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1.
Small ; : e2401902, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38949308

RESUMEN

The surface properties of biomaterials interact directly with biological systems, influencing cellular responses, tissue integration, and biocompatibility. Surface topography plays a critical role in cardiac tissue engineering by affecting electrical conductivity, cardiomyocyte alignment, and contractile function. Current methods for controlling surface properties and topography in cardiac tissue engineering scaffolds are limited, expensive, and lack precision. This study introduces a low-cost, one-step degradation process to create scaffolds with well-defined micro-grooves from multilayered 3D printed poly(lactic acid)/thermoplastic polyurethane composites. The approach provides control over erosion rate and surface morphology, allowing easy tuning of scaffold topographical cues for tissue engineering applications. The findings reported in this study provide a library of easily tuneable scaffold topographical cues. A strong dependence of neonatal rat cardiomyocyte (NRCM) contact guidance with the multilayers' dimension and shape in partially degraded polylactic acid (PLA)/thermoplastic polyurethane (TPU) samples is observed. NRCMs cultured on samples with a layer thickness of 13 ± 2 µm and depth of 4.7 ± 0.2 µm demonstrate the most regular contractions. Hence, the proposed fabrication scheme can be used to produce a new generation of biomaterials with excellent controllability determined by multilayer thickness, printing parameters, and degradation treatment duration.

2.
Small ; 20(6): e2305052, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37798622

RESUMEN

The rapid increase and spread of Gram-negative bacteria resistant to many or all existing treatments threaten a return to the preantibiotic era. The presence of bacterial polysaccharides that impede the penetration of many antimicrobials and protect them from the innate immune system contributes to resistance and pathogenicity. No currently approved antibiotics target the polysaccharide regions of microbes. Here, describe monolaurin-based niosomes, the first lipid nanoparticles that can eliminate bacterial polysaccharides from hypervirulent Klebsiella pneumoniae, are described. Their combination with polymyxin B shows no cytotoxicity in vitro and is highly effective in combating K. pneumoniae infection in vivo. Comprehensive mechanistic studies have revealed that antimicrobial activity proceeds via a multimodal mechanism. Initially, lipid nanoparticles disrupt polysaccharides, then outer and inner membranes are destabilized and destroyed by polymyxin B, resulting in synergistic cell lysis. This novel lipidic nanoparticle system shows tremendous promise as a highly effective antimicrobial treatment targeting multidrug-resistant Gram-negative pathogens.


Asunto(s)
Nanopartículas , Polimixina B , Polimixina B/farmacología , Liposomas/farmacología , Antibacterianos/farmacología , Bacterias Gramnegativas , Klebsiella pneumoniae , Polisacáridos Bacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana Múltiple
3.
Biomacromolecules ; 25(2): 829-837, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-38173238

RESUMEN

The mechanical and architectural properties of the three-dimensional (3D) tissue microenvironment can have large impacts on cellular behavior and phenotype, providing cells with specialized functions dependent on their location. This is especially apparent in macrophage biology where the function of tissue resident macrophages is highly specialized to their location. 3D bioprinting provides a convenient method of fabricating biomaterials that mimic specific tissue architectures. If these printable materials also possess tunable mechanical properties, they would be highly attractive for the study of macrophage behavior in different tissues. Currently, it is difficult to achieve mechanical tunability without sacrificing printability, scaffold porosity, and a loss in cell viability. Here, we have designed composite printable biomaterials composed of traditional hydrogels [nanofibrillar cellulose (cellulose) or methacrylated gelatin (gelMA)] mixed with porous polymeric high internal phase emulsion (polyHIPE) microparticles. By varying the ratio of polyHIPEs to hydrogel, we fabricate composite hydrogels that mimic the mechanical properties of the neural tissue (0.1-0.5 kPa), liver (1 kPa), lungs (5 kPa), and skin (10 kPa) while maintaining good levels of biocompatibility to a macrophage cell line.


