Effect of polymer foam morphology and density on kinetics of in vitro controlled release of isoniazid from compressed foam matrices

Hsu, Yung-Yueh; Gresser, Joseph D.; Trantolo, Debra J.; Lyons, Charles M.; Gangadharam, P. R. J.; Wise, Donald L.

doi:10.1002/(sici)1097-4636(199704)35:1<107::aid-jbm11>3.3.co;2-7

Cited by 40 publications

(42 citation statements)

References 8 publications

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“…Pore size ranges were determined using digital image processing of SEM images. Scaffold porosity was determined using an ethanol displacement method similar to that reported by Zhang and Ma (25), Hsu et al (11), and reported by our group previously (10). Scaffold samples were individually immersed in a cylinder containing a known volume of ethanol (V 1 ).…”

Section: Scaffold Characterizationmentioning

confidence: 95%

Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea

2006

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Our objective in this work was to develop a flexible, biodegradable scaffold for cell transplantation that would incorporate a synthetic component for strength and flexibility and type I collagen for enzymatic lability and cytocompatibility. A biodegradable poly(ester urethane)urea was synthesized from poly(caprolactone), 1,4-diisocyanatobutane, and putrescine. Using a thermally induced phase separation process, porous scaffolds were created from a mixture containing this polyurethane and 0%, 10%, 20%, or 30% type I collagen. The resulting scaffolds were found to have open, interconnected pores (from 7 to >100 um) and porosities from 58% to 86% depending on the polyurethane/collagen ratio. The scaffolds were also flexible with breaking strains of 82-443% and tensile strengths of 0.97-4.11 MPa depending on preparation conditions. Scaffold degradation was significantly increased when collagenase was introduced into an incubating buffer in a manner that was dependent on the mass fraction of collagen present in the scaffold. Mass losses could be varied from 15% to 59% over 8 weeks. When culturing umbilical artery smooth muscle cells on these scaffolds higher cell numbers were observed over a 4-week culture period in scaffolds containing collagen. In summary, a strong and flexible scaffold system has been developed that can degrade by both hydrolysis and collagenase degradation pathways, as well as support cell growth. This scaffold possesses properties that would make it attractive for future use in soft tissue applications where such mechanical and biological features would be advantageous.

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Section: Scaffold Characterizationmentioning

confidence: 95%

Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea

2006

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“…Pore sizes were calculated from SEM images by Image J software (National Institutes of Health). Scaffold porosity was determined by a liquid displacement method [26,27]. Ethanol was used as the displacement liquid.…”

Section: Scaffold Characterizationmentioning

confidence: 99%

Biodegradable elastomeric scaffolds with basic fibroblast growth factor release

Guan

Stankus

Wagner

2007

Journal of Controlled Release

149

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Scaffolds that better approximate the mechanical properties of cardiovascular and other soft tissues might provide a more appropriate mechanical environment for tissue development or healing in vivo. An ability to induce local angiogenesis by controlled release of an angiogenic factor, such as basic fibroblast growth factor (bFGF), from a biodegradable scaffold with mechanical properties more closely approximating soft tissue could find application in a variety of settings. Toward this end biodegradable poly(ester urethane)urea (PEUU) scaffolds loaded with bFGF were fabricated by thermally induced phase separation. Scaffold morphology, mechanical properties, release kinetics, hydrolytic degradation and bioactivity of the released bFGF were assessed. The scaffolds had interconnected pores with porosities of 90% or greater and pore sizes ranging from 34-173 μm. Scaffolds had tensile strengths of 0.25-2.8 MPa and elongations at break of 81-443%. Incorporation of heparin into the scaffold increased the initial burst release of bFGF, while the initial bFGF loading content did not change release kinetics significantly. The released bFGF remained bioactive over 21 days as assessed by smooth muscle mitogenicity. Scaffolds loaded with bFGF showed slightly higher degradation rates than unloaded control scaffolds. Smooth muscle cells seeded into the scaffolds with bFGF showed higher cell densities than for control scaffolds after 7 days of culture. The bFGFreleasing PEUU scaffolds thus exhibited a combination of mechanical properties and bioactivity that might be attractive for use in cardiovascular and other soft tissue applications.

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“…These conventional scaffold fabrication techniques include solvent casting-particulate leaching [66,79], gas foaming [17], fiber meshes/fiber bonding [80,81], melt molding [82,83], and thermal phase separation/freeze drying [36,37,[84][85][86][87][88][89].…”

Section: Scaffold Fabrication Techniquesmentioning

confidence: 99%

Osteoblast response to zirconia‐hybridized pyrophosphate‐stabilized amorphous calcium phosphate

Whited

Škrtić

Love

et al. 2005

J Biomedical Materials Res

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(Abstract)Biodegradable polyesters, such as poly(DL-lactic-co-glycolic acid) (PLGA), have been used to fabricate porous bone scaffolds to support bone tissue development. These scaffolds allow for cell seeding, attachment, growth and extracellular matrix production in vitro and are replaced by new bone tissue when implanted into bone sites in vivo.Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) ceramics have been incorporated into PLGA bone scaffolds and have been shown to increase their osteoconductivity (support cell attachment). Although HAP, β-TCP, and biodegradable polyesters are osteoconductive, there is no evidence that these scaffold materials are osteoinductive (support cell differentiation). Calcium and phosphate ions, in contrast, have been postulated to be osteogenic factors that enhance osteoblast differentiation and mineralization. Recently, a zirconia-hybridized pyrophosphate stabilized amorphous calcium phosphate (Zr-ACP) has been synthesized which permits controlled release of calcium and phosphate ions and thus is hypothesized to be osteoinductive. Incorporation of Zr-ACP into a highly porous poly(DL lactic-co-glycolic acid) (PLGA) scaffold could potentially increase the osteoinductivity of the scaffold and therefore promote osteogenesis when implanted in vivo.To determine the osteoinductivity of Zr-ACP, a MC3T3-E1 mouse calvarialderived osteoprogenitor cell line was used to measure cell response to Zr-ACP. To accomplish this objective, Zr-ACP was added to cell culture at different stages in cell maturation (days 0, 4 and 11). DNA synthesis, alkaline phosphatase (ALP) activity, iii osteopontin synthesis and collagen synthesis were determined. Results indicate that culture in the presence of Zr-ACP significantly increased cell proliferation, ALP activity and osteopontin synthesis but not collagen synthesis. To determine the feasibility of incorporating Zr-ACP into a PLGA scaffold, PLGA/Zr-ACP composite foams (5% or 10% (w/v) polymer:solvent with 25 wt% or 50 wt% Zr-ACP) were fabricated using a thermal phase inversion technique. Scanning electron microscopy revealed a highly porous structure with pores ranging in size from a few microns to about 100 µm. The amorphous structure of the Zr-ACP was maintained during composite fabrication as confirmed by X-ray diffraction measurements. Composite scaffolds also showed significantly greater compressive yield strengths and moduli as compared to pure polymer scaffolds.The results of this study indicate that Zr-ACP enhances the osteoblastic phenotype of MC3T3-E1 cells in vitro and can be incorporated into a porous PLGA scaffold. Porous PLGA/Zr-ACP composites are promising for use as bone scaffolds to heal bone defects.iv

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Effect of polymer foam morphology and density on kinetics of in vitro controlled release of isoniazid from compressed foam matrices

Cited by 40 publications

References 8 publications

Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea

Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea

Biodegradable elastomeric scaffolds with basic fibroblast growth factor release

Osteoblast response to zirconia‐hybridized pyrophosphate‐stabilized amorphous calcium phosphate

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