Method for manufacturing bone-regeneration material comprising biodegradable fibers by using electrospinning method
Inventors
Kasuga, Toshihiro • Nishikawa, Yasutoshi
Assignees
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Publication Number
US-10646616-B2
Publication Date
2020-05-12
Expiration Date
Abstract
A bone-regeneration material that contains calcium phosphate particles in biodegradable fibers of PLGA manufactured by electrospinning. A PLGA resin is heated in a kneader until the resin viscosity becomes 102 to 107 Pa·s. A powder of calcium phosphate fine particles is added while the blade is rotated. The mixture is kneaded by continuous rotation of the blade in the heated state to disperse the calcium phosphate fine particles to obtain a composite having calcium phosphate fine particles dispersed in the PLGA resin. The composite is dissolved by a solvent, and the PLGA resin is completely dissolved by agitation for a prescribed duration to prepare a spinning solution in which the calcium phosphate fine particles are dispersed. Electrospinning is performed on the spinning solution to manufacture biodegradable fibers having therein the calcium phosphate fine particles substantially uniformly dispersed.
Core Innovation
The invention relates to a method for manufacturing a bone-regeneration material comprising biodegradable fibers using an electrospinning process. A PLGA resin selected from PLLA/PGA or PDLA/PGA is softened to a working viscosity range by heating while rotating a blade of a kneader, and calcium phosphate fine particles are added as powder into the softened PLGA while continuing rotation.
Thermal and mechanical energy is applied by kneading under heating to produce a composite of the PLGA resin and calcium phosphate fine particles dispersed in the PLGA resin. The composite is cooled and solidified, then dissolved with a solvent while stirring to prepare a spinning solution in which the PLGA resin is completely dissolved by the solvent and the calcium phosphate fine particles are substantially uniformly dispersed.
The spinning solution is charged into a syringe of an electrospinning apparatus, and voltage is applied to produce biodegradable fibers in which the calcium phosphate fine particles are substantially uniformly dispersed. The resulting fibers have a cottonwool-like nonwoven form with porous morphology including ultramicropores on the fiber surface for early β-TCP release.
Claims Coverage
The document provides one independent claim describing a complete electrospinning-based method, with dependent claims that refine the core by specifying particular materials, morphology, and quantitative constraints. The inventive coverage centers on kneader-based softening and thermal/mechanical kneading to achieve uniform dispersion, followed by solvent dissolution to produce a spinning solution with substantially uniform particle dispersion before electrospinning to form biodegradable fibers.
Kneader softening of PLGA to a specified working viscosity
Heating a PLGA resin in a kneader while rotating a blade to soften the PLGA resin to a viscosity of 10^3.2 to 10^3.6 Pa·s.
Kneader mixing to thermally and mechanically disperse calcium phosphate fine particles
Mixing powder of calcium phosphate fine particles with the softened PLGA resin by providing the powder into the kneader while rotating the blade, and rotating the blade with continuous force under the heating to knead the mixture so that thermal and mechanical energy is applied to produce a composite of the PLGA resin and the calcium phosphate fine particles dispersed in the PLGA resin.
Solvent dissolution with stirring to form a spinning solution with uniform particle dispersion
Dissolving the cooled and solidified composite with a solvent, and stirring the dissolved composite for a predetermined time to prepare a spinning solution in which the PLGA resin is completely dissolved and the calcium phosphate fine particles are substantially uniformly dispersed in the solvent.
Electrospinning to produce biodegradable fibers with uniform particle dispersion
Charging the spinning solution into a syringe of an electrospinning apparatus and applying voltage to produce biodegradable fiber in which the calcium phosphate fine particles are substantially uniformly dispersed.
Cotton wool-like nonwoven morphology and bulk density
Producing a bone-regeneration material formed like cotton wool and having a bulk density of about 0.01 to 0.1 g/cm^3.
β-TCP calcium phosphate fine particles
Using calcium phosphate fine particles that are β-TCP fine particles.
Overall, the claims cover producing a bone-regeneration material using electrospinning where PLGA is softened to a specified working viscosity in a kneader, calcium phosphate fine particles are kneaded into the PLGA with thermal and mechanical energy for dispersion, the composite is dissolved to form a spinning solution with substantially uniform dispersion, and the solution is electrospun to yield biodegradable fibers with substantially uniform calcium phosphate dispersion. Dependent refinements specify cotton wool-like morphology, bulk density, and use of β-TCP fine particles.
Stated Advantages
Provides early β-TCP release due to porous morphology including ultramicropores on the fiber surface.
Addresses difficulty of dispersing high particle load in electrospinnable solutions.
Reduces particle aggregation problems by achieving substantially uniform dispersion of calcium phosphate fine particles.
Demonstrates effectiveness of kneading within the working viscosity range compared with stirring-only or melt-kneading approaches.
Supports intended dispersion behavior without Ca2+ coordination to PLGA carboxyl groups, as shown by experimental results.
Documented Applications
Manufacturing a bone-regeneration material comprising biodegradable fibers using an electrospinning process for early β-TCP release from porous nonwoven fibers.
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