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1.
Mater Sci Eng C Mater Biol Appl ; 113: 110998, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32487406

RESUMO

Silver-based nanomaterials are used as antibacterial agents in a number of applications, including wound dressing, where electrospun materials can effectively promote wound healing and tissue regeneration thanks to their biomimicry, flexibility and breathability. Incorporation of such nanomaterials in electrospun nonwovens is highly challenging if aiming at maximizing stability and antibacterial efficacy and minimizing silver detachment, without neglecting process straightforwardness and scalability. In this work nanostructured silver coatings were deposited by Ionized Jet Deposition (IJD) on Polylactic acid, a medical grade polyester-urethane and Polyamide 6,6 nanofibers. The resulting materials were thoroughly characterized to gain an in-depth view of coating morphology and substrate resistance to the low-temperature deposition process used. Morphology of silver coatings with well-cohesive grains having dimensions from a few tens to a few hundreds of nanometers was analyzed by SEM, TEM and AFM. TGA, DSC, FTIR and GPC showed that the polymers well withstand the deposition process with negligible effects on their properties, the only exception being the polylactic acid that resulted more susceptible to degradation. Finally, the efficacy against S. aureus and E. coli bacterial strains was demonstrated, indicating that electrospun fibers decorated with nanostructured silver by IJD represent a breakthrough solution in the field of antibacterial devices.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32406678

RESUMO

Realizing active, light-emitting fibers made of conjugated polymers by the electrospinning method is generally challenging. Electrospinning of plasma-treated conjugated polymer solutions is here developed for the production of light-emitting microfibers and nanofibers. Active fibers from conjugated polymer solutions rapidly processed by a cold atmospheric argon plasma are electrospun in an effective way, and they show a smoother surface and bead-less morphology, as well as preserved optical properties in terms of absorption, emission, and photoluminescence quantum yield. In addition, the polarization of emitted light and more notably photon waveguiding along the length of individual fibers are remarkably enhanced by electrospinning plasma-treated solutions. These properties come from a synergetic combination of favorable intermolecular coupling in the solutions, increased order of macromolecules on the nanoscale, and resulting fiber morphology. Such findings make the coupling of the electrospinning method and cold atmospheric plasma processing on conjugated polymer solutions a highly promising and possibly general route to generate light-emitting and conductive micro- and nanostructures for organic photonics and electronics.

3.
J Neurotrauma ; 2020 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-32212901

RESUMO

Spinal cord injury (SCI) is an incurable condition, in which a cascade of cellular and molecular events triggered by inflammation and excitotoxicity impairs endogenous regeneration, namely remyelination and axonal outgrowth. We designed a treatment solution based on an implantable biomaterial (electrospun poly (l-lactic acid) [PLLA]) loaded with ibuprofen and triiodothyronine (T3) to counteract inflammation, thus improving endogenous regeneration. In vivo efficacy was tested by implanting the drug-loaded PLLA in the rat model of T8 contusion SCI. We observed the expected recovery of locomotion beginning on day 7. In PLLA-implanted rats (i.e., controls), the recovery stabilized at 21 days post-lesion (DPL), after which no further improvement was observed. On the contrary, in PLLA + ibuprofen (Ibu) + T3 (PLLA-Ibu-T3) rats a further recovery and a significant treatment effect were observed, also confirmed by the gait analysis on 49 DPL. Glutamate release at 24 h and 8 DPL was reduced in PLLA-Ibu-T3- compared to PLLA-implanted rats, such as the estimated lesion volume at 60 DPL. The myelin- and 200-neurofilament-positive area fraction was higher in PLLA-Ibu-T3-implanted rats, where the percentage of astrocytes was significantly reduced. The implant of a PLLA electrospun scaffold loaded with Ibu and T3 significantly improves the endogenous regeneration, leading to an improvement of functional locomotion outcome in the SCI.

