Interpenetrating Network Formation in Gellan−Agarose Gel Composites

Amici, E.; Clark, Allan H.; Normand, Valéry; Johnson, Nick B

doi:10.1021/bm000057d

Cited by 50 publications

(26 citation statements)

References 14 publications

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“…Although agarose does not exhibit swelling or shrinking in response to salt solutions, there is observable strain-softening in response to greater levels of applied compression. The initially higher E Yi at very low applied compression, similar to the measured E +Y determined from conventional testing, is thought to arise from residual stresses of the polymer that place the hydrogel in a swollen state during gelation (Amici et al, 2000; Normand et al, 2000). As this swollen state is overcome, compressive properties are exhibited.…”

Section: Discussionmentioning

confidence: 52%

Tissue-engineered articular cartilage exhibits tension–compression nonlinearity reminiscent of the native cartilage

Kelly

Roach

Weidner

et al. 2013

Journal of Biomechanics

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The tensile modulus of articular cartilage is much larger than its compressive modulus. This tension-compression nonlinearity enhances interstitial fluid pressurization and decreases the frictional coefficient. The current set of studies examines the tensile and compressive properties of cylindrical chondrocyte-seeded agarose constructs over different developmental stages through a novel method that combines osmotic loading, video microscopy, and uniaxial unconfined compression testing. This method was previously used to examine tension-compression nonlinearity in native cartilage. Engineered cartilage, cultured under free-swelling (FS) or dynamically loaded (DL) conditions, was tested in unconfined compression in hypertonic and hypotonic salt solutions. The apparent equilibrium modulus decreased with increasing salt concentration, indicating that increasing the bath solution osmolarity shielded the fixed charges within the tissue, shifting the measured moduli along the tension-compression curve and revealing the intrinsic properties of the tissue. With this method, we were able to measure the tensile (401±83 kPa for FS and 678±473 kPa for DL) and compressive (161±33 kPa for FS and 348±203 kPa for DL) moduli of the same engineered cartilage specimens. These moduli are comparable to values obtained from traditional methods, validating this technique for measuring the tensile and compressive properties of hydrogel-based constructs. This study shows that engineered cartilage exhibits tension-compression nonlinearity reminiscent of the native tissue, and that dynamic deformational loading can yield significantly higher tensile properties.

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Section: Discussionmentioning

confidence: 52%

Tissue-engineered articular cartilage exhibits tension–compression nonlinearity reminiscent of the native cartilage

Kelly

Roach

Weidner

et al. 2013

Journal of Biomechanics

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“…Microscopy revealed an effect on network density and levels of branching. Cairns et al (1987) introduced the concept of interpenetration networks (IPNs), which have been shown in the work by Clark et al (1999) and Amici et al (2000Amici et al ( , 2002 for mixtures containing gellanmaltodextrin, gellan-agarose and agarose-kappa carrageenan, respectively. IPNs offer the opportunity to control pore size as well as network strength and connectivity of gels for controlled release.…”

Section: Hydrocolloid-hydrocolloid Interactionsmentioning

confidence: 99%

“…Therefore, the physical environment experienced by the separate polysaccharide chains at the point of gelation has to be considered in modelling and when attempting to control the physical properties of such mixtures. When agarose is added to gellan, the resultant gel is reinforced, showing higher gel moduli and stress-to-break without affecting the brittle nature of the gellan gel fracture (Amici et al, 2000). In gellan-maltodextrin systems, crystallisation of maltodextrin occurs within the pores of the gellan gels.…”

Section: Hydrocolloid-hydrocolloid Interactionsmentioning

confidence: 99%

Hydrocolloid Gums – Their Role and Interactions in Foods

Foster

Wolf

2010

Practical Food Rheology

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Hydrocolloid gums are applied in foods mainly for their thickening and gelling properties. As 'hydrocolloid' implies, these are water-soluble gums and, therefore, tend to be applied in the water-continuous foods. Additionally, low-fat spreads with a dispersed aqueous phase structured and stabilised using hydrocolloids have also been designed. Inclusion of the hydrocolloid is crucial in certain domains of the product microstructure to obtain a stable product with acceptable mouthfeel. Typically, only relatively small amounts of hydrocolloid are required to impart the desired rheological and/or textural properties of the food. This chapter introduces fundamentals of rheology relating to the behaviour of hydrocolloid gums in solution as well as fundamentals of gel rheology to cover the two types of actions of hydrocolloids in an aqueous environment: thickening and gelling. Then, in Table 4.1 a general overview of commonly applied hydrocolloids is provided. The majority of this chapter has been dedicated to presenting the effect of hydrocolloid interactions on the rheological/textural behaviour, followed by a discussion of systems applied in foods. BEHAVIOUR OF HYDROCOLLOID GUMS IN SOLUTIONIntroducing relatively small amounts of hydrocolloid gums into the aqueous phase of food formulations can lead to a dramatic change in food texture. The nature of the hydrocolloid gum combined with the solvent conditions, for example the presence of salt and the temperature history of the product, will determine whether a 'simple' thickening effect or gelation has been achieved. The focus of this section is on Practical Food Rheology: An Interpretive Approach Edited by Ian T. Norton, Fotios Spyropoulos and Philip Cox

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“…Among these, we can quote crosslinked epoxy adhesives showing a great resistance to acids, bases and many solvents, and exhibiting high glass transition temperatures and thermal resistance, crosslinked mixtures of bacterial and seaweed polysaccharides gellan and agarose [1] , novel IPNs made of polypropylene/poly( n -butyl acrylate) [2] , or polysiloxane interpenetrating networks used as electronic device encapsulants [3] . The common feature of IPNs and CPBs is that they are formed by two chemically incompatible polymers.…”

Section: Introductionmentioning

confidence: 99%

Fluctuation-induced forces in critical crosslinked polymer blends

Fassi¹,

Benhamou²,

Agouzouk³

et al. 2011

Journal of Polymer Engineering

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In this paper, we report on the computation of the induced forces in crosslinked polymer blends, with immersed small colloidal particles (nanoparticles) or confi ned to two parallel plates (fi lm). We assume that the particles or the walls prefer to be attracted by one polymer, close to the spinodal temperature where a microphase separation takes place. This is the so-called " critical adsorption " . As an assumption, the particle diameter or the fi lm thickness is considered to be small enough in comparison with the size of microdomains ( " mesh size " ). The critical fl uctuations of the crosslinked mixture induce a pair potential between particles located in the nonpreferred phase or between the confi ning walls. The purpose is to recall how this Casimir pair potential can be determined, as a function of the interparticle distance or the walls separation. To achieve calculations, use is made of an extended de Gennes model that takes into account the colloid-polymer and polymer-wall interactions. Finally, the obtained results are compared to those relatively to uncrosslinked polymer blends in the same geometries, and the main conclusion is that the induced force is reduced by the presence of permanent crosslinks.

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Interpenetrating Network Formation in Gellan−Agarose Gel Composites

Cited by 50 publications

References 14 publications

Tissue-engineered articular cartilage exhibits tension–compression nonlinearity reminiscent of the native cartilage

Tissue-engineered articular cartilage exhibits tension–compression nonlinearity reminiscent of the native cartilage

Hydrocolloid Gums – Their Role and Interactions in Foods

Fluctuation-induced forces in critical crosslinked polymer blends

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