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2.
J Pharm Sci ; 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38657756

RESUMO

The assessment of the mucoadhesive properties peak mucoadhesive force (Fmax) and work of mucoadhesion (Wmuc) with texture analyzers is a common in vitro method for analyzing formulation capabilities. Challenges arise in selecting and standardizing experimental conditions due to various variables influencing mucoadhesion. This complexity hampers direct product performance comparisons. In our study, we explored factors (contact force and time, probe speed and mucin in artificial saliva) impacting a model formulation's mucoadhesive capacity. Using Omcilon-A®Orabase on porcine buccal mucosa, we systematically varied experimental conditions, employing a statistical approach (Central Composite Design - CCD). Three variables (contact force, contact time, probe speed) and their interactions were assessed for their impact on Fmax and Wmuc. Results showed that contact time and force positively affected Fmax, while only contact time influenced Wmuc. In the mucin artificial saliva test, a force of 0.5 N, time of 600 s, and speed of 1 mm/s yielded optimal Fmax (0.587 N) and Wmuc (0.468 N.s). These conditions serve as a reference for comparing mucoadhesive properties of formulations for topical oral use.

3.
Adv Healthc Mater ; 12(19): e2203021, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37057819

RESUMO

Cartilage tissue presents low self-repair capability and lesions often undergo irreversible progression. Structures obtained by tissue engineering, such as those based in extrusion bioprinting of constructs loaded with stem cell spheroids may offer valuable alternatives for research and therapeutic purposes. Human mesenchymal stromal cell (hMSC) spheroids can be chondrogenically differentiated faster and more efficiently than single cells. This approach allows obtaining larger tissues in a rapid, controlled and reproducible way. However, it is challenging to control tissue architecture, construct stability, and cell viability during maturation. Herein, this work reports a reproducible bioprinting process followed by a successful post-bioprinting chondrogenic differentiation procedure using large quantities of hMSC spheroids encapsulated in a xanthan gum-alginate hydrogel. Multi-layered constructs are bioprinted, ionically crosslinked, and post chondrogenically differentiated for 28 days. The expression of glycosaminoglycan, collagen II and IV are observed. After 56 days in culture, the bioprinted constructs are still stable and show satisfactory cell metabolic activity with profuse extracellular matrix production. These results show a promising procedure to obtain 3D models for cartilage research and ultimately, an in vitro proof-of-concept of their potential use as stable chondral tissue implants.


Assuntos
Bioimpressão , Engenharia Tecidual , Humanos , Engenharia Tecidual/métodos , Bioimpressão/métodos , Cartilagem , Diferenciação Celular , Células-Tronco , Impressão Tridimensional , Alicerces Teciduais/química
4.
Pharmaceutics ; 15(2)2023 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-36840027

RESUMO

In this work, a simple method was proposed to produce dense composite polysaccharide-based membranes to be used for guided tissue and guided bone regeneration. The mucoadhesive polysaccharides chitosan (C) and xanthan gum (X) were used to produce polyelectrolyte-based complex membranes. Hydroxyapatite (HA) was added to the formulation as a potential drug carrier, in C:X:HA mass proportions equal to 1:1:0.4, 1:1:2, and 1:1:10, and also to improve membranes bioactivity and biomimetic properties. FTIR analysis indicated successful incorporation of HA in the membranes and XRD analysis showed that no changes in the HA crystalline structure were observed after incorporation. The residual mass evaluated by TGA was higher for the formulation produced at the proportion 1:1:10. The membranes produced showed asymmetrical surfaces, with distinct roughness. Increasing the HA concentration increased the surface roughness. Greater in vitro proliferation of dental pulp mesenchymal stem cells was observed on the surface of the membrane with 1:1:10 C:X:HA proportion. However, the 1:1:2 formulation showed the most adequate balance of mechanical and biological properties. These results suggest that adding HA to the membranes can influence mechanical parameters as well as cell adhesion and proliferation, supporting the potential application of these materials in regenerative techniques and the treatment of periodontal lesions.