4.
Mater Sci Eng C Mater Biol Appl ; 104: 109893, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500045

RESUMO

In the present study biobased and soft thermoplastic polyurethane (TPU), obtained by polymerization from fatty acids, was used to produce TPU/ZnO nanocomposite foams by thermally induced phase separation method (TIPS). The produced foams were characterized and evaluated regarding their potential uses as wound dressing materials. The structure and morphology of the prepared flexible polymer foams with different content of ZnO nanofiller (1, 2, 5 and 10 wt% related to the polymer) were studied by Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Highly porous nanocomposite structure made of interconnected pores with dimensions between 10 and 60 µm was created allowing water vapor transmission rate (WVTR) up to 8.9 mg/cm2·h. The TPU/ZnO foams, tested for their ability to support cells and their growth, showed highest cell proliferation for TPU nanocomposite foams with 2 and 5 wt% ZnO. Overall, the nanocomposite foams displayed a low cytotoxic potential (varied proportionally to the ZnO content) and good biocompatibility. All tested nanocomposite foams were found to be significantly active against biofilms formed by different Gram-positive (Enterococcus faecalis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Based on their behaviors, flexible TPU/ZnO nanocomposite foams can be considered for biomedical applications such as potential active wound dressing.


Assuntos
Nanocompostos/administração & dosagem , Nanocompostos/química , Nanopartículas/administração & dosagem , Nanopartículas/química , Poliuretanos/química , Cicatrização/efeitos dos fármacos , Óxido de Zinco/química , Bactérias/efeitos dos fármacos , Bandagens , Materiais Biocompatíveis/química , Proliferação de Células/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X/métodos
5.
Med Eng Phys ; 71: 79-90, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31262555

RESUMO

Reconstructions of ruptured tendons and ligaments currently have dissatisfactory failure rate. Failures are mainly due to the mechanical mismatch of commercial implants with respect to the host tissue. In fact, it is crucial to replicate the morphology (hierarchical in nature) and mechanical response (highly-nonlinear) of natural tendons and ligaments. The aim of this study was to develop morphologically bioinspired hierarchical Nylon 6,6 electrospun assemblies recreating the structure and performance of tendons and ligaments. First, we built different electrospun bundles to find the optimal orientation of the nanofibers. A 2nd-level hierarchical assembly was fabricated with a dedicated process that allowed tightly joining the bundles one next to the other with an electrospun sheath, so as to improve the mechanical performance. Finally, a further hierarchical 3rd-level assembly was constructed by grouping several 2nd-level assemblies. The morphology of the different structures was assessed with scanning electron microscopy and high-resolution X-ray tomography, which allowed measuring the directionality of the nanofibers in the bundles and in the sheaths. The mechanical properties of the single bundles and of the 2nd-level assemblies were measured with tensile tests. The single bundles and the hierarchical assemblies showed morphology and directionality of the nanofibers similar to the tendons and ligaments. The strength and stiffness were comparable to that of tendons and ligaments. In conclusion, this work showed an innovative electrospinning production process to build nanofibrous Nylon 6,6 hierarchical assemblies which are suitable as future implantable devices and able to mimic the multiscale morphology and the biomechanical properties of tendons and ligaments.


Assuntos
Biomimética/métodos , Caprolactama/análogos & derivados , Ligamentos/efeitos dos fármacos , Polímeros/farmacologia , Tendões/efeitos dos fármacos , Fenômenos Biomecânicos/efeitos dos fármacos , Caprolactama/química , Caprolactama/farmacologia , Ligamentos/citologia , Ligamentos/fisiologia , Teste de Materiais , Nanofibras/química , Polímeros/química , Tendões/citologia , Tendões/fisiologia , Engenharia Tecidual , Tecidos Suporte/química
6.
Biofabrication ; 11(3): 035026, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31071692

