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1.
Nat Mater ; 21(1): 103-109, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34819661

RESUMEN

Supramolecular polymer networks are non-covalently crosslinked soft materials that exhibit unique mechanical features such as self-healing, high toughness and stretchability. Previous studies have focused on optimizing such properties using fast-dissociative crosslinks (that is, for an aqueous system, dissociation rate constant kd > 10 s-1). Herein, we describe non-covalent crosslinkers with slow, tuneable dissociation kinetics (kd < 1 s-1) that enable high compressibility to supramolecular polymer networks. The resultant glass-like supramolecular networks have compressive strengths up to 100 MPa with no fracture, even when compressed at 93% strain over 12 cycles of compression and relaxation. Notably, these networks show a fast, room-temperature self-recovery (< 120 s), which may be useful for the design of high-performance soft materials. Retarding the dissociation kinetics of non-covalent crosslinks through structural control enables access of such glass-like supramolecular materials, holding substantial promise in applications including soft robotics, tissue engineering and wearable bioelectronics.


Asunto(s)
Matriz Extracelular , Polímeros , Hidrogeles/química , Polímeros/química , Ingeniería de Tejidos , Agua
2.
Zhonghua Yi Xue Yi Chuan Xue Za Zhi ; 38(3): 219-223, 2021 Mar 10.
Artículo en Zh | MEDLINE | ID: mdl-33751528

RESUMEN

OBJECTIVE: To investigate the clinical phenotype and genetic characteristics of a patient with hypohidrotic ectodermal dysplasia (HED) due to partial deletion of EDA gene. METHODS: The child has presented with HED complicated with epilepsy. Family trio whole exome sequencing (Trio-WES), copy number variation sequencing (CNV-seq), and karyotype analysis were carried out to explore the underlying genetic etiology. RESULTS: The proband, a 7-year-and-8-month-old boy, presented with thin curly hair, thin and sparse eyebrow, xerosis cutis, susceptibility to hyperthermia from childhood, hypohidrosis, sharp/sparse/absent teeth, saddle nose, prominent forehead, auricle adulation and seizure. He was found to have a normal chromosomal karyotype, and no abnormality was found by Trio-WES. Genome-wide CNV-seq revealed a 341.90 kb deletion at Xq13.1q13.1 (chrX: 68 796 566-69 138 468). As verified by PCR-electrophoresis, the deletion has removed part of the EDA gene. The deletion was derived from his mother with normal hair, mild xerosis cutis, and sparse, decidulated and nail-like teeth. The mother was detected with a heterozygous 242.10 kb deletion at Xq13.1q13.1 (chrX: 68 836 154-69 078 250). CONCLUSION: Both the proband and his mother have carried a Xq13.1 microdeletion involving part of the EDA gene. The clinical phenotypes of the mother and the proband were consistent with the clinical characteristics of X-linked recessive HED, for which partial deletion of the EDA gene is probably accountable.


Asunto(s)
Variaciones en el Número de Copia de ADN , Displasia Ectodermal Anhidrótica Tipo 1 , Displasia Ectodérmica , Niño , Displasia Ectodermal Anhidrótica Tipo 1/genética , Ectodisplasinas/genética , Humanos , Masculino , Fenotipo
3.
Soft Matter ; 16(21): 5044-5053, 2020 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-32452496

RESUMEN

Conventional approaches to mitigate fouling of membrane surfaces impart hydrophilicity to the membrane surface, which increases the water of hydration and fluidity near the surface. By contrast, we demonstrate here that tuning the membrane surface energy close to that of the dispersive component of water surface tension (21.8 mN m-1) can also improve the antifouling properties of the membrane. Specifically, ultrafiltration (UF) membranes were first modified using polydopamine (PDA) followed by grafting of amine-terminated polysiloxane (PSi-NH2). For example, with 2 g L-1 PSi-NH2 coating solution, the obtained coating layer contains 53% by mass fraction PSi-NH2 and exhibits a total surface energy of 21 mN m-1, decreasing the adsorption of bovine serum albumin by 44% compared to the unmodified membrane. When challenged with 1 g L-1 sodium alginate in a constant-flux crossflow system, the PSi-NH2-grafted membrane exhibits a 70% lower fouling rate than the pristine membrane at a water flux of 110 L (m2 h)-1 and good stability when cleaned with NaOH solutions.