5.
Brain Res ; 1802: 148229, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36592804

RESUMO

Spinal cord injuries result in severe neurological deficits and neuronal loss, with poor functional recovery. Mesenchymal stem cells have shown promising results; therefore the present objective of this work was to compare motor recovery after treatment with human dental pulp stem cells (hDPSC) cultivated in monolayer (2D) or as spheroids (3D), following avulsion and reimplantation of spinal motor roots in adult rats. Thus, 72 adult female Lewis rats were divided into 4 groups: avulsion (AV); avulsion followed by reimplantation (AR); avulsion associated with reimplant and 2D cell therapy (AR + 2D), and avulsion associated with reimplant and 3D cell therapy (AR + 3D). The application of the cells in 2D and 3D was performed by microsurgery, with subsequent functional assessment using a walking track test (Catwalk system), immunohistochemistry, neuronal survival, and qRT-PCR in 1-, 4-, and 12-weeks post-injury. The animals in the AR + 2D and AR + 3D groups showed the highest neuronal survival rates, and immunofluorescence revealed downregulation of GFAP, and Iba-1, with preservation of synaptophysin, indicating a reduction in glial reactivity, combined with the maintenance of pre-synaptic inputs. There was an increase in anti-inflammatory (IL-4, TGFß) and a reduction of pro-inflammatory factors (IL-6, TNFα) in animals treated with reimplantation and hDPSC. As for the functional recovery, in all analyzed parameters, the AR + 2D group performed better and was superior to the avulsion alone. Overall, our results indicate that the 2D and 3D cell therapy approaches provide successful immunomodulation and motor recovery, consistent with advanced therapies after spinal cord injury.


Assuntos
Traumatismos da Medula Espinal , Medula Espinal , Adulto , Animais , Feminino , Humanos , Ratos , Polpa Dentária , Neurônios Motores/fisiologia , Ratos Endogâmicos Lew , Traumatismos da Medula Espinal/terapia , Raízes Nervosas Espinhais/lesões , Raízes Nervosas Espinhais/fisiologia , Células-Tronco , Técnicas de Cultura de Células
6.
Pharmaceutics ; 14(12)2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36559066

RESUMO

The topical use of imiquimod (IMQ), a non-specific immune response modifier, showed to be a promising therapeutic option for the early-stage treatment of some type of oral cancer, even when performed with a formulation (Aldara®) developed and approved for skin application. The aim of this work was the development of buccal formulations for the topical administration of IMQ with improved mucosal retention and reduced trans-mucosal permeation when compared to the reference formulation. Three different hydrogels based on carboxymethyl chitosan (CMChit), sodium alginate (A), and xanthan gum (X) in different combinations were prepared, and the loading of imiquimod was successfully performed by using a micellar formulation based on d-α-tocopheril polyethylene glycol 100 succinate (TPGS). Except for CMChit formulation, in all the other cases, the performance in vitro on the mucosa resulted comparable to the commercial formulation, despite the drug loading being 50-fold lower. Converting the gels in films did not modify the IMQ accumulated with respect to the correspondent gel formulation but produced as a positive effect a significant reduction in the amount permeated. Compared to the commercial formulation, this reduction was significant (p < 0.01) in the case of X film, resulting in an improvement of the retained/permeated ratio from 1 to 5.44. Mucoadhesion evaluation showed similar behavior when comparing the developed gels and the commercial formulation, and an excellent bioadhesion was observed for the films.

7.
Polymers (Basel) ; 14(21)2022 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-36365748

RESUMO

The purpose of this study was to investigate tissue repair of excisional wounds in hyperglycemic animals treated with chitosan-alginate membranes (CAM) produced in the presence of glycerol. 8-week C57B1 male mice were divided into normoglycemic animals with a 0.9% saline solution topical treatment (CTSF); hyperglycemic animals with 0.9% saline solution topical treatment (DMSF) and hyperglycemic animals with glycerol-plasticized chitosan-alginate membrane topical treatment (DMCAM). On post-wound day three, the DMCAM group presented a lower number of leukocytes, mature mastocytes, a higher number of vessels (p < 0.05), and active mastocytes (p < 0.05) when compared to the CTSF and DMSF groups. There were no differences regarding the distribution, deposition, organization, and thickness of collagen fibers. On day 7 there were no differences in the analysis of fibroblasts, mastocytes, and TGF−ß1 and VEGF expressions among the groups. Regarding collagen fibers, the DMCAM group presented slight red-orange birefringence when compared to the CTSF and DMSF groups. On day 14 there was a slight concentration of thinner elastic fibers for the DMCAM group, with a greater reorganization of papillary skin and improved red-orange birefringence collagen fibers, as well as net-shaped orientation, similar to intact skin. In addition, improved elastic fiber organization distributed in the entire neo-dermis and a larger presence of elaunin fibers were observed, in a similar pattern found in the intact skin. The use of CAM in cutaneous lesions boosted tissue repair since there was a smaller number of inflammatory cells and mastocytes, and an improvement in collagen deposition and collagen fibers. These results demonstrate the high potential of plasticized chitosan-alginate membrane for skin wound dressing of hyperglycemic patients.

