title: Development of next-generation fluorinated block copolymers and bottom-up assembly of biomimetic cell interaction modules
creator: Schröter, Martin
subject: ddc-530
subject: 530 Physics
subject: ddc-540
subject: 540 Chemistry and allied sciences
subject: ddc-570
subject: 570 Life sciences
description: The construction of individual synthetic cells has been developed to achieve processes ranging from recapitulating cell division to mechanosignalling. Taken a step further, another promising implementation of synthetic cell research is the construction of artificial tissues comprising synthetic cells. These artificial tissues have the potential to form a communication network between the synthetic cells to transmit and respond to chemical or mechanical signals. In conjunction with natural tissue, this functioning could support signal transduction and thus aid in creating hybrid systems that will ultimately influence the fundamental understanding of tissue form and functioning.  In this thesis, I described the first steps towards building an artificial tissue that consists of giant unilamellar vesicles (GUVs)-based synthetic cells. In the process of charge-mediated GUV production, block copolymer surfactants consisting of PEG and PFPE were used to stabilize water-in-oil droplets that provide the charged scaffold to generate GUVs in the first place. These polymer-based surfactants have a major impact on the overall GUV production yield which is currently recognized as the major technical challenge in the field. Therefore, the first part of my thesis is dedicated to comparing different synthesis routes to achieve surfactants with desired properties. Subsequently, several functional surfactants have been synthesized: 1) a positively charged surfactant that allows electrostatically-mediated GUV formation; 2) a photoliable surfactant, which should enable a light-induced GUV release from water-in-oil droplet templates; and 3) a fluorescent surfactant for labeling the surfactant layer.  In the second part of this thesis, I focused on introducing biomimetic interactions between GUVs as well as between GUVs and natural cells. Towards this end, a pH-mediated generation of GUVs with improved release efficiency was explored. These GUVs were biofunctionalized and used for the bottom-up assembly of biomimetic cell adhesion and interaction modules: 1) mimicking epithelial cell interactions through the implementation of adherens junctions between GUVs via E-cadherin proteins; 2) GUV-substrate adhesion through the reconstitution of integrins in the GUVs membrane; and 3) implementation of droplet-based microfluidics for the reconstitution of actin cytoskeleton within GUVs to move towards linking intercellular mechanical signaling and synthetic cell mobility for future applications. Additionally, I showed how adherens junctions and substrate adhesion could be mimicked by DNA-mediated interactions. Finally, a hybrid system consisting of synthetic and natural cells was constructed and analyzed with respect to the interaction between GUVs and HEK cells.  Through the use of newly synthesized surfactants, droplet-based microfluidics, and pH-mediated GUV assembly and their efficient biofunctionalization , I was able for the first time to build an extensive network of synthetic cells and hybrid cellular system. This research establishes the foundation for reliable and reproducible production of large numbers of stable populations of GUV-based synthetic cells with pre-determined biomimetic functions and represents a substantial step towards building an artificial tissue. In future, mechanical and biochemical signal transduction can be potentially enabled by transmembrane linkages to the cytoskeleton, leading to the implementation of the advanced bioinspired hybrid cellular systems for biomedical applications.
date: 2022
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserver/32316/1/Dissertation_MartinSchroeter.pdf
identifier: DOI:10.11588/heidok.00032316
identifier: urn:nbn:de:bsz:16-heidok-323168
identifier:   Schröter, Martin  (2022) Development of next-generation fluorinated block copolymers and bottom-up assembly of biomimetic cell interaction modules.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/32316/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng