Nanofibrous spongy microspheres
AssigneeThe Regents of the University of Michigan
InventorsPeter X. Ma, Zhanpeng Zhang
Life of this patent
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Abstract
A nanofibrous spongy microsphere includes porous walls that define an exterior of the microsphere and that extend through an interior of the microsphere. The porous walls consist of interconnected nanofibers and spaces formed between the interconnected nanofibers. A plurality of micro-scale pores are formed throughout the interior of the microsphere. Each of the micro-scale pores i) is partially defined by the porous walls, ii) has an interpore opening that opens to an adjacent micro-scale pores, and iii) has a diameter ranging from about 1 μm to about 100 μm. A total diameter of the microsphere ranges from about 5 μm to about 1000 μm.
Claims15
A nanofibrous spongy microsphere, comprising:
- porous walls defining an exterior of the microsphere and extending through an interior of the microsphere, the porous walls consisting of:
- interconnected nanofibers;
- and
- spaces formed between the interconnected nanofibers;
- and
- a plurality of micro-scale pores formed throughout the interior of the microsphere, each of the micro-scale pores i) being partially defined by the porous walls, ii) having an interpore opening that opens to an adjacent micro-scale pore, and iii) having a diameter ranging from about 1 μm to about 100 μm;
- wherein a total diameter of the microsphere ranges from about 5 μm to about 1000 μm.
A method for making a nanofibrous spongy microsphere, comprising:
- selecting a polymer from the group consisting of a star-shaped poly(L-lactic acid) having X number of hydroxyl groups, wherein X≧4, and having an original hydroxyl density of 1/Y, where Y≧100;
- a star shaped block copolymer of poly(L-lactic acid) and i) an amino acid or ii) a peptide, the star shaped block copolymer having an amino acid content or a peptide content greater than or equal to 5%;
- and a graft copolymer selected from the group consisting of poly((hydroxyethyl)methacrylate)-graft-poly(L-lactic acid), poly((hydroxyethyl)propylmethacrylate)-graft-poly(L-lactic acid), and poly((hydroxyethyl)butyl acrylate)-graft-poly(L-lactic acid).;
- dissolving the polymer in a solvent to form a polymer solution;
- adding the polymer solution into glycerol while stirring the glyercol, thereby emulsifying the polymer solution into polymer solution droplets including multiple glycerol domains entrapped therein;
- inducing phase separation, thereby forming a polymer skeleton of the nanofibrous spongy microsphere;
- extracting the glycerol and the solvent from the polymer skeleton, thereby forming the nanofibrous spongy microsphere;
- and
- freeze-drying the nanofibrous spongy microsphere.
A method for making a nanofibrous spongy microsphere, comprising:
- selecting a star-shaped poly(L-lactic acid) having X number of hydroxyl groups, wherein X>16, and having a hydroxyl density ranging from 1/100 to 1/150;
- dissolving the star-shaped poly(L-lactic acid) in a solvent to form a polymer solution;
- adding glycerol into the polymer solution into while stirring, thereby inducing phase inversion and emulsifying the polymer solution into polymer solution droplets including multiple glycerol domains entrapped therein;
- inducing phase separation;
- extracting glycerol and the solvent, thereby forming the nanofibrous spongy microsphere;
- and
- freeze-drying the nanofibrous spongy microsphere.
Dependencies are inferred from the claim text.