fibrocartílago Triangular , Traumatismos de la Muñeca , Artroscopía/efectos adversos , Femenino , Estudios de Seguimiento , Humanos , Embarazo , Fracturas del Radio/complicaciones , Fracturas del Radio/cirugía , Estudios Retrospectivos , Fibrocartílago Triangular/lesiones , Traumatismos de la Muñeca/cirugía , Articulación de la Muñeca/cirugía
4.
Adv Exp Med Biol ; 1269: 387-391, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33966247

RESUMEN

The gene expression of Prox-1 and Hif-1a for the isolated primo vessels (PVs) and composite lymphatic vessels (LVs) containing PVs (LVs + PVs) was investigated by RNA-sequencing (Seq) and quantitative polymerase chain reaction (qRT-PCR) analysis. RNA-Seq on the passed 10 samples on RNA-QC for two experimental groups with PVs and PVs + LVs proceeded to the library construction stage automatically and analyzed differentially expressed genes (DEGs). From the real-time qRT-PCR analysis data, we found the marker genes of Prox-1 and Hif-1a were enriched and decreased in an isolated PVs compared to LVs, respectively. Based on mRNA transcriptional data, Prox-1 and Hif-1a were increased and decreased in PVs compared to LVs + PVs under lipopolysaccharide (LPS) treatment and relieved by acupuncture electric stimulation (AES), respectively. This finding indicates that high and low levels of Prox-1 and Hif-1a may be involved in the function of PVs and that pathophysiological and physiological condition could progress into inflamed lymphatic endothelial cells expanding the PV within the LV.


Asunto(s)
Células Endoteliales , Vasos Linfáticos , Animales , Expresión Génica , Proteínas de Homeodominio , Subunidad alfa del Factor 1 Inducible por Hipoxia , Lipopolisacáridos , Conejos , Análisis de Secuencia de ARN
5.
Nat Mater ; 13(4): 360-6, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24487495

RESUMEN

Spin currents are paramount to manipulate the magnetization of ferromagnetic elements in spin-based memory, logic and microwave devices, and to induce spin polarization in non-magnetic materials. A unique approach to create spin currents employs thermal gradients and heat flow. Here we demonstrate that a thermal spin current can be tuned conveniently by a voltage. In magnetic tunnel contacts to semiconductors (silicon and germanium), it is shown that a modest voltage (~200 mV) changes the thermal spin current induced by Seebeck spin tunnelling by a factor of five, because it modifies the relevant tunnelling states and thereby the spin-dependent thermoelectric parameters. The magnitude and direction of the spin current is also modulated by combining electrical and thermal spin currents with equal or opposite sign. The results demonstrate that spin-dependent thermoelectric properties away from the Fermi energy are accessible, and open the way towards tailoring thermal spin currents and torques by voltage, rather than material design.

6.
Mol Biol Rep ; 41(5): 2963-70, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24469727

RESUMEN

The objective of this study was to determine whether the genetic variants of CAPN1 developed in several cattle populations can be applied for Hanwoo, regarding genetic effects on meat traits. The traits were examined for 286 purebred Hanwoo steers with genotypes classified by restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP) analysis. The nucleotide positions of primers and previously identified genetic variants were based on sequences of the calpain 1 (CAPN1) gene with GenBank accession numbers (AF252504, AF248054, and AY639597). The analysis of genetic distribution estimated levels of minor allele frequencies ranged from 0.165 to 0.392, showing no significant departures from Hardy-Weinberg Equilibrium for all markers. Overall averages of heterozygosites (He) and polymorphic information contents (PICs) for all markers were calculated to 0.503 and 0.429, respectively, and the g.4558G>A marker showed the lowest He (0.425) and PIC (0.367). Animals from 29 months of age were slaughtered to measure Warner-Bratzler shear force (WBSF), cooking loss, water-holding capacity, pH, fat, and moisture. All the CAPN1 markers explained variations of WBSF, showing significant additive effects except g.5709G>A. A significant marginal mean difference in genotypes of g.6545C>T (P=0.046) was found in moisture with additive effects. From the result it may be possible to use three calpain markers (g.4558G>A, g.4685C>T, and g.6545C>T) classified by RFLP and SSCP analysis in marker assisted selection programs to improve WBSF as meat tenderness in Hanwoo.


