Polyelectrolyte complex formation between alginate and chitosan as a function of pH

Simsek-Ege, Fatma A.; Bond, G.M.; Stringer, J.

doi:10.1002/app.11989

Cited by 152 publications

(107 citation statements)

References 15 publications

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“…It has long been know that many pairs of polymers self-assemble to form gels through interchain bonding. Gelled capsules can be formed by dripping a solution of cationic polymer into a solution of anionic polymer [81,82] or by dripping alginate into calcium [83]. This process results in a thick-walled capsule with a nonuniform structure.…”

Section: Chemical and Physical Formation Of Gelsmentioning

confidence: 99%

Polymer Gel Actuators: Fundamentals

Calvert

2009

Biomedical Applications of Electroactive Polymer Actuators

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One view of materials development is to search for what materials correspond to empty spaces on a hypothetical multi-dimensional map of the properties of available materials. Following a biomimetic philosophy, for instance, it can be seen that tough ceramics and moldable short fiber composites with high moduli are possible but absent from the list of available synthetic materials. Likewise artificial muscle is missing, where the properties are defined as a developed stress of over 300 kPa, a linear contraction of 25 % and a response time of below one second. Currently dielectric elastomers come closest but have disadvantages [1,2].The actin-myosin muscle system provides the performance target for electroactive polymer actuators [3,4]. The process is driven chemically by the energy change from hydrolysis of the polyphosphate bond as ATP (adenosine triphosphate) binds to myosin and is converted to ADP (adenosine diphosphate) and phosphate. A simple chemical analogy suggests that muscle-like gels should be feasible but it is now clear that the task is much harder than it seems.Early work on gel actuation by Katchalsky-Katzir demonstrated that engines could be built using the chemical energy in diluting a lithium bromide solution to drive contraction and expansion of a collagen belt [5]. In essence, the collagen expands to take up the salt solution or contract to exclude the water. This change is both a molecular conformation change and a volume change. Other chemically driven gels, for instance polyacrylic acid fibers [6] which respond to a pH change, also rely on a solubility change giving rise to a volume change.

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Section: Chemical and Physical Formation Of Gelsmentioning

confidence: 99%

Polymer Gel Actuators: Fundamentals

Calvert

2009

Biomedical Applications of Electroactive Polymer Actuators

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“…[50][51][52][53] Most uses of alginate have been in the form of beads, microbeads, block gels with other shapes, fibers, and freestanding films.…”

Section: 5-10mentioning

confidence: 99%

“…Such layers are usually heterogeneous with a core of alginate surrounded by a PEC shell. 50,55 Only a few reports exist on alginate based coatings on solid substrates such as metal and ceramic surfaces. [56][57][58] Alginate has been applied to Ti and Ti alloy disks for improving bone cell adhesion on implant surfaces.…”

Section: 5-10mentioning

confidence: 99%

Nanoscale eluting coatings based on alginate/chitosan hydrogels

Peng¹,

Voelcker²,

Kumar³

et al. 2007

Biointerphases

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The localized availability of bioactive biomolecules directly at the implant/tissue interface presents a promising strategy for improved wound healing and thus biointegration. Bioactive molecules that cannot be incorporated into the bulk material of a device may be delivered from a compatible surface coating, while the reservoir capacity of thin surface coatings is limited, they offer localized delivery over the first few critical hours or days of wound healing. In this study an alginate/chitosan hydrogel has been utilized as the basis for nanoscale eluting coatings to provide a hydrophilic yet water insoluble surface delivery system. The release characteristics of these hydrogel coatings were measured by employing the model molecules-fluorescein isothiocyanate dextran ͓FD; molecular weights ͑MWs͒ 4, 70, and 2000 kDa͔, fluorescein isothiocyanate albumin, and rhodamine. Scanning electron microscopy and atomic force microscopy were used to study the morphology of the hydrogel coatings on model substrates, and ellipsometry was employed for measuring the coating thickness. On silicon wafers, the coatings were of good uniformity and conformal, with a thickness of ϳ120 nm and a rms roughness of 3.0 nm. A model porous substrate, paper, which afforded deep pore penetration of the hydrogel, was used to mimic hydroxyapatite. The release of FD was observed to be dependent on the MW, the release medium, charge, and surface roughness. Sustained release was recorded for FD 70 and FD 2000 with yields of about 90% and 75%, respectively, into simulated body fluid within 26 days. Concurrent elution of different molecules from one hydrogel coating was demonstrated. The observed elution profiles were fitted to release kinetics such as the Korsmeyer-Peppas model or first order release.

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“…The interaction between alginate and chitosan generates a polyelectrolyte complex that can be obtained by precipitating cationic polymers when mixed with anionic polymers in aqueous solutions, leading to mutual precipitation, which occurs in this case, because alginate and chitosan are anionic and cationic polysaccharides, respectively 13 . Another advantage of the interaction between its opposite charges is an upgrade in the mechanical strength of the developed structure formed by these two polymers 14,15 .…”

Section: Introductionmentioning

confidence: 99%

Fibers Obtained from Alginate, Chitosan and Hybrid Used in the Development of Scaffolds

et al. 2017

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The main aim of this study was to develop scaffolds based on alginate, chitosan and hybrid fibers with and without glycerol. The scaffolds developed underwent assessments for tensile property, swelling ratio and weight loss, cellular viability, degradation and biomineralization, as well as DSC/TGA thermal analysis. Tenacity values showed that use of glycerol and the interaction between alginate and chitosan as a hybrid fiber were associated with increasing tenacity values. In the swelling and weight loss study, the scaffolds containing glycerol presented lower weight loss and higher water absorption values in all scaffolds, compared to scaffolds without glycerol, indicating that glycerol acted as a stabilizer. None of the alginate, chitosan and hybrid scaffolds, with or without glycerol, decreased cell viability. On the third day of the biomineralization assay, chitosan without glycerol indicated the presence of apatite crystals. The degradation study showed that glycerol may have acted as a stabilizer.

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Polyelectrolyte complex formation between alginate and chitosan as a function of pH

Cited by 152 publications

References 15 publications

Polymer Gel Actuators: Fundamentals

Polymer Gel Actuators: Fundamentals

Nanoscale eluting coatings based on alginate/chitosan hydrogels

Fibers Obtained from Alginate, Chitosan and Hybrid Used in the Development of Scaffolds

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