Fall 2007 Newsletter

Graduate Student Receives F31 Fellowship For Hybrid Scaffolds Research

Donald O. Freytes, M.S.BME received an F31 Fellowship for hybrid research involving Extracellular Matrix (ECM) and Electrospun poly(ester-urethane) urea (PEUU) scaffolds.

Background

Extracellular Matrix (ECM) Scaffolds, which promote site specific tissue remodeling and are completely and rapidly degraded during the remodeling process, have been successfully used in more than 300,000 human patients in both soft and hard tissue replacement applications. However, ECM derived scaffolds are limited by the inherent mechanical and material properties of the tissue from which they are derived. Electrospun poly(ester-urethane) urea (PEUU) scaffolds represent an alternative elastomeric material that recreates the fibrous ultrastructure of the ECM. However, PEUU scaffolds lack the bioactivity inherent in the ECM scaffolds.

The Hypothesis

It is the central hypothesis of the research that a hybrid scaffold composed of solubilized ECM and PEUU into electrospun material will result in a bioactive elastomeric scaffold with predictable physical properties. Therefore the goal of the fellowship is to create a hybrid scaffold composed of ECM and PEUU by achieving the following: (1) solubilize a porcine urinary bladder ECM via enzymatic degradation; (2) electrospin and characterize a combination of the urinary bladder ECM with poly(ester-urethane) urea; and (3) characterize the host tissue response to both the digested ECM and the polymer-ECM scaffold after implantation in an in vivo model.

A Research Project Begins

Extracellular matrix derived scaffolds are usually characterized by a two-dimensional sheet with limited ability to conform to irregular three-dimensional shapes and sizes. They are also limited by the mechanical and material properties of the tissue from which they are derived. The idea for the fellowship came from discussions with Donald's advisor, Dr. Stephen Badylak and laboratory workers on ways to create a soluble or gel form of ECM. It also came from discussions with Dr. William Wagner and his students regarding ways to control the material properties of these scaffolds.

As part of Donald's training in Dr. Badylak's laboratory, he found the optimum way of solubilizing the ECM scaffolds while avoiding purification steps. The soluble form was ideal for use with techniques such as electrospinning which are routinely performed in Dr. Wagner's laboratory. This led to a collaborative effort between both labs to create and characterize a hybrid scaffold and also led to the ideas for the proposal.

Educational Background

Donald met Dr. Badylak while working as a biomedical engineering research assistant at Purdue where he received his BA in mechanical engineering. A few of his projects developed into a master thesis and he stayed at Purdue to obtain a Masters in Biomedical Engineering. It wasn't long before Donald decided to return to school and accepted an offer from Dr. Badylak to come to Pittsburgh.

Donald believes that Pitt's Swanson School of Engineering provided him with the opportunity to be exposed to many different projects in a wide range of disciplines. "Pitt has provided a great environment for me to learn and see things from multiple angles and to apply different types of thinking. This above all has prepared me for this project which draws from many disciplines," Donald said.

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