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1.
ACS Appl Mater Interfaces ; 13(33): 38969-38978, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34399054

RESUMO

Controlling the microstructure of materials by means of phase separation is a versatile tool for optimizing material properties. Phase separation has been exploited to fabricate intricate microstructures in many fields including cell biology, tissue engineering, optics, and electronics. The aim of this study was to use phase separation to tailor the spatial location of drugs and thereby generate release profiles of drug payload over periods ranging from 1 week to months by exploiting different mechanisms: polymer degradation, polymer diluent dissolution, and control of microstructure. To achieve this, we used drop-on-demand inkjet three-dimensional (3D) printing. We predicted the microstructure resulting from phase separation using high-throughput screening combined with a model based on the Flory-Huggins interaction parameter and were able to show that drug release from 3D-printed objects can be predicted from observations based on single drops of mixtures. We demonstrated for the first time that inkjet 3D printing yields controllable phase separation using picoliter droplets of blended photoreactive oligomers/monomers. This new understanding gives us hierarchical compositional control, from droplet to device, allowing release to be "dialled up" without manipulation of device geometry. We exemplify this approach by fabricating a biodegradable, long-term, multiactive drug delivery subdermal implant ("polyimplant") for combination therapy and personalized treatment of coronary heart disease. This is an important advance for implants that need to be delivered by cannula, where the shape is highly constrained and thus the usual geometrical freedoms associated with 3D printing cannot be easily exploited, which brings a hitherto unseen level of understanding to emergent material properties of 3D printing.


Assuntos
Anti-Hipertensivos/química , Doença das Coronárias/tratamento farmacológico , Portadores de Fármacos/química , Excipientes/química , Indóis/química , Polímeros/química , Anti-Hipertensivos/farmacologia , Dioxanos/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Humanos , Indóis/farmacologia , Metacrilatos/química , Transição de Fase , Poliésteres/química , Impressão Tridimensional , Pirrolidinonas/química , Relação Estrutura-Atividade
2.
Molecules ; 26(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072733

RESUMO

Droplet microfluidics can produce highly tailored microparticles whilst retaining monodispersity. However, these systems often require lengthy optimisation, commonly based on a trial-and-error approach, particularly when using bio-instructive, polymeric surfactants. Here, micropipette manipulation methods were used to optimise the concentration of bespoke polymeric surfactants to produce biodegradable (poly(d,l-lactic acid) (PDLLA)) microparticles with unique, bio-instructive surface chemistries. The effect of these three-dimensional surfactants on the interfacial tension of the system was analysed. It was determined that to provide adequate stabilisation, a low level (0.1% (w/v)) of poly(vinyl acetate-co-alcohol) (PVA) was required. Optimisation of the PVA concentration was informed by micropipette manipulation. As a result, successful, monodisperse particles were produced that maintained the desired bio-instructive surface chemistry.


Assuntos
Portadores de Fármacos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Polímeros/química , Álcool de Polivinil/química , Tensoativos/química , Materiais Biocompatíveis/química , Biodegradação Ambiental , Composição de Medicamentos/métodos , Ácido Láctico/química , Microfluídica , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Ácido Poliglicólico/química , Solventes , Propriedades de Superfície , Tensão Superficial
3.
Nanoscale ; 13(23): 10266-10280, 2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34085085

RESUMO

The application of nanotechnology to regenerative medicine has increased over recent decades. The development of materials that can influence biology at the nanoscale has gained interest as our understanding of the interactions between cells and biomaterials at the nanoscale has grown. Materials that are either nanostructured or influence the nanostructure of the cellular microenvironment have been developed and shown to have advantages over their microscale counterparts. There are several reviews which have been published that discuss how nanomaterials have been used in regenerative medicine, particularly in bone regeneration. Most of these studies have explored this concept in specific areas, such as the application of glass-based nanocomposites, nanotechnology for targeted drug delivery to stimulate bone repair, and the progress in nanotechnology for the treatment of osteoporosis. In this review paper, the impact of nanotechnology in biomaterials development for bone regeneration will be discussed highlighting specifically, nanostructured materials that influence mechanical properties, biocompatibility, and osteoinductivity.