Asunto(s)
Incrustaciones Biológicas/prevención & control , Membranas Artificiales , Siloxanos/química , Absorción Fisicoquímica , Alginatos/química , Indoles/química , Polímeros/química , Albúmina Sérica Bovina/química , Ultrafiltración/métodos , Purificación del Agua/métodos
4.
J Mater Sci Mater Med ; 29(9): 136, 2018 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-30120587

RESUMEN

Surface nanotopography and bioactive ions have been considered to play critical roles on the interactions of biomaterials with cells. In this study, a TiO2 nanorod film incorporated with Zn-containing bioactive glass (TiO2/Zn-BG) was prepared on tantalum substrate, trying to evaluate the synergistic effects of nanotopograpgy and bioactive ions to promote cellular osteogenic differentiation activity. The expression of osteogenic-related genes, ALP as well as the ECM mineralization on TiO2/Zn-BG film were significantly upregulated compared to that of the film without TiO2 nanorod nanostructure (Zn-BG) or without Zn (TiO2/BG). Moreover, a much low Zn2+ release level on TiO2/Zn-BG film was beneficial to promote the osteogenesis, which could be ascribed to that a semi-closed space established by TiO2 nanorods with adhered cells provided an appropriate micro-environment that facilitated Zn2+ adsorption.


Asunto(s)
Cerámica , Nanopartículas del Metal/química , Nanotubos/química , Osteogénesis , Titanio/química , Zinc/química , Células 3T3 , Adsorción , Fosfatasa Alcalina/metabolismo , Animales , Materiales Biocompatibles/química , Adhesión Celular , Diferenciación Celular , Matriz Extracelular/metabolismo , Iones , Ratones , Nanoestructuras/química , Osteocalcina/metabolismo , Propiedades de Superficie , Tantalio/química
5.
Clin Oral Implants Res ; 28(8): 911-919, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27283240

RESUMEN

OBJECTIVES: To evaluate the effect of strontium-oxide layer on new bone formation and osseointegration of sandblasted large-grit double-acid-etched (SLA) implant. MATERIAL AND METHODS: Strontium-oxide layer on the SLA surface was produced by hydrothermal treatment using a Sr-containing solution. The surface topographies, roughness, hardness values, chemical elements and ionic release of SLA and the strontium-containing SLA (Sr-SLA) surface were measured by special instruments separately. Sixty-four SLA and Sr-SLA implants were inserted into the proximal tibiae and femoral condyles of sixteen non-osteoporotic New Zealand white rabbits. The biological effects were evaluated by removal torque (RTQ) testing and histomorphometric analysis after 3 and 6 weeks of implantation. RESULTS: The surface characteristics showed Sr-SLA surfaces with dotted nanostructures can release appropriate amount of strontium ions into surrounding tissue till 14 days. In vivo, the Sr-SLA implants presented significantly higher RTQ than SLA implants at 3 and 6 weeks (P < 0.05). The Sr-SLA implants presented higher bone-to-implant contact (BIC) than SLA implants in cortical bone at 3 and 6 weeks (P < 0.05). The bone area was slightly higher for the Sr-SLA implants at 3 and 6 weeks (P > 0.05). CONCLUSIONS: The strontium-oxide layer on the SLA surface has the potential to improve implant osseointegration in non-osteoporotic rabbits.