Asunto(s)
Calpaína/genética , Variación Genética , Carne/normas , Alelos , Animales , Bovinos , Frecuencia de los Genes , Orden Génico , Estudios de Asociación Genética , Marcadores Genéticos , Genotipo , Desequilibrio de Ligamiento , Polimorfismo de Nucleótido Simple
7.
J Nanosci Nanotechnol ; 14(8): 5942-6, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25936032

RESUMEN

A new poly(octathiophene) based copolymer was designed and synthesized by the palladium catalyzed Suzuki coupling reaction. The structure of the newly obtained copolymer was confirmed by 1H-NMR and IR. The number-average molecular weight (M(n)) of the polymer was 36,000 with a poly-dispersity index of 1.15. The polymer has good solubility in common solvents such as chloroform, toluene, chlorobenzene, dichlorobenzene and tetrahydrofuran at room temperature. The optical, thermal and electrochemical properties of the polymer were characterized by UV-vis absorption, TGA and DSC and cyclovoltametry, respectively. A thin film transistor using the new polymer as an organic semiconductor was found to exhibit typical p-channel FET characteristics with a hole mobility of 5 x 10(-4) cm2/Vs.


Asunto(s)
Electrónica , Polímeros/química , Tiofenos/química , Espectroscopía de Protones por Resonancia Magnética , Espectroscopía Infrarroja por Transformada de Fourier
8.
Microbiol Immunol ; 57(5): 366-73, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23668609

RESUMEN

Infection with Helicobacter pylori leads to gastritis, peptic ulcers and gastric cancer. Moreover, when the gastric mucosa is exposed to H. pylori, gastric mucosal inflammatory cytokine interleukin-8 (Il-8) and reactive oxygen species increase. Anthocyanins have anti-oxidative, antibacterial and anti-inflammatory properties. However, the effect of anthocyanins in H. pylori-infected cells is not yet clear. In this study, therefore, the effect of anthocyanins on H. pylori-infected human gastric epithelial cells was examined. AGS cells were pretreated with anthocyanins for 24 hrs followed by H. pylori 26695 infection for up to 24 hrs. Cell viability and ROS production were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 2',7'-dichlorofluorescein diacetate assay, respectively. Western blot analyses and RT-PCR were performed to assess gene and protein expression, respectively. IL-8 secretion in AGS cells was measured by ELISA. It was found that anthocyanins decrease H. pylori-induced ROS enhancement. Anthocyanins also inhibited phosphorylation of mitogen-activated protein kinases, translocation of nuclear factor-kappa B and Iκßα degradation. Furthermore anthocyanins inhibited H. pylori-induced inducible nitric oxide synthases and cyclooxygenase-2 mRNA expression and inhibited IL-8 production by 45.8%. Based on the above findings, anthocyanins might have an anti-inflammatory effect in H. pylori-infected gastric epithelial cells.


Asunto(s)
Antocianinas/farmacología , Antiinflamatorios/farmacología , Antioxidantes/farmacología , Células Epiteliales/efectos de los fármacos , Glycine max/química , Helicobacter pylori/inmunología , Antocianinas/aislamiento & purificación , Antiinflamatorios/aislamiento & purificación , Antioxidantes/aislamiento & purificación , Western Blotting , Línea Celular , Supervivencia Celular , Ensayo de Inmunoadsorción Enzimática , Células Epiteliales/microbiología , Perfilación de la Expresión Génica , Helicobacter pylori/patogenicidad , Humanos , Interleucina-8/metabolismo , Especies Reactivas de Oxígeno , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
9.
Mol Biol Rep ; 40(7): 4651-60, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23649766

RESUMEN

Adiponectin (ADIPOQ) modulates several biological processes including energy homeostasis, glucose and lipid metabolism. The bovine ADIPOQ gene was located near the QTL affecting marbling, ribeye muscle area and fat thickness on BTA1. The gene encoding peroxisome proliferator-activated receptor-γ coactivator-1α (PPARGC1A) was located within the QTL region of the traits on BTA6. Moreover, its protein product has various biological functions such as cellular energy homeostasis, including adaptive thermogenesis, adipogenesis and gluconeogenesis. Therefore, the ADIPOQ and PPARGC1A genes are a positional and functional candidate gene for carcass traits in beef cattle. The objectives of this study were to identify polymorphisms in the bovine ADIPOQ and PPARGC1A genes, to evaluate their associations with carcass traits in Hanwoo (Korean cattle) population. We identified nine SNPs in the ADIPOQ gene. Two SNPs (DQ156119: g.1436T > C and DQ156119: g.1454A > G) in the promoter region were recognized as new SNPs identified in Hanwoo. Association analysis indicated that the g.1454A > G SNP genotype was significantly associated with effects on LMA (P = 0.004) and BF (P = 0.021). The ADIPOQ haplotype was also found to have significant effect on the LMA. In the PPARGC1A gene, we identified 11 SNPs in the two unexplored regions (intron 3 and 5). Among them, seven SNPs were located in intron 3 and four SNPs were located in intron 5. Of these 11 putative novel SNPs, two SNPs (AY839822: g.292C > T and AY839823: g.1064C > T) with minor allele frequency (MAF) > 0.20 were examined for associations with carcass traits. The association analysis revealed that both SNPs in PPARGC1A gene were significantly associated with LMA (P < 0.05). These findings suggest that the SNPs of bovine ADIPOQ and PPARGC1A genes may be a useful molecular marker for selection of carcass traits in Hanwoo.