Assuntos
Nanoestruturas , Engenharia Tecidual , Materiais Biocompatíveis , Regeneração Óssea , Nanotecnologia , Medicina Regenerativa
4.
Adv Sci (Weinh) ; 8(15): e2100249, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34050725

RESUMO

As the understanding of disease grows, so does the opportunity for personalization of therapies targeted to the needs of the individual. To bring about a step change in the personalization of medical devices it is shown that multi-material inkjet-based 3D printing can meet this demand by combining functional materials, voxelated manufacturing, and algorithmic design. In this paper composite structures designed with both controlled deformation and reduced biofilm formation are manufactured using two formulations that are deposited selectively and separately. The bacterial biofilm coverage of the resulting composites is reduced by up to 75% compared to commonly used silicone rubbers, without the need for incorporating bioactives. Meanwhile, the composites can be tuned to meet user defined mechanical performance with ±10% deviation. Device manufacture is coupled to finite element modelling and a genetic algorithm that takes the user-specified mechanical deformation and computes the distribution of materials needed to meet this under given load constraints through a generative design process. Manufactured products are assessed against the mechanical and bacterial cell-instructive specifications and illustrate how multifunctional personalization can be achieved using generative design driven multi-material inkjet based 3D printing.

5.
J Mater Chem B ; 9(20): 4120-4133, 2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-33982048

RESUMO

Effective regenerative medicine requires delivery systems which can release multiple components at appropriate levels and at different phases of tissue growth and repair. However, there are few biomaterials and encapsulation techniques that are fully suitable for the loading and controlled release of multiple proteins. In this study we describe how proteins were physically and chemically loaded into a single coaxial electrospun fibre scaffold to obtain bi-phasic release profiles. Cyto-compatible polymers were used to construct the scaffold, using polyethylene oxide (PEO) for the core and polycaprolactone (PCL) reacted or mixed with (bis-aminopropyl)polyether (Jeffamine ED2003; JFA) for the shell. Horseradish peroxidase (HRP), a model protein, was loaded in the core and functionalised onto the scaffold surface by coupling of protein carboxyl groups to the available polymer amine groups. Fibre morphologies were evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and functional group content was determined using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF SIMS). Hydrophobicity profiles of the fibres before and after protein loading were evaluated by water contact angle (WCA) and the mechanical properties of the electrospun scaffolds were determined by performing tensile tests. The electrospun fibre scaffolds generated by reacting PEO/PCL with 1,6-diaminohexane and those from mixing PEO/PCL with JFA were further characterised for protein conjugation and release. Fibres prepared by the mixed PEO/PCL/JFA system were found to be the most appropriate for the simultaneous release of protein from the core and the immobilisation of another protein on the shell of the same scaffold. Moreover, JFA enhanced scaffold properties in terms of porosity and elasticity. Finally, we successfully demonstrated the cytocompatibility and cell response to protein-loaded and -conjugated scaffolds using HepG2 cells. Enhanced cell attachment (2.5 fold) was demonstrated using bovine serum albumin (BSA)-conjugated scaffolds, and increased metabolic activity observed with retinoic acid (RA)-loaded scaffolds (2.7 fold).


