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1.
Adv Sci (Weinh) ; : e2102557, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34939355

RESUMO

Protein-based hydrogels have attracted great attention due to their excellent biocompatible properties, but often suffer from weak mechanical strength. Conventional strengthening strategies for protein-based hydrogels are to introduce nanoparticles or synthetic polymers for improving their mechanical strength, but often compromise their biocompatibility. Here, a new, general, protein unfolding-chemical coupling (PNC) strategy is developed to fabricate pure protein hydrogels without any additives to achieve both high mechanical strength and excellent cell biocompatibility. This PNC strategy combines thermal-induced protein unfolding/gelation to form a physically-crosslinked network and a -NH2/-COOH coupling reaction to generate a chemicallycrosslinked network. Using bovine serum albumin (BSA) as a globular protein, PNC-BSA hydrogels show macroscopic transparency, high stability, high mechanical properties (compressive/tensile strength of 115/0.43 MPa), fast stiffness/toughness recovery of 85%/91% at room temperature, good fatigue resistance, and low cell cytotoxicity and red blood cell hemolysis. More importantly, the PNC strategy can be not only generally applied to silk fibroin, ovalbumin, and milk albumin protein to form different, high strength protein hydrogels, but also modified with PEDOT/PSS nanoparticles as strain sensors and fluorescent fillers as color sensors. This work demonstrates a new, universal, PNC method to prepare high strength, multi-functional, pure protein hydrogels beyond a few available today.

2.
ACS Appl Mater Interfaces ; 13(19): 22774-22784, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-33944548

RESUMO

Polyacrylamide is widely employed in constructing functional hydrogels. However, the volume expansion of this hydrogel in water weakens its mechanical properties and restricts its application. Herein, we report a strategy to convert the swollen and weak polyacrylamide/carboxymethyl chitosan hydrogel into a strong and tough one by hydrolysis in acid solution with an elevated temperature. The obtained hydrolyzed hydrogels possess a high strength, toughness, and tearing fracture energy of 5.9 MPa, 22 MJ/m3 and 7517 J/m2, which are 254, 535 and 186 times higher than those of the original swollen one, respectively. In addition, the gels demonstrate low residual strain and rapid self-recovery abilities. Moreover, the gels have good shape memory behavior controlled by temperature. Furthermore, the gels can be worked as strain sensors with a broad strain window, high sensitivity, excellent linear response, and great durability in monitoring human motions after immersing treatment in a normal saline solution. This work provides a new method for preparing the stretchable and tough polyacrylamide-based hydrogels used in the areas of soft actuators and flexible electronics.

3.
J Colloid Interface Sci ; 594: 54-63, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33756368

RESUMO

Organic dye-containing wastewater has become an increasingly serious environmental problem due to the rapid development of the printing and dyeing industry. Hydrogel is a promising adsorbent for organic dyes because of its unique three-dimension network structure and versatile functional groups. Though many efforts have been made in hydrogel adsorbents recently, there is still a critical challenge to fabricate hydrogel adsorbent with high adsorption capacity and high efficiency at the same time. To address this concern, we developed a calcium hydroxide nano-spherulites/poly(acrylic acid -[2-(Methacryloxy)ethyl]trimethyl ammonium chloride) hydrogel adsorbent with novel villi-like structure. The hydrogels were prepared through a simple free radical copolymerization method using calcium hydroxide nano-spherulites as crosslinker. The resultant hydrogel adsorbents showed a maximum adsorption capacity of 2249 mg/g in a 400 mg/L methylene blue solution and a high removal ratio of 98% in 1 h for a 50 mg/L methylene blue solution. In addition, the adsorption behaviors of our hydrogel adsorbents could be well described by pseudo-second-order kinetic model and Langmuir adsorption isotherm model. Furthermore, this kind of hydrogel adsorbent showed selective adsorption behavior for methylene blue. Altogether, the hydrogel adsorbent developed in this work has a high capacity and high efficiency in organic dye removing and promised a great potential in wastewater treatment application.

