Multivalent Protein‐Loaded pH‐Stable Polymersomes: First Step toward Protein Targeted Therapeutics

Abstract

Synthetic platforms for mimicking artificial organelles or for designing multivalent protein therapeutics for targeting cell surface, extracellular matrix, and tissues are in the focus of this study. Furthermore, the availability of a multi‐functionalized and stimuli‐responsive carrier system is required that can be used for sequential in situ and/or post loading of different proteins combined with post‐functionalization steps. Until now, polymersomes exhibit excellent key characteristics to fulfill those requirements, which allow specific transport of proteins and the integration of proteins in different locations of polymeric vesicles. Herein, different approaches to fabricate multivalent protein‐loaded, pH‐responsive, and pH‐stable polymersomes are shown, where a combination of therapeutic action and targeting can be achieved, by first choosing two model proteins such as human serum albumin and avidin. Validation of the molecular parameters of the multivalent biohybrids is performed by dynamic light scattering, cryo‐TEM, fluorescence spectroscopy, and asymmetrical flow‐field flow fractionation combined with light scattering techniques. To demonstrate targeting functions of protein‐loaded polymersomes, avidin post‐functionalized polymersomes are used for the molecular recognition of biotinylated cell surface receptors. These versatile protein‐loaded polymersomes present new opportunities for designing sophisticated biomolecular nanoobjects in the field of (extracellular matrix) protein therapeutics.

Potential of Small‐Angle Neutron Scattering for Evaluating Protein Locus within a Polymersome

“…[ 7,8 ] Furthermore, functional groups sensitive to glucose/sugar concentration, [ 9,10 ] redox levels [ 11 ] or irradiation can also be incorporated onto the BCPs. [ 12,13 ] Surface functionalization of the polymersomes [ 14 ] allows selective targeting of cells, thereby promoting the use of polymersomes as drug‐delivery systems. [ 15 ]…”

Current Perspectives on Synthetic Compartments for Biomedical Applications

“…Covalent attachment of molecules at the compartment surface involves different chemical approaches. For example, strategies based on Cu 2+ -free click chemistry are achieved by: (i) azide–alkyne cycloaddition [ 106 , 107 , 108 , 109 , 110 ], (ii) maleimide and thiol-ene [ 111 , 112 , 113 , 114 , 115 ], and (iii) amine coupling [ 114 , 116 , 117 , 118 ]. Using a combination of strain-promoted azide–alkyne cycloaddition (SPAAC) and thiol-ene reactions, the surface modification of poly(2-methyl-2-oxazoline)- block -poly(dimethylsiloxane) (PMOXA- b -PDMS) polymersomes served to immobilize polymersomes on surfaces [ 111 , 112 , 119 ].…”

Biomimetic cell structures: Probing Induced pH-Feedback Loops and pH Self-Monitoring in Cytosol Using Binary Enzyme-loaded Polymersomes in Proteinosome

“…The pH-responsive and crosslinked Psomes have previously been used to incorporate active biomacromolecules, especially enzymes, to design artificial organelles. They are versatile, chemically and physically stable, membrane permeability for different bio(macro)molecules, and capable of regulating enzyme activity through the pH-sensitive membrane permeability, 9,10,38,[43][44][45][46][47][48][49][50][51][52] such as crosslinking and permeabilizing of pH-responsive GOx/CAT-Psomes by S. Liu group 50 . The preparation process and characterization methods of artificial organelles GOx-Psomes A and Urease-Psomes B are based on our previous report, 38,43,47 at which the collapsed membrane state of pH-responsive Psomes does not allow the feeding of lumen-located enzyme in Psomes with any low-molecular weight substrate or intermediates (e.g.…”

“…Asymmetrical flow-field flow fractionation with light scattering detection (AF4-LS) as a powerful method to confirm molar mass, size, and conformational properties of Empty-Psomes and Enzyme-Psomes has been well established in our group. 9,10,38,[44][45][46][47][48] Previous studies on GOx-Psomes A and Urease-Psomes B in PBS buffer at pH 7.0 and 5.0 by AF4-LS have been presented. 38 These results demonstrated that the scaling parameters ν of GOx-Psomes A and Urease-Psomes B are relatively close to 0.33, implying Enzyme-Psomes with a regular spherical morphology at different conditions.…”