RESUMO

Lesions of tendons and ligaments account for over 40% of the musculoskeletal lesions. Surgical techniques and materials for repair and regeneration are currently not satisfactory. The high rate of post-operative complications and failures mainly relates to the technical difficulties in replicating the complex multiscale hierarchical structure and the mechanical properties of the native tendons and ligaments. With the aim of overcoming the limitations of non-biomimetic devices, we developed a hierarchical structure replicating the organization of tendons and ligaments. The scaffold consists of multiple bundles made of resorbable electrospun nanofibers of Poly-L-Lactic acid (PLLA) having tailored dimensions, wrapped in a sheath of nanofibers able to compact the construct. The bundles in turn consist of electrospun nanofibers with a preferential direction. High-resolution x-ray tomographic investigation at nanometer resolution confirmed that the morphology of the single bundles and of the entire scaffold replicated the hierarchical arrangement in the natural tendons and ligaments. To confirm that these structures could adequately restore tendons and ligaments, we measured the tensile stiffness, strength and toughness. The mechanical properties were in the range required to replace and repair tendons and ligaments. Furthermore, human fibroblasts were able to attach to the scaffolds and showed an increase in cell number, indicated by an increase in metabolic activity over time. Fibroblasts were preferentially aligned along the electrospun nanofibers. These encouraging in vitro results open the way for the next steps towards in vivo regeneration of tendons and ligaments.


Assuntos
Ligamentos/fisiologia , Regeneração/fisiologia , Tendões/fisiologia , Tecidos Suporte/química , Proliferação de Células , Fibroblastos/citologia , Humanos , Poliésteres/química , Resistência à Tração , Engenharia Tecidual
7.
Sci Rep ; 8(1): 17167, 2018 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-30464300

RESUMO

Surgical treatment of tendon lesions still yields unsatisfactory clinical outcomes. The use of bioresorbable scaffolds represents a way forward to improve tissue repair. Scaffolds for tendon reconstruction should have a structure mimicking that of the natural tendon, while providing adequate mechanical strength and stiffness. In this paper, electrospun nanofibers of two crosslinked PLLA/Collagen blends (PLLA/Coll-75/25, PLLA/Coll-50/50) were developed and then wrapped in bundles, where the nanofibers are predominantly aligned along the bundles. Bundle morphology was assessed via SEM and high-resolution x-ray computed tomography (XCT). The 0.4-micron resolution in XCT demonstrated a biomimetic morphology of the bundles for all compositions, with a predominant nanofiber alignment and some scatter (50-60% were within 12° from the axis of the bundle), similar to the tendon microstructure. Human fibroblasts seeded on the bundles had increased metabolic activity from day 7 to day 21 of culture. The stiffness, strength and toughness of the bundles are comparable to tendon fascicles, both in the as-spun condition and after crosslinking, with moderate loss of mechanical properties after ageing in PBS (7 and 14 days). PLLA/Coll-75/25 has more desirable mechanical properties such as stiffness and ductility, compared to the PLLA/Coll-50/50. This study confirms the potential to bioengineer tendon fascicles with enhanced 3D structure and biomechanical properties.


Assuntos
Bioengenharia/métodos , Fenômenos Biomecânicos , Materiais Biomiméticos/química , Colágeno , Nanofibras/química , Poliésteres , Tecidos Suporte/química , Humanos , Microscopia Eletroquímica de Varredura , Medicina Regenerativa/métodos , Tomografia Computadorizada por Raios X
8.
Int J Mol Sci ; 19(10)2018 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-30336625