4.
ACS Appl Mater Interfaces ; 13(6): 7443-7452, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33528998

RESUMO

Flexible electronics greatly facilitate human life due to their convenience and comfortable utilization. Liquid metals are an ideal candidate for flexible devices; however, the high surface tension and poor surface wettability restrict their application on diverse substrates. Herein, a printable and recyclable ink composed of poly(vinyl alcohol) and a liquid metal (PVA-LM) was developed to resolve these problems. The materials were designed considering the compatibility between PVA and the liquid metal, and the composite theory was applied to determine the component proportion. The developed composites improved the surface wettability of the liquid metal on diverse substrates, and three-dimensional (3D) printing technology was chosen to maximize the use of this material. Moreover, the PVA-LM ink showed excellent conductivity of about 1.3 × 105 S/m after being turned on, which favored the designing of alarm systems and object locators. The flexible sensors produced with this ink have broad application, high sensitivity, and superstable signal generation even after 200 cycles. When acting as strain sensors, the constructed composites had high sensitivity for monitoring the human movements. Furthermore, liquid metals in printed products can be recycled under alkaline conditions. This study opens a new direction for the next generation of environmentally friendly flexible devices.

5.
Acta Biochim Biophys Sin (Shanghai) ; 53(1): 54-62, 2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33289795

RESUMO

Excessive accumulation of cholesterol in ß cells initiates endoplasmic reticulum (ER) stress and associated apoptosis. We have reported that excessive uptake of cholesterol by MIN6 cells decreases the expression of secretagogin (SCGN) and then attenuates insulin secretion. Here, we aimed to determine whether cholesterol-induced SCGN decrease is involved in the modulation of ER stress and apoptosis in pancreatic ß cells. In this study, MIN6 cells were treated with oxidized low-density lipoprotein (ox-LDL) for 24 h, and then intracellular lipid droplets and cell apoptosis were quantified, and SCGN and ER stress markers were identified by western blot analysis. Furthermore, small interfer RNA (siRNA)-mediated SCGN knockdown and recombinant plasmid-mediated SCGN restoration experiments were performed to confirm the role of SCGN in ER stress and associated cell apoptosis. Finally, the interaction of SCGN with ATF4 was computationally predicted and then validated by a co-immunoprecipitation assay. We found that ox-LDL treatment increased the levels of ER stress markers, such as phosphorylated protein kinase-like endoplasmic reticulum kinase, phosphorylated eukaryotic initiation factor 2 alpha, activating transcription factor 4 (ATF4), and transcription factor CCAAT-enhancer-binding protein homologous protein, and promoted MIN6 cell apoptosis; in addition, the expression of SCGN was downregulated. siRNA-mediated SCGN knockdown exacerbated ß-cell ER stress by increasing ATF4 expression. Pretreatment of MIN6 cells with the recombinant SCGN partly antagonized ox-LDL-induced ER stress and apoptosis. Furthermore, a co-immunoprecipitation assay revealed an interaction between SCGN and ATF4 in MIN6 cells. Taken together, these results demonstrated that pancreatic ß-cell apoptosis induced by ox-LDL treatment can be attributed, in part, to an SCGN/ATF4-dependent ER stress response.


Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Células Secretoras de Insulina/metabolismo , Secretagoginas/genética , Secretagoginas/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Sítios de Ligação , Linhagem Celular , Biologia Computacional , Regulação para Baixo/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Técnicas de Silenciamento de Genes , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Lipídeos/análise , Lipoproteínas LDL/toxicidade , Camundongos , Modelos Moleculares , Mapeamento de Interação de Proteínas
6.
J Biomater Appl ; 35(1): 59-71, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32233716

RESUMO

The purpose of this two-year study was to evaluate the histocompatibility and osteogenic properties of a composite material consisting of poly(l-co-d,l lactide) (PLDLA) and silica-based bioactive glass fibers in vivo. PLDLA and PLDLA/silica-based bioactive glass fibers pins were implanted into the erector spinae muscles and femurs of beagles. Muscle and bone tissue samples were harvested 6, 12, 16, 26, 52, 78, and 104 weeks after implantation. Histology analysis was used to assess the histocompatibility, angiogenesis, and bone-implant contact. Micro-computed tomography was used to evaluate bone formation around the pins. Immunohistochemistry and western blotting revealed the expression level of the osteogenesis-related proteins. Addition of bioactive glass was demonstrated to possess better histocompatibility and reduce the inflammatory reactions in vivo. Moreover, PLDLA/silica-based bioactive glass fibers pins were demonstrated to promote angiogenesis and increase osteogenesis-related proteins expression, and thus played a positive role in osteogenesis and osseointegration after implantation. Our findings indicated that a composite of PLDLA and silica-based bioactive glass fiber is a promising biodegradable material for clinical use.


