PEG-containing copolymers play a prominent role as biomaterials for different applications ranging from drug delivery to tissue engineering. These custom-designed materials offer enormous possibilities to change the overall characteristics of biomaterials by improving their biocompatibility and solubility, as well as their ability to crystallize in polymer blends and to resist protein adsorption. This article demonstrates various principles of PEG-based material design that are applied to fine tune the properties of biomaterials for different tissue engineering applications. More specifically, strategies are described to develop PEG copolymers with various block compositions and specific bulk properties, including low melting points and improved surface hydrophilicity. Highly hydrated polymer gel networks for promoting cellular growth or suppressing protein adsorption and cell adhesion are introduced. By incorporating selectively cleavable cross-links, these hydrophilic polymers can also serve as smart hydrogel scaffolds, mimicking the natural extracellular matrix for cell cultivation and tissue growth. Ultimately, these developments lead to the creation of biomimetic materials to immobilize bioactive compounds, allowing precise control of cellular adhesion and tissue growth. [image: see text] 相似文献
Composites with a matrix of poly(2-hydroxyethyl methacrylate) (PHEMA) and 10% by volume of various crosslinked PHEMA polymer fillers (prepared by copolymerization with 0.1, 0.4, 1.0, and 20.0% by weight of ethylenedimethacrylate) of particle size about 1 μm were prepared. Some polymer matrixes were prepared from soluble branched PHEMA (Hydron S), and others by copolymerization, in the presence of the filler with 0.4 and 1.0% of ethylenedimethacrylate as a crosslinking agent. In the case of the uncrosslinked matrix, a linear polymer–crosslinked polymer system, resulted; in the case of the crosslinked matrix, a composite heterogeneous network was formed (in the latter case, the particles of the filler were swollen with monomer during the crosslinking polymerization). Stress–strain, equilibrium, and ultimate characteristics were measured at 3, 10, 25, 40, 60, and 80°C on samples swollen to equilibrium in water (Tg ≈ ?50°C) and at 80, 110, and 140°C on dry samples (Tg ≈ 100°C). Depending on experimental conditions, above all on the distance from the main transition region and on whether the polymer is dry or swollen, it was found that the measured hydrophilic composite systems behaves as a filled system (with the polymer filler acting mostly as solid particles, irrespective of the crosslink density) or as a system with crosslink density fluctuations (where both networks, the matrix and the filler, contribute roughly additively to the properties of the system), or finally as defect heterogeneous systems (where the properties depend primarily on the character of the polymer–filler interface). 相似文献
The characteristics of tissue engineered scaffolds are major concerns in the quest to fabricate ideal scaffolds for tissue engineering applications. The polymer scaffolds employed for tissue engineering applications should possess multifunctional properties such as biocompatibility, biodegradability and favorable mechanical properties as it comes in direct contact with the body fluids in vivo. Additionally, the polymer system should also possess biomimetic architecture and should support stem cell adhesion, proliferation and differentiation. As the progress in polymer technology continues, polymeric biomaterials have taken characteristics more closely related to that desired for tissue engineering and clinical needs. Stimuli responsive polymers also termed as smart biomaterials respond to stimuli such as pH, temperature, enzyme, antigen, glucose and electrical stimuli that are inherently present in living systems. This review highlights the exciting advancements in these polymeric systems that relate to biological and tissue engineering applications. Additionally, several aspects of technology namely scaffold fabrication methods and surface modifications to confer biological functionality to the polymers have also been discussed. The ultimate objective is to emphasize on these underutilized adaptive behaviors of the polymers so that novel applications and new generations of smart polymeric materials can be realized for biomedical and tissue engineering applications.
Bone tissue engineering strategies utilize biodegradable polymeric matrices alone or in combination with cells and factors to provide mechanical support to bone, while promoting cell proliferation, differentiation, and tissue ingrowth. The performance of mechanically competent, micro‐nanostructured polymeric matrices, in combination with bone marrow stromal cells (BMSCs), is evaluated in a critical sized bone defect. Cellulose acetate (CA) is used to fabricate a porous microstructured matrix. Type I collagen is then allowed to self‐assemble on these microstructures to create a natural polymer‐based, micro‐nanostructured matrix (CAc). Poly (lactic‐co‐glycolic acid) matrices with identical microstructures serve as controls. Significantly higher number of implanted host cells are distributed in the natural polymer based micro‐nanostructures with greater bone density and more uniform cell distribution. Additionally, a twofold increase in collagen content is observed with natural polymer based scaffolds. This study establishes the benefits of natural polymer derived micro‐nanostructures in combination with donor derived BMSCs to repair and regenerate critical sized bone defects. Natural polymer based materials with mechanically competent micro‐nanostructures may serve as an alternative material platform for bone regeneration. 相似文献
Hydrogels are attractive biomaterials for three-dimensional cell culture and tissue engineering applications. The preparation of hydrogels using alginate and gelatin provides cross-linked hydrophilic polymers that can swell but do not dissolve in water. In this work, we first reinforced pure alginate by using polyoxyethylene as a supporting material. In an alginate/PEO sample that contains 20 % polyoxyethylene, we obtained a stable hydrogel for cell culture experiments. We also prepared a stable alginate/gelatin hydrogel by cross-linking a periodate-oxidized alginate with another functional component such as gelatin. The hydrogels were found to have a high fluid uptake. In this work, preparation, characterization, swelling, and surface properties of these scaffold materials were described. Lyophilized scaffolds obtained from hydrogels were used for cell viability experiments, and the results were presented in detail. 相似文献