Asunto(s)
Adiponectina/genética , Estudios de Asociación Genética , Carne/normas , Polimorfismo de Nucleótido Simple , Carácter Cuantitativo Heredable , Factores de Transcripción/genética , Alelos , Animales , Bovinos , Mapeo Cromosómico , Frecuencia de los Genes , Orden Génico , Genotipo , Haplotipos , Análisis de Secuencia de ADN
10.
bioRxiv ; 2023 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-37066190

RESUMEN

While the human body has many different examples of perfusable structures with complex geometries, biofabrication methods to replicate this complexity are still lacking. Specifically, the fabrication of self-supporting, branched networks with multiple channel diameters is particularly challenging. Here, we present the Gelation of Uniform Interfacial Diffusant in Embedded 3D Printing (GUIDE-3DP) approach for constructing perfusable networks of interconnected channels with precise control over branching geometries and vessel sizes. To achieve user-specified channel dimensions, this technique leverages the predictable diffusion of crosslinking reaction-initiators released from sacrificial inks printed within a hydrogel precursor. We demonstrate the versatility of GUIDE-3DP to be adapted for use with diverse physiochemical crosslinking mechanisms by designing seven printable material systems. Importantly, GUIDE-3DP allows for the independent tunability of both the inner and outer diameters of the printed channels and the ability to fabricate seamless junctions at branch points. This 3D bioprinting platform is uniquely suited for fabricating lumenized structures with complex shapes characteristic of multiple hollow vessels throughout the body. As an exemplary application, we demonstrate the fabrication of vasculature-like networks lined with endothelial cells. GUIDE-3DP represents an important advance toward the fabrication of self-supporting, physiologically relevant networks with intricate and perfusable geometries.

11.
Nat Commun ; 14(1): 4346, 2023 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-37468483

RESUMEN

The biofabrication of three-dimensional (3D) tissues that recapitulate organ-specific architecture and function would benefit from temporal and spatial control of cell-cell interactions. Bioprinting, while potentially capable of achieving such control, is poorly suited to organoids with conserved cytoarchitectures that are susceptible to plastic deformation. Here, we develop a platform, termed Spatially Patterned Organoid Transfer (SPOT), consisting of an iron-oxide nanoparticle laden hydrogel and magnetized 3D printer to enable the controlled lifting, transport, and deposition of organoids. We identify cellulose nanofibers as both an ideal biomaterial for encasing organoids with magnetic nanoparticles and a shear-thinning, self-healing support hydrogel for maintaining the spatial positioning of organoids to facilitate the generation of assembloids. We leverage SPOT to create precisely arranged assembloids composed of human pluripotent stem cell-derived neural organoids and patient-derived glioma organoids. In doing so, we demonstrate the potential for the SPOT platform to construct assembloids which recapitulate key developmental processes and disease etiologies.


Asunto(s)
Bioimpresión , Células Madre Pluripotentes , Humanos , Organoides , Bioimpresión/métodos , Hidrogeles , Materiales Biocompatibles
12.
Mol Biol Rep ; 39(5): 5323-30, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22179692

RESUMEN

This study was aimed to search new genetic variants in the bovine FABP4 gene as molecular markers for meat quality and carcass traits. PCR-RFLP analysis revealed that three SNPs located at nucleotide positions g.2834C>G, g.3533T>A, and g.3691G>A were identified based on a GenBank accession number (NC_007312.4). Sequence analysis revealed that SNPs were located in intron 1 (g.2834C>G) and 2 (g.3533T>A), and an exon 3 (g.3691G>A), showing allele frequencies as 0.592, 0.579, and 0.789, respectively. Genetic variabilities of heterozygosity (He) and polymorphic information contents (PIC) were estimated for g.2834C>G (0.608 and 0.531), g.3533T>A (0.615 and 0.539), and g.3691G>A (0.498 and 0.401) loci, respectively. A SNP located in the exon 3 of FABP4 was characterized and associated with desirable increases of MS (marbling scores) and MG (meat quality grades) in Hanwoo. The statistical analysis revealed that additive effects by GG genotypes in g.3691G>A SNP were significantly greater than AA genotypes in MS and MG traits. These findings suggest that the FABP4g.3691G>A SNP will be a useful candidate locus to maximize economic benefits for cattle populations.


