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1.
Biomacromolecules ; 2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-32202418

RESUMO

Chitosan (CS), a natural biopolymer, has been extensively explored for multiple applications including tissue engineering, gene therapy, bioimaging, and sewage treatment due to its abundant availability, intrinsic biocompatibility, biodegradability, and tunable biological properties. Nevertheless, the actual use of CS is limited because of its water-insolubility in physiological circumstances, which could be optimized by chemical modifications via active side groups. Etherification is one of the most widely used reactions to obtain water-soluble CS derivatives, such as hydroxybutyl CS (HBC). HBC, synthesized by grafting hydroxybutyl groups to the functional hydroxyl and amino groups of CS skeleton, has been demonstrated to possess superior biological properties over those of CS, especially satisfactory water solubility in neutral condition and reversible stimulus-response against external heat. Meanwhile, the unique characteristics of thermally sensitive "sol-gel" and "sol-micelle" transition have gained tremendous attention, which differ in heterogeneously and homogeneously synthesized HBC. Herein, we discuss the synthesis (heterogeneously and homogeneously) of HBC, favorable physiochemical properties of HBC, and HBC-centered biocomposites in a range of formulations or dosage forms such as sponges, gels, nanoparticles, nanofibers, and films. Meanwhile, we summarize the potential bioapplications and trends of HBC and HBC centered biocomposites and offer our perspectives on the plausible advances in this field in the near future.

2.
Carbohydr Polym ; 236: 116051, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32172865

RESUMO

Effective bleeding control is critical first step in current civilian and military trauma treatment, however commercially available hemostatic materials are difficult to achieve expected effects. In this study, a composite sponge (H-D) based on hydroxybutyl chitosan (HBC) and diatom-biosilica (DB) was designed for hemorrhage control. H-D exhibited hierarchical porous structure, favorable biocompatibility (hemolysis ratio < 5 %, no cytotoxicity), along with high and fast fluid absorbability (11-16 times than that of weight), given effective hemostasis effect (clotting time shortened by 70 % than that of control). In vitro coagulation tests demonstrated that H-D could provide strong interface effect to induce erythrocyte absorption and aggregation, as well as activating the intrinsic coagulation pathway and thus accelerated blood coagulation. These results proved that H-D composite sponge has great potential for hemorrhage control.

3.
Carbohydr Polym ; 236: 116067, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32172882

RESUMO

Stimuli-responsive gel volume variation is reversible and has shown promising applications, which may be potential for contraction or expansion fabrication, generating shrinking or swelling volume of the original. In this study, a thermo/photo dual-crosslinking hydrogel is prepared with methacrylated hydroxylbutyl chitosan (MHBC) and gelatin methacrylate (GelMA). The M/G hydrogel undergoes sol-gel phase transition under room temperature and shrinking deformation upon elevating temperature. Besides nontoxicity and biodegradability, dual crosslink endowed the composite hydrogel with strengthened and tunable mechanical property, controlled and repeatable contraction property in response to temperature elevation from 25 ℃ to 37 ℃, and enhanced cell adhesion in 3D culture. These peculiarities of M/G hydrogel provide great potential for application in contraction fabrication to acquire high resolution or small scale features that may be limited by fabrications devices.

4.
Int J Biol Macromol ; 146: 99-109, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31874265

RESUMO

Biocompatibility and mechanical properties have always been important indicators for the application of hydrogel materials in tissue engineering. In this work, a high strength and toughness chitosan-poly (vinyl alcohol) (PVA) DN (double network) hydrogel based on multiple hydrogen bonding interactions was prepared by applying the simple freezing-heating alternate treatment to the chitosan-PVA alkaline solution. The PVA first network was prepared by freeze crystallization, and the chitosan second network was constructed by raising the chitosan/KOH/urea temperature to 45 °C. The dynamic hydrogen bonding presented in the first PVA network and the second chitosan network given the hydrogel superior compressive (60%-230 KPa), tensile (152 KPa-360%), recoverability (90.77% after 5 cycles) and anti-swelling properties. The results of in vitro cell compatibility and in vivo subcutaneous implantation in rats both indicated that the chitosan-PVA DN hydrogel had the ability to promote cell attachment and wound healing. This DN hydrogel based on hydrogen bonding is expected to be applied in the tissue engineering repair. In addition, the hydrogel preparation process is simple and non-toxic, which provides a reference for the production of green and safe tissue engineering hydrogels.

