Date of Award
MS in Biomedical Engineering
Biomedical and General Engineering
Kristen O'Halloran Cardinal
Developing an in vitro Blood Brain Barrier model that will replicate the physiological, anatomical, and functional characteristics of the native BBB has gained significant attention. Such a model would enable prediction of the penetration of CNS targeting drug candidates across the BBB, allow pre-screening and optimization strategies to be developed for new drugs and gene delivery formulations, and permit research groups to further understand how a dysfunctional BBB is involved in the pathogenesis of several neurological diseases.
The Tissue Engineering laboratory at the California Polytechnic State University, San Luis Obispo is currently in the process of developing a dynamic in vitro blood brain barrier model that will implement an in-house fabricated electrospun PLGA scaffold pressure sodded with C6 glial cells and BAECs (Bovie Aortic Endothelial Cells). The aims of this thesis were to upgrade and refine the existing electrospinner system, develop a BBB scaffold electrospinning protocol, and characterize and evaluate the consistency of the scaffolds fabricated using the protocol.
Ultimately, the electrospinner system was optimized in the following areas: the high voltage power supply, electrical layout and safety, as well as the syringe pump and stand. The modifications to the system will now permit new electrospinning strategies and ensure operator safety. The protocol developed for electrospinning scaffolds for the DIV-BBB system utilized 15 wt% PLGA in CHCl3 with a 4.5 ml/hr flow rate, an applied voltage of 18,000V with a negative polarity, and a gap distance of 25.4 cm.
Characterization and consistency studies revealed that scaffolds electrospun were statistically inconsistent with one another with regards to fiber diameter (P < 0.0001), porosity (P < 0.0001), and wall thickness (P < 0.0001). However, the scaffolds were mechanically consistent (P-value of 0.6134) according to the calculated Young's modulii. The average fiber diameter for the electrospun scaffolds was 2.556 µm, and had an average porosity of 70.06 µm2. Additionally, the wall thickness between the electrospun scaffolds ranged between 0.31 and 0.54 mm. The average Young's modulus of the electrospun scaffolds was determined to be 86.141 MPa. While the results associated with fiber diameter, porosity, and wall thickness were statistically inconsistent, it will be important to evaluate whether the variation between each scaffold will translate to a difference when conducting cellular studies after the DIV-BBB system is complete.