CROSS-LINKED ALGINATE-POLYALKYLENE GLYCOL POLYMER COATINGS FOR ENCAPSULATION AND METHODS OF MAKING THE SAME

• US 20100143464A1
• Filed: 12/08/2009
• Published: 06/10/2010
• Est. Priority Date: 12/08/2008
• Status: Active Grant

• Current Assignee: University of Miami
• Original Assignee: University of Miami
• Inventors: Stabler, Cherie, Finn, Kristina, Rengifo, Hernan R., Gattas-Asfura, Kerim, Ricordi, Camillo
• Granted Patent: US 8,728,520 B2
• Time in Patent Office: Days
• US Class Current: 424/463
• CPC Class Codes: A61K 9/5031 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, poly(lactide-co-glycolide)

Abstract

A biocompatible capsule comprising a biological material encapsulated by a covalently stabilized coating and a method of making the same are disclosed. The biological material can be a material selected from the group consisting of cells, such as islets of Langerhans, pharmaceuticals, and biological agents. The coating can be formed by reacting an alginate-[polyalkylene glycol (PAG)-X¹]_n, and a multi-functional PAG-X², to form covalent bonds, wherein n is an integer greater than 0, a first one of X¹ and X² is N₃, and a second one of X¹ and X² is selected from the group consisting of:

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂,

• • R²=N(CH₃)₂, OCH₃, OH, CH₃, H, F, Cl, Br or NO₂, and
  • R³=OCH₃, CH₃, H, F, Cl or NO₂.

Claims

1. A biocompatible capsule, comprising:

a biological material; and

a covalently stabilized coating encapsulating said biological material, said covalently stabilized coating formed by reacting

(i) alginate-[polyalkylene glycol (PAG)-X¹]_n, and

(ii) multi-functional PAG-X², to form covalent bonds, wherein n is an integer greater than 0, a first one of X¹ and X² is N₃, and a second one of X¹ and X² is selected from the group consisting of;

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂,

R²=N(CH₃)₂, OCH₃, OH, CH₃, H, F, Cl, Br or NO₂, and

R³=OCH₃, CH₃, H, F, Cl or NO₂.

2. The biocompatible capsule according to claim 1, wherein the biological material comprises a material selected from the group consisting of cells, pharmaceuticals, biological agents, biopolymers, RNA, DNA and fragments of DNA or RNA.

3. The biocompatible capsule according to claim 1, wherein said biological material comprises islets of Langerhans.

4. The biocompatible capsule according to claim 1, wherein said covalently stabilized coating comprises a plurality of monolayers.

5. The biocompatible capsule according to claim 3, wherein said plurality of monolayers alternate between monolayers of Alginate-[PAG-X¹]_n reaction products and monolayers of multi-functional PAG-X² reaction products.

6. The biocompatible capsule according to claim 1, wherein said multi-functional PAG-X² comprises a multi-arm PAG-X² having at least three PAG-X² arms.

7. The biocompatible capsule according to claim 1, wherein the second one of X¹ and X² is selected from the group consisting of:

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂ or salts thereof and

R²=N(CH₃)₂, OCH₃, OH, CH₃ or H.

8. The biocompatible capsule according to claim 1, wherein said alginate-[polyethylene glycol (PAG)-X¹]_n molecule or said multi-functional PAG-X² molecule further comprise an additional terminal ligand, X³, wherein X³ is selected from the group consisting of proteins, imaging labels, nanoparticles, biopolymers, RNA, DNA, and fragments of RNA or DNA.

9. The biocompatible capsule according to claim 1, wherein said covalently stabilized coating is covalently bonded to said biological material.

10. The biocompatible capsule according to claim 9, wherein said coating is covalently bonded to said biological material by reacting a first terminal ligand of compound (A) with amino groups on a surface of said biological material, wherein compound (A) comprises:

said first terminal ligand comprising

and

a second terminal ligand comprising a ligand selected from the group consisting of;

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂,

R²=N(CH₃)₂, OCH₃, OH, CH₃, H, F, Cl, Br or NO₂, and

R³=OCH₃, CH₃, H, F, Cl or NO₂.