8.
Mater Sci Eng C Mater Biol Appl ; 135: 112685, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35589471

RESUMO

Three-dimensional cellular aggregates can mimic the natural microenvironment of tissues and organs and obtaining them through controlled and reproducible processes is mandatory for scaling up and implementing drug cytotoxicity and efficacy tests, as well as tissue engineering protocols. The purpose of this work was to develop and evaluate the performance of a device with two different geometries fabricated by additive manufacturing. The methodology was based on casting a microwell array insert using a non-adhesive hydrogel to obtain highly regular microcavities to standardize spheroid formation and morphology. Spheroids of dental pulp stem cells, bone marrow stromal cells and embryonic stem cells showing high cell viability and average diameters of around 253, 220, and 500 µm, respectively, were produced using the device with the geometry considered most adequate. The cell aggregates showed sphericity indexes above 0.9 and regular surfaces (solidity index higher than 0.96). Around 1000 spheroids could be produced in a standard six-well plate. Overall, these results show that this method facilitates obtaining a large number of uniform, viable spheroids with pre-specified average diameters and through a low-cost and reproducible process for a myriad of applications.


Assuntos
Células-Tronco Mesenquimais , Esferoides Celulares , Sobrevivência Celular , Células-Tronco , Engenharia Tecidual/métodos
9.
Polymers (Basel) ; 14(6)2022 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-35335440

RESUMO

This work focuses on the mathematical analysis of the controlled release of a standardized extract of A. chica from chitosan/alginate (C/A) membranes, which can be used for the treatment of skin lesions. Four different types of C/A membranes were tested: a dense membrane (CA), a dense and flexible membrane (CAS), a porous membrane (CAP) and a porous and flexible membrane (CAPS). The Arrabidae chica extract release profiles were obtained experimentally in vitro using PBS at 37 °C and pH 7. Experimental data of release kinetics were analyzed using five classical models from the literature: Zero Order, First Order, Higuchi, Korsmeyer-Peppas and Weibull functions. Results for the Korsmeyer-Peppas model showed that the release of A. chica extract from four membrane formulations was by a diffusion through a partially swollen matrix and through a water filled network mesh; however, the Weibull model suggested that non-porous membranes (CA and CAS) had fractal geometry and that porous membranes (CAP and CAPS) have highly disorganized structures. Nevertheless, by applying an explicit optimization method that employs a cost function to determine the model parameters that best fit to experimental data, the results indicated that the Weibull model showed the best simulation for the release profiles from the four membranes: CA, CAS and CAP presented Fickian diffusion through a polymeric matrix of fractal geometry, and only the CAPS membrane showed a highly disordered matrix. The use of this cost function optimization had the significant advantage of higher fitting sensitivity.

10.
Pharmaceutics ; 15(1)2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36678640

RESUMO

There are several routes of drug administration, and each one has advantages and limitations. In the case of the topical application in the oral cavity, comprising the buccal, sublingual, palatal, and gingival regions, the advantage is that it is painless, non-invasive, allows easy application of the formulation, and it is capable of avoiding the need of drug swallowing by the patient, a matter of relevance for children and the elderly. Another advantage is the high permeability of the oral mucosa, which may deliver very high amounts of medication rapidly to the bloodstream without significant damage to the stomach. This route also allows the local treatment of lesions that affect the oral cavity, as an alternative to systemic approaches involving injection-based methods and oral medications that require drug swallowing. Thus, this drug delivery route has been arousing great interest in the pharmaceutical industry. This review aims to condense information on the types of biomaterials and polymers used for this functionality, as well as on production methods and market perspectives of this topical drug delivery route.

