Synthesis and characterization of degradable hydrogels formed from acrylate modified poly(vinyl alcohol) macromers (original) (raw)
Related papers
Acta Biomaterialia, 2010
Hyperbranched poly(ester amide) polymer (Hybrane™ S1200; M n 1200 g/mol) was functionalized with maleic anhydride (MA) and propylene sulfide, to obtain multifunctional crosslinkers with fumaric and thiol-end groups, S1200MA and S1200SH, respectively. The degree of substitution of maleic acid groups (DS) was controlled by varying the molar ratio of MA to S1200 in the reaction mixture. Hydrogels were obtained by UV crosslinking of functionalized S1200 and poly(ethyleneglycol) diacrylate (PEGDA) in aqueous solutions. Compressive modulus increased with decreasing the S1200/PEG ratio and also depended on the DS of the multifunctional crosslinker (S1200). Also, heparin-based macromonomers together with functionalized hyperbranched polymers were used to construct novel functional hydrogels. The multivalent hyperbranched polymers allowed high crosslinking densities in heparin modified gels while introducing biodegradation sites. Both heparin presence and acrylate/thiol ratio have an impact on degradation profiles and morphologies. Hyperbranched crosslinked hydrogels showed no evidence of cell toxicity. Overall, the multifunctional crosslinkers afford hydrogels with promising properties that suggest that these may be suitable for tissue engineering applications.
European Polymer Journal, 2008
This work describes the synthesis and macromolecular reactions of maleic anhydride (MA)-acrylic acid (AA) binary reactive copolymers with ␥-aminopropyltriethoxysilane (APTS) as a polyfunctional crosslinker. Copolymers with a given composition of MA-AA (47.17-52.83 wt %) were synthesized by radical binary copolymerization with benzoyl peroxide as an initiator in p-dioxane at 70°C in nitrogen atmosphere and initial monomer ratio of 1 : 1. It is shown that the network structure is formed in MA-AA/ APTS in water by intermolecular reaction between the anhydride unit and the amine group, as well as between the etoxysilyl fragment and free carboxyl groups of the acrylic acid and maleic anhydride unit. Swelling parameters such as beginning time of hydrogel formation, initial rate of swelling, swelling rate constant, equilibrium swelling, and equilibrium water content were determined for copolymer/ APTS/water systems with various copolymer/crosslinker ratios. Formation of a hyperbranched network structure through the fragmentation of side-chain reactive groups in the studied systems was confirmed by FTIR, TGA, and DSC methods.
Strategies toward development of biodegradable hydrogels for biomedical applications
Polymer-Plastics Technology and Materials, 2020
Hydrogel is a macromolecular gel constructed of a network of cross-linked polymer chains. Hydrogels are class of materials that can be tuned toward the subjected stimuli and can be modified to imitate the extracellular environment of the body which makes hydrogel worthy of being used in tissue regeneration, drug delivery, and other fields of science. Hydrogels offer excellent potential as oral therapeutic systems due to inherent biocompatibility, and biodegradability. Hydrogels are having various tissue engineering and drug delivery application due to its high loading with ensured molecule efficacy, high encapsulation, variable release profile, stable, and inexpensive.
Biomaterials, 2007
Biocompatible, degradable hydrogel systems that can cure in situ following injection as a liquid are useful as a base for tissue engineering and drug delivery. In this study, poly (vinyl alcohol) (PVA) polymers were modified with degradable crosslinkers and formulated for either ultraviolet (UV) light initiation or chemical initiation using an oxidation/reduction (redox) curing method. A major objective was to compare the properties of degradable PVA hydrogels formed via two routes of curing. The effect of macromer concentration, degree of hydrolysis and functional group density on the degradation profiles was investigated. Also, since the hydrogels have been designed to be injected as a liquid for in situ curing, the effect of modified macromer solutions and degradation products on cell growth was investigated. Total degradation times ranged from approximately 20 days up to 120 days and increased in direct proportion with percent macromer. Initiation method (UV or redox) did not significantly impact on time for total degradation. While aqueous solutions of the modified macromer induced some cell growth inhibition, mainly associated with oxidative solutions, degradation products showed relatively low cell growth inhibition. Degradable PVA hydrogels tailored to produce networks with various degradation profiles can be cured by redox initiation and have potential as injectable polymers for soft-tissue engineering and drug delivery. r
Photodegradable Hydrogels for Cell Encapsulation and Tissue Adhesion
ACS Applied Materials & Interfaces, 2020
Synthesis and manipulation of photo-sensitive compounds were performed in the dark. Analytical and semi-preparative reverse phase high performance liquid chromatography (RP-HPLC) was performed with a HPLC JASCO 4000 (Japan) equipped with a diode array UV/Vis detector and fraction collector. Elution solvents used were solvent A (water + 0.1% TFA) and solvent B (acetonitrile + 5% water + 0.1% TFA). Reprosil C18 columns were used for semi-preparative (250 × 25 mm) and analytical (250 × 5 mm) runs. Typically, a run was performed over 40 min of duration and consisted in a isocratic pre-run at 30% B for 3 min, followed by a gradient increase of 30% B to 95% B for 30 min and isocratic run at 95% B for 7 min. Detection of the compounds was performed at triple wavelengths λ = 210, 254 and 360 nm. Retention time of the compounds is reported in min. Dialysis purification of substituted PEG polymers was performed using membrane tubing (MW cutoff of 3.5 kDa), against acetone and acetone-water combination or methanol and methanol-water combination, typically for at least 48 h (dialysate was changed 2-3 times per day). 1 H-NMR spectra (300 MHz) were recorded using a Bruker Avance 300 spectrometer. Chemical shifts are reported in units of parts per million (ppm) using the solvent residual peak (S.R.P.) of CDCl3 (δ = 7.26 ppm), D2O (δ = 4.79 ppm), DCM-d2 (δ = 5.32 ppm) or acetone-d6 (δ = 2.05 ppm) as internal reference. Multiplicities are reported by using the following abbreviations; s: singlet; bs: broad singlet; d: doublet; dd: doublet of doublets; t: triplet; q: quartet; quint: quintet; m: multiplet. The degree of substitution during polymer modification reactions was obtained by 1 H NMR end-group determination method. The integral of the signal corresponding to the PEG backbone (4.2−3.9 ESI-MS+: 464.2 (M+Na).
