Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 11 de 11
Filtrar
Filtros adicionais











Intervalo de ano
1.
Mar Drugs ; 17(6)2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31226756

RESUMO

Local administration of platelet-derived growth factor-BB (PGDF-BB) and bone morphogenetic protein-2 (BMP-2) in a sequential release manner could substantially promote bone healing. To achieve this goal, a delivery system that could sustain the release of PGDF-BB and BMP-2 by way of temporal separation was developed. One type of PGDF-BB-encapsulated alginate microsphere and another type of BMP-2-encapsulated microsphere with a core-shell structure were respectively produced using emulsification methods. These two types of microspheres were then embedded into chitosan/glycerophosphate hydrogel for constructing composite gels. Some of them were found to be injectable at ambient temperature and had thermo-sensitive features near physiological temperature and pH. The optimally formulated composite gels showed the ability to control the release of PGDF-BB and BMP-2 in a sequential fashion in which PDGF-BB was released earlier than BMP-2. In vitro release patterns indicated that the release rates could be significantly regulated by varying the embedded amount of the factor-encapsulated microspheres, which can in turn mediate the temporal separation release interval between PGDF-BB and BMP-2. The released PDGF-BB and BMP-2 were detected to be bioactive based on their respective effects on Balb/c 3T3 and C2C12 cells. These results suggest that the presently developed composite gels have the potential for bone repair by synergistically utilizing the early chemotactic effect of PDGF-BB and the subsequent osteogenic and angiogenic functions of PDGF-BB and BMP-2.

2.
Acta Biomater ; 91: 60-71, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30986530

RESUMO

Copper-containing bioactive glass nanoparticles (Cu-BG NPs) with designed compositions and sizes were synthesized and incorporated into chitosan (CH)/silk fibroin (SF)/glycerophosphate (GP) composites to prepare injectable hydrogels for cell-free bone repair. The resulting Cu-BG/CH/SF/GP gels were found to exhibit well-defined injectability and to undergo rapid gelation at physiological temperature and pH. They were highly porous and showed the ability to administer Si, Ca and Cu ions at their respective safe doses in a sustained and controlled manner. In vitro studies revealed that the gels supported the growth of seeded MC3T3-E1 and human umbilical vein endothelial cells, and effectively induced them toward osteogenesis and angiogenesis, respectively. In vivo bone repair based on a critical-size rat calvarial bone defect model demonstrated that the optimal Cu-BG/CH/SF/GP gel was able to fully restore the bone defect with formation of vascularized bone tissue and mineralized collagen deposition during a treatment period of 8 weeks without utilization of any cells and/or growth factors. The results suggest that the presently developed Cu-BG/CH/SF/GP composite hydrogels have great potential and translation ability for bone regeneration owing to their thermo-sensitive properties, cell-free bioactivity, and cost-effectiveness. STATEMENT OF SIGNIFICANCE: Hydrogels loaded with cells and/or growth factors exhibit potential in bone repair. However, they have been facing obstacles related to the clinic translation. Here, a novel type of hydrogel system consisting of copper-containing bioactive glass nanoparticles and chitosan/silk fibroin composite was developed. These gels showed injectability and thermally triggered in situ gelation properties and were able to administer the release of ions at safe but effective doses in a controlled manner while inducing the seeded cells toward osteogenesis and angiogenesis. The optimal gel showed the ability to fully repair critical-size rat calvarial bone defects without involving time consuming cell processing and/or the use of expensive growth factors, confirming that this novel hydrogel system has great potential for translation to the clinic.