11.
Biofabrication ; 13(3)2021 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-33592595

RESUMO

Three-dimensional (3D) cell culture has tremendous advantages to closely mimic thein vivoarchitecture and microenvironment of healthy tissue and organs, as well as of solid tumors. Spheroids are currently the most attractive 3D model to produce uniform reproducible cell structures as well as a potential basis for engineering large tissues and complex organs. In this review we discuss, from an engineering perspective, processes to obtain uniform 3D cell spheroids, comparing dynamic and static cultures and considering aspects such as mass transfer and shear stress. In addition, computational and mathematical modeling of complex cell spheroid systems are discussed. The non-cell-adhesive hydrogel-based method and dynamic cell culture in bioreactors are focused in detail and the myriad of developed spheroid characterization techniques is presented. The main bottlenecks and weaknesses are discussed, especially regarding the analysis of morphological parameters, cell quantification and viability, gene expression profiles, metabolic behavior and high-content analysis. Finally, a vast set of applications of spheroids as tools forin vitrostudy model systems is examined, including drug screening, tissue formation, pathologies development, tissue engineering and biofabrication, 3D bioprinting and microfluidics, together with their use in high-throughput platforms.


Assuntos
Bioimpressão , Esferoides Celulares , Técnicas de Cultura de Células , Hidrogéis , Engenharia Tecidual
12.
Polymers (Basel) ; 12(7)2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32708645

RESUMO

Polycaprolactone (PCL) is a synthetic polymer with good mechanical properties that are useful to produce biomaterials of clinical application. It can be successfully combined with chitosan, which enhances the biomaterial properties through the modulation of molecular and cellular mechanisms. The objective of this study was to evaluate the effects of the use of electrospun fibrous membranes consisting of polycaprolactone (PCL) or polycaprolactone coated with chitosan and poly(ethylene oxide) (PCL+CHI/PEO) on mouse skin lesions. Sixty four Black-57 mice were divided into PCL and PCL+CHI/PEO groups. A 1 cm2 lesion was made on the animals' backs, and the membranes were sutured in place. The tissues were extracted on the 3rd, 7th, and 14th days after the lesion. The tissues were analyzed by histology with Hematoxylin and Eosin (H&E) and Sirius Red stains, morphometry, immunohistochemistry, and Western blot. On the 3rd, 6th, and 9th days after the lesion, the PCL+CHI/PEO group showed a higher wound-healing rate (WHR). On the 3 day, the PCL+CHI/PEO group showed a greater amount of inflammatory infiltrate, greater expression of proliferating cell nuclear antigen (PCNA), and smooth muscle actin (α-SMA) (p < 0.05) compared to the PCL group. On the 7th day after the lesion, the PCL+CHI/PEO group showed a greater amount of inflammatory infiltrate, expression of Tumor Necrosis Factor (TNF-α) and PCNA (p < 0.05). In addition, it showed a greater immunolabeling of Monocyte Chemoattractant Protein-1 (MCP-1) and deposition of collagen fibers compared to the PCL group. The PCL+CHI/PEO membrane modulated the increase in the inflammatory infiltrate, the expression of MCP-1, PCNA, and α-SMA in lesions of mice.

13.
Int J Biol Macromol ; 143: 619-632, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31811849

RESUMO

The periosteum is a membrane that surrounds bones, providing essential cellular and biological components for fracture healing and bone repair. Tissue engineered scaffolds able to function as periosteum substitutes can significantly improve bone regeneration in severely injured tissues. Efforts to develop more bioactive and tunable periosteal substitutes are required to improve the success of this tissue engineering approach. In this work, a chemical modification was performed in chitosan, a polysaccharide with osteoconductive properties, by introducing phosphate groups to its structure. The phosphorylated polymer (Chp) was used to produce chitosan-xanthan-based scaffolds for periosteal tissue engineering. Porous and mechanically reinforced matrices were obtained with addition of the surfactant Kolliphor® P188 and the silicone rubber Silpuran® 2130A/B. Scaffolds properties, such as large pore sizes (850-1097 µm), micro-roughness and thickness (0.7-3.5 mm in culture medium), as well as low thrombogenicity compared to standard implantable materials, extended degradation time and negligible cytotoxicity, enable their application as periosteum substitutes. Moreover, the higher adsorption of bone morphogenetic protein mimic (cytochrome C) by Chp-based formulations suggests improved osteoinductivity of these materials, indicating that, when used in vivo, the material would be able to concentrate native BMPs and induce osteogenesis. The scaffolds produced were not toxic to adipose tissue-derived stem cells, however, cell adhesion and proliferation on the scaffolds surfaces can be still further improved. The mineralization observed on the surface of all formulations indicates that the materials studied have promising characteristics for the application in bone regeneration.


