New Biodegradable Biocompatible Citric Acid Nano Polymers for Cell Culture Growth & Implantation Engineered by Northwestern University Scientists

FIG. 1 is a schematic representation of the synthesis of poly (1,8-octanediol-co-citric acid) (POC) engineered at Northwestern University as depicted in U.S. Patent Application 20090325859. 

A Northwestern University (Evanston, IL) research team of Professor Guillermo Ameer,  Jian Yang and Ryan Hoshi  has created nano citric acid polymers for use as biocompatible scaffolds on which to culture a variety of cells.   

Northwestern University’s U.S. Patent Application 20090325859  describes a series of  elastomeric citric acid nano-polymers and methods of making and using these polymers as a biologically active molecule delivery platform. The patent application also details a novel biphasic scaffold design for blood vessel tissue engineering and nanoporous citrate polymer. 

A crosslinked polymer network using biodegradable poly(1,8 octanediol-co-citric acid) (POC) polymer in conjunction with a nonreactive porogen, polyethylene glycol dimethyl ether (PEGDM) can be used for drug delivery.  Due to the unique properties of nanoscale systems, such as a relatively large surface area to volume ratio, the nanoporous POC can be used as a material to encapsulate and deliver bioactive molecules, protein based drug therapies such as enzymes, and growth factors and other therapeutic agents under very mild and physiologically relevant conditions. 

The polymers can adsorb biologically active molecules. The polymers contain pores that are between about 7 and 15 nanometers in diameter. In other embodiments, the polymer comprises poly(1,8 octanediol-co-ctric acid). In certain embodiments, the polymers are made by employing polyethylene glycol dimethyl ether (PEGDM), according to Ameer, Yang and Hoshi. 

Biodegradable citric acid polymers can be used as scaffolds for the growth of cells and culturing cells of the tissue on the scaffold. The polymer poly 1,8-octanediol-co-citric acid, or a derivative are particularly useful as scaffold material.  The cells selected for growth can be endothelial cells, ligament tissue, muscle cells, bone cells, cartilage cells. The tissue engineering method comprises growing the cells on the scaffold in a bioreactor. 

 FIG. 11 is a photomicrograph (.times.100) (A, B, C, and D) and SEM pictures (E and F) of human aortic endothelial cells on POC at different culture times: A) 1 hour; B) 24 hours: C) 4 days; D) 6 days; E) and F) 6 days

FIG. 13 is a photograph depicting porous and non-porous tube scaffold and sponge scaffold made by POC.

FIG. 16 shows SEM pictures of A) a cross section of a POC biphasic scaffold; B) the pore structure of the porous phase; C) human aortic smooth muscles cells on the porous phase of co-cultured biphasic scaffold; D) human aortic endothelial cells on the lumen of co-cultured biphasic scaffold.

 FIG. 20. SEM images of a) Control non leached 50% wt. PEGDM to cross-linked POC polymer and b) same sample that was leached in acetone and critically point dried.

Other organs for which tissue implantation patches may be generated include, but are not limited to skin tissue for skin grafts, myocardial tissue, bone tissue for bone regeneration, testicular tissue, endothelial cells, blood vessels, and any other cells from which a tissue patch may be generated.  It should be understood that cells from any organ may be seeded onto the biocompatible polymers to produce useful tissue for implantation and/or study.