RESUMO

We report the study of novel biodegradable electrospun scaffolds from poly(butylene 1,4-cyclohexandicarboxylate-co-triethylene cyclohexanedicarboxylate) (P(BCE-co-TECE)) as support for in vitro and in vivo muscle tissue regeneration. We demonstrate that chemical composition, i.e., the amount of TECE co-units (constituted of polyethylene glycol-like moieties), and fibre morphology, i.e., aligned microfibrous or sub-microfibrous scaffolds, are crucial in determining the material biocompatibility. Indeed, the presence of ether linkages influences surface wettability, mechanical properties, hydrolytic degradation rate, and density of cell anchoring points of the studied materials. On the other hand, electrospun scaffolds improve cell adhesion, proliferation, and differentiation by favouring cell alignment along fibre direction (fibre morphology), also allowing for better cell infiltration and oxygen and nutrient diffusion (fibre size). Overall, C2C12 myogenic cells highly differentiated into mature myotubes when cultured on microfibres realised with the copolymer richest in TECE co-units (micro-P73 mat). Lastly, when transplanted in the tibialis anterior muscles of healthy, injured, or dystrophic mice, micro-P73 mat appeared highly vascularised, colonised by murine cells and perfectly integrated with host muscles, thus confirming the suitability of P(BCE-co-TECE) scaffolds as substrates for skeletal muscle tissue engineering.


Assuntos
Cicloexanos/química , Músculo Esquelético/fisiologia , Oxigênio/química , Polienos/química , Polietilenoglicóis/química , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Forma Celular , Implantes Experimentais , Inflamação/patologia , Antígeno Ki-67/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica
9.
Adv Mater ; 30(39): e1802813, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30133005

RESUMO

Mechanochromic polymeric systems are intensively investigated for real-time stress detection applications. However, an effective stress-sensing material must respond to low deformation with a detectable color change that should be quickly reversible upon force unloading. In this work, mechanochromic nanofibers made by electrospinning are used to produce mechanochromic nanofiber/poly(dimethylsiloxane) (PDMS) composites with isotropic and anisoptropic response. Due to chain alignment of spiropyran copolymer chains within the nanofibers, only very small strains are required to yield a mechanochromic response. Composites with aligned and isotropic nanofibers show anisotropic and isotropic mechanochromic behavior, respectively. Due to the special substitution pattern of spiropyran in the copolymer, the mechanochromic response of these nanofiber/PDMS composites shows fast reversibility upon force unloading. The outstanding benefit of using highly sensitive mechanochromic nanofibers as filler in composite materials allows the detection of directional stress and strain, and it is a step forward in the development of smart, mechanically responsive materials.

10.
Biomacromolecules ; 18(8): 2499-2508, 2017 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-28636337

RESUMO

A biodegradable and biocompatible electrospun scaffold with shape memory behavior in the physiological temperature range is here presented. It was obtained starting from a specifically designed, biobased PLLA-based triblock copolymer, where the central block is poly(propylene azelate-co-propylene sebacate) (P(PAz60PSeb40)) random copolymer. Shape memory properties are determined by the contemporary presence of the low melting crystals of the P(PAz60PSeb40) block, acting as switching segment, and of the high melting crystal phase of PLLA blocks, acting as physical network. It is demonstrated that a straightforward annealing process applied to the crystal phase of the switching element gives the possibility to tune the shape recovery temperature from about 25 to 50 °C, without the need of varying the copolymer's chemical structure. The thermal annealing approach here presented can be thus considered a powerful strategy for "ad hoc" programming the same material for applications requiring different recovery temperatures. Fibroblast culture experiments demonstrated scaffold biocompatibility.


Assuntos
Materiais Biocompatíveis/química , Temperatura Corporal , Poliésteres/química , Animais , Humanos , Camundongos , Células NIH 3T3
11.
Biofabrication ; 9(1): 015025, 2017 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-28224971