Asunto(s)
Bioimpresión , Andamios del Tejido , Porosidad , Ingeniería de Tejidos/métodos , Hidrogeles , Bioimpresión/métodos , Impresión Tridimensional , Materiales Biocompatibles , Polímeros , Gelatina , Celulosa , Técnicas de Cultivo Tridimensional de Células
4.
Biomacromolecules ; 23(3): 720-730, 2022 03 14.
Artículo en Inglés | MEDLINE | ID: mdl-34730348

RESUMEN

Highly porous emulsion templated polymers (PolyHIPEs) provide a number of potential advantages in the fabrication of scaffolds for tissue engineering and regenerative medicine. Porosity enables cell ingrowth and nutrient diffusion within, as well as waste removal from, the scaffold. The properties offered by emulsion templating alone include the provision of high interconnected porosity, and, in combination with additive manufacturing, the opportunity to introduce controlled multiscale porosity to complex or custom structures. However, the majority of monomer systems reported for PolyHIPE preparation are unsuitable for clinical applications as they are nondegradable. Thiol-ene chemistry is a promising route to produce biodegradable photocurable PolyHIPEs for the fabrication of scaffolds using conventional or additive manufacturing methods; however, relatively little research has been reported on this approach. This study reports the groundwork to fabricate thiol- and polycaprolactone (PCL)-based PolyHIPE materials via a photoinitiated thiolene click reaction. Two different formulations, either three-arm PCL methacrylate (3PCLMA) or four-arm PCL methacrylate (4PCLMA) moieties, were used in the PolyHIPE formulation. Biocompatibility of the PolyHIPEs was investigated using human dermal fibroblasts (HDFs) and human osteosarcoma cell line (MG-63) by DNA quantification assay, and developed PolyHIPEs were shown to be capable of supporting cell attachment and viability.


Asunto(s)
Metacrilatos , Ingeniería de Tejidos , Emulsiones , Humanos , Metacrilatos/química , Poliésteres , Polímeros/química , Porosidad , Estirenos , Compuestos de Sulfhidrilo , Ingeniería de Tejidos/métodos , Andamios del Tejido/química
5.
Angew Chem Int Ed Engl ; 61(5): e202114536, 2022 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-34861091

RESUMEN

Diffusion-ordered NMR spectroscopy (DOSY) allows for accurate molecular weight calibration and determination that can be corrected for solvent influences. Polystyrene and poly(ethylene glycol) standards have been used to calibrate DOSY diffusion data for a variety of solvents, showing a high correlation of data when the bulk viscosity of the solvent is accounted for following the Stokes-Einstein equation. In this way, a type of universal calibration is introduced that allows for determinations of average molecular weight that are at least as accurate as those of traditional size-exclusion chromatography (SEC), if not better. Further, we demonstrate that DOSY calibrations can be used between laboratories, hence removing the need for individual calibration of setups as currently done.

6.
Small ; 16(39): e2003269, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32864831

RESUMEN

Skin-like energy devices can be conformally attached to the human body, which are highly desirable to power soft wearable electronics in the future. Here, a skin-like stretchable fuel cell based on ultrathin gold nanowires (AuNWs) and polymerized high internal phase emulsions (polyHIPEs) scaffolds is demonstrated. The polyHIPEs can offer a high porosity of 80% yet with an overall thickness comparable to human skin. Upon impregnation with electronic inks containing ultrathin (2 nm in diameter) and ultrahigh aspect-ratio (>10 000) gold nanowires, skin-like strain-insensitive stretchable electrodes are successfully fabricated. With such designed strain-insensitive electrodes, a stretchable fuel cell is fabricated by using AuNWs@polyHIPEs, platinum (Pt)-modified AuNWs@polyHIPEs, and ethanol as the anode, cathode, and fuel, respectively. The resulting epidermal fuel cell can be patterned and transferred onto skin as "tattoos" yet can offer a high power density of 280 µW cm-2 and a high durability (>90% performance retention under stretching, compression, and twisting). The results presented here demonstrate that this skin-thin, porous, yet stretchable electrode is essentially multifunctional, simultaneously serving as a current collector, an electrocatalyst, and a fuel host, indicating potential applications to power future soft wearable 2.0 electronics for remote healthcare and soft robotics.

