β‐Cyclodextrin‐Appended Giant Amphiphile: Aggregation to Vesicle Polymersomes and Immobilisation of Enzymes

Abstract

A giant amphiphile consisting of polystyrene end-capped with permethylated beta-cyclodextrin was synthesised and found to form vesicular structures when injected as a solution in THF into water. The ability of the cyclodextrins on the surface of the polymersomes to form inclusion complexes with hydrophobic compounds was tested by carrying out a competition experiment with a fluorescent probe sensitive to the polarity of the surrounding medium. It was found that 1-adamantol can displace the fluorescent probe from the cavities of the cyclodextrin moieties of the polymersomes. The recognition of molecules by cell membranes in nature is often based on interactions with specific membrane receptors. To mimic this behaviour, the enzyme horseradish peroxidase was modified with adamantane groups through a poly(ethylene glycol) spacer and its interaction with the polymersomes was investigated. It was established that the presence of adamantane moieties on each enzyme allowed a host-guest interaction with the multifunctional surface of the polymersomes.

Dynamic Macromolecular Material Design—The Versatility of Cyclodextrin‐Based Host–Guest Chemistry

“…Polymer/enzyme conjugates based on b-CD were presented by Feiters and co-workers [130] as well as Chen and coworkers. [131] Thel atter group showed the supramolecular attachment of adamantyl-functionalized PNIPAM or POEGMA to pyrophosphatase with preserved enzyme activity.A deli and co-workers utilized b-CD/polyglycerol conjugates to form supramolecular complexes with human serum albumin.…”

Functionalization of Block Copolymer Vesicle Surfaces

“…Oligohistidine sequence Complexation PDB-b-PEG [37,38] Fluorescein labeled maltose binding protein [37], eGFP [37,38], RFP [38] Cyclodextrin (CD) Adamantane Hydrophobic interactions PS-CD [39], CD-PEI-CD [40] HRP [39], PEG [40] N-hydroxysuccinimidyl ester Thiol C-S bond PCL-b-PEG [41] Antibody OX26 [41] Vinyl sulfone Thiol C-S bond PEG-b-PMCL [42] Cysteine-RGD peptide [42] …”

“…PS homopolymer terminated with a permethylated β-cyclodextrin (β-CD) group [39], as well as polyether imide (PEI) terminated at both chain ends with β-CDs [40] self-assembled into polymersomes, due to the hydrophilicity of the carbohydrate headgroups and the hydrophobicity of the polymer. The surface of these vesicles is a corona of β-CDs, which allowed the conjugation of adamantane-tagged horse radish peroxidase [39] and adamantane-terminated PEG [40]. Isothermal titration calorimetry (ITC) and static light scattering (SLS) revealed that both the inner and the outer polymersome surfaces were modified with the PEG.…”

“…The enzyme-coated polymersomes were subjected to multiple washing steps. The amount of enzyme on the vesicles was found to decrease, indicating that the non-covalent interaction between β-CD and adamantane is too weak to withstand the washing procedure [39].…”

Supramolecular Protein Immobilization on Lipid Bilayers

“…By incorporation of theses ynthetic receptors on as olids upport, proteins containing the correspondingl igand can be immobilized. [20,26,[31][32][33][34][35][36][37][38][39] There are, however, only very limited examples of the use of supramolecular chemistry fort he immobilization of proteins on lipid bilayers. The potentialo f as upramolecular approach forp rotein immobilization on lipid membranes is most impressively illustrated by the membrane incorporation of nitrilotriacetic acids that recruit His 6 -tagged proteins upon addition of nickel.…”