Tri-block copolymers and nano-fibrous gelling microspheres including the same

A method, comprising:

• synthesizing an asymmetrical hydrophilic polymer having two different functional end groups, thereby forming a middle block of a tri-block copolymer;
• polymerizing a hydrophobic monomer using a first of the two different functional end groups, thereby forming a first end block of the tri-block copolymer attached to the middle block;
• and
• polymerizing a temperature-responsive monomer using a second of the two different functional end groups, thereby forming a second end block of the tri-block copolymer attached to the middle block;
• wherein:
• the first end block consists of a hydrophobic, nano-fiber forming polymer;
• the hydrophobic, nano-fiber forming polymer is selected from the group consisting of poly(L-lactic acid), poly(lactide-co-glycolide), polyglycolide, polyanhydrides, poly(ortho ethers), polycaprolactone, poly(hydroxy butyrate), poly(phosphoesters), poly(glycerol sebacate), poly(propylene fumarate), polyphosphazenes, polycarbonates, polyurethanes, non-water-soluble collagen, non-water-soluble gelatin, non-water-soluble elastin, and copolymers thereof;
• the first end block is present in the tri-block copolymer at a weight percentage ranging from about 68% to about 84%;
• the middle block consists of a hydrophilic polymer;
• the middle block is present in the tri-block copolymer at a weight percentage ranging from about 5% to about 9%;
• the second end block consists of a temperature-responsive polymer;
• and
• the second end block is present in the tri-block copolymer at a weight percentage ranging from about 11% to about 23%.

A method, comprising:

• synthesizing an asymmetrical hydrophilic polymer having two different functional end groups, thereby forming a middle block of a tri-block copolymer, the middle block consisting of the asymmetrical hydrophilic polymer;
• conjugating a first end block to the middle block through a first of the two different functional end groups, the first end block consisting of a hydrophobic, nano-fiber forming polymer;
• and
• conjugating a second end block to the middle block through a second of the two different functional end groups, the second end block consisting of a temperature-responsive polymer,
• wherein:
• the hydrophobic, nano-fiber forming polymer is selected from the group consisting of poly(L-lactic acid), poly(lactide-co-glycolide), polyglycolide, polyanhydrides, poly(ortho ethers), polycaprolactone, poly(hydroxy butyrate), poly(phosphoesters), poly(glycerol sebacate), poly(propylene fumarate), polyphosphazenes, polycarbonates, polyurethanes, non-water-soluble collagen, non-water-soluble gelatin, non-water-soluble elastin, and copolymers thereof;
• the first end block is present in the tri-block copolymer at a weight percentage ranging from about 68% to about 84%;
• the middle block is present in the tri-block copolymer at a weight percentage ranging from about 5% to about 9%;
• and
• the second end block is present in the tri-block copolymer at a weight percentage ranging from about 11% to about 23%.