7.
Langmuir ; 36(6): 1538-1551, 2020 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-31968943

RESUMEN

The flocculation efficiency of polyelectrolytes in a high-ionic-strength environment is often affected and reduced due to shielding of the active ionizable functional groups, as well as changes in the surface chemistry of the solid slurry. To address this problem, a series of well-defined novel ABA triblock copolymers were employed for the flocculation of high-ionic-strength kaolin slurries at three different Ca2+ concentrations (0.05, 0.10, and 0.50 M). The primary focus was on the advancement in the polymer architecture, where the anionic functionalities were localized at the terminal ends. Typical commercial flocculants tend to have anionic functionalities randomly distributed throughout the polymer chain and hence a higher propensity toward condensed conformation and formation of insoluble species. In comparison to a control random copolymer, the ABA triblock copolymers were able to flocculate kaolin slurries to give faster settlement rates, particularly at the high Ca2+ concentrations of 0.10 and 0.50 M. In addition, these polymers had significantly better clarification ability at higher Ca2+ concentrations compared to the control random copolymer. The ABA triblock copolymer architecture may therefore have potential as a flocculant in high-ionic-strength applications.

8.
Macromol Rapid Commun ; 41(18): e2000366, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32757259

RESUMEN

Catechol-Fe(III) complexes contain some of the strongest known metal-chelate coordination bonds. Despite this, they have until now not been utilized in (polymeric linker) linear coordination polymer (LCP) synthesis. With the view of generating catechol end-functional polymers, a new, symmetrical bis-catechol functionalized trithiocarbonate reversible addition fragmentation chain transfer (RAFT) agent is synthesized (CatDMAT). Acrylamide (AM) and dimethylacrylamide (DMA) polymerizations are conducted with CatDMAT using direct photoactivation RAFT polymerization to yield bis-catechol end-functionalized homo- and block-copolymers of molecular weight 10-15 kDa. Catechol-Fe(III) LCPs are successfully formed from the telechelic catechol polymers by bis-complexation to Fe(III). The tetrahedral bis-complex is detected by UV-vis spectroscopy (λmax  = 570 nm), while increases in relative viscosity and Mn,GPC over their respective uncomplexed polymers confirm the occurrence of supramolecular polymerization. The catechol-LCPs are shown to undergo oxidation and crosslinking in aqueous solution after 24 h.


Asunto(s)
Compuestos Férricos , Polímeros , Catecoles , Peso Molecular , Polimerizacion
9.
Int J Mol Sci ; 21(12)2020 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-32630398

RESUMEN

Engineered dermal templates have revolutionised the repair and reconstruction of skin defects. Their interaction with the wound microenvironment and linked molecular mediators of wound repair is still not clear. This study investigated the wound bed and acellular "off the shelf" dermal template interaction in a mouse model. Full-thickness wounds in nude mice were grafted with allogenic skin, and either collagen-based or fully synthetic dermal templates. Changes in the wound bed showed significantly higher vascularisation and fibroblast infiltration in synthetic grafts when compared to collagen-based grafts (P ≤ 0.05). Greater tissue growth was associated with higher prostaglandin-endoperoxide synthase 2 (Ptgs2) RNA and cyclooxygenase-2 (COX-2) protein levels in fully synthetic grafts. Collagen-based grafts had higher levels of collagen III and matrix metallopeptidase 2. To compare the capacity to form a double layer skin substitute, both templates were seeded with human fibroblasts and keratinocytes (so-called human skin equivalent or HSE). Mice were grafted with HSEs to test permanent wound closure with no further treatment required. We found the synthetic dermal template to have a significantly greater capacity to support human epidermal cells. In conclusion, the synthetic template showed advantages over the collagen-based template in a short-term mouse model of wound repair.


Asunto(s)
Trasplante de Piel/métodos , Piel Artificial/tendencias , Animales , Colágeno/metabolismo , Modelos Animales de Enfermedad , Epidermis , Fibroblastos/metabolismo , Queratinocitos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Desnudos , Piel/lesiones , Enfermedades de la Piel/metabolismo , Cicatrización de Heridas/fisiología
10.
Biomacromolecules ; 20(3): 1297-1307, 2019 03 11.
Artículo en Inglés | MEDLINE | ID: mdl-30694656