Assuntos
Materiais Biocompatíveis/química , Polímeros/química , Soroalbumina Bovina/química , Tecidos Suporte/química , Animais , Bovinos , Células Hep G2 , Humanos , Tamanho da Partícula , Propriedades de Superfície , Engenharia Tecidual
6.
Biomaterials ; 271: 120740, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33714019

RESUMO

Human mesenchymal stem cells (hMSCs) are widely represented in regenerative medicine clinical strategies due to their compatibility with autologous implantation. Effective bone regeneration involves crosstalk between macrophages and hMSCs, with macrophages playing a key role in the recruitment and differentiation of hMSCs. However, engineered biomaterials able to simultaneously direct hMSC fate and modulate macrophage phenotype have not yet been identified. A novel combinatorial chemistry-topography screening platform, the ChemoTopoChip, is used here to identify materials suitable for bone regeneration by screening 1008 combinations in each experiment for human immortalized mesenchymal stem cell (hiMSCs) and human macrophage response. The osteoinduction achieved in hiMSCs cultured on the "hit" materials in basal media is comparable to that seen when cells are cultured in osteogenic media, illustrating that these materials offer a materials-induced alternative to osteo-inductive supplements in bone-regeneration. Some of these same chemistry-microtopography combinations also exhibit immunomodulatory stimuli, polarizing macrophages towards a pro-healing phenotype. Maximum control of cell response is achieved when both chemistry and topography are recruited to instruct the required cell phenotype, combining synergistically. The large combinatorial library allows us for the first time to probe the relative cell-instructive roles of microtopography and material chemistry which we find to provide similar ranges of cell modulation for both cues. Machine learning is used to generate structure-activity relationships that identify key chemical and topographical features enhancing the response of both cell types, providing a basis for a better understanding of cell response to micro topographically patterned polymers.


Assuntos
Materiais Biocompatíveis , Células-Tronco Mesenquimais , Materiais Biocompatíveis/farmacologia , Regeneração Óssea , Diferenciação Celular , Humanos , Osteogênese
7.
J Biophotonics ; 13(10): e202000190, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32658374

RESUMO

A wide range of biomaterials and tissue-engineered scaffolds are being investigated to support and stimulate bone healing in animal models. Using phantoms and rat cadavers, we investigated the feasibility of using spatially offset Raman spectroscopy (SORS) to monitor changes in collagen concentration at levels similar to those expected to occur in vivo during bone regeneration (0-0.84 g/cm3 ). A partial least squares (PLS) regression model was developed to quantify collagen concentration in plugs consisting of mixtures or collagen and hydroxyapatite (predictive power of ±0.16 g/cm3 ). The PLS model was then applied on SORS spectra acquired from rat cadavers after implanting the collagen: hydroxyapatite plugs in drilled skull defects. The PLS model successfully predicting the profile of collagen concentration, but with an increased predictive error of ±0.30 g/cm3 . These results demonstrate the potential of SORS to quantify collagen concentrations, in the range relevant to those occurring during new bone formation.


Assuntos
Análise Espectral Raman , Tecidos Suporte , Animais , Colágeno , Durapatita , Estudos de Viabilidade , Ratos , Crânio , Cicatrização
8.
Adv Biosyst ; 4(6): e2000016, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32329968

RESUMO

Maintenance of the epithelium relies on stem cells residing within specialized microenvironments, known as epithelial crypts. Two-photon polymerization (2PP) is a valuable tool for fabricating 3D micro/nanostructures for stem cell niche engineering applications. Herein, biomimetic gelatin methacrylate-based constructs, replicating the precise geometry of the limbal epithelial crypt structures (limbal stem cell "microniches") as an exemplar epithelial niche, are fabricated using 2PP. Human limbal epithelial stem cells (hLESCs) are seeded within the microniches in xeno-free conditions to investigate their ability to repopulate the crypts and the expression of various differentiation markers. Cell proliferation and a zonation in cell phenotype along the z-axis are observed without the use of exogenous signaling molecules. Significant differences in cell phenotype between cells located at the base of the microniche and those situated towards the rim are observed, demonstrating that stem cell fate is strongly influenced by its location within a niche and the geometrical details of where it resides. This study provides insight into the influence of the niche's spatial geometry on hLESCs and demonstrates a flexible approach for the fabrication of biomimetic crypt-like structures in epithelial tissues. This has significant implications for regenerative medicine applications and can ultimately lead to implantable synthetic "niche-based" treatments.