Assuntos
Materiais Biocompatíveis/química , Poliésteres/química , Dióxido de Silício/química , Animais , Materiais Biocompatíveis/farmacologia , Cerâmica/química , Cerâmica/farmacologia , Cães , Histocompatibilidade , Teste de Materiais , Osteogênese/efeitos dos fármacos , Poliésteres/farmacologia , Próteses e Implantes , Dióxido de Silício/farmacologia
7.
Biomed Mater ; 15(3): 035010, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32066131

RESUMO

The present study aimed to evaluate the mechanical and degradative properties of poly(L-co-D,L-lactic acid)/silicate bioactive glass fibers (PLDLA/SGFs) composite pins in vivo. Both PLDLA and PLDLA/SGFs pins were inserted into the erector spinae muscles and femurs of beagle dogs and were harvested 6, 12, 16, 26, 52, 78, and 104 weeks after insertion. Bone formation around the pins was evaluated by micro-computed tomography. Mechanical properties were measured by the shear strength test. Thermogravimetric analysis, differential scanning calorimetry, and gel permeation chromatography were used to assess the degradation of these materials. The surface and cross-sectional morphology of both pins were observed using a scanning electron microscope. The experimental data demonstrated that PLDLA/SGFs pins can support new bone formation due to the influence of bioactive glass fibers. PLDLA/SGFs composite pins had higher initial shear strength and were relatively stable for at least 26 weeks. The addition of bioactive glass fibers accelerated the degradation rate of the composite pins. Thus, PLDLA/SGFs composite pins have promising potential for bone fixation applications.


Assuntos
Materiais Biocompatíveis/química , Vidro/química , Poliésteres/química , Animais , Pinos Ortopédicos , Varredura Diferencial de Calorimetria , Cães , Fêmur/cirurgia , Inflamação , Teste de Materiais , Microscopia Eletrônica de Varredura , Resistência ao Cisalhamento , Estresse Mecânico , Resistência à Tração , Termogravimetria , Microtomografia por Raio-X
8.
FEBS Open Bio ; 9(11): 1968-1982, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31571430

RESUMO

Hirschmanniella mucronata is a plant-parasitic nematode that is widespread in rice production areas and causes 10-25% yield losses a year on average. Here, we investigated the mechanism of resistance to this nematode by comparing the transcriptomes of roots from resistant (Jiabali) and susceptible (Bawangbian) varieties of rice. Of 39 233 unigenes, 2243. exhibited altered total expression levels between control and infected resistant and susceptible varieties. Significant differences were observed in the expression levels of genes related to stress, peptidase regulation or inhibition, oxidoreductase activity, peroxidase activity and antioxidant activity. The up-regulated genes related to plant secondary metabolites, such as phenylpropanoid, lignin, cellulose or hemicellulose, may result in an increase in the degree of resistance of Jiabali to the H. mucronata infection compared with that of Bawangbian by affecting cell wall organization or biogenesis. Of the genes that responded similarly to H. mucronata infection, ~252 (~76.59%) showed greater changes (whether induced or suppressed) in RN155 (susceptible varieties infected by rice root nematode) than in RN51 (resistance varieties infected by rice root nematode). Nineteen pathogenesis-related genes belonging to nine pathogenesis-related gene families were significantly induced by H. mucronata in the infected roots of Jiabali and Bawangbian, and 13 differentially expressed genes showed changes in their abundance only in the susceptible Bawangbian variety. This study may help enhance our understanding of the mechanisms underlying plant resistance to nematodes.


Assuntos
Regulação da Expressão Gênica de Plantas/genética , Oryza/genética , Doenças das Plantas/genética , Raízes de Plantas/genética , Tylenchoidea/patogenicidade , Animais , Perfilação da Expressão Gênica , Oryza/parasitologia , Doenças das Plantas/parasitologia , Raízes de Plantas/parasitologia
9.
Int J Biol Macromol ; 141: 108-116, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31479668