Asunto(s)
Bovinos/genética , Proteínas de Unión a Ácidos Grasos/genética , Estudios de Asociación Genética , Carne/normas , Polimorfismo de Nucleótido Simple/genética , Carácter Cuantitativo Heredable , Animales , Secuencia de Bases , Electroforesis en Gel de Agar , Frecuencia de los Genes/genética , Genotipo , Heterocigoto , Análisis de los Mínimos Cuadrados , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción/genética , República de Corea
13.
Mol Biol Rep ; 39(4): 4869-74, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21960012

RESUMEN

Quantitative trait loci for fat deposition and carcass traits have been identified in the vicinity of the gene encoding phosphodiesterase 1B (PDE1B) on bovine chromosome 5. Therefore, the PDE1B gene can be considered as a positional and functional candidate gene for carcass traits in beef cattle. This study aimed to identify single nucleotide polymorphisms (SNPs) in the PDE1B gene and to evaluate their associations with carcass traits in Korean cattle. Eight SNPs, g.440T>G, g.17122A>G, g.17507A>C, g.17575A>G, g.17607T>C, g.17609C>A, g.17692C>T, and g.17707C>G, were identified in the region ranged from exon 1 to intron 6. Five of them were used for association analysis because of their availability of restriction fragment length polymorphisms. As a result, g.17122A>G in intron 3 was significantly associated with backfat thickness (BFT), and g.17507A>C in exon 5 was associated with longissimus dorsi muscle area (LMA, P < 0.05). Animals with the AG genotype of g.17122 had thicker BFT than those with the AA genotype. Animals with the AA or AC genotype of g.17507A>C had larger LMA than those with the CC genotype. We suggested the PDE1B gene as a candidate gene for carcass traits of beef cattle. Fine mapping would be required for application to marker-assisted selection.


Asunto(s)
Bovinos/genética , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 1/genética , Estudios de Asociación Genética , Carne , Carácter Cuantitativo Heredable , Animales , Frecuencia de los Genes/genética , Marcadores Genéticos , Haplotipos/genética , Carne/normas , Nucleótidos/genética , Reacción en Cadena de la Polimerasa , Polimorfismo de Longitud del Fragmento de Restricción/genética , Polimorfismo de Nucleótido Simple/genética , República de Corea
14.
Phytother Res ; 26(12): 1904-12, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22431150

RESUMEN

Citrus fruits (Citrus aurantium L.) have long been used as a traditional herbal medicine. The benefits of the flavonoids found in Citrus aurantium L. include anti-inflammation, anti-cancer, anti-viral and anti-bacterial activities, and enhancement of the immune response. The study investigated the effect of the flavonoids isolated from Citrus aurantium L. native to Korea on the production of pro-inflammatory mediators by blocking signal transduction mediated by nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) in lipopolysaccharide (LPS)-induced L6 skeletal muscle cells. The flavonoids decreased the production of inducible nitric oxide synthase, cyclooxygenase-2, interleukin-6 and tumor necrosis factor-alpha by suppressing NF-κB and MAPKs signal pathways in LPS-induced L6 skeletal muscle cells. These findings suggest that the flavonoids isolated from Korea Citrus aurantium L. might have anti-inflammatory effects that regulate the expression of inflammatory mediators in L6 skeletal muscle cells.


Asunto(s)
Citrus/química , Flavonoides/farmacología , Mediadores de Inflamación/metabolismo , Células Musculares/efectos de los fármacos , Antiinflamatorios/farmacología , Línea Celular , Ciclooxigenasa 2/metabolismo , Humanos , Interleucina-6/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Células Musculares/metabolismo , FN-kappa B/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo
15.
ACS Appl Mater Interfaces ; 14(46): 52516-52523, 2022 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-36354752

RESUMEN

It is challenging to fabricate 3D architectures of conductive hydrogels and impart uniform conductivity at the same time. Here, we demonstrate a one-step 3D printing technique for controlling the 3D structure of hydrogel materials while simultaneously conferring uniform conductivity. The core technology lies in the in situ polymerization of conductive polymers by the diffusion of monomers and redox initiators to an interface. An alginate ink containing ammonium peroxide as a redox initiator is printed in a silica nanoparticle matrix containing a pyrrole monomer. A 3D structure of conductive polypyrrole is uniformly fabricated on the surface of the alginate immediately after the printing. This simple process provides uniform electrical conductivity throughout the bulk structure.

