Method for manufacturing bone-regeneration material comprising biodegradable fibers by using electrospinning method

Inventors

Kasuga, Toshihiro • Nishikawa, Yasutoshi

Assignees

Nagoya Institute of Technology NUC • Orthorebirth Co Ltd

Abstract

A bone-regeneration material that contains calcium phosphate particles in a biodegradable fiber containing PLGA by using electrospinning. A PLGA resin is heated in a kneader to soften until the viscosity of the resin becomes 102 to 107 Pa·s. A powder of calcium phosphate fine particles is added and mixed with the softened PLGA resin, while the blade of the kneader rotates. The mixture is kneaded by applying thermal and mechanical energy to the mixture through the continuous rotation of the blade of the kneader in the heated state, and aggregations of the calcium phosphate fine particles are disintegrated to prepare a composite in which the calcium phosphate fine particles are dispersed in the PLGA resin. The composite is dissolved in a solvent to prepare a spinning solution. 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 provides a bone-regeneration material including a biodegradable fiber produced by an electrospinning process. The biodegradable fiber comprises 30 to 50 wt % of PLLGA resin and 70 to 50 wt % of β-TCP fine particles substantially uniformly dispersed in the PLLGA resin. The β-TCP fine particles are not chemically bonded to the PLLGA resin, while the surroundings of the β-TCP fine particles are covered by the PLLGA resin so that the β-TCP fine particles are not separated from the biodegradable fiber during formation of the fiber.

The biodegradable fiber is produced by electrospinning a spinning solution produced by dissolving a composite of PLLGA resin and β-TCP fine particles using a solvent and stirring the solution such that the β-TCP fine particles are dispersed substantially uniformly in the biodegradable fiber. The composite is produced by providing softened PLLGA resin of a working viscosity range s and β-TCP fine particles to a kneader in a weight ratio of 30-50:70-50, and kneading by applying thermal and mechanical energy so that aggregates of the β-TCP fine particles are physically crushed and the β-TCP fine particles are dispersed in the PLLGA resin.

The disclosed approach includes a relationship between β-TCP dispersion and stability of electrospinning, where kneading at an appropriate viscosity is described as critical for stable electrospinning and maintaining a cottonwool-like nonwoven form with controlled fiber diameter and bulk density. The document further states that solid-state NMR indicates that β-TCP calcium ions are not chemically bonded to PLGA carboxyl groups, and that PLGA/PLLGA covers the particles to prevent separation. The material is also described as showing faster shape decay in an aqueous base and increased osteogenic potential, with explanation connected to ultramicropores and increased ceramic-fluid interface.

Claims Coverage

The coverage is focused on one independent claim directed to a bone-regeneration material, with additional dependent claims refining quantitative features of composition, particle size, fiber diameter, resin working viscosity, and resulting cotton-wool form bulk density. The independent claim specifies a structural/material composition and the linked preparation route that yields uniform dispersion without chemical bonding and prevents separation during fiber formation.

Overall, the claim set centers on an electrospun biodegradable bone-regeneration fiber having substantially uniform β-TCP dispersion in PLLGA at defined weight ranges. The manufacturing chain requires forming a composite by kneader kneading that physically crushes β-TCP aggregates, dissolving that composite to form a uniformly dispersed spinning solution, and producing fibers in which β-TCP is not chemically bonded to PLLGA yet is covered by PLLGA to avoid particle separation during fiber formation.

Stated Advantages

Documented Applications