Assuntos
Quitosana/farmacologia , Osseointegração/efeitos dos fármacos , Periósteo/fisiologia , Polissacarídeos Bacterianos/farmacologia , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Tecido Adiposo/citologia , Adsorção , Fosfatase Alcalina/metabolismo , Cálcio/metabolismo , Morte Celular/efeitos dos fármacos , Células Cultivadas , Citocromos c/metabolismo , Módulo de Elasticidade , Humanos , L-Lactato Desidrogenase/metabolismo , Muramidase/metabolismo , Osteogênese/efeitos dos fármacos , Periósteo/efeitos dos fármacos , Fosforilação , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Estresse Mecânico , Trombose/patologia
14.
Mater Sci Eng C Mater Biol Appl ; 104: 109973, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499972

RESUMO

Coronary artery and peripheral vascular diseases are the leading cause of morbidity and mortality worldwide and often require surgical intervention to replace damaged blood vessels, including the use of vascular patches in endarterectomy procedures. Tissue engineering approaches can be used to obtain biocompatible and biodegradable materials directed to this application. In this work, dense or porous scaffolds constituted of chitosan (Ch) complexed with alginate (A) or pectin (P) were fabricated and characterized considering their application as tissue-engineered vascular patches. Scaffolds fabricated with alginate presented higher culture medium uptake capacity (up to 17 g/g) than materials produced with pectin. A degradation study of the patches in the presence of lysozyme showed longer-term stability for Ch-P-based scaffolds. Pectin-containing matrices presented higher elastic modulus (around 280 kPa) and ability to withstand larger deformations. Moreover, these materials demonstrated better performance when tested for hemocompatibility, with lower levels of platelet adhesion and activation. Human smooth muscle cells (HSMC) adhered, spread and proliferated better on matrices produced with pectin, probably as a consequence of cell response to higher stiffness of this material. Thus, the outcomes of this study demonstrate that Ch-P-based scaffolds present superior characteristics for the application as vascular patches. Despite polysaccharides are yet underrated in this field, this work shows that biocompatible tridimensional structures based on these polymers present high potential to be applied for the reconstruction and regeneration of vascular tissues.


Assuntos
Polissacarídeos/química , Engenharia Tecidual/métodos , Doenças Vasculares/terapia , Alginatos/química , Materiais Biocompatíveis/química , Células Cultivadas , Quitosana/química , Humanos , Miócitos de Músculo Liso/efeitos dos fármacos , Pectinas/química , Polímeros/química , Alicerces Teciduais/química
15.
Mater Sci Eng C Mater Biol Appl ; 100: 493-504, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948086

RESUMO

Advanced wound dressings capable of interacting with lesions and changing the wound microenvironment to improve healing are promising to increase the therapeutic efficacy of this class of biomaterials. Aiming at the production of bioactive wound dressings with the ability to control the wound microenvironment, biomaterials of three different chemical compositions, but with the same architecture, were produced and compared. Electrospinning was employed to build up a biomimetic extracellular matrix (ECM) layer consisting of poly(caprolactone) (PCL), 50/50 dl-lactide/glycolide copolymer (PDLG) and poly(l-lactide) (PLLA). As a post-treatment to broaden the bioactivity of the dressings, an alginate coating was applied to sheathe and functionalize the surface of the hydrophobic electrospun wound dressings, in combination with the extract of the plant Arrabidaea chica Verlot, known for its anti-inflammatory and healing promotion properties. Wettable bioactive structures capable to interact with media simulating lesion microenvironments, with tensile strength and elongation at break ranging respectively from 155 to 273 MPa and from 0.94 to 1.39% were obtained. In simulated exudative microenvironment, water vapor transmission rate (WVTR) values around 700 g/m2/day were observed, while water vapor permeability rates (WVPR) reached about 300 g/m2/day. In simulated dehydrated microenvironment, values of WVTR around 200 g/m2/day and WVPR around 175 g/m2/day were attained.