17.
Carbohydr Polym ; 263: 117976, 2021 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33858573

RESUMEN

Optimization of the rheological properties of the matrix is ​​critical for high-fidelity matrix-assisted 3D printing (MAP), which enables the free-form fabrication of fluidic soft materials. This report describes the generic criteria observable in the printing process of cellulose nanofiber (CNF) hydrogels: the sharpness of an angled line, the cross-sectional ratio of a feature, the surface roughness of features, and the completeness of multi-line writing. The concentration and physical properties of the CNF affects the printing fidelity by changing the values of the four criteria, which are closely related to the rheological properties of the matrix. The printing fidelity can be enhanced by the optimal combination of the inks and the CNF matrix. Hydrophilic and hydrophobic inks are printed in the CNF matrix demonstrating as a universal matrix for free-form fabrication with liquid inks.


Asunto(s)
Celulosa/química , Hidrogeles/química , Nanofibras/química , Impresión Tridimensional , Celulasa/química , Estudios Transversales , Interacciones Hidrofóbicas e Hidrofílicas , Tinta , Reología , Madera/química
18.
Adv Healthc Mater ; 10(18): e2100644, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34342179

RESUMEN

Granular, microgel-based materials have garnered interest as promising tissue engineering scaffolds due to their inherent porosity, which can promote cell infiltration. Adapting these materials for 3D bioprinting, while maintaining sufficient void space to enable cell migration, can be challenging, since the rheological properties that determine printability are strongly influenced by microgel packing and void fraction. In this work, a strategy is proposed to decouple printability and void fraction by blending UV-crosslinkable gelatin methacryloyl (GelMA) microgels with sacrificial gelatin microgels to form composite inks. It is observed that inks with an apparent viscosity greater than ≈100 Pa s (corresponding to microgel concentrations ≥5 wt%) have rheological properties that enable extrusion-based printing of multilayered structures in air. By altering the ratio of GelMA to sacrificial gelatin microgels, while holding total concentration constant at 6 wt%, a family of GelMA:gelatin microgel inks is created that allows for tuning of void fraction from 0.20 to 0.57. Furthermore, human umbilical vein endothelial cells (HUVEC) seeded onto printed constructs are observed to migrate into granular inks in a void fraction-dependent manner. Thus, the family of microgel inks holds promise for use in 3D printing and tissue engineering applications that rely upon cell infiltration.


Asunto(s)
Bioimpresión , Microgeles , Gelatina , Células Endoteliales de la Vena Umbilical Humana , Humanos , Metacrilatos , Impresión Tridimensional , Ingeniería de Tejidos , Andamios del Tejido
19.
Carbohydr Polym ; 253: 117238, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33278994

RESUMEN

We investigate the three-dimensional (3D) structuring of cellulose nanofiber (CNF) foam-based ink using direct ink writing 3D printing and the transformation of CNF foam from an insulator to a conductor. The colloidal stability of a CNF foam is critical to producing a solid CNF foam which can be used as a template for the synthesis of conducting polymers. Liquid CNF foam ink is produced by simple stirring of CNF suspension with sodium dodecyl sulfate as an emulsifier. The shear thinning behavior of the liquid CNF foam ink enables printing through a needle. Flexible design of CNF foam structures is enabled by 3D printing using computer-aided design. Lightweight conductive CNF foams are prepared via in situ polymerization of polypyrrole on a solid CNF foam. The topological features of the resultant porous conductive CNF foams are observed, and their conductivity is investigated.

20.
Carbohydr Polym ; 258: 117688, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33593561

RESUMEN

Since shelf life of perishable foods is short, a compelling challenge is to prolong the freshness of foods with a cost-effective strategy. A perishable fruit, the strawberry, is chosen as a model perishable food and an edible film coating is applied to it using carboxymethylated cellulose nanofibers (CM-CNFs) stabilized by cationic salts. A transparent and impermeable CM-CNF film is formed at the strawberry surface using a dip coating process. The formation of the film is dependent on the electrostatic interaction between anionic CM-CNF and salt cations. Physical properties of the film are characterized and the effectiveness of edible film coating on the freshness of perishable fruit is evaluated by the measurement of weight loss, CO2 release, firmness, total solid sugar and acidity. Cellulose nanofiber is a promising cost-effective material appropriate for use as an edible coating that contributes to the long-term storage and prolonged freshness of foods.


Asunto(s)
Celulosa/química , Reactivos de Enlaces Cruzados/química , Películas Comestibles , Conservación de Alimentos/instrumentación , Fragaria/metabolismo , Nanofibras/química , Calcio/química , Dióxido de Carbono/química , Cationes , Química/métodos , Conservación de Alimentos/métodos , Iones , Electricidad Estática
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