RESUMO

Electrospinning is a promising technique for the production of scaffolds aimed at the regeneration of soft tissues. The aim of this work was to develop electrospun bundles mimicking the architecture and mechanical properties of the fascicles of the human Achille tendon. Two different blends of poly(L-lactic acid) (PLLA) and collagen (Coll) were tested, PLLA/Coll-75/25 and PLLA/Coll-50/50, and compared with bundles of pure PLLA. First, a complete physico-chemical characterization was performed on non-woven mats made of randomly arranged fibers. The presence of collagen in the fibers was assessed by thermogravimetric analysis, differential scanning calorimetry and water contact angle measurements. The collagen release in phosphate buffer solution (PBS) was evaluated for 14 days: results showed that collagen loss was about 50% for PLLA/Coll-75/25 and 70% for PLLA/Coll-50/50. In the bundles, the individual fibers had a diameter of 0.48 ± 0.14 µm (PLLA), 0.31 ± 0.09 µm (PLLA/Coll-75/25), 0.33 ± 0.08 µm (PLLA/Coll-50/50), whereas bundle diameter was in the range 300-500 µm for all samples. Monotonic tensile tests were performed to measure the mechanical properties of PLLA bundles (as-spun) and of PLLA/Coll-75/25 and PLLA/Coll-50/50 bundles (as-spun, and after 48 h, 7 days and 14 days in PBS). The most promising material was the PLLA/Coll-75/25 blend with a Young modulus of 98.6 ± 12.4 MPa (as-spun) and 205.1 ± 73.0 MPa (after 14 days in PBS). Its failure stress was 14.2 ± 0.7 MPa (as-spun) and 6.8 ± 0.6 MPa (after 14 days in PBS). Pure PLLA withstood slightly lower stress than the PLLA/Coll-75/25 while PLLA/Coll-50/50 had a brittle behavior. Human-derived tenocytes were used for cellular tests. A good cell adhesion and viability after 14 day culture was observed. This study has therefore demonstrated the feasibility of fabricating electrospun bundles with multiscale structure and mechanical properties similar to the human tendon.


Assuntos
Técnicas de Cultura de Células/métodos , Colágeno/química , Poliésteres/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Varredura Diferencial de Calorimetria , Adesão Celular/efeitos dos fármacos , Técnicas de Cultura de Células/instrumentação , Células Cultivadas , Colágeno Tipo I/metabolismo , Módulo de Elasticidade , Fibronectinas/metabolismo , Humanos , Microscopia Eletrônica de Transmissão , Pessoa de Meia-Idade , Tendões/citologia , Tendões/metabolismo , Resistência à Tração , Termogravimetria , Vimentina/metabolismo
12.
Sci Rep ; 6: 38542, 2016 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-27924840

RESUMO

Electrospun gelatin nanofibers attract great interest as a natural biomaterial for cartilage and tendon repair despite their high solubility in aqueous solution, which makes them also difficult to crosslink by means of chemical agents. In this work, we explore the efficiency of non-equilibrium atmospheric pressure plasma in stabilizing gelatin nanofibers. We demonstrate that plasma represents an innovative, easy and environmentally friendly approach to successfully crosslink gelatin electrospun mats directly in the solid state. Plasma treated gelatin mats display increased structural stability and excellent retention of fibrous morphology after immersion in aqueous solution. This method can be successfully applied to induce crosslinking both in pure gelatin and genipin-containing gelatin electrospun nanofibers, the latter requiring an even shorter plasma exposure time. A complete characterization of the crosslinked nanofibres, including mechanical properties, morphological observations, stability in physiological solution and structural modifications, has been carried out in order to get insights on the occurring reactions triggered by plasma.

13.
Biores Open Access ; 5(1): 201-11, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27588220

RESUMO

Biomimetic materials are designed to stimulate specific cellular responses at the molecular level. To improve the soundness of in vitro testing of the biological impact of new materials, appropriate cell systems and technologies must be standardized also taking regulatory issues into consideration. In this study, the biological and molecular effects of different scaffolds on three neural systems, that is, the neural cell line SH-SY5Y, primary cortical neurons, and neural stem cells, were compared. The effect of poly(L-lactic acid) scaffolds having different surface geometry (conventional two-dimensional seeding flat surface, random or aligned fibers as semi3D structure) and chemical functionalization (laminin or ECM extract) were studied. The endpoints were defined for efficacy (i.e., neural differentiation and neurite elongation) and for safety (i.e., cell death/survival) using high-content analysis. It is demonstrated that (i) the definition of the biological properties of biomaterials is profoundly influenced by the test system used; (ii) the definition of the in vitro safety profile of biomaterials for neural repair is also influenced by the test system; (iii) cell-based high-content screening may well be successfully used to characterize both the efficacy and safety of novel biomaterials, thus speeding up and improving the soundness of this critical step in material science having medical applications.

14.
Macromol Biosci ; 16(10): 1533-1544, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27282336

RESUMO

Electrospun poly-l-lactic acid (PLLA) nanofiber mats carrying surface amine groups, previously introduced by nitrogen atmospheric pressure nonequilibrium plasma, are embedded into aqueous solutions of oligomeric acrylamide-end capped AGMA1, a biocompatible polyamidoamine with arg-gly-asp (RGD)-reminiscent repeating units. The resultant mixture is finally cured giving PLLA-AGMA1 hydrogel composites that absorb large amounts of water and, in the swollen state, are translucent, soft, and pliable, yet as strong as the parent PLLA mat. They do not split apart from each other when swollen in water and remain highly flexible and resistant, since the hydrogel portion is covalently grafted onto the PLLA nanofibers via the addition reaction of the surface amine groups to a part of the terminal acrylic double bonds of AGMA1 oligomers. Preliminary tested as scaffolds, the composites prove capable of maintaining short-term undifferentiated cultures of human pluripotent stem cells in feeder-free conditions.


Assuntos
Hidrogéis/química , Nanofibras/química , Células-Tronco Pluripotentes/metabolismo , Poliaminas/química , Poliésteres/química , Tecidos Suporte/química , Agmatina/análogos & derivados , Agmatina/química , Técnicas de Cultura de Células , Humanos , Células-Tronco Pluripotentes/citologia
15.
Biomed Mater ; 11(2): 025007, 2016 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-26987305

RESUMO

Crosslinking of gelatin nanofibers maintaining a fibrous morphology after exposure to an aqueous solution is still a challenge. In this work, we developed an innovative method based on the use of an ad hoc designed co-axial needle to fabricate gelatin mats crosslinked with a very small amount of genipin and still able to retain their morphology when immersed in aqueous solution. Genipin-containing gelatin nanofibers are obtained by allowing mixing of the two solutions just within the needle. Genipin content of the electrospun mats can be modulated by varying feeding rates of the inner and outer solutions and their relative concentration. A subsequent thermal treatment of the mats, performed at 55 °C or 37 °C for 1 or 3 days and followed by rapid rinsing in ethanol and then in PB, allows one to obtain highly crosslinked gelatin nanofibers that perfectly maintain their morphology after immersion in an aqueous solution, display improved mechanical properties and enhanced stability. This new approach allows us to achieve gelatin mat stabilization using a very small amount of genipin with respect to other methods and to avoid post-treatment of the mats with the crosslinking agent, with a consequent significant reduction of the final cost of the materials. Moreover, in vitro tests demonstrate that the crosslinked mats support normal human primary chondrocyte culture, promoting their differentiation.


Assuntos
Gelatina/química , Nanofibras/química , Tecidos Suporte/química , Materiais Biocompatíveis/química , Diferenciação Celular , Sobrevivência Celular , Células Cultivadas , Condrócitos/citologia , Condrócitos/enzimologia , Reagentes para Ligações Cruzadas , Humanos , Iridoides , L-Lactato Desidrogenase/metabolismo , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanofibras/ultraestrutura , Nanotecnologia , Engenharia Tecidual/métodos
16.
Biomaterials ; 76: 261-72, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26546918