Assuntos
Bandagens , Materiais Revestidos Biocompatíveis/farmacologia , Fenômenos Mecânicos , Cicatrização , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Liberação Controlada de Fármacos , Íons , Testes de Sensibilidade Microbiana , Permeabilidade , Extratos Vegetais/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor , Termogravimetria , Fatores de Tempo , Água/química , Difração de Raios X
16.
Int J Biol Macromol ; 132: 178-189, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30926498

RESUMO

Polyelectrolyte complexes of chitosan (Ch) and pectin (Pc) or alginate (Alg) were produced in the presence or absence of the silicone gel Silpuran® 2130 A/B (Sil) and the surfactant Kolliphor® P188 (Kol). Ch-Pc-Kol-based formulations presented higher porosity (up to 83.3%) and thickness (maximum of 2273.5 µm in PBS). Lower water contact angle was observed for Ch-Alg formulations (minimum of 36.8°) and these formulations presented higher swelling and mass loss in PBS (reaching up to 21.7 g/g and 80.4%, respectively). The addition of Sil to the matrices improved their elastic moduli, reaching a maximum of 4-fold change at 40% strain. The use of pectin instead of alginate augmented the elastic moduli, reaching 66 and 4-fold changes for dense and porous formulations, respectively. Pectin-containing scaffolds presented poroviscoelasticity, a typical mechanical feature of many soft tissues. The suitability of the materials for tissue engineering applications was demonstrated in terms of stability upon degradation in culture medium or lysozyme solution, as well as lack of cytotoxicity. This study evidences the potential of Ch-Pc-based materials to be further explored for this purpose, especially to improve the mechanical properties of chitosan-based scaffolds aiming medical applications.


Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Pectinas/química , Polímeros/química , Engenharia Tecidual , Alicerces Teciduais/química , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/toxicidade , Linhagem Celular , Quitosana/farmacologia , Quitosana/toxicidade , Fenômenos Mecânicos , Polieletrólitos , Água/química
17.
Mater Sci Eng C Mater Biol Appl ; 94: 364-375, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30423719

RESUMO

Collagen-based materials are probably among the most used class of biomaterials in tissue engineering and regenerative medicine. Although collagen is often privileged for providing a suitable substrate on which cells can be cultured or a matrix in which cells can be dispersed, its mechanical properties represent a major limitation for clinical translation and even for handling of the obtained regenerated tissue. In this work, the combination of polysaccharides chitosan (Ch) and xanthan gum (X) was investigated as an alternative for scaffolds for soft tissue engineering. Moreover, in an attempt to reach a compromise between obtaining highly porous biomaterials while maintaining appropriate mechanical properties, a surfactant (Kolliphor® P188, K) was added to Ch-X matrices to generate pores, while silicone rubber (Silpuran® 2130A/B, S) was used to balance their mechanical properties. Addition of K (10 or 25% w/w) increased the porosity and pore-dimensions, while addition of S improved by up to 156% and 85% the elastic moduli and the elastic behavior of Ch-X-based scaffolds, under both compressive and tensile loads, respectively, at 50% strain. Relaxation tests confirmed that these materials do have a viscoelastic behavior. The presence of S increased thickness and microscale surface roughness and did not affect liquid uptake and stability, thrombogenicity, biodegradation and cytotoxicity of polysaccharide-based scaffolds. In conclusion, this work shows that Ch-X-S porous blends constitute suitable scaffolds for soft tissue engineering.


Assuntos
Fenômenos Mecânicos , Polissacarídeos/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Morte Celular , Quitosana/química , Módulo de Elasticidade , Fibroblastos/citologia , Humanos , Muramidase/metabolismo , Polissacarídeos Bacterianos/química , Porosidade , Estresse Mecânico , Trombose/patologia , Água/química
18.
Mater Sci Eng C Mater Biol Appl ; 93: 671-678, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30274100

RESUMO

This work is a continuation of a previous study which described the development of dense and porous chitosan-alginate polyelectrolyte complexes through the addition of different amounts of Pluronic F68 to the polymeric mixture. The present study consisted in the incorporation of an antimicrobial agent, polyhexamethylene biguanide (PHMB), to the previously developed system. PHMB was incorporated at 1 and 10% (w/w) with high incorporation efficiencies, varying from 72 to 86%. Release profiles in phosphate buffered saline were evaluated using the Korsmeyer-Peppas equation, which suggested a quasi-Fickian diffusion mechanism for all obtained formulations. The maximum release percentage was approximately 15% as a result from the high affinity between PHMB and the polysaccharides. The obtained polyelectrolyte complexes were able to prevent the growth of both Staphylococcus aureus and Pseudomonas aeruginosa on their surfaces, being considered potentially effective wound dressings.