RESUMO

Natural protein hydrogels are considered as the promising candidates for biomaterials. However, natural protein hydrogels often exhibit poor mechanical properties. Herein, using bovine serum albumin (BSA) as natural protein model, a new kind of D/C-hybrid DN gels, consisting of tetrakis(hydroxymethyl)phosphonium chloride (THPC) cross-linked BSA (THPC-BSA) as dynamic covalent bond cross-linked first network and covalently cross-linked polyacrylamide (PAAm) as second network, were successfully synthesized by a facile method. Different from fully chemical DN gels without recovery, the optimized THPC-BSA/PAAm D/C-hybrid DN gel not only demonstrated excellent tensile properties, but also displayed extremely fast self-recovery property and fatigue resistance. More importantly, various natural proteins could be also used to prepare natural protein-based D/C-hybrid DN gels, and all of them showed improved mechanical properties and fast self-recovery properties. The results indicate our new strategy to fabricate recoverable natural protein-based D/C-hybrid DN gels is general. We hope our new strategy as well as our natural protein-based D/C-hybrid DN gels will provide a new avenue to prepare and study high performance natural protein hydrogels.


Assuntos
Resinas Acrílicas/química , Hidrogéis/química , Hidrogéis/síntese química , Soroalbumina Bovina/química , Animais , Bovinos
10.
J Mater Chem B ; 7(10): 1708-1715, 2019 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-32254912

RESUMO

Regenerated silk fibroin hydrogels (RSF gels) are extensively investigated in the biomedical field. However, the mechanical properties of RSF hydrogels are often weak or brittle, which limits their potential for applications where high strength is required. Herein, strong and tough RSF-based hydrogels with large extensibility and rapid self-recovery property were developed via the double network (DN) concept. RSF/HPAAm DN gels, consisting of a physical RSF/SDS gel as the first network and a physically cross-linked HPAAm as the second network, are fully physical network structures. At optimal conditions, the RSF/HPAAm DN gel exhibited integrated high mechanical properties, including high compressive strength (122 MPa), high tensile strength (σf of 1.17 MPa), large extensibility (εf of 19.03 mm mm-1), high toughness (W of 11.75 MJ m-3 and T of 1769 J m-2) and rapid self-recovery (61% toughness recovery after 1 min of resting at room temperature). Interestingly, owing to contained sodium dodecyl sulfate (SDS) and NaCl, RSF/HPAAm DN gels also displayed ionic conductivity, which could be used as a strain sensor, a touch screen pen and the electronic skin of artificial robots. We believe that this design strategy as well as our RSF/HPAAm DN gel will provide a new route for achieving high performance RSF-based gels with new functionalities.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Humanos
11.
J Mater Chem B ; 6(41): 6629-6636, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-32254871

RESUMO

Shape-shifting materials have received increasing attention owing to their promising applications in soft robotics, biomedical devices, actuators, morphing aircraft and so on. However, their practical applications are limited due to their weak mechanical strength, low interfacial adhesion and complex preparation method. In this paper, bilayer films were synthesized by in situ one-step forming soft and water-swellable nanocomposite hydrogels on the surface of the rigid and nonresponsive poly(ethylene terephthalate) (PET) film without any surface modification. The strong interfacial toughness between the hydrogel layer and the PET layer, the high swelling ability of the soft hydrogel layer, and the high strength of the rigid PET film endowed the bilayer film with excellent self-bending behaviour. The shape deformation of the bilayer films can be controlled by adjusting the geometry parameters of the bilayer film, such as the hydrogel thickness, the aspect ratio and the width of the bilayer film. Moreover, the bilayer film exhibited excellent reversible bidirectional self-bending behaviour. In addition, the mechanisms for driving the shape transformation were discussed. We believe this work will provide a promising and simple strategy to develop novel responsive materials with controlled shape deformation.