RESUMEN

A synthetic cell mimic in the form of giant glycosylated polymersomes (GGPs) comprised of a novel amphiphilic diblock copolymer is reported. A synthetic approach involving a poly(dimethylsiloxane) (PDMS) macro-chain transfer agent (macroCTA) and postpolymerization modification was used to marry the hydrophobic and highly flexible properties of PDMS with the biological activity of glycopolymers. 2-Bromoethyl acrylate (BEA) was first polymerized using a PDMS macroCTA ( Mn,th ≈ 4900 g·mol-1, D = 1.1) to prepare well-defined PDMS- b-pBEA diblock copolymers ( D = 1.1) that were then substituted with 1-thio-ß-d-glucose or 1-thio-ß-d-galactose under facile conditions to yield PDMS- b-glycopolymers. Compositions possessing ≈25% of the glycopolymer block (by mass) were able to adopt a vesicular morphology in aqueous solution (≈210 nm in diameter), as indicated by TEM and light scattering techniques. The resulting carbohydrate-decorated polymersomes exhibited selective binding with the lectin concanavalin A (Con A), as demonstrated by turbidimetric experiments. Self-assembly of the same diblock copolymer compositions using an electroformation method yielded GGPs (ranging from 2-20 µm in diameter). Interaction of these cell-sized polymersomes with fimH positive E. coli was then studied via confocal microscopy. The glucose-decorated GGPs were found to cluster upon addition of the bacteria, while galactose-decorated GGPs could successfully interact with (and possibly immobilize) the bacteria without the onset of clustering. This demonstrates an opportunity to modulate the response of these synthetic cell mimics (protocells) toward biological entities through exploitation of selective ligand-receptor interactions, which may be readily tuned through a considered choice of carbohydrate functionality.


Asunto(s)
Dimetilpolisiloxanos/química , Escherichia coli/química , Polímeros/química , Glicosilación , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía Electrónica de Transmisión , Nefelometría y Turbidimetría , Dispersión de Radiación
11.
Biomacromolecules ; 19(8): 3343-3350, 2018 08 13.
Artículo en Inglés | MEDLINE | ID: mdl-29928802

RESUMEN

Novel approaches for culturing primary human cells in vitro are increasingly needed to study cell and tissue physiology and to grow replacement tissue for regenerative medicine. Conventional 2D monolayer cultures of endometrial epithelial and stromal cells fail to replicate the complex 3D architecture of tissue. A fully synthetic scaffold that mimics the microenvironment of the human endometrium can ultimately provide a robust platform for investigating tissue physiology and, hence, take significant steps toward tackling female infertility and IVF failure. In this work, emulsion-templated porous polymers (known as polyHIPEs) were investigated as scaffolds for the culture of primary human endometrial epithelial and stromal cells (HEECs and HESCs). Infiltration of HEECs and HESCs into cell-seeded polyHIPE scaffolds was assessed by histological studies, and phenotype was confirmed by immunostaining. Confocal microscopy revealed that the morphology of HEECs and HESCs is representative of that found in vivo. RNA sequencing was used to investigate transcriptome differences between cells grown on polyHIPE scaffolds and in monolayer cultures. The differentiation status of HEECs and HESCs grown in polyHIPE scaffolds and in monolayer cultures was further evaluated by monitoring the expression of endometrial marker genes. Our observations suggest that a 3D cell culture model that could approximate native human endometrial architecture and function can be developed using tailored polyHIPE scaffolds.


Asunto(s)
Diferenciación Celular , Endometrio/citología , Polímeros/farmacología , Estirenos/farmacología , Andamios del Tejido/química , Células Cultivadas , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Femenino , Humanos , Polímeros/química , Células del Estroma/citología , Células del Estroma/efectos de los fármacos , Estirenos/química , Andamios del Tejido/efectos adversos
12.
Macromol Rapid Commun ; 39(19): e1700831, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29450934

RESUMEN

Since their discovery in 1993, interest in various aspects of cyclic peptides (CPs) has expanded rapidly. Of particular note is their potential to form artificial ion channels in lipid membranes, an attractive characteristic in supramolecular chemistry and biological research. The design and synthesis of cyclic peptide-polymer conjugates (CPPCs) that can self-assemble within lipid bilayers into nanotubes, mimicking naturally occurring membrane channels and pores, has been reported. However, methods that allow direct detection of the transport process with high levels of certainty are still lacking. This work focuses on the development of a simple but reliable approach to verify and quantify proton transport across a bilayer membrane. Giant unilamellar vesicles (GUVs) are created via the electroformation method and CPPCs are incorporated in GUV membranes at varying concentrations (0-10%). Confocal fluorescence microscopy is used to demonstrate full inclusion of fluorescein-labeled CPPCs in the GUV membranes. The pH-sensitive dye carboxyfluorescein is encapsulated within the water pool of the GUVs and used as an indicator of proton transport. This assay is versatile and can be exploited on other existing proton transporter systems, providing a consistent tool to compare their performances. It should also aid the development of novel antineoplastics and drug delivery systems.