5.
Int J Biol Macromol ; 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31739062

RESUMO

The effect of NaOH/urea solution freeze-thaw pretreatment to the chitosan of purity and the degree of deacetylation from the crab shell was examined. Higher purity chitosan (CS1) was prepared. On this basis, the raw materials after the first demineralization were pretreated with NaOH/urea solution freeze-thaw under different freeze-thaw situations. The produced chitosans (CS1-CS4) were characterized in the ash content, solubility, protein content, degree of deacetylation, viscosity average molecular weight, SEM, FTIR, XRD, antimicrobial activity. The results showed that the freeze-thaw process had advantageous influence on decreasing the ash content and increasing degree of deacetylation and antibacterial activity. Moreover, the antibacterial property of the extracted chitosans seemed to be positively related to their degree of deacetylation. It is concluded that CS4 had the lowest ash content (0.052%), the highest degree of deacetylation (86.02%) and the greatest antibacterial activity. Therefore, we recommend CS4 as agent for industrial and pharmaceutical applications.

6.
IEEE Trans Cybern ; 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31567111

RESUMO

With the development of social network platforms, discussion forums, and question answering websites, a huge number of short messages that typically contain a few words for an individual document are posted by online users. In these short messages, emotions are frequently embedded for communicating opinions, expressing friendship, and promoting influence. It is quite valuable to detect emotions from short messages, but the corresponding task suffers from the sparsity of feature space. In this article, we first generate term groups co-occurring in the same context to enrich the number of features. Then, two basic supervised topic models are proposed to associate emotions with topics accurately. To reduce the time cost of parameter estimation, we further propose an accelerated algorithm for our basic models. Extensive evaluations using three short corpora validate the efficiency and effectiveness of the accelerated models for predicting the emotions of unlabeled documents, in addition to generate the topic-level emotion lexicons.

7.
Carbohydr Polym ; 224: 115176, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472871

RESUMO

Weak mechanical properties, lack biocompatibility and relatively bioinert are formidable obstruct in application of bone repair materials. Multifunctional composite materials have been considered as a viable solution to this problem. Here, a new double network (DN) hydrogel was constructed by physical cross-linking of medical grade poly (vinyl alcohol) (PVA) and chitosan in KOH/urea dissolution system. The obtained hydrogel demonstrated excellent tensile strength (0.24 MPa), elongation at break (286%), and high compressive strength (0.11 MPa on the strain of 60%). Our studies showed that the prepared hydrogel had excellent biocompatibility in vitro and the introduction of hydroxyapatite (HAp) by surface mineralization imparted hydrogel the ability to induce rat bone marrow stem cells (rBMSCs) differentiation. The in vivo experiments revealed that the surface mineralized double network hydrogel significantly accelerated simultaneous regeneration of bone defects in a rabbit bone defect model. All the results indicated that this hydrogel has the potential as a bone repair material.


Assuntos
Osso e Ossos/efeitos dos fármacos , Quitosana/química , Hidrogéis/química , Hidrogéis/farmacologia , Minerais/química , Álcool de Polivinil/química , Adsorção , Animais , Osso e Ossos/citologia , Osso e Ossos/fisiologia , Adesão Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Força Compressiva , Hidróxidos/química , Osteogênese/efeitos dos fármacos , Compostos de Potássio/química , Coelhos , Soroalbumina Bovina/química , Propriedades de Superfície , Resistência à Tração , Engenharia Tecidual , Ureia/química
8.
J Mater Chem B ; 7(31): 4854-4866, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31389952

RESUMO

The efficient delivery of vaccines to draining lymph nodes and the induction of robust local immune responses are crucial for immunotherapy. Transdermal administration has been evidenced to facilitate the delivery of ingredients to lymph nodes. In this study, transfersomes with opposite surface charges were applied for antigen encapsulation and these were integrated with dissolving microneedles to investigate their effects on immune responses via transdermal immunization. The microneedles were easily inserted into mouse skin and achieved the local release of nanovaccines into the dermis through dissolution. Although anionic nanovaccines promoted cellular uptake via DC2.4, cationic nanovaccines exhibited stronger escape capacities from endocytic compartments, facilitating antigen processing via an MHC-I presentation pathway, and formed larger accumulations in lymph nodes. Compared with their anionic counterparts, the cationic nanovaccines more efficiently activated DC maturation and induced Th1 immunity; this was suggested by the significantly increased IgG2a/IgG1 ratio and elevated cytokine secretion from Th1 cells, without an enhancement in the Th2 response. Such an enhanced Th1 antigen-specific immune response in lymph nodes via a transdermal vaccine delivery platform is beneficial for potential immunotherapy approaches.