3.
Pharmaceutics ; 10(4)2018 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-30453642

RESUMO

Chitosan(CH)-polylactide(PLA) copolymers containing varied PLA percentages were synthesized using a group-protection method and one of them with solubility in water-based solvents was used to prepare CH-PLA/hyaluronic acid (HA) complex microspheres for the delivery of transforming growth factor-ß1 (TGF-ß1). An emulsification processing method was developed for producing TGF-ß1-loaded CH-PLA/HA microspheres using sodium tripolyphosphate (TPP) as ionic crosslinker and the size of the microspheres was devised to the micron level in order to achieve high encapsulating efficiency. The encapsulating efficiency, swelling property and release administration of the microspheres could be synergistically regulated by PLA component, the applied TPP dose and the incorporated HA amount. In comparison to CH/HA microspheres, the CH-PLA/HA microspheres had greatly reduced TGF-ß1 release rates and were able to administrate the TGF-ß1 release at controlled rates over a significant longer period of time. The released TGF-ß1 was detected to be bioactive when compared to the free TGF-ß1. These results suggest that the presently developed CH-PLA/HA complex microspheres have promising potential in delivering TGF-ß1 for cartilage repair applications where the applied TGF-ß1 amount in the early stage needs to be low whilst the sustained TGF-ß1 release at an appropriate dose in the later stage has to be maintained.

4.
Int J Mol Sci ; 19(8)2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30096842

RESUMO

Chitosan (CH), silk fibroin (SF), and hydroxyapatite (HA) were used to prepare CH/SF/HA composites and the resulting composites were electrospun into nanofibrous membrane units with gradient compositional and structural features. The optimal membrane unit was used together with CH/HA and CH/SF composites to fabricate a type of three-layer scaffold that is intended for osteochondral repair. The bottom layer of the scaffold was built with CH/HA composites and it served as a subchondral layer, the integrated nanofibrous membrane unit functioned as the middle layer for mimicking the calcified layer and the top layer was constructed using CH/SF composites for acting as a chondral layer. The nanofibrous membrane unit was found to be permeable to some molecules with limited molecular weight and was able to prevent the seeded cells from migrating cross the unit, functioning approximately like the calcified layer in the osteochondral matrix. Layered scaffolds showed abilities to promote the growth of both chondrocytes and osteoblasts that were seeded in their chondral layer and bony layer, respectively, and they were also able to support the phenotype preservation of seeded chondrocytes and the mineralization of neotissue in the bony layer. Results suggest that this type of layered scaffolds can function as an analogue of the osteochondral matrix and it has potential in osteochondral repair.

5.
J Mech Behav Biomed Mater ; 77: 671-682, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29102892

RESUMO

Chitosan/silk fibroin/glycerophosphate gels were loaded with nerve growth factor (NGF) and further processed into multi-tubule fillers. NGF was loaded into the fillers in such a way so that a NGF gradient was established longitudinally along the filler length. A type of poly(lactide-co-glycolide)(PLGA)/chitosan(CH) porous conduit was fabricated using a pre-crosslinking method. The filler was fully filled into the lumen of conduits to build multi-tubule conduit-filler constructs that are intended for long-gap peripheral nerve repair. In vitro degradation in a lysozyme-contained medium revealed that constructs had degradation-tolerant features and the optimized multi-tubule filler was capable of maintaining its multi-tubules unblocked for around 10-week. After being degraded for various periods up to 8 weeks, the optimal conduit-filler constructs showed confirmative ability to retain their compressive load, deformation recovery and tensile strength at about 80N/m, 75% and 15N/cm2 in wet state, respectively. The constructs were able to administer NGF release and to maintain persistent NGF gradients longitudinally distributed inside the PLGA/CH conduit for about 6 weeks or even longer. The PC12 cell neurite extension assay confirmed that the presently developed multi-tubule conduit-filler constructs were reliable for effectively preserving the bioactivity of released NGF.


Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Fibroínas/química , Ácido Láctico/química , Fator de Crescimento Neural/química , Ácido Poliglicólico/química , Engenharia Tecidual/métodos , Animais , Força Compressiva , Géis , Glicerofosfatos/química , Microscopia Eletrônica de Varredura , Muramidase/química , Células PC12 , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Porosidade , Ratos , Estresse Mecânico , Temperatura Ambiente
6.
Colloids Surf B Biointerfaces ; 160: 598-609, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29028608

RESUMO

Nerve conduits containing aligned fibrous fillers with gradiently distributed signal molecules are essential for long-gap nerve repair. This study was to develop an approach for establishing nerve growth factor (NGF) gradients onto the aligned chitosan-polylactide (CH-PLA) fibers. CH-PLA containing 37wt% of PLA was spun into fibers using a wet-spinning technique. CH-PLA fibers showed much higher wet-state tensile strength, enhanced degradation tolerance and significantly lower swelling degree in comparison to chitosan fibers. The CH-PLA fibers with diameters from 40 to 60µm were selected and segmentally coated in bundles using NGF-contained alginate solutions to establish NGF gradients lengthwise along fibers. The diameter of resulting NGF-loaded CH-PLA/alginate fibers was well controlled within a range between 60 and 120µm. Calcium ion crosslinked alginate coating layers on fibers showed abilities to administer the sustainable NGF release in a gradient distribution manner for at least 5 weeks. NGF-induced neurite outgrowth of PC12 cells confirmed that bioactivity of NGF released from fibers was well retained.


