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Summarizes developments in the construction of synthetic cells made from polymers with a particular focus on mimicking the structure and behavior of blood cells. Description of the bio-inspired polymer membranes; Information on the self-assembling polymer membranes; Stability of polymer vesicles; Interactions with biological cells.

Abstract: Nanoparticles are being developed as delivery vehicles for therapeutic pharmaceuticals and contrast imaging agents. Polymersomes (mesoscopic polymer vesicles) possess a number of attractive biomaterial properties that make them ideal for these applications. Synthetic control over block copolymer chemistry enables tunable design of polymersome material properties. The polymersome architecture, with its large hydrophilic reservoir and its thick hydrophobic lamellar membrane, provides significant storage capacity for both water soluble and insoluble substances (such as drugs and imaging probes). Further, the brush-like architecture of the polymersome outer shell can potentially increase biocompatibility and blood circulation times. A further recent advance is the development of multi-functional polymersomes that carry pharmaceuticals and imaging agents simultaneously. The ability to conjugate biologically active ligands to the brush surface provides a further means for targeted therapy and imaging. Hence, polymersomes hold enormous potential as nanostructured biomaterials for future in vivo drug delivery and diagnostic imaging applications. [Copyright &y& Elsevier]

Abstract: The functionalization of hydrogels for receptor-mediated cell adhesion is one approach for targeted cell and tissue engineering applications. In this study, polyacrylamide gel surfaces were functionalized with specific cell adhesion ligands via the self-assembly of a peptide-based heterodimer. The system was comprised of a cysteine-terminated monomer, A (MW ∼ 5400), grafted to the polyacrylamide gels and a complementary ligand presenting monomer, BX (MW ∼ 5800) that was designed to heterodimerize with A. Two ligand presenting monomers were synthesized: one presenting the RGDS ligand, BD, for receptor-mediated cell adhesion, and the other, a control monomer presenting the nonadhesive RGES ligand, BE. Assembly of the peptide pair A–BX by association of the monomers into a coiled coil was verified by circular dichroism in solution. Binding studies were conducted to determine the dissociation constant of the pair A–BX, which was found to be m. Polyacrylamide gels functionalized with A–BX heterodimers were evaluated for cell adhesion using bovine aortic endothelial cells (BAECs). Endothelial cells cultured on the A–BD functionalized surfaces demonstrated typical cell morphologies and expected spreading behavior as a function of the density of RGDS ligand, calculated as the amount of BD associated with grafted A on the surface of the gels. In contrast, A–BE linked surfaces supported no cell adhesion. The adhesion of the substrate was dynamically altered through the reassembly of A–BX dimers as BD molecules in the solution replaced BE molecules at the substrate. The molecular constructs described here demonstrate the potential to design a broad family of switchable peptides that impart the dynamic control of biofunctionality at an interface, which would be useful for precise manipulation of cell physiology. [Copyright &y& Elsevier]

We demonstrate that synthetic soft materials can extend the utility of natural vesicles, from predominantly hydrophilic reservoirs to functional colloidal carriers that facilitate the biomedical application of large aqueous-insoluble compounds. Near-infrared (NIR)- emissive polymersomes (50-nm- to 50-μm-diameter polymer yes-ides) were generated through cooperative self assembly of amphiphilic diblock copolymers and conjugated multi(porphyrin)- based NIR fluorophores (NIRFs). When compared with natural vesicles comprised of phospholipids, polymersomes were uniquely capable of incorporating and uniformly distributing numerous large hydrophobic NIRFs exclusively in their lamellar membranes. Within these sequestered compartments, long polymer chains regulate the mean fluorophore-fluorophore interspatial separation as well as the fluorophore-localized electronic environment. Porphyrin-based NIRFs manifest photophysical properties within the polymersomal matrix akin to those established for these high-emission dipole strength fluorophores in organic solvents, thereby yielding uniquely emissive vesicles. Furthermore, the total fluorescence emanating from the assemblies gives rise to a localized optical signal of sufficient intensity to penetrate through the dense tumor tissue of a live animal. Robust NIR-emissive polymersomes thus define a soft matter platform with exceptional potential to facilitate deep-tissue fluorescence-based imaging for in vivo diagnostic and drug-delivery applications [ABSTRACT FROM AUTHOR]

Presents research which made vesicles from amphiphilic diblock copolymers. Average molecular weight of polyethyleneoxide-polyethylethylene (EO40-EE37); Traits of electroformed polymersomes; Permeability of the polymersome membrane compared with common phospholipid bilayers; Implications of research for block copolymer chemistry.