9.
Int J Biol Macromol ; 132: 1090-1097, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30902715

RESUMO

We have designed microcapsules-immobilized composite capsules and evaluated the oral delivery efficacy. The composite capsules were developed by encapsulating Perinereis aibuhitensis extract (PaE), a model substance possessing antioxidant activity, loaded gum Arabic/gelatin microcapsules in calcium alginate (CA) hydrogel (PaE:CA/GA/GE-CCs). In vitro antioxidant assay showed the obtained composite capsules were able to protect PaE from gastric acid, since O2- scavenging rate of encapsulated PaE was about 1.8 folds as that of free PaE after 5 h incubation in simulated gastrointestinal fluid. Moreover, in vivo study showed that after the treatment of oral administration for 30 days, the mice of PaE:CA/GA/GE-CCs group suffered significantly lower oxidative stress level than those of other groups, illustrated as higher SOD and catalase activity, as well as lower malondialdehyde content in liver cells. The results demonstrated the composite capsules could concentrate PaE in small intestine, and enhance the absorption efficiency and in vivo efficacy.


Assuntos
Alginatos/química , Antioxidantes/administração & dosagem , Antioxidantes/química , Portadores de Fármacos/química , Gelatina/química , Goma Arábica/química , Hidrogéis/química , Administração Oral , Animais , Antioxidantes/farmacologia , Cápsulas , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/toxicidade , Teste de Materiais , Camundongos , Estresse Oxidativo/efeitos dos fármacos
10.
Int J Biol Macromol ; 121: 293-300, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30287376

RESUMO

A thermo-sensitive hydroxybutyl chitosan (HBC) hydrogel was prepared by using 1,2­butene oxide as an etherification modifying agent. To obtain the maximum yield of HBC, response surface methodology (RSM) was applied to optimize its preparation conditions. Key factors were chosen firstly by Plackett-Burman design (PBD) experiments, such as the concentration of NaOH, the ratio of isopropanol to water and reaction temperature. Steepest ascent experiments were employed to reach the top region of the response and determine the appropriate levels of three key factors. A three-level-three-variable Box-Behnken design (BBD) was used to further optimize the synthesis parameters. The results indicated that when the concentration of NaOH and the ratio of isopropyl alcohol to water were 40.65% and 2.68:1 at reaction temperature of 59 °C, respectively, the yield of HBC production was 5.897 ±â€¯0.112 g and close to the predicted value (6.002 g), which demonstrated that the effectiveness of BBD model and the controllability for the yield of HBC in the heterogeneous reaction system.


Assuntos
Quitosana/análogos & derivados , Hidrogéis/química , Temperatura Ambiente , Alcenos/química , Quitosana/química
11.
PLoS One ; 12(9): e0184120, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28877211

RESUMO

Growth performance and meat quality are important traits for the pig industry and consumers. Adipose tissue is the main site at which fat storage and fatty acid synthesis occur. Therefore, we combined high-throughput transcriptomic sequencing in adipose and muscle tissues with the quantification of corresponding phenotypic features using seven Chinese indigenous pig breeds and one Western commercial breed (Yorkshire). We obtained data on 101 phenotypic traits, from which principal component analysis distinguished two groups: one associated with the Chinese breeds and one with Yorkshire. The numbers of differentially expressed genes between all Chinese breeds and Yorkshire were shown to be 673 and 1056 in adipose and muscle tissues, respectively. Functional enrichment analysis revealed that these genes are associated with biological functions and canonical pathways related to oxidoreductase activity, immune response, and metabolic process. Weighted gene coexpression network analysis found more coexpression modules significantly correlated with the measured phenotypic traits in adipose than in muscle, indicating that adipose regulates meat and carcass quality. Using the combination of differential expression, QTL information, gene significance, and module hub genes, we identified a large number of candidate genes potentially related to economically important traits in pig, which should help us improve meat production and quality.


Assuntos
Tecido Adiposo/metabolismo , Metabolismo dos Lipídeos/fisiologia , Músculo Esquelético/metabolismo , Tecido Adiposo/crescimento & desenvolvimento , Animais , Perfilação da Expressão Gênica , Genes/genética , Genes/fisiologia , Metabolismo dos Lipídeos/genética , Músculo Esquelético/crescimento & desenvolvimento , Fenótipo , Análise de Componente Principal , Característica Quantitativa Herdável , Suínos/genética , Suínos/metabolismo , Transcriptoma/genética , Transcriptoma/fisiologia
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