9.
Sci Rep ; 9(1): 14015, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31570730

RESUMO

After spinal cord injury (SCI) chronic inflammation hampers regeneration. Influencing the local microenvironment after SCI may provide a strategy to modulate inflammation and the immune response. The objectives of this work were to determine whether bone or spinal cord derived ECM hydrogels can deliver human mesenchymal stem cells from the apical papilla (SCAP) to reduce local inflammation and provide a regenerative microenvironment. Bone hydrogels (8 and 10 mg/ml, B8 and B10) and spinal cord hydrogels (8 mg/ml, S8) supplemented with fibrin possessed a gelation rate and a storage modulus compatible with spinal cord implantation. S8 and B8 impact on the expression of anti and pro-inflammatory cytokines (Arg1, Nos2, Tnf) in LPS treated microglial cells were assessed using solubilised and solid hydrogel forms. S8 significantly reduced the Nos2/Arg1 ratio and solubilised B8 significantly reduced Tnf and increased Arg1 whereas solid S8 and B8 did not impact inflammation in microglial cells. SCAP incorporation within ECM hydrogels did not impact upon SCAP immunoregulatory properties, with significant downregulation of Nos2/Arg1 ratio observed for all SCAP embedded hydrogels. Tnf expression was reduced with SCAP embedded in B8, reflecting the gene expression observed with the innate hydrogel. Thus, ECM hydrogels are suitable vehicles to deliver SCAP due to their physical properties, preservation of SCAP viability and immunomodulatory capacity.


Assuntos
Papila Dentária/citologia , Matriz Extracelular/metabolismo , Hidrogéis/administração & dosagem , Inflamação/terapia , Células-Tronco Mesenquimais/metabolismo , Microglia/metabolismo , Medula Espinal/metabolismo , Transplante de Células-Tronco/métodos , Humanos
10.
ACS Appl Mater Interfaces ; 11(38): 34560-34574, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31502820

RESUMO

Surface-functionalized microparticles are relevant to fields spanning engineering and biomedicine, with uses ranging from cell culture to advanced cell delivery. Varying topographies of biomaterial surfaces are also being investigated as mediators of cell-material interactions and subsequent cell fate. To investigate competing or synergistic effects of chemistry and topography in three-dimensional cell cultures, methods are required to introduce these onto microparticles without modification of their underlying morphology or bulk properties. In this study, a new approach for surface functionalization of poly(lactic acid) (PLA) microparticles is reported that allows decoration of the outer shell of the polyesters with additional polymers via aqueous atom transfer radical polymerization routes. PLA microparticles with smooth or dimpled surfaces were functionalized with poly(poly(ethylene glycol) methacrylate) and poly[N-(3-aminopropyl)methacrylamide] brushes, chosen for their potential abilities to mediate cell adhesion. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry analysis indicated homogeneous coverage of the microparticles with polymer brushes while maintaining the original topographies. These materials were used to investigate the relative importance of surface chemistry and topography both on the formation of human immortalized mesenchymal stem cell (hiMSCs) particle-cell aggregates and on the enhanced contractility of cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs). The influence of surface chemistry was found to be more important on the size of particle-cell aggregates than topographies. In addition, surface chemistries that best promoted hiMSC attachment also improved hiPSC-CM attachment and contractility. These studies demonstrated a new route to obtain topo-chemical combinations on polyester-based biomaterials and provided clear evidence for the predominant effect of surface functionality over micron-scale dimpled topography in cell-microparticle interactions. These findings, thus, provide new guiding principles for the design of biomaterial interfaces to direct cell function.