Assuntos
Alginatos/química , Quitosana/química , Fator de Crescimento Neural/farmacologia , Tecido Nervoso/efeitos dos fármacos , Poliésteres/química , Animais , Liberação Controlada de Fármacos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microscopia Eletrônica de Varredura , Fator de Crescimento Neural/farmacocinética , Regeneração Nervosa/efeitos dos fármacos , Tecido Nervoso/fisiologia , Neuritos/efeitos dos fármacos , Neuritos/fisiologia , Células PC12 , Ratos , Engenharia Tecidual/métodos , Tecidos Suporte/química
7.
Colloids Surf B Biointerfaces ; 148: 308-316, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27619183

RESUMO

Platelet-derived growth factor-BB (PGDF-BB) loaded gelatin microspheres with an average size of about 2µm was incorporated into chitosan/silk fibroin/glycerophosphate (GP) solutions to prepare composites. The formulated composite solutions were able to form into hydrogels in a temperature range between 32 and 37°C at a pH of ca.7. They had good fluidity at 25°C and showed shear-thinning features at both 25 and 37°C, revealing that they are injectable at room temperature. Elastic modulus of some composites at 37°C was about 10-fold higher than that of chitosan/GP gel, confirming that these composites behave like mechanically strong gels. Optimal composites showed abilities to administrate PDGF-BB release in an approximately linear manner up to 5 weeks. The PDGF-BB release could be regulated by the PDGF-BB load and the silk fibroin content in the composites in an individual or cooperative way. In vivo degradation of composites demonstrated that some of them had markedly enhanced degradation endurance as compared to the chitosan/GP gel. PDGF-BB-stimulated DNA synthesis in Balb/c 3T3 fibroblasts and PDGF-BB-induced cell migration suggested that the bioactivity of released PDGF-BB was well retained.


Assuntos
Hidrogéis , Microesferas , Proteínas Proto-Oncogênicas c-sis/administração & dosagem , Animais , Becaplermina , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Varredura , Reologia
8.
J Mech Behav Biomed Mater ; 64: 161-72, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27498426

RESUMO

Silk fibroin (SF) and hydroxyapatite (HA) were incorporated into chitosan/glycerophosphate (GP) system to prepare new types of hydrogels. The formulated chitosan/SF/GP and chitosan/SF/HA/GP solutions were found to be injectable at room temperature, and able to form into hydrogels at near-physiological temperature and pH. Rheological measurements showed that elastic modulus of certain chitosan/SF/GP and chitosan/SF/HA/GP gels could reach around 1.8 and 15kPa, respectively, and was much higher than their respective viscous modulus. Compressive measurements revealed that some chitosan/SF/GP and chitosan/SF/HA/GP gels had 8 and 20-fold modulus and strength higher than the chitosan/GP gel, respectively, confirming that compressive properties of these gels were greatly improved. Results obtained from in vivo degradation demonstrated that degradation endurance of the optimized chitosan/SF/GP and chitosan/SF/HA/GP gels was significantly enhanced as compared to the chitosan/GP gel, and the degradation rate of the gels could be regulated by the SF component alone or by the combination of SF and HA components.