RESUMO

Bioactive scaffolds for tissue engineering call for demands on new materials which can enhance traditional biocompatibility requirements previously considered for clinical implantation. The current commercially available thermoplastic materials, such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(ε-caprolactone) (PCL) and their copolymers, have been used to fabricate scaffolds for regenerative medicine. However, these polymers have limitations including lacking of broadly tuning mechanical and degradable properties, and activation of specific cell-scaffold interactions, which limit their further application in tissue engineering. In the present study, electrospun scaffolds were successfully fabricated from a new class of block poly(butylene succinate)-based (PBS-based) copolyesters containing either butylene thiodiglycolate (BTDG) or butylene diglycolate (BDG) sequences. The polyesters displayed tunable mechanical properties and hydrolysis rate depending on the molecular architecture and on the kind of heteroatom introduced along the polymer backbone. To investigate their potential for skeletal regeneration, human mesenchymal stromal cells (hMSCs) were cultured on the scaffolds in basic, osteogenic and chondrogenic media. Our results demonstrated that PBS-based copolyesters containing thio-ether linkages (i.e. BTDG segments) were more favorable for chondrogenesis of hMSCs than those containing ether linkages (i.e. BDG sequences). In contrast, PBS-based copolyesters containing ether linkages showed enhanced mineralization. Therefore, these new functional scaffolds might hold potential for osteochondral tissue engineering applications.


Assuntos
Osso e Ossos/citologia , Diferenciação Celular , Células-Tronco Mesenquimais/citologia , Poliésteres/química , Tecidos Suporte , Osso e Ossos/metabolismo , Células Cultivadas , Meios de Cultura , Éter , Humanos , Hidrólise , Células-Tronco Mesenquimais/metabolismo
17.
J Mater Sci Mater Med ; 25(10): 2313-21, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24664673

RESUMO

Collagen electrospun scaffolds well reproduce the structure of the extracellular matrix (ECM) of natural tissues by coupling high biomimetism of the biological material with the fibrous morphology of the protein. Structural properties of collagen electrospun fibers are still a debated subject and there are conflicting reports in the literature addressing the presence of ultrastructure of collagen in electrospun fibers. In this work collagen type I was successfully electrospun from two different solvents, trifluoroethanol (TFE) and dilute acetic acid (AcOH). Characterization of collagen fibers was performed by means of SEM, ATR-IR, Circular Dichroism and WAXD. We demonstrated that collagen fibers contained a very low amount of triple helix with respect to pristine collagen (18 and 16% in fibers electrospun from AcOH and TFE, respectively) and that triple helix denaturation occurred during polymer dissolution. Collagen scaffolds were crosslinked by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), a commonly employed crosslinker for electrospun collagen, and 1,4-butanediol diglycidyl ether (BDDGE), that was tested for the first time in this work as crosslinking agent for collagen in the form of electrospun fibers. We demonstrated that BDDGE successfully crosslinked collagen and preserved at the same time the scaffold fibrous morphology, while scaffolds crosslinked with EDC completely lost their porous structure. Mesenchymal stem cell experiments demonstrated that collagen scaffolds crosslinked with BDDGE are biocompatible and support cell attachment.


Assuntos
Colágeno/química , Reagentes para Ligações Cruzadas/farmacologia , Nanofibras/química , Solventes/farmacologia , Tecidos Suporte , Animais , Materiais Biocompatíveis/química , Butileno Glicóis , Células Cultivadas , Colágeno/efeitos dos fármacos , Estabilidade de Medicamentos , Galvanoplastia/métodos , Matriz Extracelular/química , Teste de Materiais , Coelhos , Engenharia Tecidual/métodos , Tecidos Suporte/química
18.
Mater Sci Eng C Mater Biol Appl ; 36: 130-8, 2014 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24433895

RESUMO

Bio-synthetic scaffolds of interspersed poly(l-lactic acid) (PLLA) and gelatin (GEL) fibers are fabricated by co-electrospinning. Tailored PLLA/GEL compositions are obtained and GEL crosslinking with genipin provides for the maintenance of good fiber morphology. Scaffold tensile mechanical properties are intermediate between those of pure PLLA and GEL and vary as a function of PLLA content. Primary human chondrocytes grown on the scaffolds exhibit good proliferation and increased values of the differentiation parameters, especially for intermediate PLLA/GEL compositions. Mineralization tests enable the deposition of a uniform layer of poorly crystalline apatite onto the scaffolds, suggesting potential applications involving cartilage as well as cartilage-bone interface tissue engineering.