Assuntos
Diferenciação Celular , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Mesenquimais/metabolismo , Microplásticos , Miócitos Cardíacos/metabolismo , Poliésteres , Agregação Celular/efeitos dos fármacos , Linhagem Celular Transformada , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Mesenquimais/citologia , Microplásticos/química , Microplásticos/farmacologia , Miócitos Cardíacos/citologia , Poliésteres/química , Poliésteres/farmacologia
11.
Front Microbiol ; 10: 879, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31114553

RESUMO

Interactions of anaerobic gut bacteria, such as Clostridium difficile, with the intestinal mucosa have been poorly studied due to challenges in culturing anaerobes with the oxygen-requiring gut epithelium. Although gut colonization by C. difficile is a key determinant of disease outcome, precise mechanisms of mucosal attachment and spread remain unclear. Here, using human gut epithelial monolayers co-cultured within dual environment chambers, we demonstrate that C. difficile adhesion to gut epithelial cells is accompanied by a gradual increase in bacterial numbers. Prolonged infection causes redistribution of actin and loss of epithelial integrity, accompanied by production of C. difficile spores, toxins, and bacterial filaments. This system was used to examine C. difficile interactions with the commensal Bacteroides dorei, and interestingly, C. difficile growth is significantly reduced in the presence of B. dorei. Subsequently, we have developed novel models containing a myofibroblast layer, in addition to the epithelium, grown on polycarbonate or three-dimensional (3D) electrospun scaffolds. In these more complex models, C. difficile adheres more efficiently to epithelial cells, as compared to the single epithelial monolayers, leading to a quicker destruction of the epithelium. Our study describes new controlled environment human gut models that enable host-anaerobe and pathogen-commensal interaction studies in vitro.

12.
Biomed Opt Express ; 10(4): 1678-1690, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31061762

RESUMO

Using phantom samples, we investigated the feasibility of spatially-offset Raman spectroscopy (SORS) as a tool for monitoring non-invasively the mineralization of bone tissue engineering scaffold in-vivo. The phantom samples consisted of 3D-printed scaffolds of poly-caprolactone (PCL) and hydroxyapatite (HA) blends, with varying concentrations of HA, to mimic the mineralisation process. The scaffolds were covered by a 4 mm layer of skin to simulate the real in-vivo measurement conditions. At a concentration of HA approximately 1/3 that of bone (~0.6 g/cm3), the characteristic Raman band of HA (960 cm-1) was detectable when the PCL:HA layer was located at 4 mm depth within the scaffold (i.e. 8 mm below the skin surface). For the layers of the PCL:HA immediately under the skin (i.e. top of the scaffold), the detection limit of HA was 0.18 g/cm3, which is approximately one order of magnitude lower than that of bone. Similar results were also found for the phantoms simulating uniform and inward gradual mineralisation of the scaffold, indicating the suitability of SORS to detect early stages of mineralisation. Nevertheless, the results also show that the contribution of the materials surrounding the scaffold can be significant and methods for subtraction need to be investigated in the future. In conclusion, these results indicate that spatially-offset Raman spectroscopy is a promising technique for in-vivo longitudinal monitoring scaffold mineralization and bone re-growth.

13.
Front Pharmacol ; 10: 456, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31133850

RESUMO

Advances in drug research not only depend on high throughput screening to evaluate large numbers of lead compounds but also on the development of in vitro models which can simulate human tissues in terms of drug permeability and functions. Potential failures, such as poor permeability or interaction with efflux drug transporters, can be identified in epithelial Caco-2 monolayer models and can impact a drug candidate's progression onto the next stages of the drug development process. Whilst monolayer models demonstrate reasonably good prediction of in vivo permeability for some compounds, more developed in vitro tools are needed to assess new entities that enable closer in vivo in vitro correlation. In this study, an in vitro model of the human intestinal epithelium was developed by utilizing nanofibers, fabricated using electrospinning, to mimic the structure of the basement membrane. We assessed Caco-2 cell response to these materials and investigated the physiological properties of these cells cultured on the fibrous supports, focusing on barrier integrity and drug-permeability properties. The obtained data illustrate that 2D Caco-2 Transwell® cultures exhibit artificially high trans-epithelial electrical resistance (TEER) compared to cells cultured on the 3D nanofibrous scaffolds which show TEER values similar to ex vivo porcine tissue (also measured in this study). Furthermore, our results demonstrate that the 3D nanofibrous scaffolds influence the barrier integrity of the Caco-2 monolayer to confer drug-absorption properties that more closely mimic native gut tissue particularly for studying passive epithelial transport. We propose that this 3D model is a suitable in vitro model for investigating drug absorption and intestinal metabolism.