Assuntos
Quitosana/química , Durapatita/química , Fibroínas/química , Glicerofosfatos/química , Hidrogéis/química , Reologia
9.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 40(10): 1115-20, 2015 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-26541846

RESUMO

OBJECTIVE: To understand the influential factors for depression in patients with facial acne vulgaris and to provide scientific evidence for a comprehensive and systematic treatment for acne vulgaris.
 METHODS: A total of 287 outpatients with facial acne vulgaris, who visited the dermatology of the Third Xiangya Hospital, were surveyed by Beck Depression Inventory (BDI). The data was collected by Epidata software (version 3.1) and processed by SPSS software package (version 18.0). The influential factors for the depression of outpatients with facial acne vulgaris were analyzed by multinomial logistic regression.
 RESULTS: A total of 181 patients with facial acne vulgaris showed various degrees of depression (BDI score≥5) and the rate was 63.1%. The symptoms for depression included sad and pessimistic attitude as well as the decreased attention to others (social withdrawal). The influential factors for mild, moderate or severe depression were gender, the degree and the course of acne. Female patients were more likely to suffer mild, moderate or severe depression (OR=3.62, 2.63, respectively); the risk of depression in acne patients was increased with the increase in degree of the severity (OR=2.31, 4.51, respectively); the patients with the acne course more than a year were more likely to show mild depression than those with a course less than a year (OR=4.30, 7.44, respectively). The patients with acne course more than 3 years were more likely to show moderate or severe depression compared to those with a course less than a year (OR=3.60).
 CONCLUSION: Most of facial acne patients show a different degree of depression. The acne course is longer in female patients. The more severe the acne vulgaris is, the more suffering of the depression is. Psychological care should be considered to improve the treatment and quality of life.


Assuntos
Acne Vulgar/epidemiologia , Depressão/epidemiologia , Qualidade de Vida , Face/patologia , Feminino , Humanos , Modelos Logísticos , Masculino , Escalas de Graduação Psiquiátrica , Inquéritos e Questionários
10.
Biomed Mater ; 10(4): 045013, 2015 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26225911

RESUMO

Chitosan/nano-hydroxyapatite (HA) composites were first prepared and then used together with chitosan and silk fibroin (SF) to produce a type of four-layer porous scaffold that is potentially applicable for articular cartilage repair. The bottom layer of the scaffold was built with the chitosan/HA composite and the other three layers of the scaffold were fabricated using chitosan/SF composites in which the content of the chitosan and SF was altered in a mutually reversed trend. The so-produced chitosan/SF/HA scaffolds were further crosslinked using tripolyphosphate to achieve enhanced mechanical properties. Interconnected porous microstructures throughout the scaffolds were constructed using a temperature gradient processing technique, and the resultant scaffolds were endowed with graded pore-sizes and porosities as well as porous interface zones between contiguous layers without visual clefts. The compressive modulus and stress at 10% strain of the scaffolds in wet state showed a gradient-changed trend which partially mimics the compressive mechanical properties of an articular cartilage matrix. Cell culture on some chitosan/SF/HA scaffolds for a period of time of up to 14 d showed that the scaffolds were able to well support the growth and infiltration of cells, suggesting that the presently developed chitosan/SF/HA scaffolds have promising potential for articular cartilage repair.


Assuntos
Quitosana/química , Condrócitos/citologia , Condrócitos/fisiologia , Durapatita/química , Fibroínas/química , Tecidos Suporte , Animais , Células Cultivadas , Força Compressiva , Módulo de Elasticidade , Desenho de Equipamento , Análise de Falha de Equipamento , Dureza , Teste de Materiais , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Impressão Tridimensional , Coelhos , Estresse Mecânico , Resistência à Tração
11.
Inorg Chem ; 53(6): 3210-9, 2014 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-24559169

RESUMO

We report our systematic studies of novel, simple, selective, and sensitive optical (both colorimetric and fluorescent) chemosensors for detecting Al(3+) based on transmetalation reactions (metal displacement or exchange reactions) of a series of K(I), Ca(II), Zn(II), Cu(II), and Pt(II) complexes containing different ligands of salen-based Schiff bases. Both the chemical structure of the salen ligand and the identity of the central metal ion have a tremendous impact on the sensing performance, which is mainly determined by the stability constant of the complex. Moreover, the selectivities of the salen-complex-based chemosensors are much better than those of the corresponding free salen ligands because of the shielding function of the filled-in metal ion in the complex. Therefore, the present work potentially provides a new and simple way to design optical probes via complex-based transmetalation reactions.


Assuntos
Metais/química , Óptica e Fotônica , Bases de Schiff/química , Ligantes , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA