RESUMEN
Multicompartment particles, which are particles composed of smaller building units, have gained considerable interest during the past decade to facilitate simultaneous and differential delivery of several biomolecules in various applications. Supercritical carbon dioxide (CO2) processing is an industrial technology widely used for large-scale synthesis and processing of materials. However, the application of this technology for production of multicompartment particles from colloidal particles has not yet been explored. Here, we report the formation of raspberry-like gelatin (RLG) microparticles composed of gelatin nanoparticles as colloidal building blocks through supercritical CO2 processing. We show that these RLG microparticles exhibit a high stability upon dispersion in aqueous media without requiring chemical cross-linking. We further demonstrate that these microparticles are cytocompatible and facilitate differential release of two different model compounds. The strategy presented here can be utilized as a cost-effective route for production of various types of multicompartment particles using colloidal particles with suitable interparticle interactions. STATEMENT OF SIGNIFICANCE: Multicompartment particles have gained considerable interest during the past decade to facilitate simultaneous and differential delivery of multiple biomolecules in various biomedical applications. Nevertheless, common methods employed for the production of such particles are often complex and only offer small-scale production. Here, we report the formation of raspberry-like gelatin (RLG) microparticles composed of gelatin nanoparticles as colloidal building blocks through supercritical CO2 processing. We show that these microparticles are cytocompatible and facilitate differential release of two model compounds with different molecular sizes, promising successful applications in various biomedical areas. Summarizing, this paper presents a novel strategy that can be utilized as a cost-effective route for production of various types of multicompartment particles using a wide range of colloidal building blocks.
Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Gelatina , Microesferas , Nanopartículas/química , Animales , Dióxido de Carbono/química , Gelatina/química , Gelatina/farmacología , Humanos , Ratones , Células 3T3 NIHRESUMEN
The present work investigated correlations between cartilage and subchondral bone repair, facilitated by a growth factor-delivering scaffold, in a rabbit osteochondral defect model. Histological scoring indices and microcomputed tomography morphological parameters were used to evaluate cartilage and bone repair, respectively, at 6 and 12 weeks. Correlation analysis revealed significant associations between specific cartilage indices and subchondral bone parameters that varied with location in the defect (cortical vs. trabecular region), time point (6 vs. 12 weeks), and experimental group (insulin-like growth factor-1 only, bone morphogenetic protein-2 only, or both growth factors). In particular, significant correlations consistently existed between cartilage surface regularity and bone quantity parameters. Overall, correlation analysis between cartilage and bone repair provided a fuller understanding of osteochondral repair and can help drive informed studies for future osteochondral regeneration strategies.
Asunto(s)
Implantes Absorbibles , Proteína Morfogenética Ósea 2/farmacología , Regeneración Ósea/efectos de los fármacos , Cartílago/metabolismo , Hidrogeles/farmacología , Factor I del Crecimiento Similar a la Insulina/farmacología , Animales , Cartílago/lesiones , Cartílago/patología , Humanos , ConejosRESUMEN
In the last decade, the biomedical applications of nanoparticles (NPs) (e.g. cell tracking, biosensing, magnetic resonance imaging (MRI), targeted drug delivery, and tissue engineering) have been increasingly developed. Among the various NP types, superparamagnetic iron oxide NPs (SPIONs) have attracted considerable attention for early detection of diseases due to their specific physicochemical properties and their molecular imaging capabilities. A comprehensive review is presented on the recent advances in the development of in vitro and in vivo SPION applications for molecular imaging, along with opportunities and challenges.
Asunto(s)
Compuestos Férricos/química , Imagen por Resonancia Magnética/métodos , Nanopartículas del Metal/química , HumanosRESUMEN
The present work investigated the use of biodegradable hydrogel composite scaffolds, based on the macromer oligo(poly(ethylene glycol) fumarate) (OPF), to deliver growth factors for the repair of osteochondral tissue in a rabbit model. In particular, bilayered OPF composites were used to mimic the structural layers of the osteochondral unit, and insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) were loaded into gelatin microparticles and embedded within the OPF hydrogel matrix in a spatially controlled manner. Three different scaffold formulations were implanted in a medial femoral condyle osteochondral defect: 1) IGF-1 in the chondral layer, 2) BMP-2 in the subchondral layer, and 3) IGF-1 and BMP-2 in their respective separate layers. The quantity and quality of osteochondral repair was evaluated at 6 and 12 weeks with histological scoring and micro-computed tomography (micro-CT). While histological scoring results at 6 weeks showed no differences between experimental groups, micro-CT analysis revealed that the delivery of BMP-2 alone increased the number of bony trabecular islets formed, an indication of early bone formation, over that of IGF-1 delivery alone. At 12 weeks post-implantation, minimal differences were detected between the three groups for cartilage repair. However, the dual delivery of IGF-1 and BMP-2 had a higher proportion of subchondral bone repair, greater bone growth at the defect margins, and lower bone specific surface than the single delivery of IGF-1. These results suggest that the delivery of BMP-2 enhances subchondral bone formation and that, while the dual delivery of IGF-1 and BMP-2 in separate layers does not improve cartilage repair under the conditions studied, they may synergistically enhance the degree of subchondral bone formation. Overall, bilayered OPF hydrogel composites demonstrate potential as spatially-guided, multiple growth factor release vehicles for osteochondral tissue repair.