Asunto(s)
Implantación Dental Endoósea/métodos , Oseointegración/efectos de los fármacos , Estroncio , Titanio , Animales , Interfase Hueso-Implante , Implantes Dentales , Masculino , Conejos , Propiedades de Superficie
6.
Langmuir ; 32(13): 3226-33, 2016 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-27010624

RESUMEN

Bone regeneration and scaffold degradation do not usually follow the same rate, representing a daunting challenge in bone repair. Toward this end, we propose to use an external field such as light (in particular, a tissue-penetrating near-infrared light) to precisely monitor the degradation of the mineralized scaffold (demineralization) and the formation of apatite mineral (mineralization). Herein, CaTiO3:Yb(3+),Er(3+)@bioactive glass (CaTiO3:Yb(3+),Er(3+)@BG) nanofibers with upconversion (UC) photoluminescence (PL) were synthesized. Such nanofibers are biocompatible and can emit green and red light under 980 nm excitation. The UC PL intensity is quenched during the bone-like apatite formation on the surface of the nanofibers in simulated body fluid; more mineral formation on the nanofibers induces more rapid optical quenching of the UC PL. Furthermore, the quenched UC PL can recover back to its original magnitude when the apatite on the nanofibers is degraded. Our work suggests that it is possible to optically monitor the apatite mineralization and demineralization on the surface of nanofibers used in bone repair.


Asunto(s)
Materiales Biocompatibles/efectos de la radiación , Nanofibras/efectos de la radiación , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/toxicidad , Materiales Biomiméticos , Compuestos de Calcio/síntesis química , Compuestos de Calcio/efectos de la radiación , Compuestos de Calcio/toxicidad , Células Cultivadas , Erbio/química , Erbio/efectos de la radiación , Erbio/toxicidad , Luminiscencia , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/efectos de los fármacos , Nanofibras/química , Nanofibras/toxicidad , Óxidos/síntesis química , Óxidos/efectos de la radiación , Óxidos/toxicidad , Titanio/efectos de la radiación , Titanio/toxicidad , Iterbio/química , Iterbio/efectos de la radiación , Iterbio/toxicidad
7.
J Nanosci Nanotechnol ; 16(6): 5577-85, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27427599

RESUMEN

The chitosan/alginate-trace element-codoped octacalcium phosphate/nano-sized bioactive glass (CS/ALG-teOCP/nBG) composite membranes were prepared by a layer-by-layer coating method for the functional requirement of guided bone regeneration (GBR). The morphology, mechanical properties and moisture content of the membranes was studied by scanning electron microscopy (SEM) observation, mechanical and swelling test. The results showed that the teOCP/nBG distributed uniformly in the composite membranes, and such as-prepared composite membrane exhibited an excellent tensile strength, accompanying with mechanical decay with immersion in aqueous medium. Cell culture and MTT assays showed that the surface microstructure and the ion dissolution products from teOCP/nBG components could enhance the cell proliferation, and especially the composite membranes was suitable for supporting the adhesion and growth behavior of human bone marrow mesenchymal stem cells (hBMSCs) in comparison with the CS/ALG pure polymer membranes. These results suggest that the new CS/ALG-teOCP/nBG composite membrane is highly bioactive and biodegradable, and favorable for guiding bone regeneration.


Asunto(s)
Alginatos/química , Regeneración Ósea/efectos de los fármacos , Fosfatos de Calcio/química , Quitosano/química , Vidrio/química , Regeneración Tisular Dirigida/métodos , Membranas Artificiales , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Supervivencia Celular/efectos de los fármacos , Ácido Glucurónico/química , Ácidos Hexurónicos/química , Humanos , Fenómenos Mecánicos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/efectos de los fármacos , Nanoestructuras/química , Agua/química
8.
Anal Chem ; 86(20): 10021-4, 2014 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-24517078

RESUMEN

In this work, a novel enzyme-linked immunosorbent assay (ELISA) with a low limit of detection and high sensitivity was developed using atom transfer radical polymer (ATRP)-modified gold nanoparticles (AuNPs). Clear signal amplification was achieved by introducing an abundance of horseradish peroxidase (HRP) to the AuNPs, because of the ATRP modification. This result suggested that the new ELISA was able to detect antigens in complex mixtures, and the limit of detection (LOD) was lower than that of conventional ELISA by a factor of 81. The new ELISA strategy greatly decreased the LOD during analysis and exhibited excellent reproducibility, stability, and feasibility. Therefore, it is a promising technique with many potential applications in biochemistry and medical science research.


Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos , Oro/química , Nanopartículas del Metal/química , Polímeros/química , Peroxidasa de Rábano Silvestre/química , Microscopía Electrónica de Transmisión
9.
Int J Biol Macromol ; 267(Pt 2): 131595, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38621564

RESUMEN

The development of modern construction and transportation industries demands increasingly high requirements for thin, lightweight, high-strength, and highly tough composite materials, such as metal carbides and concrete. Bamboo is a green, low-carbon, fast-growing, renewable, and biodegradable material with high strength and toughness. However, the density of its inner layer is low due to the functional gradient (the volume fraction of vascular bundles decreases from the outer layer to the inner layer), resulting in low performance, high compressibility, and significant amounts of bamboo waste. We utilized chemical and mechanical treatments of bamboo's low-density, low-strength inner layers to create lightweight, ultra-thin, high-strength, and high-toughness composites. The treatment included the partial removal of lignin and hemicellulose to alter the chemical components, followed by mechanical drying and hot pressing. The treated bamboo had 100.8 % higher tensile strength (150.35 MPa), 47.7 % higher flexural strength (97.67 MPa), and 132.0 % higher water resistance and was approximately 68.9 % thinner than the natural bamboo. The excellent physical and mechanical properties of the treated bamboo are attributed to the contraction of parenchyma cells during delignification, the interlocking due to the collapse of parenchyma cells during mechanical drying, and an increase in the density of hydrogen bonds between cellulose molecular chains during hot pressing. Our research provides a new strategy for obtaining sustainable, ultra-thin, lightweight, high-strength, and high-toughness composite materials from bamboo for construction and transportation applications.


Asunto(s)
Lignina , Polisacáridos , Sasa , Lignina/química , Polisacáridos/química , Sasa/química , Resistencia a la Tracción , Poaceae/química
10.
Opt Express ; 21(7): 8831-43, 2013 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-23571973

RESUMEN

This paper reports experimental studies on speckles produced by the rough silver films. The speckles on the rough glass/silver surfaces are measured with a microscopic imaging system. The structures of speckle patterns have the characteristics of fractals and multi-scaled sizes. We find that with the increase of the silver film thickness, the contrast of the speckles increases, and the intensity probability density functions gradually transit to exponential decay. We calculate the global and the local correlation functions of the speckle patterns, and find that both the fractal exponent and correlation length of the small-sized speckles decrease with the thickness of the silver films. We use the mechanisms of rough dielectric interface scattering and random surface plasmon waves to give the preliminary explanations for the evolutions of the speckles.


Asunto(s)
Vidrio/química , Membranas Artificiales , Plata/química , Resonancia por Plasmón de Superficie/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Ensayo de Materiales , Propiedades de Superficie
11.
ACS Biomater Sci Eng ; 9(5): 2524-2533, 2023 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-37092816

RESUMEN

Surface potentials of biomaterials have been shown to regulate cell fate commitment. However, the effects of chirality-patterned potential distribution on macrophage polarization are still only beginning to be explored. In this work, we demonstrated that the chirality-patterned potential distribution of CoFe2O4/poly(vinylidene fluoride-trifluoroethylene) (CFO/P(VDF-TrFE)) films could significantly down-regulate the M1 polarization of bone marrow-derived macrophages (BMDMs). Specifically, the dextral-patterned surface potential distribution simultaneously up-regulated the expression of M2-related markers of BMDMs. The results were attributed to the sensitive difference of integrin subunits (α5ß1 and αvß3) to the dextral- and sinistral-patterned surface potential distribution, respectively. The interaction difference between the integrin subunits and surface potential distribution altered the cell adhesion and cytoskeletal structure and thereby the polarization behavior of BMDMs. This work, therefore, emphasizes the importance of chirality of potential distribution on cell behavior and provides a new strategy to regulate the immune response of biomaterials.


