Evaluation of Blood Vessel Mimic Scaffold Biocompatibility

The Tissue Engineering Research Lab at California Polytechnic State University, San Luis Obispo focuses on creating tissue-engineered blood vessel mimics (BVMs) for use in preclinical testing of vascular devices. These BVMs are composed of electrospun scaffolds made of an assortment of polymers that are seeded with different cell types. This integration of polymers with cells leads to the need for biocompatibility testing of the polymer scaffolds. Many of the lab’s newest scaffolds have not been fully characterized for biologic interactions. Therefore, the first aim of this thesis developed methods for in vitro cytotoxicity testing of polymers used in the fabrication of BVMs. This included cytotoxicity testing using direct contact and elution-based methods, along with fluorescent staining to visualize the scaffold effects on cells. The second aim of this thesis implemented the newly developed cytotoxicity protocols to evaluate the biocompatibility of existing polymers, ePTFE and PLGA, used in the tissue engineering lab. The results demonstrated that ePTFE and PLGA were noncytotoxic to cells. The third aim of this thesis evaluated the biocompatibility of novel polymers used to fabricate BVMs: PLGA with salt, PLLA, and PCL. Elution-based methods concluded that PLGA with salt, PLLA, and PCL were noncytotoxic to cells; however, the direct contact method illustrated PLGA with salt and PCL were mildly cytotoxic at 24 and 48 hours. Potential causes of this variability include the addition of salt to PLGA, dissolving PCL in dichloromethane, inadequate sample sizing, and the inherent differences between the test methods. Overall, this thesis developed and implemented methods to evaluate the biocompatibility of polymer scaffolds used in the BVM model, and found that ePTFE, PLGA, and PLLA scaffold materials were biocompatible and could be implemented in future BVM setups without concerns. Meanwhile, PLGA with salt and PCL’s toxicity was mild enough to urge future cytotoxicity testing on PLGA with salt and PCL before further use in the lab