Joachim B. Kohn Professor Rutgers University Department of Chemistry Wright Laboratories Piscataway. NJ 08854 08854-0939 (732) 445-0488 FAX - 5312 joachim@rutchem.rutgers.edu

Biocompatibility of medical implant materials. artificial biopolymers

The work of this group is focused on tissue engineering and biomaterials science with a unique focus on the development of new degradable polymers. During the last years. we established the feasibility of preparing "pseudo"-poly(amino acids). amino acid derived. degradable polymers in which individual amino acids are linked by non-amide bonds. Among the pseudo-poly(amino acids). we identified a number of new polymers that exhibited good engineering and physicomechanical properties. as well as a high degree of biocompatibility. For example. tyrosine derived polycarbonates were shown to be promising materials for implantable drug delivery systems and orthopedic implants. copolymers of the natural amino acid L-lysine and poly(ethylene glycol) were successfully used as drug carriers. and polymeric conjugates of cis-hydroxyproline were prepared and found to exhibit powerful antifibrotic activity. We are also engaged in a detailed investigation of the biological properties of pseudo-poly(amino acids). including toxicological testing. cell-polymer interactions. and the effect of surface properties on the attachment and growth of various cell lines. The insights gained from these basic studies are used to create optimized polymeric scaffolds (sponge-like implants) for tissue reconstruction and tissue engineering. Thus. our long-term goals are to contribute to a better understanding of the interactions of pseudo-poly(amino acids) with living tissues and to use the knowledge gained to develop optimized polymeric implant materials for a wide range of medical applications.

Selected Publications

Weber N, Pesnell A, Bolikal D, Zeltinger J, Kohn J. (2007) Viscoelastic properties of fibrinogen adsorbed to the surface of biomaterials used in blood-contacting medical devices. Langmuir. 23(6):3298-304.

Sheihet L, Piotrowska K, Dubin RA, Kohn J, Devore D. (2007) Effect of tyrosine-derived triblock copolymer compositions on nanosphere self-assembly and drug delivery.
Biomacromolecules. 8(3):998-1003.

Liu E, Treiser MD, Johnson PA, Patel P, Rege A, Kohn J, Moghe PV. (2007) Quantitative biorelevant profiling of material microstructure within 3D porous scaffolds via multiphoton fluorescence microscopy. J Biomed Mater Res B Appl Biomater. Jan 19; [Epub ahead of print]

Meechaisue C, Dubin R, Supaphol P, Hoven VP, Kohn J. (2006) Electrospun mat of tyrosine-derived polycarbonate fibers for potential use as tissue scaffolding material.
J Biomater Sci Polym Ed. 17(9):1039-56.

Sousa A, Sengonul M, Latour R, Kohn J, Libera M. (2006) Selective protein adsorption on a phase-separated solvent-cast polymer blend. Langmuir. 22(14):6286-92.

Bae YH, Johnson PA, Florek CA, Kohn J, Moghe PV. (2006) Minute changes in composition of polymer substrates produce amplified differences in cell adhesion and motility via optimal ligand conditioning. Acta Biomater. 2(5):473-82.

Auguste DT. Armes SP. Brzezinska KR. Deming TJ. Kohn J. Prud'homme RK. (2006) pH triggered release of protective poly(ethylene glycol)-b-polycation copolymers from liposomes. Biomaterials. 27(12):2599-608.

Sheihet L. Dubin RA. Devore D. Kohn J. (2005) Hydrophobic drug delivery by self-assembling triblock copolymer-derived nanospheres. Biomacromolecules. 6(5):2726-31.

Ryan. P. L.. Foty. R. A.. Kohn. J. and Steinberg. M. (2001) Tissue spreading on implantable substrates is a competitive outcome of cell-cell vs. cell-substratum adhesivity. Proc. Natl. Acad. Sci.. 98(8):4323-4327.

Yang. B.-S.. Lal. J.. Kohn. J.. Huang. J. S.. Russel W. B. and Prud'homme. R. K. (2001) Interaction of surfactant lamellar phase and a strictly alternating comb-graft amphiphilic polymer based on PE. Langmuir 17:6692-6698.

Suarez. N.. Brocchini. S. and Kohn. J. (2001) Study of relaxation mechanisms in structurally related biomaterials by thermally stimulated depolarization currents. Polymer:42(21). 8671-8680.

Tangpasuthadol. V.. Pendharkar. S. M. and Kohn. J. (2000) Hydrolytic degradation of tyrosine-derived polycarbonates. a class of new biomaterials. Part I: Study of model compounds. Biomaterials 21:2371-2378.

Tziampazis. E.. Kohn. J. and Moghe. P. V. (2000) PEG-variant biomaterials as selectively adhesive protein templates: Model surfaces for controlled cell adhesion and migration. Biomaterials 21:511-520.