Asunto(s)
Canales Iónicos/química , Nanotubos/química , Péptidos Cíclicos/química , Protones , Liposomas Unilamelares/química , Transporte Iónico , Microscopía Fluorescente
13.
Biomacromolecules ; 17(8): 2672-9, 2016 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-27434596

RESUMEN

Synthetic polymer nanoparticles that can be tailored through multivalent ligand display on the surface, while at the same time allowing encapsulation of desired bioactive molecules, are especially useful in providing a versatile and robust platform in the design of specific delivery vehicles for various purposes. Glycosylated nanoparticles (glyco-NPs) of a poly(n-butyl acrylate) (pBA) core and poly(N-2-(ß-d-glucosyloxy)ethyl acrylamide) (p(NßGlcEAM)) or poly(N-2-(ß-D-galactosyloxy)ethyl acrylamide) (p(NßGalEAM)) corona were prepared via nanoprecipitation in aqueous solutions of preformed amphiphilic glycopolymers. Well-defined block copolymers of (poly(pentafluorophenyl acrylate) (pPFPA) and pBA were first prepared by RAFT polymerization followed by postpolymerization functionalization with aminoethyl glycosides to yield p(NßGlcEAM-b-BA) and p(NßGalEAM-b-BA), which were then used to form glyco-NPs (glucosylated and galactosylated NPs, Glc-NPs and Gal-NPs, respectively). The glyco-NPs were characterized by dynamic light scattering (DLS) and TEM. Encapsulation and release of ampicillin, leading to nanoparticles that we have termed "glyconanobiotics", were studied. The ampicillin-loaded glyco-NPs were found to induce aggregation of Staphylococcus aureus and Escherichia coli and resulted in antibacterial activity approaching that of ampicillin itself. This glyconanobiotics strategy represents a potential new approach for the delivery of antibiotics close to the surface of bacteria by promoting bacterial aggregation. Defined release in the proximity of the bacterial envelope may thus enhance antibacterial efficiency and potentially reduce the quantities of agent required for potency.


Asunto(s)
Antiinfecciosos/administración & dosificación , Sistemas de Liberación de Medicamentos , Escherichia coli/efectos de los fármacos , Nanopartículas/química , Polímeros/química , Staphylococcus aureus/efectos de los fármacos , Glicosilación
14.
Biomacromolecules ; 17(8): 2719-25, 2016 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-27403588

RESUMEN

PEGylation, the covalent modification of proteins with polyethylene glycol, is an abundantly used technique to improve the pharmacokinetics of therapeutic proteins. The drawback with this methodology is that the covalently attached PEG can impede the biological activity (e.g., reduced receptor-binding capacity). Protein therapeutics with "disposable" PEG modifiers have potential advantages over the current technology. Here, we show that a protein-polymer "Medusa complex" is formed by the combination of a hexavalent lectin with a glycopolymer. Using NMR spectroscopy, small-angle X-ray scattering (SAXS), size exclusion chromatography, and native gel electrophoresis it was demonstrated that the fucose-binding lectin RSL and a fucose-capped polyethylene glycol (Fuc-PEG) form a multimeric assembly. All of the experimental methods provided evidence of noncovalent PEGylation with a concomitant increase in molecular mass and hydrodynamic radius. The affinity of the protein-polymer complex was determined by ITC and competition experiments to be in the micromolar range, suggesting that such systems have potential biomedical applications.