14.
Acta Biomater ; 95: 427-438, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30669005

RESUMO

A three-dimensional thermoresponsive fibrous scaffold system for the subsequent extended culture and enzyme-free passaging of a range of mammalian cell types is presented. Poly(PEGMA188) was incorporated with poly(ethylene terephthalate) (PET) via blend-electrospinning to render the fibre thermoresponsive. Using primary human corneal stromal stem cells as an therapeutically relevant exemplar, cell adhesion, viability, proliferation and phenotype on this fibrous culture system over numerous thermal enzyme-free passages is described. We also illustrate the versatility of this system with respect to fabricating thermoresponsive fibres from biodegradable polymers and for the culture of diverse mammalian cell types including mesenchymal stem cells, colon adenocarcinoma cells and NIH-3T3 fibroblasts. This thermoresponsive scaffold system combines the advantages of providing a physiologically relevant environment to maintain a desirable cell phenotype, allowing routine enzyme-free passaging and expansion of cultured cells, whilst offering mechanical support for cell growth. The system described in this study presents a versatile platform for biomedical applications and more specifically for the expansion of mammalian cells destined for the clinic. STATEMENT OF SIGNIFICANCE: The lack of three-dimensional (3D) cell culture environments significantly impacts mammalian cell morphology, proliferation and phenotype in vitro. A versatile, 3D fibrous scaffold system for the extended culture and passaging of a range of clinically-relevant cell types is presented herein. This methodology can be used to fabricate thermoresponsive fibres from polymer blends of any polymer amenable to electrospinning and with a thermoresponsive component. A variety of mammalian cells cultured on the thermoresponsive system were detached from the surface solely by lowering the temperature whilst retaining high viability, a desirable cell phenotype, and supported long-term cell proliferation over numerous thermal enzyme-free passages. This is a significant advance for in vitro expansion of diverse cell types destined for the clinic.


Assuntos
Técnicas de Cultura de Células/métodos , Mamíferos/metabolismo , Temperatura , Animais , Proliferação de Células , Regulação da Expressão Gênica , Humanos , Camundongos , Células NIH 3T3 , Tecidos Suporte/química , Água/química
15.
J Biomed Mater Res A ; 107(4): 828-838, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30578722

RESUMO

The advent of innovative surgical procedures utilizing partial thickness corneal grafts has created a need for the development of synthetic implants to recreate corneal stromal tissue. This work evaluates electrospun gelatin and polycaprolactone (PCL) scaffolds as a potential biomaterial suitable for use in regeneration of corneal stromal tissue. Electrospun gelatin has been used for many years in tissue engineering; however, post-production modification, such as crosslinking, is usually required to mechanically strengthen such scaffolds. This article aims therefore to compare glutaraldehyde (GA) crosslinked electrospun gelatin scaffolds with electrospun blends of gelatin and PCL at different ratios. Scaffolds were fabricated using electrospinning and characterized by scanning electron microscopy, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, and tensile testing. To evaluate biocompatibility, primary human corneal stromal cells (hCSC) were seeded upon the scaffolds to assess adherence, proliferation, and phenotype. Results demonstrated that scaffolds fabricated from mixtures of gelatin and PCL showed increased mechanical strength and plasticity compared to scaffolds fabricated from GA crosslinked gelatin alone. In addition, scaffolds fabricated from PCL and gelatin showed comparable support of hCSC adhesion and proliferation. In conclusion, blended mixtures of gelatin and PCL can be considered as an option in the selection of corneal repair materials in the future© 2018 The Authors. Journal of Biomedical Materials Research Part A published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 828-838, 2019.