Assuntos
Condrócitos/citologia , Gelatina/farmacologia , Ácido Láctico/farmacologia , Fenômenos Mecânicos/efeitos dos fármacos , Polímeros/farmacologia , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Calcificação Fisiológica/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Condrócitos/efeitos dos fármacos , Condrócitos/enzimologia , Condrócitos/ultraestrutura , Reagentes para Ligações Cruzadas/química , Humanos , L-Lactato Desidrogenase/metabolismo , Poliésteres , Espectroscopia de Infravermelho com Transformada de Fourier , Sus scrofa , Resistência à Tração/efeitos dos fármacos
19.
Nano Lett ; 13(11): 5385-90, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24144429

RESUMO

Several methods for creating vascular structures, made of either discrete or interconnected channels have been developed. The currently employed methods enable the formation of channels with diameters in the millimetric and micrometric scale. However, the formation of an interconnected three-dimensional (3D) vasculature by using a rapid and scalable process is a challenge and largely limits the fields of applicability of these innovative materials. Here, we propose the use of electrospun nonwoven mats as sacrificial fibers to easily generate 3D macroscale vascularized composites containing interconnected networks with channels and tubes having submicrometric and nanometric diameters. The novel approach has the potentialities to give rise to a novel generation of composites potentially displaying new and enhanced functionalities thanks to the nanoscale features of the cavities.

20.
Exp Cell Res ; 319(10): 1515-22, 2013 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-23583658

RESUMO

We present a multi-technique study on in vitro epithelial-mesenchymal transition (EMT) in human MCF-7 cells cultured on electrospun scaffolds of poly(l-lactic acid) (PLA), with random and aligned fiber orientations. Our aim is to investigate the morphological and genetic characteristics induced by extracellular matrix in tumor cells cultured in different 3D environments, and at different time points. Cell vitality was assessed with AlamarBlue at days 1, 3, 5 and 7. Scanning electron microscopy was performed at culture days 3 and 7. Immunohistochemistry (for E-cadherin, ß-catenin, cytokeratins, nucleophosmin, tubulin, Ki-67 and vimentin), immunofluorescence (for F-actin) western blot (for E-cadherin, ß-catenin and vimentin) and transmission electron microscopy were carried out at day 7. An EMT gene array followed by PCR analysis confirmed the regulation of selected genes. At day 7, scanning electron microscopy on aligned-PLA revealed spindle-shaped cells gathered in buds and ribbon-like structures, with a higher nucleolar/nuclear ratio and a loss in E-cadherin and ß-catenin at immunohistochemistry and western blot. An up-regulation of SMAD2, TGF-ß2, TFPI2 and SOX10 was found in aligned-PLA compared to random-PLA cultured cells. The topography of the extracellular matrix has a role in tumor EMT, and a more aggressive phenotype characterizes MCF-7 cells cultured on aligned-PLA scaffold.


Assuntos
Forma Celular , Transição Epitelial-Mesenquimal , Matriz Extracelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Microambiente Tumoral , Actinas/genética , Actinas/metabolismo , Antígenos CD , Western Blotting , Caderinas/genética , Caderinas/metabolismo , Adesão Celular , Feminino , Glicoproteínas/genética , Glicoproteínas/metabolismo , Humanos , Imuno-Histoquímica , Antígeno Ki-67/genética , Antígeno Ki-67/metabolismo , Ácido Láctico/metabolismo , Células MCF-7 , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Análise de Sequência com Séries de Oligonucleotídeos , Oxazinas , Fenótipo , Proteína Smad2/genética , Proteína Smad2/metabolismo , Fatores de Tempo , Tecidos Suporte , Fator de Crescimento Transformador beta2/genética , Fator de Crescimento Transformador beta2/metabolismo , Vimentina/genética , Vimentina/metabolismo , Xantenos , beta Catenina/genética , beta Catenina/metabolismo
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