Biomineral-inspired fabrication of semi-permeable calcium phosphate–polysaccharide microcapsules

Leveque, Ingrid; Rhodes, Katja H.; Mann, Stephen

doi:10.1039/b204599k

Cited by 45 publications

(32 citation statements)

References 10 publications

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“…[18] Recent studies have shown that the deposition of the alginate/chitosan membrane can be coupled with the controlled precipitation of calcium phosphate arising from counter-diffusion of ions across the polysaccharide interface. [19] Nucleation of calcium phosphate occurs within the membrane to produce microspheres with modified mechanical strength and reduced permeability to encapsulated molecules such as haemoglobin and ibuprofen. Here we extend and develop these preliminary studies for the encapsulation and release of a range of human cell types and growth factors within calcium phosphate/polyThe construction of biomimetic microenvironments with specific chemical and physical cues for the organization and modulation of a variety of cell populations is of key importance in tissue engineering.…”

Section: Introductionmentioning

confidence: 99%

Biomineralized Polysaccharide Capsules for Encapsulation, Organization, and Delivery of Human Cell Types and Growth Factors

et al. 2005

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The construction of biomimetic microenvironments with specific chemical and physical cues for the organization and modulation of a variety of cell populations is of key importance in tissue engineering. We show that a range of human cell types, including promyoblasts, chondrocytes, adipocytes, adenovirally transduced osteoprogenitors, immunoselected mesenchymal stem cells, and the osteogenic factor, rhBMP‐2 (BMP: bone morphogenic protein), can be successfully encapsulated within mineralized polysaccharide capsules without loss of function in vivo. By controlling the extent of mineralization within the alginate/chitosan shell membrane, degradation of the shell wall and release of cells or rhBMP‐2 into the surrounding medium can be regulated. In addition, we describe for the first time the ability to generate bead‐in‐bead capsules consisting of spatially separated cell populations and temporally separated biomolecule release, entrapped within alginate/chitosan shells of variable thickness, mineralization, and stability. Such materials offer significant potential as multifunctional scaffolds and delivery vehicles in tissue regeneration of hard and soft tissues.

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Section: Introductionmentioning

confidence: 99%

Biomineralized Polysaccharide Capsules for Encapsulation, Organization, and Delivery of Human Cell Types and Growth Factors

et al. 2005

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“…[21][22][23][24][25][26][27][28][29][30][31][32][33][34] On the other hand, a thin release coating provides a limited reservoir, and release may be effective only over a short period of time. The kinetics of release depend markedly on effects such as cross-linking and swelling of the hydrogel.…”

Section: Discussionmentioning

confidence: 99%

“…There has been considerable recent interest in the use of alginate or chitosan hydrogel coatings, sometimes with dispersed calcium phosphate particles, for orthopaedic and periodontal implants as well as nerve regeneration. [21][22][23][24][25][26][27][28][29][30][31][32][33][34] The concurrent release of active biomacromolecules may provide additional means of directing biological responses to implants, but prior to the design of clinical investigations it is essential to acquire in vitro data, and understand the performance and limitations of the release system. Thus, we here characterize the release behavior and release rates of both macromolecules and inorganic ions from or through hydrogel coatings, after detailed chemical, structural, and morphological characterizations of the coatings and the embedded nanoparticles by a range of analytical techniques.…”

Section: Introductionmentioning

confidence: 99%

Concurrent elution of calcium phosphate and macromolecules from alginate/chitosan hydrogel coatings

et al. 2008

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The concurrent release of calcium phosphate and biomacromolecules may improve wound healing responses at the interface with ceramic materials of orthopaedic and dental implants. Hydrogel coatings consisting of a mixture of alginate and chitosan were doped and applied onto solid carriers with the aim of investigating their use as local delivery vehicles. Coatings containing both the model macromolecule FITC-dextran 70 kDa (FD 70) and dispersed calcium phosphate carbonate (CPC) nanoparticles were coated onto a solid, nonporous model substrate to study the concurrent release of FD 70 and calcium and phosphate ions from within the hydrogel. Hydrogel coatings containing only FD 70 were cast onto porous calcium phosphate coatings, similar to hydroxyapatite, to study the release of FD 70 from, and calcium and phosphate ions through, the hydrogel coating. Transmission electron microscopy showed good dispersion of the CPC nanoparticles, and scanning electron microscopy and atomic force microscopy showed that increased CPC loading resulted in an increase in surface roughness but to extents well below those affecting cell responses. The release of FD 70 from CPC-loaded coatings was similar to release from the hydrogel alone, although higher CPC loadings resulted in small changes. The release of FD 70 was better described by double or triple phase zero order release kinetics; this complex time dependence indicates that in addition to outdiffusion, other, time-dependent factors apply, such as swelling of the gel, as expected from the known effects of calcium ions on alginate. Calcium and phosphate ions were also released, with similar release kinetics, through the hydrogel layer from the underlying CaP layer. In either case, release decreased to negligible levels after 3 days, suggesting that the systems of this study are suitable for short-term concurrent release of water-soluble biomacromolecules and calcium and phosphate ions.

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“…[10] Previous studies demonstrated that inorganic/organic hybrid materials [11][12][13][14] were likely to be of generic importance in the design of biocompatible microcapsules because they often exhibit complementary properties, and, in this regard, synthetic approaches based on mimicking natural processes such as biomineralization should be promising. [15][16][17] Biomineralization often involves a diffusioncontrolled deposition of inorganic minerals within porous organic polymeric matrices. Biomineralized polysaccharide capsules have potential applications for cell growth, [15,18] release of functional biomolecules, [17] gene delivery, [19] and the implications therein for tissue engineering.…”

Section: Full Papermentioning

confidence: 99%

Biomineralized Polysaccharide Beads for Dual‐Stimuli‐Responsive Drug Delivery

Shi

Liu

Sun

et al. 2008

Macromolecular Bioscience

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Biomineralized polysaccharide-coated alginate beads containing PNIPAAM were prepared. The resulting beads can be used as carriers for sustained pH/temperature-sensitive drug delivery. Characterizations using SEM, EDS, FTIR, and POM revealed that the beads were covered by the calcium-phosphate-mineralized alginate/chitosan membrane. The drug-release behavior was examined using indomethacin as a model drug, and the release profile of the developed materials was found to be responsive to pH and temperature. The release profile could be sustained under neutral conditions, indicating that the mineralized polysaccharide membrane could prevent the permeability of the encapsulated drug and reduce the drug release rate.

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Biomineral-inspired fabrication of semi-permeable calcium phosphate–polysaccharide microcapsules

Cited by 45 publications

References 10 publications

Biomineralized Polysaccharide Capsules for Encapsulation, Organization, and Delivery of Human Cell Types and Growth Factors

Biomineralized Polysaccharide Capsules for Encapsulation, Organization, and Delivery of Human Cell Types and Growth Factors

Concurrent elution of calcium phosphate and macromolecules from alginate/chitosan hydrogel coatings

Biomineralized Polysaccharide Beads for Dual‐Stimuli‐Responsive Drug Delivery

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