Characterization of hydrogels formed from acrylate modified poly(vinyl alcohol) macromers
Polymer, 2000
Poly(vinyl alcohol) was modified with pendent acrylate groups to form a macromer that was crosslinked via photopolymerization. Polymerization behavior was studied for several initial macromer concentrations using DSC and Near-IR spectroscopy. Under mild photoinitiating conditions (e.g. 0.05 wt% initiator and less than 20 mW/cm 2 of 365 nm light), the hydrogels polymerized to 100% conversion in less than 5 min. To characterize the network structure, the hydrogels formed from the acrylated poly(vinyl alcohol) macromer were compared to gels that were chemically crosslinked with glutaraldehyde and gels that were physically crosslinked by semi-crystalline regions introduced through freeze-thaw cycles. The equilibrium swelling ratio and compressive modulus were characterized for all of the resulting PVA hydrogels, and related to the network structure (i.e. M c through a modified Flory-Rehner equation and rubber elasticity theory. ᭧
Langmuir : the ACS journal of surfaces and colloids, 2016
The Diels-Alder [4 + 2] cycloaddition between furan- and maleimide-functional polyanions was used to form crosslinked synthetic polymer hydrogels. Poly(methyl vinyl ether-alt-maleic anhydride) was reacted with furfurylamine or N-(2-aminoethyl)maleimide in acetonitrile to form pairs of furan- and maleimide-functionalized poly(methyl vinyl ether-alt-maleic acid)s, PMM-FFA and PMM-MAL. Mixtures of these mutually reactive polyanions in water gelled within 15 minutes to 18 hours, depending on degree of functionalization and polymer concentrations. Solution and magic-angle spinning (MAS) 1H-NMR were used to confirm the formation of the Diels-Alder adduct, to analyze competing hydrolytic side reactions, and demonstrate post-gellation functionalization. The effect of the degree of furan and maleimide functionalization, polymer concentration, pH, and calcium ion concentration, on gelation time, gel mechanical properties and equilibrium swelling, are described. Release of dextran as model dru...
Applied Mechanics and Materials, 2019
Tissue Engineering depends on broadly techniques to regenerate tissues and/or organ functions. To do so, tailored polymeric and/or hydrogel scaffolds may be used to ensure the appropriate regeneration. Hydrogels are suitable materials for constructing cell-laden matrices as they can be produced with incorporation of cells and rapidly cross-linkedin situthrough photopolymerisation reactions. Measurement of the polymerization degree, as well as resistance to compression and water retention are fundamental tests to evaluate the characteristics of hydrogels. In this work, free-radical polymerisation of poly (ethylene glycol)-dimethacrylate (PEGDMA) in UV light was assessed. Several hydrogels with different photoinitiator and water contents were produced to evaluate their influence on hydrogels behaviour. Experiments showed that variations on water and photoinitiator content induce changes in the physical and chemical behaviour of hydrogels. As it was found, water content prevents polyme...
Biomacromolecules, 2005
Toward the development of synthetic bioactive materials to support tissue repair, we present here the design, production, and characterization of genetically engineered protein polymers carrying specific key features of the natural extracellular matrix, as well as cross-linking with functionalized poly(ethylene glycol) (PEG) to form hybrid hydrogel networks. The repeating units of target recombinant protein polymers contain a cell-binding site for ligation of cell-surface integrin receptors and substrates for plasmin and matrix metalloproteinases (MMPs), proteases implicated in wound healing and tissue regeneration. Hydrogels were formed under physiological conditions via Michael-type conjugate addition of vinyl sulfone groups of endfunctionalized PEG with thiols of cysteine residues, representing designed chemical cross-linking sites within recombinant proteins. Cross-linking kinetics was shown to increase with the pH of precursor solutions. The elastic moduli (G′) and swelling ratios (Q m) of the resulting hydrogels could be varied as a function of the stoichiometry of the reacting groups and precursor concentration. Optima of G′ and Q m , maximum and minimum, respectively, were obtained at stoichiometry ratios r slightly in excess of 1 (r) cysteine/vinyl sulfone). The pool of technologies utilized here represents a promising approach for the development of artificial matrixes tailored for specific medical applications.