Assuntos
Córnea/metabolismo , Gelatina/química , Poliésteres/química , Tecidos Suporte/química , Córnea/citologia , Humanos , Células Estromais/citologia , Células Estromais/metabolismo
16.
Int J Pharm ; 546(1-2): 272-278, 2018 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-29753905

RESUMO

Polymer microparticles are widely used as acellular drug delivery platforms in regenerative medicine, and have emerging potential as cellular scaffolds for therapeutic cell delivery. In the clinic, PLGA microparticles are typically administered intramuscularly or subcutaneously, with the clinician and clinical application site determining the precise needle gauge used for delivery. Here, we explored the role of needle diameter in microparticle delivery yield, and develop a modified viscosity formulation to improve microparticle delivery across a range of clinically relevant needle diameters. We have identified an optimal biocompatible formulation containing 0.25% pluronic F127 and 0.25% carboxymethyl cellulose, which can increase delivery payload to 520% across needle gauges 21-30G, and note that needle diameter impacts delivery efficacy. We use this formulation to increase the delivery yield of PLGA microparticles, and separately, PLGA-cell scaffolds supporting viable mesenchymal stem cells (MSCs), demonstrating the first in vitro delivery of this cell scaffold system. Together, these results highlight an optimal formulation for the delivery of microparticle and microparticle-cell scaffolds, and illustrate how careful choice of delivery formulation and needle size can dramatically impact delivery payload.


Assuntos
Ácido Láctico/administração & dosagem , Células-Tronco Mesenquimais , Ácido Poliglicólico/administração & dosagem , Carboximetilcelulose Sódica/administração & dosagem , Carboximetilcelulose Sódica/química , Sobrevivência Celular , Terapia Baseada em Transplante de Células e Tecidos , Humanos , Ácido Láctico/química , Agulhas , Poloxâmero/administração & dosagem , Poloxâmero/química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Viscosidade
17.
Eur Respir J ; 51(5)2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29700102

RESUMO

Bronchial thermoplasty is a treatment for asthma. It is currently unclear whether its histopathological impact is sufficiently explained by the proportion of airway wall that is exposed to temperatures necessary to affect cell survival.Airway smooth muscle and bronchial epithelial cells were exposed to media (37-70°C) for 10 s to mimic thermoplasty. In silico we developed a mathematical model of airway heat distribution post-thermoplasty. In vivo we determined airway smooth muscle mass and epithelial integrity pre- and post-thermoplasty in 14 patients with severe asthma.In vitro airway smooth muscle and epithelial cell number decreased significantly following the addition of media heated to ≥65°C. In silico simulations showed a heterogeneous heat distribution that was amplified in larger airways, with <10% of the airway wall heated to >60°C in airways with an inner radius of ∼4 mm. In vivo at 6 weeks post-thermoplasty, there was an improvement in asthma control (measured via Asthma Control Questionnaire-6; mean difference 0.7, 95% CI 0.1-1.3; p=0.03), airway smooth muscle mass decreased (absolute median reduction 5%, interquartile range (IQR) 0-10; p=0.03) and epithelial integrity increased (14%, IQR 6-29; p=0.007). Neither of the latter two outcomes was related to improved asthma control.Integrated in vitro and in silico modelling suggest that the reduction in airway smooth muscle post-thermoplasty cannot be fully explained by acute heating, and nor did this reduction confer a greater improvement in asthma control.


