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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.
Biomacromolecules ; 21(3): 1157-1170, 2020 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-32011862

RESUMO

Regulating stem cell adhesion and growth onto functionalized biomaterial scaffolds is an important issue in the field of tissue engineering and regenerative medicine. In this study, new electrospun scaffolds of poly(l-lactic acid) (PLLA), as bioresorbable polymer, and ß-lactam compounds agonists of selected integrins, as functional components with cell adhesive properties, are designed. The new ß-lactam-PLLA scaffolds contribute significantly in guiding protein translation involved in human bone marrow mesenchymal stem cells (hBM-MSC) adhesion and integrin gene expression. Scanning electron microscopy, confocal laser scanning microscopy, and Western Blot analyses reveal that GM18-PLLA shows the best results, promoting cell adhesion by significantly driving changes in focal adhesion proteins distribution (ß1 integrin and vinculin) and activation (pFAK), with a notable increase of GM18-targets subunits integrin gene expression, α4 and ß1. These novel functionalized submicrometric fibrous scaffolds demonstrate, for the first time, the powerful combination of selective ß-lactams agonists of integrins with biomimetic scaffolds, suggesting a designed rule that could be suitably applied to tissue repair and regeneration.

5.
Biomed Mater ; 15(3): 035006, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-31995538

RESUMO

The bacterial colonization of absorbable membranes used for guided tissue regeneration (GTR), as well as their rapid degradation that can cause their rupture, are considered the major reasons for clinical failure. To address this, composite membranes of polycaprolactone (PCL) and gelatin (Gel) loaded with zinc oxide nanoparticles (ZnO-NPs; 1, 3 and 6 wt% relative to PCL content) were fabricated by electrospinning. To fabricate homogeneous fibrillar membranes, acetic acid was used as a sole common solvent to enhance the miscibility of PCL and Gel in the electrospinning solutions. The effects of ZnO-NPs in the physico-chemical, mechanical and in vitro biological properties of composite membranes were studied. The composite membranes showed adequate mechanical properties to offer a satisfactory clinical manipulation and an excellent conformability to the defect site while their degradation rate seemed to be appropriate to allow successful regeneration of periodontal defects. The presence of ZnO-NPs in the composite membranes significantly decreased the planktonic and the biofilm growth of the Staphylococcus aureus over time. Finally, the viability of human osteoblasts and human gingival fibroblasts exposed to the composite membranes with 1 and 3 wt% of ZnO-NPs indicated that those membranes are not expected to negatively influence the ability of periodontal cells to repopulate the defect site during GTR treatments. The results here obtained suggest that composite membranes of PCL and Gel loaded with ZnO-NPs have the potential to be used as structurally stable GTR membranes with local antibacterial properties intended for enhancing clinical treatments.

6.
Materials (Basel) ; 12(17)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31480538

RESUMO

The majority of the crosslinking approaches employed to confer water resistance properties to electrospun gelatin mats are based on the use of potential cytotoxic agents, turning out to be not suitable for biomedical applications. Environmentally friendly chemical strategies based on the use of non-toxic agents are, therefore, strongly demanded. In the present work, the possibility to produce crosslinked electrospun fish gelatin mats by electrospinning an aqueous solution, containing citric acid as a crosslinking agent, is reported. The effect of pH on solution rheological properties, as well as on the electrospun mat morphology, chemistry, and crosslinking degree, is assessed. The increase of solution pH from 1.8 to 3.7 allows for obtaining fibers that maintain the fibrous morphology also in the mat. Subsequent thermal treatment of the electrospun mat (80 °C for 30 min) turns out to increase the crosslinking degree and morphological stability of the mat.

7.
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
8.
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
9.
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
10.
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
11.
Molecules ; 23(10)2018 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-30297641

RESUMO

In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.


Assuntos
Anticorpos Neutralizantes/imunologia , Neoplasias/terapia , Vírus Oncolíticos/imunologia , Ácido Poliglutâmico/análogos & derivados , Adenoviridae/genética , Adenoviridae/imunologia , Anticorpos Neutralizantes/efeitos dos fármacos , Quitosana/química , Quitosana/imunologia , Quitosana/uso terapêutico , Portadores de Fármacos/química , Portadores de Fármacos/uso terapêutico , Humanos , Imunidade Celular/efeitos dos fármacos , Ligantes , Nanopartículas/química , Nanopartículas/uso terapêutico , Neoplasias/imunologia , Terapia Viral Oncolítica/efeitos adversos , Vírus Oncolíticos/genética , Ácido Poliglutâmico/química , Ácido Poliglutâmico/imunologia , Ácido Poliglutâmico/uso terapêutico , Polímeros/química , Polímeros/uso terapêutico
12.
Artigo em Inglês | MEDLINE | ID: mdl-30258842

RESUMO

Stimuli-responsive hydrogel matrices are inspiring manifold applications in controlled delivery of bioactive compounds. Elastin-derived polypeptides form hydrogel matrices that may release bioactive moieties as a function of local increase of active elastases, as it would occur in several processes like inflammation. In view of the development of a patch for healing wounds, recombinant elastin-based polypeptides were combined with a proteolysis-resistant scaffold, made of electrospun poly-L-lactic acid (PLLA) fibers. The results of this study demonstrated the compatibility of these two components. An efficient procedure to obtain a composite material retaining the main features of each component was established. The release of the elastin moiety was monitored by means of a simple protocol. Our data showed that electrospun PLLA can form a composite with fusion proteins bound to elastin-derived polypeptides. Therefore, our approach allows designing a therapeutic agent delivery platform to realize devices capable of responding and interacting with biological systems at the molecular level.