11. A method of forming a biocompatible capsule, comprising:

forming a covalently stabilized coating encapsulating a biological material, said forming step comprising;

providing an aqueous solution having said biological material suspended therein, said aqueous solution further comprising a reactant dissolved therein, said reactant selected from the group consisting of;

(i) alginate-[polyalkylene glycol (PAG)-X¹]_n,

(ii) multi-functional PAG-X², and

(iii) both; and

reacting alginate-[PAG-X¹]_n with multi-functional PAG-X² in said aqueous solution, wherein n is an integer greater than 0, a first one of X¹ and X² is N₃, and a second one of X¹ and X² is selected from the group consisting of;

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂,

R²=N(CH₃)₂, OCH₃, OH, CH₃, H, F, Cl, Br or NO₂, and

R³=OCH₃, CH₃, H, F, Cl, and NO₂.

12. The method according to claim 11, wherein said reacting step proceeds without a free-radical initiator.

13. The method according to claim 11, wherein said reacting step produces a covalent bond resulting from reacting an X¹ ligand of said alginate-[PAG-X¹]_n with an X² ligand of said multi-functional PAG-X².

14. The method according to claim 11, wherein said aqueous solution comprises either alginate-[PAG-X¹]_n or multi-functional PAG-X², and

said covalently stabilized coating comprising alginate-[PAG-X¹]_n, multi-functional PAG-X², or both, and

wherein said reacting step produces a surface monolayer, said reacting step comprising:

reacting alginate-[PAG-X¹]_n dissolved in said aqueous solution with multi-functional PAG-X² in said covalently stabilized coating, thereby adding an alginate-[PAG-X¹]_n surface monolayer to said covalently stabilized coating, or

reacting multi-functional PAG-X² dissolved in said aqueous solution with alginate-[PAG-X¹]_n in said covalently stabilized coating, thereby adding a multi-functional PAG-X² surface monolayer to said covalently stabilized coating.

15. The method according to claim 14, wherein said forming step further comprises:

rinsing a product of said reacting step to remove unreacted reactant from said biological material to isolate an intermediate biocompatible capsule; and

adding an additional surface monolayer to said intermediate biocompatible capsule, wherein

if said surface monolayer is an alginate-[PAG-X¹]_n surface monolayer, said adding step comprises reacting multi-functional PAG-X² dissolved in an aqueous solution with alginate-[PAG-X¹]_n in said surface monolayer; and

if said surface monolayer is a multi-functional PAG-X² surface monolayer, said adding step comprises reacting alginate-[PAG-X¹]_n dissolved in an aqueous solution with multi-functional PAG-X² in said surface monolayer.

16. The method according to claim 11, wherein said forming step further comprises:

covalently bonding a base layer of said covalently stabilized coating to a surface of said biological material, said forming step comprising;

providing an aqueous solution having said biological material suspended therein, said aqueous solution further comprising a reactant dissolved therein, said reactant comprising compound (A), and

reacting compound (A) with amino groups on said surface of said biological material, wherein compound (A) comprises;

a first terminal ligand comprising

and

a second terminal ligand comprising a ligand selected from the group consisting of;

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂ or

and salts thereof,

R²=N(CH₃)₂, OCH₃, OH, CH₃, H, F, Cl, Br or NO₂, and

R³=OCH₃, CH₃, H, F, Cl or NO₂.

17. The method according to claim 11, wherein the biological material comprises a material selected from the group consisting of cells, pharmaceuticals, biological agents, biopolymers, RNA, DNA and fragments of DNA or RNA.

18. The method according to claim 11, wherein said biological material comprises islets of Langerhans.

19. The method according to claim 11, wherein said multi-functional PAG-X² comprises a multi-arm PAG-X² having at least three PAG-X² arms.

20. The method according to claim 11, wherein the second one of X¹ and X² is selected from the group consisting of:

wherein R¹=CH₃, CH₂CH₃, CH(CH₃)₂, and

R²=N(CH₃)₂, OCH₃, OH, CH₃, H.