Assuntos
Asma/terapia , Termoplastia Brônquica/métodos , Células Epiteliais/metabolismo , Modelos Biológicos , Músculo Liso/patologia , Adulto , Idoso , Remodelação das Vias Aéreas , Apoptose , Termoplastia Brônquica/efeitos adversos , Broncoscopia , Simulação por Computador , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
18.
Stem Cell Res Ther ; 9(1): 39, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29467014

RESUMO

BACKGROUND: Numerous stem cell therapies use injection-based administration to deliver high-density cell preparations. However, cell retention rates as low as 1% have been observed within days of transplantation. This study investigated the effects of varying administration and formulation parameters of injection-based administration on cell dose recovery and differentiation fate choice of human mesenchymal stem cells. METHODS: The impact of ejection rate via clinically relevant Hamilton micro-syringes and biomaterial-assisted delivery was investigated. Cell viability, the percentage of cell dose delivered as viable cells, proliferation capacity as well as differentiation behaviour in bipotential media were assessed. Characterisation of the biomaterial-based cell carriers was also carried out. RESULTS: A significant improvement of in-vitro dose recovery in cells co-ejected with natural biomaterials was observed, with ejections within 2% (w/v) gelatin resulting in 87.5 ± 14% of the cell dose being delivered as viable cells, compared to 32.2 ± 19% of the dose ejected in the commonly used saline vehicle at 10 µl/min. Improvement in cell recovery was not associated with the rheological properties of biomaterials utilised, as suggested by previous studies. The extent of osteogenic differentiation was shown to be substantially altered by choice of ejection rate and cell carrier, despite limited contact time with cells during ejection. Collagen type I and bone-derived extracellular matrix cell carriers yielded significant increases in mineralised matrix deposited at day 21 relative to PBS. CONCLUSIONS: An enhanced understanding of how administration protocols and biomaterials influence cell recovery, differentiation capacity and choice of fate will facilitate the development of improved administration and formulation approaches to achieve higher efficacy in stem cell transplantation.


Assuntos
Adipogenia , Materiais Biocompatíveis/química , Diferenciação Celular , Transplante de Células-Tronco Mesenquimais/instrumentação , Células-Tronco Mesenquimais , Osteogênese , Sobrevivência Celular , Humanos , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo
19.
Stem Cell Rev Rep ; 13(3): 430-441, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28573367

RESUMO

In recent years, there has been increased research interest in generating corneal substitutes, either for use in the clinic or as in vitro corneal models. The advancement of 3D microfabrication technologies has allowed the reconstruction of the native microarchitecture that controls epithelial cell adhesion, migration and differentiation. In addition, such technology has allowed the inclusion of a dynamic fluid flow that better mimics the physiology of the native cornea. We review the latest innovative products in development in this field, from 3D microfabricated hydrogels to microfluidic devices.


Assuntos
Materiais Biomiméticos/química , Córnea/metabolismo , Células Epiteliais/metabolismo , Hidrogéis/química , Dispositivos Lab-On-A-Chip , Tecidos Suporte/química , Animais , Adesão Celular , Córnea/citologia , Células Epiteliais/citologia , Humanos
20.
J Biomed Mater Res B Appl Biomater ; 105(6): 1645-1657, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-27177716

RESUMO

A new type of photocrosslinkable polycaprolactone (PCL) based ink that is suitable for three-dimensional (3D) inkjet printing has been developed. Photocrosslinkable Polycaprolactone dimethylacrylate (PCLDMA) was synthesized and mixed with poly(ethylene glycol) diacrylate (PEGDA) to prepare an ink with a suitable viscosity for inkjet printing. The ink performance under different printing environments, initiator concentrations, and post processes was studied. This showed that a nitrogen atmosphere during printing was beneficial for curing and material property optimization, as well as improving the quality of structures produced. A simple structure, built in the z-direction, demonstrated the potential for this material for the production of 3D printed objects. Cell tests were carried out to investigate the biocompatibility of the developed ink. © 2016 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1645-1657, 2017.


Assuntos
Implantes Experimentais , Tinta , Teste de Materiais , Poliésteres , Impressão Tridimensional , Animais , Camundongos , Células NIH 3T3 , Poliésteres/química , Poliésteres/farmacologia
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