Assuntos
Alginatos/química , Anti-Infecciosos/química , Biguanidas/química , Quitosana/química , Membranas Artificiais , Pseudomonas aeruginosa/crescimento & desenvolvimento , Staphylococcus aureus/crescimento & desenvolvimento , Porosidade
19.
Surg. cosmet. dermatol. (Impr.) ; 10(1): 28-35, Jan.-Mar. 2018. graf., ilus.
Artigo em Inglês, Português | LILACS | ID: biblio-884640

RESUMO

Introdução: Dermatomiosite juvenil (DMJ) é doença sistêmica que afeta a musculatura proximal e a pele de crianças. A doença ulcerada é um desafio terapêutico. Objetivo: Avaliar a melhora da doença ulcerada na DMJ, pelo uso de terapia celular. Métodos: Realização de cocultura de fibroblastos e queratinócitos autólogos e aplicação dessas células nas úlceras juntamente com cola de fibrina e colocação de membrana de quitosana-alginato ou quitosana-xantana sobre as lesões. Resultados: Menos de 12 horas após a terapia, o paciente referiu completa eliminação da dor e, dentro de dois dias, estava presente tecido de cicatrização. Algumas das úlceras estavam quase completamente cicatrizadas no final da primeira semana, e algumas das calcinoses desapareceram. Essa técnica não cura a doença, mas melhora a qualidade de vida, sendo possível criopreservar as células saudáveis do paciente para tratar novas lesões. Sendo as células de origem autóloga, elimina-se o risco de rejeição. Além disso, esse procedimento não necessita de debridamento das lesões nem hospitalização. Conclusões: A aplicação de culturas autólogas de fibroblastos e queratinócitos em úlceras já é considerada tratamento efetivo em pacientes com queimaduras e outras feridas cutâneas e, agora mostrou-se também eficaz no tratamento de feridas na DMJ.


Introduction: Juvenile dermatomyositis (JDM) is a systemic disease that affects children's proximal musculature and skin. The ulcerated stage of the disease is a therapeutic challenge. Objective: To evaluate the improvement of ulcerated stage of JDM caused by the use of cell therapy. Methods: Co-culture of autologous fibroblasts and keratinocytes, application of these cells in ulcers in conjunction with fibrin glue, and placement of chitosan-alginate or chitosan-xanthan membrane on the lesions. Results: Less than 12 hours after therapy, the patient reported complete cessation of pain and, within 2 days, healing tissue emerged. Some of the ulcers were almost completely healed by the end of the 1st week, and some of the calcinoses disappeared. This technique does not cure the disease, however it improves the patient's quality of life, and it is possible to cryopreserve healthy cells to treat new lesions. Given the fact that the cells are of autologous origin, the risk of rejection is eliminated. Furthermore, this procedure does not require debridement of the lesions or hospitalization. Conclusions: The application of autologous cultures of fibroblasts and keratinocytes in ulcers is already considered an effective treatment in patients with burns and other skin wounds, and has now also been proven effective in the treatment of wounds in JDM.

20.
Mater Sci Eng C Mater Biol Appl ; 76: 287-294, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28482529

RESUMO

Suture threads of cotton or linen, in crossed and random orientation, were added to alginate-chitosan membranes intended to wound coatings application to improve the mechanical properties. The elongation at break increased to about 5 and 8 times for membranes with linen and cotton, respectively, both in the crossed orientation. The addition of the threads increased roughness and opacity of the membranes and reduced the liquid absorption capacity and water vapor transmission rate. The lowest toxicity to human fibroblasts was observed for extracts of membranes produced with linen, and incorporation in them of epidermal growth factor was able to slightly increase cell proliferation.


Assuntos
Família de Proteínas EGF/química , Alginatos , Quitosana , Ácido Glucurônico , Ácidos Hexurônicos , Membranas Artificiais
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