13.
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.

14.
Biomaterials ; 178: 193-203, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29936153

RESUMO

Intracranial delivery of therapeutic agents is limited by penetration beyond the blood-brain barrier (BBB) and rapid metabolism of the drugs that are delivered. Convection-enhanced delivery (CED) of drug-loaded nanoparticles (NPs) provides for local administration, control of distribution, and sustained drug release. While some investigators have shown that repeated CED procedures are possible, longer periods of sustained release could eliminate the need for repeated infusions, which would enhance safety and translatability of the approach. Here, we demonstrate that nanoparticles formed from poly(ethylene glycol)-poly(ω-pentadecalactone-co-p-dioxanone) block copolymers [PEG-poly(PDL-co-DO)] are highly efficient nanocarriers that provide long-term release: small nanoparticles (less than 100 nm in diameter) continuously released a radiosensitizer (VE822) over a period of several weeks in vitro, provided widespread intracranial drug distribution during CED, and yielded significant drug retention within the brain for over 1 week. One advantage of PEG-poly(PDL-co-DO) nanoparticles is that hydrophobicity can be tuned by adjusting the ratio of hydrophobic PDL to hydrophilic DO monomers, thus making it possible to achieve a wide range of drug release rates and drug distribution profiles. When administered by CED to rats with intracranial RG2 tumors, and combined with a 5-day course of fractionated radiation therapy, VE822-loaded PEG-poly(PDL-co-DO) NPs significantly prolonged survival when compared to free VE822. Thus, PEG-poly(PDL-co-DO) NPs represent a new type of versatile nanocarrier system with potential for sustained intracranial delivery of therapeutic agents to treat brain tumors.


Assuntos
Materiais Biocompatíveis/química , Neoplasias Encefálicas/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Nanopartículas/química , Poliésteres/química , Polietilenoglicóis/química , Animais , Neoplasias Encefálicas/patologia , Convecção , Liberação Controlada de Fármacos , Hidrodinâmica , Isoxazóis/farmacologia , Masculino , Nanopartículas/ultraestrutura , Poliésteres/síntese química , Polietilenoglicóis/síntese química , Pirazinas/farmacologia , Radiossensibilizantes/farmacologia , Ratos Endogâmicos F344 , Ensaios Antitumorais Modelo de Xenoenxerto
15.
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
16.
Macromol Biosci ; 17(3)2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27754612

RESUMO

Oligo(Glu70 -co-Leu30 ), a peptide synthesized by protease catalysis, is functionalized at the N-terminus with a 4-pentenoyl unit and grafted to polyLSL[6'Ac,6″Ac], a glycopolymer prepared by ring-opening metathesis polymerization of lactonic sophorolipid diacetate. First, polyLSL[6'Ac,6"Ac] fiber mats are fabricated by electrospinning. Oxidation of the fiber mats and subsequent reaction with cysteamine lead to thiol-functionalized fiber mats with no significant morphology changes. Grafting of the alkene-modified oligopeptide to thiol-functionalized polyLSL[6'Ac,6″Ac] fiber mats is achieved via "thiol-ene" click reaction. X-ray photoelectron spectroscopy analysis to characterize peptide grafting reveals that about 50 mol% of polyLSL[6'Ac,6''Ac] repeat units at fiber surfaces are decorated with a peptide moiety, out of which about 1/3 of the oligo(Glu70 -co-Leu30 ) units are physically adsorbed to polyLSL[6'Ac,6''Ac]. The results of this work pave the way to precise engineering of polyLSL fiber mats that can be decorated with a potentially wide range of molecules that tailor surface chemistry and biological properties.


Assuntos
Materiais Biocompatíveis/química , Biopolímeros/química , Glicoproteínas/química , Peptídeos/química , Materiais Biocompatíveis/síntese química , Glicoproteínas/síntese química , Peptídeos/síntese química , Espectroscopia Fotoeletrônica , Propriedades de Superfície
17.
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.

18.
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.

19.
Chemistry ; 22(34): 12106-12, 2016 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-27417509

RESUMO

We present herein the preparation of four different hydrogels based on the pseudopeptide gelator Fmoc-l-Phe-d-Oxd-OH (Fmoc=fluorenylmethyloxycarbonyl), either by changing the gelator concentration or adding graphene oxide (GO) to the water solution. The hydrogels have been analysed by rheological studies that demonstrated that pure hydrogels are slightly stronger compared to GO-loaded hydrogels. Then the hydrogels efficiency to trap the cationic methylene blue (MB) and anionic eosin Y (EY) dyes has been analyzed. MB is efficiently trapped by both the pure hydrogel and the GO-loaded hydrogel through π-π interactions and electrostatic interactions. In contrast, the removal of the anionic EY is achieved in less satisfactory yields, due to the unfavourable electrostatic interactions between the dye, the gelator and GO.


Assuntos
Corantes/química , Amarelo de Eosina-(YS)/química , Grafite/química , Hidrogéis/química , Íons/química , Azul de Metileno/química , Peptídeos/química , Tiazinas/química , Adsorção , Concentração de Íons de Hidrogênio , Peptídeos/metabolismo , Reologia , Poluentes Químicos da Água
20.
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
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