Homogeneous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel exhibits a narrow range of swelling at equilibrium in water (% H2O, 41.09 ± 0.15 standard error of the mean of 24 samples), regardless of the dilution of the monomer solution and relatively low level of crosslinking. It is postulated that PHEMA hydrogel has, in addition to its covalently linked network structure, a secondary structure stabilized by hydrophobic bonding. The addition of microsolutes to the hydrogel seems to confirm this hypothesis. The hydrogel swells beyond its swelling equilibrium in water in presence of urea and its methyl derivatives. Swelling is also induced by organic solvents like alcohol and acetone, and by anions like iodide, acetate, trichloroacetate, and thiocyanate. Chlorides and sulfates produce a less swollen hydrogel than pure water, while bromides and cetylpyridinium chloride, in the concentrations tested, induce only a slight deswelling of the gel. When PHEMA gel prepared in organic solvent–water solutions is placed in water, the gel passes through an opaque state before becoming transparent again. This phenomenon is interpreted as being caused by the inability of water to solvate the hydrophilic ends of the unorganized polymer segments. Homogeneity returns to the gel after a rearrangement of the chains, directed by the interaction of the hydrophobic portions of the polymer segments, exposing to the solvent–water most of the hydrophilic sites in the network. 相似文献
Polyhydroxyalkanoates (PHAs) are biodegradable, biocompatible polyesters and very attractive candidates for biomedical applications as materials for tissue engineering. They have a hydrophobic character, but some are able to spread at the air-water interface to form monomolecularly thin films (Langmuir monolayers). This is a very convenient model to analyze PHA self-assembly in two dimensions and to study their molecular interactions with other amphiphilic compounds, which is very important considering compatibility between biomaterials and cell membranes. We used the Langmuir monolayer technique and Brewster angle microscopy to study the properties of poly([R]-3-hydroxy-10-undecenoate) (PHUE) films on the free water surface in various experimental conditions. Moreover, we investigated the interactions between the polymer and one of the main biomembrane components, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). The addition of lipid to a polymer film does not change the monolayer phase behavior; however, the interactions between these two materials are repulsive and fall in two composition-dependent regimes. In summary, this is the first systematic study of the monolayer behavior of PHUE, thus forming a solid basis for a thorough understanding of material interactions, in particular in the context of biomaterials and implants. 相似文献
Efficient azo-linked polymers of 2,4,6-tris(4-nitrophenyl)pyridine-melamine (TNPP-M), and 2,4,6-tris(4-nitrophenyl)pyridine-sulfanilamide (TNPP-S) were prepared by condensation polymerization technique from TNPP-based monomer reacting with amines as melamine and sulfanilamide. The synthesized polymer structure was confirmed by various experimental techniques, such as Fourier transform infrared spectroscopy, solid-state 13C NMR, and X-ray diffraction (XRD). Particle size was calculated using Williamson–Hall (W–H) plot from powder XRD pattern. The thermal analysis and scanning electron microscopy of TNPP-S polymer displayed an excellent thermal stability and capsule-like morphology was observed. UV/visible absorptions of TNPP-S and TNPP-M polymers exhibit two bands, a strong band at 365?nm, and a shoulder at 385?nm for TNPP-M; these polymeric semiconducting materials could be useful for solar fuel cell applications. 相似文献
Three‐dimensional printing (3DP) technologies, which are sets of powerful deposition methods employed to fabricate 3D objects with materials in the fields of material sciences and engineering, biomedical and biocompatible structural components, automotive, aviation, and polymers, among others, are currently rapidly developing manufacturing technologies. The methods have significant advantages, which include designing flexibility, enhanced geometrical freedom, low cost, and net shape manufacture, among others, over the traditional “subtractive” method. This review highlights the major 3D printing techniques, especially in the fields of advanced polymeric material fabrication and engineering, as well as the synergy in the incorporation of different types of polymeric materials and composites in a process that will lead to an enhancement of dimensional accuracy for 3D technologies. Furthermore, composite ink systems especially polymer‐based and hydrogel‐based in tissue engineering applications are also discussed. 相似文献
Both quantum functional material (Ψ‐engineering material) and molecular engineering materials are of interest as ultimate functional materials. The former creates a novel property which is specific to the structure, and the latter gives he functional material of the smallest size. In this paper, some aspects to construct those materials with polymer having big varieties and flexible applications are described: 1. Conjugating polymer superlattice (conjugating polymer multilayers which is able to change wave length of emission light). 2. Porphyrin arrays connected with molecular wires (a proto‐type photo‐information housing‐in and reading out polymeric material). 3. Oligonucleotide shackled with porphyrin (an artificial restrictive photoactive enzyme). 相似文献
Carboxymethyl Chitosan (CMCh) is a semi-synthetic derivative of chitosan (a natural biopolymer) with increasing biomedical applications as a matrix or scaffold material for tissue engineering applications. Since, the presence of impurities can cause immunological reactions in vivo where ultimately pure materials are needed. To this end, purity of commercial-grade CMCh samples was investigated here along with their purification by a solvent/nonsolvent technique. The resulting polymer was characterized by differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX) to confirm the validity of the purification process. 相似文献