Diana Hammerstone

Three-dimensional (3D) printing is popular for fabricating biodegradable polymeric biomaterials due to its high-resolution control and ability to produce multi-material scaffolds.1 In our previous study, print parameters were optimized empirically for poly(caprolactone) (PCL) by systematically changing print speed and pressure.2 The goal of this work was to expand solvent-cast 3D printing to another biodegradable polymer, poly(lactide-co-glycolide) (PLGA), by matching rheological properties of PLGA inks to the optimized PCL ink. We hypothesized inks with the same rheological properties can be printed using the same print parameters. This would enable us to create scaffolds with different biodegradable polymers to tune mechanical properties while maintaining the same architecture. Inks were prepared by separately dissolving PCL and PLGA in hexafluoroisopropanol (HFIP). Rheometry was performed on PLGA inks at 40, 45, and 50% (w/v) and a PCL ink at 37% (w/v). Scaffolds were solvent-cast 3D printed for SEM and microindentation. The 45% (w/v) PLGA ink exhibited similar rheological behavior to the 37% (w/v) PCL ink. Scaffolds were printed with 45% (w/v) PLGA using the same print parameters as the 37% (w/v) PCL inks and showed similar and consistent fiber morphologies. These data verified our hypothesis. Microindentation showed that the compressive moduli of 45% (w/v) PLGA and 37% (w/v) PCL scaffolds printed with the same architecture were 2.8 and 2.2 MPa, respectively, illustrating how scaffold mechanical properties can be tuned independently of scaffold morphology. This work expands the library of printable polymers for solvent-cast 3D printing and enables tuning of mechanical properties for a desired application.

References: [1] Guvendiren M, et al. ACS Biomater Sci Eng. 2016, [2] Camacho P, et al. Biomater Sci. 2019 

Diana Hammerstone is a senior materials science and engineering major at Lehigh University. She has been doing research in the Chow Lab, under Professor Lesley Chow, since June 2018 and has been a Clare Boothe Luce Scholar since January 2019. Diana’s research focuses on developing methods to 3D print different polymers using solvent-cast 3D printing and creating solvent-cast 3D printed scaffolds with tunable mechanical properties. She was previously selected to present this research at the Biomedical Engineering Society annual meeting in Philadelphia, Pennsylvania in October 2019 as well as the Lehigh University Materials Science and Engineering Undergraduate Research Symposium in February 2020. Outside of academics, Diana is a member of Lehigh’s cross country and track & field teams. She is a member of the leadership council of both teams and is also a member of the athletic department’s Flight 45 leadership academy.