Asunto(s)
Proteína Morfogenética Ósea 2/administración & dosificación , Cartílago/fisiología , Fémur/fisiología , Fumaratos/química , Factor I del Crecimiento Similar a la Insulina/administración & dosificación , Polietilenglicoles/química , Regeneración/efectos de los fármacos , Andamios del Tejido/química , Animales , Proteína Morfogenética Ósea 2/uso terapéutico , Cartílago/efectos de los fármacos , Cartílago/patología , Fémur/efectos de los fármacos , Fémur/patología , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Factor I del Crecimiento Similar a la Insulina/uso terapéutico , Masculino , ConejosRESUMEN
Hydrogels can provide a suitable environment for tissue formation by embedded cells, which makes them suitable for applications in regenerative medicine. However, hydrogels possess only limited mechanical strength, and must therefore be reinforced for applications in load-bearing conditions. In most approaches the reinforcing component and the hydrogel network have poor interactions and the synergetic effect of both materials on the mechanical properties is not effective. Therefore, in the present study, a thermoplastic polymer blend of poly(hydroxymethylglycolide-co-ε-caprolactone)/poly(ε-caprolactone) (pHMGCL/PCL) was functionalized with methacrylate groups (pMHMGCL/PCL) and covalently grafted to gelatin methacrylamide (gelMA) hydrogel through photopolymerization. The grafting resulted in an at least fivefold increase in interface-binding strength between the hydrogel and the thermoplastic polymer material. GelMA constructs were reinforced with three-dimensionally printed pHMGCL/PCL and pMHMGCL/PCL scaffolds and tested in a model for a focal articular cartilage defect. In this model, covalent bonds at the interface of the two materials resulted in constructs with an improved resistance to repeated axial and rotational forces. Moreover, chondrocytes embedded within the constructs were able to form cartilage-specific matrix both in vitro and in vivo. Thus, by grafting the interface of different materials, stronger hybrid cartilage constructs can be engineered.
Asunto(s)
Cartílago/química , Gelatina/química , Hidrogeles , Rastreo Diferencial de Calorimetría , Células Cultivadas , Niño , HumanosRESUMEN
The aim of this study was to fabricate nanofibrous scaffolds based on blends of a hydroxyl functionalized polyester (poly(hydroxymethylglycolide-co-ε-caprolactone), pHMGCL) and poly(ε-caprolactone) (PCL), loaded with bovine serum albumin (BSA) as a protein stabilizer and vascular endothelial growth factor (VEGF) as a potent angiogenic factor by means of a coaxial electrospinning technique. The scaffolds were characterized by scanning electron microscopy (SEM), fluorescence microscopy (FM), and differential scanning calorimetry (DSC). The scaffolds displayed a uniform fibrous structure with a fiber diameter around 700 nm. The release of BSA from the core of the fibers was studied by high performance liquid chromatography (HPLC), and it was shown that the coaxial scaffolds composed of blends of pHMGCL and PCL exhibited faster release than the comparative PCL scaffolds. VEGF was also incorporated in the core of the scaffolds, and the effect of the released protein on the attachment and proliferation of endothelial cells was investigated. It was shown that the incorporated protein preserved its biological activity and resulted in initial higher numbers of adhered cells. Thus, these bioactive scaffolds based on blends of pHMGCL/PCL loaded with VEGF can be considered as a promising candidate for tissue engineering applications.
Asunto(s)
Poliésteres/química , Ingeniería de Tejidos/métodos , Andamios del Tejido , Factor A de Crecimiento Endotelial Vascular/metabolismo , Línea Celular , Humanos , Albúmina Sérica Bovina/metabolismoRESUMEN
The aim of current study was to evaluate the effect of nano-apatitic particles (nAp) incorporation on the degradation characteristics and biocompatibility of poly(lactide-co-glycolide) (PLGA)-based nanofibrous scaffolds. Composite PLGA/poly(É-caprolactone) (PCL) blended (w/w = 3/1) polymeric electrospun scaffolds with 0-30 wt% of nAp incorporation (n0-n30) were prepared. The obtained scaffolds were firstly evaluated by morphological, physical and chemical characterization, followed by an in vitro degradation study. Further, n0 and n30 in both virgin and 3-week pre-degraded status were subcutaneously implanted in rats, either directly or in stainless steel mesh cages, to evaluate in vivo tissue response. The results showed that the incorporation of nAp yields an nAp amount-dependent buffering effect on pH-levels during degradation and delayed polymer degradation based on molecular weight analysis. Regarding biocompatibility, nAp incorporation significantly improved the tissue response during a 4-week subcutaneous implantation, showing less infiltration of inflammatory cells (monocyte/macrophages) as well as less foreign body giant cells (FBGCs) formation surrounding the scaffolds. Similar cytokine expression (gene and protein level) was observed for all groups of implanted scaffolds, although marginal differences were found for TNF-α and TGF-ß at gene level as well as GRO-KC at protein level after 1 week of implantation. The results of the current study indicate that hybridization of the weak alkaline salt nAp is effective to control the in vivo adverse tissue reaction of PLGA materials, which is beneficial for optimizing final clinical application of different PLGA-based biomedical devices.
Asunto(s)
Apatitas/metabolismo , Materiales Biocompatibles/metabolismo , Citocinas/análisis , Exudados y Transudados/química , Ácido Láctico/química , Ácido Poliglicólico/química , Andamios del Tejido/química , Animales , Apatitas/química , Materiales Biocompatibles/química , Quimiocina CXCL1/análisis , Células Gigantes de Cuerpo Extraño/inmunología , Concentración de Iones de Hidrógeno , Ácido Láctico/metabolismo , Macrófagos/inmunología , Masculino , Ensayo de Materiales , Nanofibras/química , Nanofibras/ultraestructura , Poliésteres/química , Ácido Poliglicólico/metabolismo , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ratas , Ratas Wistar , Factor de Crecimiento Transformador beta/análisis , Factor de Necrosis Tumoral alfa/análisisRESUMEN
The aim of this study was to evaluate the in vivo biodegradation and biocompatibility of three-dimensional (3D) scaffolds based on a hydroxyl-functionalized polyester (poly(hydroxymethylglycolide-co-ε-caprolactone), PHMGCL), which has enhanced hydrophilicity, increased degradation rate, and improved cell-material interactions as compared to its counterpart poly(ε-caprolactone), PCL. In this study, 3D scaffolds based on this polymer (PHMGCL, HMG:CL 8:92) were prepared by means of fiber deposition (melt-plotting). The biodegradation and tissue biocompatibility of PHMGCL and PCL scaffolds after subcutaneous implantation in Balb/c mice were investigated. At 4 and 12 weeks post implantation, the scaffolds were retrieved and evaluated for extent of degradation by measuring the residual weight of the scaffolds, thermal properties (DSC), and morphology (SEM) whereas the polymer was analyzed for both its composition ((1)H NMR) and molecular weight (GPC). The scaffolds with infiltrated tissues were harvested, fixed, stained and histologically analyzed. The in vitro enzymatic degradation of these scaffolds was also investigated in lipase solutions. It was shown that PHMGCL 3D-scaffolds lost more than 60% of their weight within 3 months of implantation while PCL scaffolds showed no weight loss in this time frame. The molecular weight (M(w)) of PHMGCL decreased from 46.9 kDa before implantation to 23.2 kDa after 3 months of implantation, while the molecular weight of PCL was unchanged in this period. (1)H NMR analysis showed that the degradation of PHMGCL was characterized by a loss of HMG units. In vitro enzymatic degradation showed that PHMGCL scaffolds were degraded within 50 h, while the degradation time for PCL scaffolds of similar structure was 72 h. A normal foreign body response to both scaffold types characterized by the presence of macrophages, lymphocytes, and fibrosis was observed with a more rapid onset in PHMGCL scaffolds. The extent of tissue-scaffold interactions as well as vascularization was shown to be higher for PHMGCL scaffolds compared to PCL ones. Therefore, the fast degradable PHMGCL which showed good biocompatibility is a promising biomaterial for tissue engineering applications.
Asunto(s)
Materiales Biocompatibles/farmacología , Ensayo de Materiales , Poliésteres/farmacología , Andamios del Tejido/química , Actinas/metabolismo , Animales , Biodegradación Ambiental/efectos de los fármacos , Femenino , Hidroxilación/efectos de los fármacos , Inflamación/patología , Lipasa/metabolismo , Espectroscopía de Resonancia Magnética , Ratones , Ratones Endogámicos BALB C , Microscopía Electrónica de Rastreo , Poliésteres/química , Porosidad/efectos de los fármacos , Implantación de Prótesis , Tejido Subcutáneo/efectos de los fármacosRESUMEN
Scaffolds based on a novel functionalized polyester, pHMGCL, are electrospun and characterized morphologically and physically. In vitro degradation studies of pHMGCL films show considerable mass loss and molecular weight reduction within 70 weeks. Scaffolds composed of fibers with uniform diameter (≈ 900 nm) and with melting temperatures higher than body temperature are prepared. As an indication for the feasibility of this material for regenerative medicine approaches, articular chondrocytes are seeded onto electrospun pHMGCL scaffolds. Chondrocytes attach to the fibers and re-differentiate as demonstrated by the production of GAG and collagen type II within four weeks of in vitro culture. Hydrophilic pHMGCL scaffolds may thus be useful for tissue engineering applications.