Asunto(s)
Materiales Biocompatibles , Integrinas , Diferenciación Celular
12.
Analyst ; 137(12): 2757-61, 2012 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-22575850

RESUMEN

With an ultra-high surface area and abundant functional groups, graphene oxide (GO) provides an ideal substrate for the immobilization of trypsin. We demonstrated that trypsin could be immobilized on GO sheets assisted by polymers as molecular spacers to maintain the activity of the enzyme. And with the trypsin-linked GO as the enzyme immobilization probe, a novel microwave-assisted on-plate digestion method has been developed with subsequent analysis by MALDI-MS. The feasibility and performance of the digestion approach were demonstrated by the proteolysis of standard proteins. The results show that this novel approach substantially accelerated proteolysis and reduced the time required for traditional procedures involving on-plate enzymatic digestion and sample preparation prior to MALDI-MS analysis. The novel digestion approach is simple and efficient, offering great promise for high throughput protein identification.


Asunto(s)
Enzimas Inmovilizadas/química , Grafito/química , Microondas , Óxidos/química , Proteolisis , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Tripsina/química , Enzimas Inmovilizadas/metabolismo , Modelos Moleculares , Conformación Molecular , Polímeros/química , Tripsina/metabolismo
13.
ACS Appl Mater Interfaces ; 14(3): 3633-3642, 2022 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-35018773

RESUMEN

Urine is the most appropriate body fluid for analysis because it is easily and less-invasively obtained than blood; thus, urinary miRNAs can better represent the local stage of the disease and might grow up to be a new class of noninvasive biomarkers of postmyocardial infarction (MI). Monofunctionalized Au nanoparticles (AuNPs) with only one selective DNA at a specific location are more promising in nanotechnology. This study developed a urinary miRNA ultratrace detection strategy based on single-target DNA-functionalized AuNPs for the noninvasive prognosis of post-MI. The AuNPs were designed with only single-stranded biotinylated DNA complementary to the target miRNA through a ratio-optimized stoichiometric method for the first time. Combined with the duplex specific nuclease-assisted target recycling amplification, the single-target DNA-functionalized AuNPs for the first time were used in inductively coupled plasma-mass spectrometry for the determination of urinary miRNA with high sensitivity. After optimizing the reaction conditions, a linear detection range between 1 fM and 10 pM for miR-155 and a detection limit of 0.47 fM were obtained. Finally, the target miR-155 in urine samples collected from MI rats was quantified and the level of miR-155 in MI groups was 30 times higher than in the control groups. The results suggest that urinary miR-155 could be a novel biomarker for the noninvasive diagnosis of MI.


Asunto(s)
Materiales Biocompatibles/química , ADN/química , Oro/química , Nanopartículas del Metal/química , MicroARNs/orina , Infarto del Miocardio/diagnóstico , Humanos , Ensayo de Materiales , Pronóstico
14.
Nanoscale ; 14(31): 11343-11352, 2022 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-35894543

RESUMEN

As the changes of biomarkers directly reflect the occurrence of degenerative diseases, accurate detection of biomarkers is of great significance for disease diagnosis and control. However, single index detection has high uncertainties to accurately reflect the pathological characteristics because of the complexity of the human internal environment and the extremely trace concentration of indicators. To this end, a method for simultaneous detection of dual-biomarkers based on anti-interference magnetic molecularly imprinted polymers (D-mag-MIPs) is thereby proposed, and successfully applied in human urine analysis for the detection of Parkinson's disease bio-indicators 4-dihydroxyphenylacetic acid (DOPAC) and dopamine (DA). In this work, carboxyl functionalized ferric oxide served as a magnetic core, laying a solid foundation for batch detection. Hyperbranched polyethylenimine, whose abundant amino groups can provide multiple interaction forces to templates with high affinity, is employed as a functional monomer. Relative to single-template MIPs, D-mag-MIPs achieve the detection of dual bio-indicators in a one-time test, reducing the false positive result probability and enhancing the detection accuracy. The proposed methodology has been evaluated to exhibit good anti-interference, satisfactory precision, low detection limits, wide linear ranges and fast batch detection for DA and DOPAC. This work thus offers an alternative and efficient pathway for convenient batch detection of dual bio-indicators from biofluids at once.