Asunto(s)
Lectinas/química , Polietilenglicoles/química , Cromatografía en Gel , Espectroscopía de Resonancia Magnética , Dispersión del Ángulo Pequeño , Difracción de Rayos X
15.
Biomacromolecules ; 16(12): 3970-9, 2015 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-26544047

RESUMEN

Poly(ionic liquid)s (P(IL)s) of different degrees of polymerization (10, 50, and 100) were prepared via RAFT polymerization using an alkyne-terminated xanthate as transfer agent, with a monomer conversion of up to ∼80% and a DM of 1.5 for P(IL)100. Subsequently, P(IL) chains were coupled to (15)N-labeled azido-functionalized hydroxyethyl cellulose (HEC), forming graft copolymers of HEC with different chain length and graft densities, which were characterized using ((13)C and (15)N) CP-MAS NMR and FT-IR spectroscopies. The antibacterial activities of HEC-g-P(IL)s were tested against Escherichia coli and Staphylococcus aureus and were comparable to ampicillin, a well-known antibiotic, demonstrating efficient activity of the graft copolymers against bacteria. Moreover, HEC-g-P(IL)s were slightly more effective against E. coli than S. aureus. A decrease in graft density of P(IL)10 on the HEC backbone decreased the activity of the graft copolymers against both bacteria. These findings suggest that HEC-g-P(IL) could find applications as an antiseptic compound, for example, in paint formulation.


Asunto(s)
Antibacterianos/síntesis química , Hidrocarburos Aromáticos con Puentes/química , Celulosa/análogos & derivados , Líquidos Iónicos/síntesis química , Polímeros/síntesis química , Tionas/química , Ampicilina/farmacología , Antibacterianos/farmacología , Isótopos de Carbono , Celulosa/química , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Líquidos Iónicos/farmacología , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Isótopos de Nitrógeno , Norbornanos , Polimerizacion , Polímeros/farmacología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/crecimiento & desarrollo , Relación Estructura-Actividad , Tiocarbamatos
16.
Macromol Rapid Commun ; 36(9): 834-9, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25732898

RESUMEN

Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 µm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying.


Asunto(s)
Acrilatos/química , Polímeros/química , Estirenos/química , Compuestos de Sulfhidrilo/química , Emulsiones/química , Procesos Fotoquímicos , Porosidad
17.
Chem Soc Rev ; 43(20): 7217-35, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25016958

RESUMEN

In this comprehensive review, we report on the preparation of graft-copolymers of cellulose and cellulose derivatives using atom transfer radical polymerization (ATRP) under homogeneous conditions. The review is divided into four sections according to the cellulosic material that is graft-copolymerised; (i) cellulose, (ii) ethyl cellulose, (iii) hydroxypropyl cellulose and (iv) other cellulose derivatives. In each section, the grafted synthetic polymers are described as well as the methods used for ATRP macro-initiator formation and graft-copolymerisation. The physical properties of the graft-copolymers including their self-assembly in solution into nanostructures and their stimuli responsive behaviour are described. Potential applications of the self-assembled graft copolymers in areas such as nanocontainers for drug delivery are outlined.


Asunto(s)
Celulosa/análogos & derivados , Celulosa/química , Polimerizacion
18.
Artículo en Inglés | MEDLINE | ID: mdl-39022819

RESUMEN

In vitro three-dimensional (3D) models are better able to replicate the complexity of real organs and tissues than 2D monolayer models. The human endometrium, the inner lining of the uterus, undergoes complex changes during the menstrual cycle and pregnancy. These changes occur in response to steroid hormone fluctuations and elicit crosstalk between the epithelial and stromal cell compartments, and dysregulations are associated with a variety of pregnancy disorders. Despite the importance of the endometrium in embryo implantation and pregnancy establishment, there is a lack of in vitro models that recapitulate tissue structure and function and as such a growing demand for extracellular matrix hydrogels that can support 3D cell culture. To be physiologically relevant, an in vitro model requires mechanical and biochemical cues that mimic those of the ECM found in the native tissue. We report a semisynthetic gelatin methacryloyl (GelMA) hydrogel that combines the bioactive properties of natural hydrogels with the tunability and reproducibility of synthetic materials. We then describe a simple protocol whereby cells can quickly be encapsulated in GelMA hydrogels. We investigate the suitability of GelMA hydrogel to support the development of an endometrial model by culturing the main endometrial cell types: stromal cells and epithelial cells. We also demonstrate how the mechanical and biochemical properties of GelMA hydrogels can be tailored to support the growth and maintenance of epithelial gland organoids that emerge upon 3D culturing of primary endometrial epithelial progenitor cells in a defined chemical medium. We furthermore demonstrate the ability of GelMA hydrogels to support the viability of stromal cells and their function measured by monitoring decidualization in response to steroid hormones. This study describes the first steps toward the development of a hydrogel matrix-based model that recapitulates the structure and function of the native endometrium and could support applications in understanding reproductive failure.

