Cucurbit[8]uril templated supramolecular ring structure formation and protein assembly modulation

The interplay of Phe-Gly-Gly (FGG)-tagged proteins and bivalent FGG-tagged penta(ethylene glycol) as guest molecules with cucurbit[8]uril (Q8) hosts is studied to modulate the supramolecular assembly process. Ring structure formation of the bivalent guest molecule with Q8 leads to enhanced binding properties and efficient inhibition of protein assemblies. Graphical abstract: Cucurbit[8]uril templated supramolecular ring structure formation and protein assembly modulatio

Self-Assembly of Chiral Supramolecular Ureido-Pyrimidinone-Based Poly(ethylene glycol) Polymers via Multiple Pathways

The recently developed supramolecular hydrogelator system based on poly­(ethylene glycols) end-functionalized with ureido-pyrimidinone (UPy) units has been shown to be eminently suitable as a drug delivery vehicle in soft tissues such as the heart and kidney. To understand the assembly behavior of this system in more detail, we here report on the introduction of a stereogenic center. This allowed for the investigation of the self-assembly mechanism of this system by circular dichroism, which showed the presence of helical fibers. Additionally, fluorescence spectroscopy and scattering techniques in combination with cryoTEM showed elongated rod-like structures as the major species, next to spherical micelles. Interestingly, different self-assembly pathways occurred when using two aggregate preparation methods based on different cooling rates. Both positive and negative bisignate Cotton effects were observed only by changing the method of preparation, indicating that the UPy-polymer constructs self-assemble via multiple pathways. A similar phenomenon is observed in biology, which illustrates the versatility of the system. This versatility is key to the optimization of material properties for biomedical applications

Development of Non-Cell Adhesive Vascular Grafts Using Supramolecular Building Blocks

Cell-free approaches to in situ tissue engineering require materials that are mechanically stable and are able to control cell-adhesive behavior upon implantation. Here, the development of mechanically stable grafts with non-cell adhesive properties via a mix-and-match approach using ureido-pyrimidinone (UPy)-modified supramolecular polymers is reported. Cell adhesion is prevented in vitro through mixing of end-functionalized or chain-extended UPy-polycaprolactone (UPy-PCL or CE-UPy-PCL, respectively) with end-functionalized UPy-poly(ethylene glycol) (UPy-PEG) at a ratio of 90:10. Further characterization reveals intimate mixing behavior of UPy-PCL with UPy-PEG, but poor mechanical properties, whereas CE-UPy-PCL scaffolds are mechanically stable. As a proof-of-concept for the use of non-cell adhesive supramolecular materials in vivo, electrospun vascular scaffolds are applied in an aortic interposition rat model, showing reduced cell infiltration in the presence of only 10% of UPy-PEG. Together, these results provide the first steps toward advanced supramolecular biomaterials for in situ vascular tissue engineering with control over selective cell capturin