Asunto(s)
Impresión Molecular , Ácido 3,4-Dihidroxifenilacético , Adsorción , Dopamina , Humanos , Fenómenos Magnéticos , Impresión Molecular/métodos , Polímeros Impresos Molecularmente , Polímeros
15.
Biomater Sci ; 10(16): 4576-4587, 2022 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-35791864

RESUMEN

Piezoelectric poly(vinylidene fluoride-trifluoroethylene) has demonstrated an ability to promote osteogenesis, and biomaterials with a chirality-patterned topological surface could enhance cellular osteogenic differentiation. In this work, we created a chirality-patterned surface potential distribution of CoFe2O4/poly(vinylidene fluoride-trifluoroethylene (CFO/P(VDF-TrFE)) membranes to explore their osteogenic response under no change in surface chemical and topology, attempting to further strengthen the ability of the membranes to promote osteogenesis. The chirality-patterned surface potential distribution was established by microdomain contact polarization with the help of sinistral/dextral-patterned ITO interdigital microelectrodes. In the in vitro evaluations, the mesenchymal stem cells showed a positive response in osteogenic differentiation to CFO/P(VDF-TrFE) membranes with both sinistral- and dextral-patterned surface potential distributions, however, the dextral-patterned distribution gave a stronger response than the sinistral-patterned one. And the in vivo evaluation showed a response tend in new bone tissue formation similar to the in vitro evaluations. The stronger response in osteogenic differentiation and osteogenesis for the CFO/P(VDF-TrFE) membrane with the dextral-patterned distributions may be attributed to that the intense interaction of the cells with the electrophysiological microenvironment appears due to a correspondingly higher expression of integrin α5ß1, which significantly up-regulates the Arp2/3 complex expression, a crucial factor for cytoskeleton reorganization, possibly increases cytoskeleton contractility, and strengthens the transduction of the osteogenesis-related signaling cascade. This work proves that the chirality-patterns in surface potential distributions could provide an osteogenic response similar to a chirality-patterned topological surface.


Asunto(s)
Osteogénesis , Polivinilos , Materiales Biocompatibles/química , Diferenciación Celular , Polivinilos/química , Titanio/química
16.
Elife ; 112022 10 28.
Artículo en Inglés | MEDLINE | ID: mdl-36305580

RESUMEN

The skeletal system contains a series of sophisticated cellular lineages arising from the mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) that determine the homeostasis of bone and bone marrow. Here, we reasoned that osteocyte may exert a function in regulation of these lineage cell specifications and tissue homeostasis. Using a mouse model of conditional deletion of osteocytes by the expression of diphtheria toxin subunit α in dentin matrix protein 1 (DMP1)-positive osteocytes, we demonstrated that partial ablation of DMP1-positive osteocytes caused severe sarcopenia, osteoporosis, and degenerative kyphosis, leading to shorter lifespan in these animals. Osteocytes reduction altered mesenchymal lineage commitment, resulting in impairment of osteogenesis and induction of osteoclastogensis. Single-cell RNA sequencing further revealed that hematopoietic lineage was mobilized toward myeloid lineage differentiation with expanded myeloid progenitors, neutrophils, and monocytes, while the lymphopoiesis was impaired with reduced B cells in the osteocyte ablation mice. The acquisition of a senescence-associated secretory phenotype (SASP) in both osteogenic and myeloid lineage cells was the underlying cause. Together, we showed that osteocytes play critical roles in regulation of lineage cell specifications in bone and bone marrow through mediation of senescence.


A hallmark of aging is the weakening of our muscles and bones, which become more fragile as we get older. These gradual changes can result in a humpback and muscle shrinking among other conditions. At the same time little is known about what role osteocytes ­ the most abundant type of bone cell ­ play in the process of bone and muscle aging. One way to investigate the role of osteocytes in aging is to remove them and observe what happens to nearby cells as they age. To achieve this Ding, Gao, Gao et al. genetically altered mice so that they would carry and activate a gene called DTA in their osteocytes. DTA is a gene derived from the bacterium that causes diphtheria, and when it is activated, it produces a toxin that accumulates in cells, eventually killing them. In the mice line developed by Ding, Gao, Gao et al. DTA slowly killed osteocytes, leading to adult mice lacking most of their osteocyte population that have a normal embryonic development. This is important because the fact that the mice develop normally before birth allowed the team to rule out embryonic defects when looking at their results. Ding, Gao, Gao et al. found that, without enough osteocytes, the nearby bone and bone marrow cells aged faster than expected. Indeed, the skeleton and muscles of adult mice was severely affected by the loss of osteocytes, leading to fragile bones with lower mass and muscle shrinking. These mice looked old in their young age and died earlier. At the cellular level, the removal of osteocytes impaired the formation of osteoblasts, the cells that are responsible for making bones. It also led to an increase in the numbers of osteoclasts ­ the cells that destroy bone tissue to repair it and maintain it ­ and fat tissue cells. Furthermore, cells in the bone marrow, which go on to make white blood cells, were also affected. The mechanisms through which osteocytes affect the growth of these other cells is yet to be fully understood. However, Ding, Gao, Gao et al. did observe that these cells acquired traits characteristic of aging cells, implying that osteocytes have a role in regulating cellular aging or senescence. Among these senescence traits is the increased production and secretion of molecules that interact with the immune system, a feature known as the 'senescence-associated secretory phenotype'. Overall, the results of Ding, Gao, Gao et al. suggest that reducing the number of osteocytes in mice leads to faster bone aging and affects the balance of the different cell types required for healthy bone and bone marrow growth. Future research could focus on finding drugs that allow osteocytes to keep performing their role during aging, and thus help maintain bone health. The findings of Ding, Gao, Gao et al. also suggest that osteocytes may be playing a previously underappreciated role in age-related diseases, which warrants further investigation.


Asunto(s)
Osteoblastos , Osteocitos , Animales , Osteocitos/metabolismo , Osteoblastos/metabolismo , Médula Ósea , Huesos , Osteogénesis/fisiología
17.
J Biomed Mater Res B Appl Biomater ; 109(12): 2227-2236, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34080765

RESUMEN

Electrical stimulation has been proved to be critical to regulate cell behavior. But, cell behavior is also susceptible to multiple parameters of the adverse interferences such as surface current, electrochemical reaction products, and non-uniform compositions, which often occur during direct electric stimulation. To effectively prevent the adverse interferences, a novel piezoelectric poly(vinylidene fluoride-trfluoroethylene)(P(VDF-TrFE)) layer was designed to coat onto the indium tin oxide (ITO) planar microelectrode. We found the electrical stimulation was able to regulate the osteogenic differentiation of mesenchymal stem cells (MSCs) through calcium-mediated PKC signaling pathway. Meanwhile, the surface charge of the designed P(VDF-TrFE) coating layer could be easily controlled by the pre-polarization process, which was demonstrated to trigger integrin-mediated FAK signaling pathway, finally up-regulating the osteogenic differentiation of MSCs. Strikingly, the crosstalk in the downstream of the two signaling cascades further strengthened the ERK pathway activation for osteogenic differentiation of MSCs. This P(VDF-TrFE) layer coated electrical stimulation microelectrodes therefore provide a distinct strategy to manipulate multiple-elements of biomaterial surface to regulate stem cell fate commitment.


Asunto(s)
Células Madre Mesenquimatosas , Osteogénesis , Diferenciación Celular , Microelectrodos , Polivinilos/química
18.
Talanta ; 233: 122496, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34215114

RESUMEN

In this work, a synergistic imprinting strategy combined with metal coordination based on ligand-free Fe3O4-Cu was proposed to fabricate molecularly imprinted polymers (MIPs) for the recognition and isolation of bovine hemoglobin (BHb) specifically in biological samples. Copper doped magnetic microspheres prepared solvothermally in a one-pot pathway act as both magnetic core and metal affinity substrate. Upon anchoring BHb to Fe3O4-Cu through metal coordination, the imprinted layer was formed via dopamine self-polymerization. Profiting from the synergistic effect, the obtained imprinted microspheres exhibited an enhanced adsorption performance with the adsorption capacity of 400.86 mg g-1, imprinting factor of 11.88, selectivity coefficient above 5.8, superior to most of other reported BHb-MIPs. Furthermore, kinetic adsorption analyses pointed to a chemisorption-limited process as described by the pseudo-second-order model, and the isothermal adsorption analyses implied monolayer adsorption, as described by the Langmuir model. In addition, the resultant magnetic MIPs can be used at least six adsorption-desorption cycles without re-incubation in the metallic salt solution, avoiding secondary environmental pollution. Furthermore, the well-defined materials showed selectivity both in individual protein samples and bovine serum, providing a promising potential in bioseparation.


Asunto(s)
Impresión Molecular , Adsorción , Animales , Bovinos , Hemoglobinas , Fenómenos Magnéticos , Microesferas , Polímeros
19.
Anal Chim Acta ; 1161: 338475, 2021 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-33896554

RESUMEN

The common elution process of molecularly imprinted polymers (MIPs) is carried out in an acidic medium, which greatly affects the stability and reusability of synthetic MIPs, especially for magnetic MIPs. In this study, we fabricated an acid-resistant imprinted layer formed by phase-transitioned lysozyme on magnetic nanomaterials for selective extraction of chlorogenic acid in Honeysuckle, which often coexists with structural analogs. The newly designed acid-resistant imprinted layer can not only protect the internal magnetic core from denudation and dissolution, but also maintain the integrity of the imprinted layer during the elution process. The resultant magnetic MIPs exhibited good stability with no change on morphology after the repeatedly eluting process, and satisfactory reusability that can be used at least ten adsorption-desorption cycles with almost no decrease for adsorption capacity. In addition, the resultant materials possess satisfactory magnetism, uniform morphology with typical core-shell structure, stable crystallization, and good adsorption performance showing on high adsorption amount (10.82 mg g-1), fast kinetic equilibrium time (as short as 30 min), and satisfactory selectivity (IF = 2.85, SC > 1.5). At last, the obtained magnetic MIPs as adsorbents coupled with HPLC were successfully used to selective extract CGA in Honeysuckle samples with the high recoveries in the range of 92.0-104.4%, and the contents of CGA in Honeysuckle samples from the different origin are calculated in the range of 0.98%-1.24%.


Asunto(s)
Lonicera , Impresión Molecular , Nanoestructuras , Adsorción , Ácido Clorogénico , Fenómenos Magnéticos , Polímeros , Extracción en Fase Sólida
20.
Carbohydr Polym ; 257: 117636, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33541661

RESUMEN

Development of multifunctional antibacterial agent with long-lasting antibacterial activity and biofilm ablation performance is significant for the effective treatment of bacterial infections. Here, by utilizing the electrostatic interaction between sulfonated chitosan (SCS) and Ag+ and chitosan (CS), and the sodium borohydride reduction method, a versatile antibacterial agent (AgNPs@CS/SCS) capable of generating silver nanoparticles (AgNPs) in-situ and long-acting slow-release Ag+ was developed. AgNPs@CS/SCS has a good physiological stability and can long-acting slow-release of Ag+ due to the pH-dependent Ag+ release behavior of AgNPs. Noteworthy, AgNPs@CS/SCS can exert both excellent short- and long-term antibacterial and biofilm ablation activity. Importantly, it also exhibits superior antibacterial activity in the treatment of implant infections, accompanied by good biocompatibility. Together, this study suggest that AgNPs@CS/CSC is indeed a versatile antibacterial agent, and is expected to provide an effective treatment modality for implant infections in the clinic settings.


Asunto(s)
Antibacterianos/farmacología , Materiales Biocompatibles/química , Quitosano/química , Sistemas de Liberación de Medicamentos , Nanopartículas del Metal/química , Nanogeles/química , Plata/química , Biopelículas/crecimiento & desarrollo , Preparaciones de Acción Retardada/química , Escherichia coli/efectos de los fármacos , Concentración de Iones de Hidrógeno , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos , Electricidad Estática
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