Matt O’Connell

Student(s): Matt O'Connell

Project: Decoupling Bulk and Surface Properties of Functionalized Solvent Cast 3D Printed Constructs | View Poster (PDF)

Major(s): Materials Science and Engineering (Music minor)

Advisor(s): Chris Kiely, Lesley Chow

Abstract

Osteoarthritis (OA) is a painful degenerative joint disease which involves the degradation of cartilage tissue. Total joint replacements (TJRs) are the gold standard treatment for OA, but they can fail due to wear, loosening, or infection. TJRs also restrict patients to low impact activities and often only last 15 to 20 years. Instead, tissue engineering combines biodegradable polymer scaffolds and stem cells to regenerate healthy cartilage. Cells respond to physical and biochemical cues in their microenvironment, so scaffold properties are critical to determining stem cell fate towards either cartilage or bone. However, it is often difficult to decouple material properties to fine-tune cell-biomaterial interactions independently and synergistically.

The Chow Lab has developed a novel solvent-cast 3D printing platform with peptide-polymer conjugates to create peptide-functionalized scaffolds without significantly affecting bulk properties. Building on this work, we wanted to explore other functionalized polymer conjugates to independently tune surface and bulk mechanical properties. To achieve this, poly(caprolactone)-bromoisobutryl bromide (PCL-BiBB) conjugates were 3D printed with bulk high molecular weight PCL to surface-functionalize PCL scaffolds with a polymerization initiator. Oligo(ethylene glycol) methyl ether methacrylate (OEGMA) bottlebrushes can then be polymerized from the surface to create a soft surface while maintaining the bulk properties of the overall scaffold.

The goal of my work is to demonstrate that initial bulk properties are not affected by the inclusion of the PCL-initiator conjugate. To this end, PCL constructs with varying amounts of PCL-BiBB were evaluated for scaffold architecture and mechanical properties.