Molecular Bottlebrushes for Biorelevant Applications

This thesis focuses on the synthesis and applications of hydrophilic polymers with advanced architectures. Chapter 1 introduces molecular bottlebrushes (MBs) in context of their synthesis, properties, and applications in biomedicine. The chapter aims to provide fundamental knowledge and state-of-the-art of research on MBs in biorelevant applications. Chapters 2-5 focus on research projects performed during my PhD study. 

Chapter 2 describes the synthesis and characterization of new sulfoxide-containing polymers with complex architecture. The first section focuses on poly(2-(methylsulfinyl)ethyl acrylamide) (PMSEAM). Linear homopolymers, DNA-PSEAM block copolymers and PMSEAM-protein conjugates were synthesized by PICAR ATRP in biologically relevant conditions in a small volume and without degassing the reaction mixture. The section discusses the hydrophilicity and biocompatibility of PMSEAM. The second section of the chapter focuses on MBs with poly(2-(methylsulfinyl)ethyl acrylate) (PMSEA) side chains. In addition to biocompatibility studies and kinetic optimization, this section discusses how the density of grafted chains and MB size impacts the lubricating properties of sulfoxide containing MBs. 

Chapter 3 focuses on the lubrication and antifouling performance of MBs with zwitterionic side chains. The first section explores the lubrication properties of MBs with poly(2- methacryloyloxyethyl phosphorylcholine) (PMPC) side chains in presence of multivalent ions. The second section of the chapter extends the applications of PMPC MBs to antifouling films. A new system consisting of a combination of PMPC MBs and hyaluronic acid is investigated as protective films to prevent protein adhesion to gold surfaces. 

Chapter 4 demonstrates the synthesis of degradable MBs with cellulose-based backbones. The chapter discusses the challenges of synthesis of well-defined MBs from natural polymers. Additionally, the influence of the density of grafted chains on the degradation mechanism is discussed. 

Chapter 5 focuses on MBs, and star polymers based on poly(ethylene glycol) and its (meth)acrylate derivatives in context of their behavior in water/oil interfaces and in biologically relevant conditions. The first section discusses how the properties of the PEG star layer on oil/water interfaces dependent on the interaction between the PEG arms and the nature of the oil phase. The second section in this chapter discusses the interactions of poly[oligo(ethylene glycol) methacrylate] (POEGMA) MBs with different biological barriers in vivo and in vitro compared to those of nanospheres with PEO pendant chains. 

Finally, Chapter 6 is a summary of current state-of-the-art and future perspective on the developments on new hydrophilic polymers with complex architectures in context of their applications in biomedicine. 

The Appendix contains a summary of all academic papers submitted or published with my contribution and my responsibilities during my PhD along with other achievements.