19.
J Am Chem Soc ; 135(25): 9362-5, 2013 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-23763610

RESUMEN

Mucin-related carbohydrates are overexpressed on the surface of cancer cells, providing a disease-specific target for cancer immunotherapy. Here, we describe the design and construction of peptide-free multivalent glycosylated nanoscale constructs as potential synthetic cancer vaccines that generate significant titers of antibodies selective for aberrant mucin glycans. A polymerizable version of the Tn-antigen glycan was prepared and converted into well-defined glycopolymers by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. The polymers were then conjugated to gold nanoparticles, yielding 'multicopy-multivalent' nanoscale glycoconjugates. Immunological studies indicated that these nanomaterials generated strong and long-lasting production of antibodies that are selective to the Tn-antigen glycan and cross-reactive toward mucin proteins displaying Tn. The results demonstrate proof-of-concept of a simple and modular approach toward synthetic anticancer vaccines based on multivalent glycosylated nanomaterials without the need for a typical vaccine protein component.


Asunto(s)
Vacunas contra el Cáncer/síntesis química , Oro/química , Nanopartículas del Metal/química , Polímeros/química , Antígenos de Carbohidratos Asociados a Tumores/química , Vacunas contra el Cáncer/química , Estructura Molecular , Polimerizacion , Polímeros/síntesis química
20.
Biomacromolecules ; 14(12): 4271-7, 2013 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-24180291

RESUMEN

Three-dimensional (3D) cell culture is regarded as a more physiologically relevant method of growing cells in the laboratory compared to traditional monolayer cultures. Recently, the application of polystyrene-based scaffolds produced using polyHIPE technology (porous polymers derived from high internal phase emulsions) for routine 3D cell culture applications has generated very promising results in terms of improved replication of native cellular function in the laboratory. These materials, which are now available as commercial scaffolds, are superior to many other 3D cell substrates due to their high porosity, controllable morphology, and suitable mechanical strength. However, until now there have been no reports describing the surface-modification of these materials for enhanced cell adhesion and function. This study, therefore, describes the surface functionalization of these materials with galactose, a carbohydrate known to specifically bind to hepatocytes via the asialoglycoprotein receptor (ASGPR), to further improve hepatocyte adhesion and function when growing on the scaffold. We first modify a typical polystyrene-based polyHIPE to produce a cell culture scaffold carrying pendent activated-ester functionality. This was achieved via the incorporation of pentafluorophenyl acrylate (PFPA) into the initial styrene (STY) emulsion, which upon polymerization formed a polyHIPE with a porosity of 92% and an average void diameter of 33 µm. Histological analysis showed that this polyHIPE was a suitable 3D scaffold for hepatocyte cell culture. Galactose-functionalized scaffolds were then prepared by attaching 2'-aminoethyl-ß-D-galactopyranoside to this PFPA functionalized polyHIPE via displacement of the labile pentafluorophenyl group, to yield scaffolds with approximately ca. 7-9% surface carbohydrate. Experiments with primary rat hepatocytes showed that cellular albumin synthesis was greatly enhanced during the initial adhesion/settlement period of cells on the galactose-functionalized material, suggesting that the surface carbohydrates are accessible and selective to cells entering the scaffold. This porous polymer scaffold could, therefore, have important application as a 3D scaffold that offers enhanced hepatocyte adhesion and functionality.


Asunto(s)
Medios de Cultivo/síntesis química , Galactosa/química , Hepatocitos/fisiología , Polímeros/química , Estirenos/química , Acrilatos/química , Albúminas/biosíntesis , Animales , Adhesión Celular , Células Hep G2 , Humanos , Porosidad , Cultivo Primario de Células , Ratas , Ratas Sprague-Dawley , Espectroscopía Infrarroja por Transformada de Fourier
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