12.
ACS Appl Mater Interfaces ; 10(3): 2946-2956, 2018 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-29278483

RESUMO

Hydrophobically associated hydrogels (HA gels) are one of most extensively investigated high strength hydrogels. Semicrystalline HA gels, prepared by micellar copolymerization, show high strength and notable functionalities of self-healing and shape-memory. However, the hydrophobic comonomers in these semicrystalline HA gels are usually limited to the long alkyl length monomers (18-alkyl(meth)acrylates). In the present work, N-acryloyl 11-aminoundecanoic acid (A11AUA), consisting of 10 -CH2 groups and a -COOH group at the end of alkyl chain, was used as hydrophobic comonomer to prepare physical A11AUA-based HA gels in the presence of high concentration cetyltrimethylammonium bromide (CTAB) or sodium dodecyl sulfate. Differential scanning calorimetry, wide-angle X-ray scattering, and small-angle X-ray scattering experiments had identified that the A11AUA-based HA gels possessed crystalline domains and clusters of crystalline domains, while lauryl methacrylate (C12M)-based HA gels were amorphous. As a result, A11AUA-based HA gels displayed much better tensile properties than those of C12M-based HA gels. At the optimal condition, the A11AUA-CTAB HA gel demonstrated integrated high performances, including high stiffness (E of 1016 kPa), high strength (σf of 0.75 MPa), high toughness (T of 7540 J/m2), rapid self-recovery (94% recovery after heat treatment at 60 °C for 2 min), outstanding shape memory (fully recovered to the permanent shape only 2-14 s), and excellent self-healing properties (as healed at 60 °C for 2 h; stress and strain healing efficiency reached to 64% and 85%, respectively). We believe this work provides a new insight for HA gels, which is beneficial to design new hydrogels with integrated high performances, such as high strength, high toughness, large extensibility, and shape-memory and self-healing properties.

13.
J Mater Chem B ; 5(37): 7683-7691, 2017 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32264369

RESUMO

Double network (DN) hydrogels composed of two different polymer networks with strong asymmetry are excellent structural platforms to integrate different mechanical properties into a single material. However, simultaneously achieving high strength and self-healing properties in DN hydrogels still remains a challenge. In this work, we design and synthesize Gelatin/Polyacrylamide (Gelatin/PAAm) DN gels by combining thermo-reversible and physically crosslinked gelatin as the first network and covalently crosslinked PAAm as the second network. The optimized Gelatin/PAAm DN gels demonstrated high mechanical properties (E of 84 kPa, σf of 0.268 MPa, εf of 40.69 mm mm-1 and W of 6.01 MJ m-3), large hysteresis (up to 1012 kJ m-3 at λ = 30), and rapid self-recovery properties (∼87% toughness recovery at room temperature). These superior properties were largely attributed to effective energy dissipation via the rupture of the first gelatin network. Most interestingly, Gelatin/PAAm DN gels without any chemical crosslinkers in the second network enabled the achievement of both high mechanical strength and fast self-healing properties. By modulating the heating temperatures and healing times, the healed Gelatin/PAAm gels could achieve 53% healing efficiency at a physiological temperature range, which greatly expands their uses for biomedical applications. The combination of high strength, self-recovery, and self-healing properties makes Gelatin/PAAm gels promising candidates for further development and use as thermoresponsive biomaterials under physiological conditions.

14.
Biochem Biophys Res Commun ; 476(4): 204-211, 2016 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-27207834

RESUMO

Oxidative stress is known to contribute to insulin resistance in diabetes, however the mechanism is not clear. Here we show that reactive oxygen species (ROS) could reprogram the glucose metabolism through upregulating the pentose pathway so as to induce insulin resistance in type 2 diabetes (T2DM). By using streptozotocin-high fat diet (STZ-HFD) induced T2DM in rats, we show that diabetic rats exhibited high level of oxidative stress accompanied with insulin resistance. Hypoxia inducible factor (HIF-1α) protein expression as well as its downstream target glucokinase (GK), were upregulated; The glycogen synthesis increased accordingly; However the glycolysis was inhibited as indicated by decreased phosphofructokinase-1 (PFK-1), pyruvate kinase (PK), phospho-PFK-2/PFK-2 (p-PFK-2/PFK-2) ratio, lactate dehydrogenase (LDH) and pyruvate dehydrogenase kinase (PDK); Pyruvate dehydrogenase (PDH) which promotes pyruvate to generate acetyl-CoA declined as well. While phospho-acetyl-CoA carboxylase/acetyl-CoA carboxylase (p-ACC/ACC) ratio increased, meaning that lipid beta-oxidation increased. The pentose pathway was activated as indicated by increased G6PD activity and NADPH level. Our results suggest that diabetic rats countervail ROS stress through increasing pentose pathway, and reprogram the energy metabolic pathway from glycolysis into lipid oxidation in order to compensate the ATP requirement of the body, which causes insulin resistance.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Glucose/metabolismo , Resistência à Insulina , Espécies Reativas de Oxigênio/metabolismo , Animais , Glicólise , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Insulina/metabolismo , Metabolismo dos Lipídeos , Masculino , NADP/metabolismo , Estresse Oxidativo , Via de Pentose Fosfato , Ratos , Ratos Sprague-Dawley
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