Asunto(s)
Cartílago Articular/citología , Condrocitos/citología , Poliésteres/síntesis química , Ingeniería de Tejidos/métodos , Andamios del Tejido , Animales , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/metabolismo , Materiales Biocompatibles/farmacología , Biodegradación Ambiental , Cartílago Articular/fisiología , Adhesión Celular/efectos de los fármacos , Técnicas de Cultivo de Célula , Diferenciación Celular/efectos de los fármacos , Condrocitos/efectos de los fármacos , Condrocitos/fisiología , Cromatografía en Gel , Colágeno Tipo II/biosíntesis , Caballos , Interacciones Hidrofóbicas e Hidrofílicas , Espectroscopía de Resonancia Magnética , Poliésteres/metabolismo , Poliésteres/farmacologíaRESUMEN
Functional aliphatic polyesters are biodegradable polymers with many possibilities to tune physico-chemical characteristics such as hydrophilicity and degradation rate as compared to traditional polyesters (e.g. PLLA, PLGA and PCL), making the materials suitable for drug delivery or as scaffolds for tissue engineering. Lately, a large number of polyesters have been synthesized by homopolymerization of functionalized monomers or co-polymerization with other monomers mainly via ring-opening polymerization (ROP) of cyclic esters. This review presents the recent trends in the synthesis of these materials and their application for protein delivery and tissue engineering.
Asunto(s)
ADN/administración & dosificación , Técnicas de Transferencia de Gen , Poliésteres/química , Proteínas/administración & dosificación , Ingeniería de Tejidos , Animales , Humanos , Poliésteres/síntesis químicaRESUMEN
At present there is a strong need for suitable scaffolds that meet the requirements for bone tissue engineering applications. The objective of this study was to investigate the suitability of porous scaffolds based on a hydroxyl functionalized polymer, poly(hydroxymethylglycolide-co-ε-caprolactone) (pHMGCL), for tissue engineering. In a recent study this polymer was shown to be a promising material for bone regeneration. The scaffolds consisting of pHMGCL or poly(ε-caprolactone) (PCL) were produced by means of a rapid prototyping technique (three-dimensional plotting) and were shown to have a high porosity and an interconnected pore structure. The thermal and mechanical properties of both scaffolds were investigated and human mesenchymal stem cells were seeded onto the scaffolds to evaluate the cell attachment properties, as well as cell viability and differentiation. It was shown that the cells filled the pores of the pHMGCL scaffold within 7 days and displayed increased metabolic activity when compared with cells cultured in PCL scaffolds. Importantly, pHMGCL scaffolds supported osteogenic differentiation. Therefore, scaffolds based on pHMGCL are promising templates for bone tissue engineering applications.
Asunto(s)
Huesos/fisiología , Poliésteres/química , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Huesos/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Humanos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/metabolismo , Osteogénesis/efectos de los fármacos , Poliésteres/síntesis química , Poliésteres/farmacologíaRESUMEN
The aim of this study was to develop new hydrophilic polyesters for tissue engineering applications. In our approach, poly(benzyloxymethyl glycolide-co-epsilon-caprolactone)s (pBHMG-CLs) were synthesized through melt copolymerization of epsilon-caprolactone (CL) and benzyl-protected hydroxymethyl glycolide (BHMG). Deprotection of the polymers yielded copolymers with pendant hydroxyl groups, poly(hydroxymethylglycolide-co-epsilon-caprolactone) (pHMG-CL). The synthesized polymers were characterized by GPC, NMR, and DSC techniques. The resulting copolymers consisting of up to 10% of HMG monomer were semicrystalline with a melting temperature above body temperature. Water contact angle measurements of polymeric films showed that increasing HMG content resulted in higher surface hydrophilicity, as evidenced from a decrease in receding contact angle from 68 degrees for PCL to 40 degrees for 10% HMG-CL. Human mesenchymal stem cells showed good adherence onto pHMG-CL films as compared to the more hydrophobic PCL surfaces. The cells survived and were able to differentiate toward osteogenic lineage on pHMG-CL surfaces. This study shows that the aforementioned hydrophilic polymers are attractive candidates for the design of scaffolds for tissue engineering applications.