Effectiveness of cell adhesive additives in different supramolecular polymers.

Supramolecular motifs in elastomeric biomaterials facilitate the modular incorporation of additives with corresponding motifs. The influence of the elastomeric supramolecular base polymer on the presentation of additives has been sparsely examined, limiting the knowledge of transferability of effective functionalization between polymers. Here it was investigated if the polymer backbone and the additive influence biomaterial modification in two different types of hydrogen bonding supramolecular systems, that is, based on ureido-pyrimidinone or bis-urea units. Two different cell-adhesive additives, that is, catechol or cyclic RGD, were incorporated into different elastomeric polymers, that is, polycaprolactone, priplast or polycarbonate. The additive effectiveness was evaluated with three different cell types. AFM measurements showed modest alterations on nano-scale assembly in ureido-pyrimidinone materials modified with additives. On the contrary, additive addition was highly intrusive in bis-urea materials. Detailed cell adhesive studies revealed additive effectiveness varied between base polymers and the supramolecular platform, with bis-urea materials more potently affecting cell behavior. This research highlights that additive transposition might not always be as evident. Therefore, additive effectiveness requires re-evaluation in supramolecular biomaterials when altering the polymer backbone to suit the biomaterial application.

Supramolecular Additive-Initiated Controlled Atom Transfer Radical Polymerization of Zwitterionic Polymers on Ureido-pyrimidinone-Based Biomaterial Surfaces.

Surface-initiated controlled radical polymerization is a popular technique for the modification of biomaterials with, for example, antifouling polymers. Here, we report on the functionalization of a supramolecular biomaterial with zwitterionic poly(sulfobetaine methacrylate) via atom transfer radical polymerization from a macroinitiator additive, which is embedded in the hard phase of the ureido-pyrimidinone-based material. Poly(sulfobetaine methacrylate) was successfully polymerized from these surfaces, and the polymerized sulfobetaine content, with corresponding antifouling properties, depended on both the macroinitiator additive concentration and polymerization time. Furthermore, the polymerization from the macroinitiator additive was successfully translated to functional electrospun scaffolds, showing the potential for this functionalization strategy in supramolecular material systems.

Glucose Single-Chain Polymer Nanoparticles for Cellular Targeting.

Naturally occurring glycoconjugates possess carbohydrate moieties that fulfill essential roles in many biological functions. Through conjugation of carbohydrates to therapeutics or imaging agents, naturally occurring glycoconjugates are mimicked and efficient targeting or increased cellular uptake of glycoconjugated macromolecules is achieved. In this work, linear and cyclic glucose moieties were functionalized with methacrylates via enzymatic synthesis and used as building blocks for intramolecular cross-linked single-chain glycopolymer nanoparticles (glyco-SCNPs). A set of water-soluble sub-10 nm-sized glyco-SCNPs was prepared by thiol-Michael addition cross-linking in water. Bioactivity of various glucose-conjugated glycopolymers and glyco-SCNPs was evaluated in binding studies with the glucose-specific lectin Concanavalin A and by comparing their cellular uptake efficiency in HeLa cells. Cytotoxicity studies did not reveal discernible cytotoxic effects, making these SCNPs promising candidates for ligand-based targeted imaging and drug delivery.