Semi‐interpenetrating networks based on poly(<i>N</i>‐isopropyl acrylamide) and poly(<i>N</i>‐vinylpyrrolidone)

Žugić, Dragana L.; Spasojević, Pavle; Petrovìć, Zoran S.; Djonlagić, Jasna

doi:10.1002/app.30075

Cited by 27 publications

(13 citation statements)

References 38 publications

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“…Previous IPN studies have reported similar deviations in failure properties within sample groups. 16,55 Failure point determination in unconfined compressive testing can be difficult because a partially fractured gel still supports a compressive load, and therefore tensile mechanical data are usually preferred for analysis of failure properties. In spite of these drawbacks, compressive testing with characterization of failure strain is necessary for evaluation of potential materials for cartilage implantation.…”

Section: Discussionmentioning

confidence: 99%

Hierarchically Designed Agarose and Poly(Ethylene Glycol) Interpenetrating Network Hydrogels for Cartilage Tissue Engineering

DeKosky

Dormer

Ingavle

et al. 2010

Tissue Engineering Part C: Methods

133

128

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A new method for encapsulating cells in interpenetrating network (IPN) hydrogels of superior mechanical integrity was developed. In this study, two biocompatible materials-agarose and poly(ethylene glycol) (PEG) diacrylate-were combined to create a new IPN hydrogel with greatly enhanced mechanical performance. Unconfined compression of hydrogel samples revealed that the IPN displayed a fourfold increase in shear modulus relative to a pure PEG-diacrylate network (39.9 vs. 9.9 kPa) and a 4.9-fold increase relative to a pure agarose network (8.2 kPa). PEG and IPN compressive failure strains were found to be 71% ± 17% and 74% ± 17%, respectively, while pure agarose gels failed around 15% strain. Similar mechanical property improvements were seen when IPNs-encapsulated chondrocytes, and LIVE/DEAD cell viability assays demonstrated that cells survived the IPN encapsulation process. The majority of IPN-encapsulated chondrocytes remained viable 1 week postencapsulation, and chondrocytes exhibited glycosaminoglycan synthesis comparable to that of agarose-encapsulated chondrocytes at 3 weeks postencapsulation. The introduction of a new method for encapsulating cells in a hydrogel with enhanced mechanical performance is a promising step toward cartilage defect repair. This method can be applied to fabricate a broad variety of cell-based IPNs by varying monomers and polymers in type and concentration and by adding functional groups such as degradable sequences or cell adhesion groups. Further, this technology may be applicable in other cell-based applications where mechanical integrity of cell-containing hydrogels is of great importance.

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Section: Discussionmentioning

confidence: 99%

Hierarchically Designed Agarose and Poly(Ethylene Glycol) Interpenetrating Network Hydrogels for Cartilage Tissue Engineering

DeKosky

Dormer

Ingavle

et al. 2010

Tissue Engineering Part C: Methods

133

128

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“…The hydrogels were prepared by crosslinking polymerization (24 h at 4°C) of NIPA monomers (molar fraction m mon = 0.885 mol L -1 ) by using N,N 0 -methylenebisacrylamide (BIS) (m cr = 35.4 mmol L -1 ) as a crosslinker. 55 Equilibrium swelling diagrams on gels with the lowest (ψ = 0) and highest (ψ = 3 wt%) mass fractions of PVP chains are depicted in Figs 4(A) and 4(B) together with results of numerical simulation, and those on gels with intermediate ψ values (ψ = 1 and 2 wt%) are presented in Figs S1A and S1B.…”

Section: Copolymer Gelsmentioning

confidence: 99%

“…We now approximate observations on double‐network semi‐interpenetrating PNIPA gels prepared in aqueous solutions of poly( N ‐vinylpyrrolidone) (PVP) (molecular weight M w = 1.3 × 10 6 g mol –1 ) with various mass fractions ψ of PVP chains ranging from 0 to 3 wt%. The hydrogels were prepared by crosslinking polymerization (24 h at 4 °C) of NIPA monomers (molar fraction m mon = 0.885 mol L –1 ) by using N , N ′‐methylenebisacrylamide (BIS) ( m cr = 35.4 mmol L –1 ) as a crosslinker 55 . Equilibrium swelling diagrams on gels with the lowest ( ψ = 0) and highest ( ψ = 3 wt%) mass fractions of PVP chains are depicted in Figs 4(A) and 4(B) together with results of numerical simulation, and those on gels with intermediate ψ values ( ψ = 1 and 2 wt%) are presented in Figs S1A and S1B.…”

Section: Comparison With Experimental Datamentioning

confidence: 99%

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Mechanical response and equilibrium swelling of thermoresponsive copolymer hydrogels

Drozdov

Christiansen

2020

Polymer International

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Covalently crosslinked thermoresponsive (TR) gels form a special class of hydrogels that swell noticeably below their volume phase transition temperature Tc and shrink above Tc. As the critical temperature is weakly affected by the preparation conditions and molar fractions of monomers and crosslinkers in the pre‐gel solution, a facile method to modulate Tc (which is required for biomedical applications of TR gels and their use as temperature‐triggered actuators) is to incorporate relatively small amounts of neutral monomers whose hydrophilicity differs from that of the basic monomers. Although observations on copolymer gels confirm the effectiveness of this method, the molar fractions of comonomers necessary for the tuning of Tc remain unknown. A model was developed for the mechanical response and equilibrium swelling of TR gels. Adjustable parameters in the governing relations were found by fitting equilibrium swelling diagrams for poly(N‐isopropylacrylamide) homopolymer and copolymer gels. Good agreement is demonstrated between the experimental data and the results of simulation. Based on the model, an analytical formula is derived that expresses the volume phase transition temperature in terms of the molar fraction of comonomers. Its ability to predict the critical temperature is confirmed by comparison with observations on several copolymer gels. © 2020 Society of Chemical Industry

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“…(77) are influenced by the concentration of monomers C mon , we approximate the swelling diagrams [42] for PNIPA gels with C mon = 100. [19].…”

Section: Unconstrained Swellingmentioning

confidence: 99%

Volume phase transition in thermo-responsive hydrogels: constitutive modeling and structure–property relations

Drozdov

2014

Acta Mech

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A model is developed for the elastic response of a thermo-responsive hydrogel subjected to swelling under an arbitrary deformation with finite strains. The constitutive equations involve the stress-strain relation, the nonlinear diffusion equation for water molecules, the heat conduction equation, and the Allen-Cahn equation for a scalar order parameter (proportional to the concentration of hydrophilic segments in polymer chains). Material constants are found by fitting equilibrium mass uptake diagrams for macro-and microgels under unconstrained and constrained swelling in the vicinity of the volume phase transition temperature. Quantitative agreement is demonstrated between the experimental data and the results of simulation. The effect of composition of hydrogels (concentrations of monomers and cross-linker) on adjustable parameters is analyzed numerically.

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Semi‐interpenetrating networks based on poly(N‐isopropyl acrylamide) and poly(N‐vinylpyrrolidone)

Cited by 27 publications

References 38 publications

Hierarchically Designed Agarose and Poly(Ethylene Glycol) Interpenetrating Network Hydrogels for Cartilage Tissue Engineering

Hierarchically Designed Agarose and Poly(Ethylene Glycol) Interpenetrating Network Hydrogels for Cartilage Tissue Engineering

Mechanical response and equilibrium swelling of thermoresponsive copolymer hydrogels

Volume phase transition in thermo-responsive hydrogels: constitutive modeling and structure–property relations

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