POLYMERIC BIOMATERIAL DRUG DELIVERY SYSTEMS FOR GLIOBLASTOMA THERAPY AND VACCINES Kathryn Margaret Moore A dissertation submitted to the faculty at the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biomedical Engineering in the School of Medicine. Chapel Hill 2020 Approved by: Kristy M. Ainslie David Zaharoff Yevgeny Brudno Shawn D. Hingtgen Aaron Anselmo 2020 Kathryn Margaret Moore ALL RIGHTS RESERVED ii ABSTRACT Kathryn Margaret Moore: Polymeric Biomaterial Drug Delivery Systems for Glioblastoma Therapy and Vaccines (Under the direction of Kristy M. Ainslie) Polymeric biomaterial drug delivery systems have been explored to improve therapies for a wide range of diseases, including cancer and infectious diseases, by providing control over delivery of therapeutic cargo. Scaffolds composed of polymeric biomaterials have been used to increase efficacy of cell therapies by promoting cell implantation and viability thereafter. Both scaffolds and particles can be loaded with small molecules and biological agents to enhance delivery to target cells. This dissertation aims to explore the use of polymeric biomaterials to improve both glioblastoma therapy and vaccines. In the case of glioblastoma, the most common primary brain tumor, local drug delivery is a beneficial therapeutic strategy because its bypasses the blood brain barrier and allows for direct access to the site of tumor recurrence. Herein, scaffolds were fabricated by the process of electrospinning and characterized for the delivery of tumoricidal agent producing stem cells and chemotherapeutics into the glioblastoma surgical resection cavity. This work places a strong emphasis on the impact of scaffold degradation on the local glioblastoma therapies by utilizing the tunable polymer, acetalated dextran. Vaccine formulations often require adjuvants to stimulate the immune system to generate a protective immune response. Polymeric biomaterials have been employed to deliver antigen and adjuvant more efficiently to antigen presenting cells, as well as create an immunostimulatory iii depot. In this dissertation, electrospun acetalated dextran ribbon-like particles called microconfetti, generated by fragmenting scaffolds, were investigated as a new vaccine platform. iv ACKNOWLEDGEMENTS I would like to express my deepest gratitude to all of those who have been with me through this challenging and rewarding journey – through the failures and the successes and everything in between. Thank you to my advisor and mentor, Dr. Kristy Ainslie, for guiding me through this process. You have challenged me to work hard and to do my best. I will never forget the enormous amount of time and energy that you have devoted towards my success and your steadfast confidence in me throughout these five years. Thank you to Dr. Eric Bachelder and my committee for helping me shape my projects and assisting in my professional development. Thank you to Dr. Elizabeth Graham-Gurysh for being an incredible mentor, role model, and friend. Words cannot express my appreciation for the abundant wisdom and encouragement with which you have generously gifted me, inside and outside of the lab. I would not be the scientist or person that I am today without you. To all the members of the Ainslie Lab, current and past, working with you is my favorite part of doing science. I cannot overstate how grateful I am to have known every single one of you and the immense joy that you have brought me. You have made lab a fun place to do hard work and have inspired me with your curiosity and intellect. I will forever treasure your friendship and diverse perspectives. I could not have done the work in this dissertation without you and sincerely thank you. v And finally, thank you to my family – to my parents, brother, and grandparents. I am so fortunate to be loved and supported by you all. I could not have accomplished this without you. vi PREFACE This dissertation is composed of 4 chapters and 2 appendices. The chapters comprise my first author publications and discussion of that work, and the appendices are publications of which I was a major contributing second author. Chapter 1 is a review article published in ACS Biomaterials Science & Engineering summarizing the development of polymeric biomaterial scaffolds for tumoricidal stem cell therapy. Chapter 2 is published in Materials Science & Engineering C and describes our work evaluating the impact of scaffold degradation on neural stem cell persistence in the brain after implantation into the surgical resection cavity for glioblastoma therapy through the development of composite acetalated dextran scaffolds. Chapter 3 has been submitted to ACS Applied Materials & Interfaces and encompasses our work characterizing high aspect ratio ribbon-like particles called microconfetti, derived from acetalated dextran scaffolds, as a vaccine platform. The contents of Chapters 1-3 are summarized, and future directions are discussed in Chapter 4. None of the work in Chapters 1-3 would have been possible without the help from the members of the Ainslie Lab. Appendix 1 and 2 are publications centered around local drug delivery via electrospun acetalated dextran scaffolds for glioblastoma therapy spearheaded by Dr. Elizabeth Graham-Gurysh. vii TABLE OF CONTENTS LIST OF TABLES ....................................................................................................................... xiii LIST OF FIGURES ..................................................................................................................... xiv LIST OF ABBREVIATIONS ..................................................................................................... xvii CHAPTER 1: REVIEW OF BIOPOLYMERIC SCAFFOLDS FOR TUMORICIDAL STEM CELL GLIOBLASTOMA THERAPY ........................................ 1 1.1 Introduction ........................................................................................................................... 1 1.1.1 Glioblastoma and Treatment Strategies ......................................................................... 1 1.1.2 Tumoricidal Stem Cell Therapy for Glioblastoma ........................................................ 3 1.1.3 Animal Models of Glioblastoma .................................................................................... 5 1.1.4 Role of Biopolymeric Scaffolds in Tumoricidal Stem Cell Therapy ............................ 7 1.2 Hydrogels ............................................................................................................................ 10 1.2.1 Bulk Hydrogels for Tumoricidal Stem Cell Therapy .................................................. 11 1.2.2 Alginate Hydrogel Microcapsules for Tumoricidal Stem Cell Therapy ...................... 14 1.3 Electrospun Scaffolds ......................................................................................................... 16 1.3.1 Electrospun Scaffolds for Tumoricidal Stem Cell Therapy ......................................... 17 1.4 Conclusions ......................................................................................................................... 19 CHAPTER 2: IMPACT OF COMPOSITE SCAFFOLD DEGRADATION RATE ON NEURAL STEM CELL PERSISTENCE IN GLIOBLASTOMA RESECTION CAVITY ............................................................................................................... 30 2.1 Introduction ......................................................................................................................... 30 2.2 Materials and Methods ........................................................................................................ 32 2.2.1 Acetalated Dextran (Ace-DEX) Synthesis................................................................... 32 viii 2.2.2 Ace-DEX Gelatin Scaffold Fabrication ....................................................................... 32 2.2.3 Scaffold Materials Characterization ............................................................................ 33 2.2.4 In Vitro Degradation and Release Studies ................................................................... 33 2.2.5 ICG Scaffold Degradation In Vivo .............................................................................. 34 2.2.6 Cell Lines ..................................................................................................................... 35 2.2.7 In Vitro NSC Seeding and Viability on Scaffolds ....................................................... 36 2.2.8 Quantification of TRAIL Output from TRAIL-NSCs on Scaffolds ............................ 36 2.2.9 In Vitro GBM Killing .................................................................................................. 37 2.2.10 NSC Persistence Model ............................................................................................. 37 2.2.11 Statistical Analysis ..................................................................................................... 38 2.3 Results and Discussion ....................................................................................................... 38 2.3.1 Fabricating Ace-DEX Gelatin Scaffolds by Electrospinning and Dehydrothermal Crosslinking ........................................................................................ 38 2.3.2 Degradation of Ace-DEX Gelatin Scaffolds In Vitro and In Vivo .............................. 40 2.3.3 Effect of Ace-DEX Gelatin Scaffold Degradation on NSCs