Sequence-defined positioning of amine and amide residues to control catechol driven wet adhesion.

Catechol and amine residues, both abundantly present in mussel adhesion proteins, are known to act cooperatively by displacing hydration barriers before binding to mineral surfaces. In spite of synthetic efforts toward mussel-inspired adhesives, the effect of positioning of the involved functional groups along a polymer chain is not well understood. By using sequence-defined oligomers grafted to soft hydrogel particles as adhesion probes, we study the effect of catechol-amine spacing, as well as positioning relative to the oligomer terminus.

Temperature-Controlled Adhesion to Carbohydrate Functionalized Microgel Films: An E. coli and Lectin Binding Study.

The preparation of thermoresponsive mannose functionalized monolayers of poly(N-isopropylacrylamide) microgels and the analysis of the specific binding of concanavalin A (ConA) and E. coli above and below the lower critical solution temperature (LCST) are shown. Via inhibition and direct binding assays it is found that ConA binding is time-dependent, where at short incubation times binding is stronger above the LCST.

Lectin and Binding to Carbohydrate-Functionalized Oligo(ethylene glycol)-Based Microgels: Effect of Elastic Modulus, Crosslinker and Carbohydrate Density.

The synthesis of carbohydrate-functionalized biocompatible poly(oligo(ethylene glycol) methacrylate microgels and the analysis of the specific binding to concanavalin A (ConA) and () is shown. By using different crosslinkers, the microgels' size, density and elastic modulus were varied. Given similar mannose (Man) functionalization degrees, the softer microgels show increased ConA uptake, possibly due to increased ConA diffusion in the less dense microgel network.

Quantifying Thermoswitchable Carbohydrate-Mediated Interactions via Soft Colloidal Probe Adhesion Studies.

Thermosensitive polymers enable externally controllable biomolecular interactions but hysteresis effects hamper the reversibility and repeated use of these materials. To quantify the temperature-dependent interactions and hysteresis effects, an optical adhesion assay based on poly(ethylene glycol) microgels (soft colloidal probes, SCPs) with mannose binding concanavalin A surfaces is used. A series of thermoresponsive glycopolymers is synthesized varying the carbohydrate type, their density, and linker type, and then grafted to the SCPs.

Temperature-Switchable Glycopolymers and Their Conformation-Dependent Binding to Receptor Targets.

The temperature-dependent binding of copolymers from poly(-isopropylacrylamide) (PNIPAM) and mannose ligands to and concanavalin A (ConA) is determined. Through polymer analogous reactions using poly(-acryloxysuccinimide) and amine-linked mannose residues with different linkers, glycopolymers are prepared with the variation of the mannose density. Quantitative adhesion inhibition assays show the inhibitory potential of the glycopolymers as a function of the mannose/NIPAM ratio and linker type above and below their lower critical solution temperature (LCST).

Thermosensitive Display of Carbohydrate Ligands on Microgels for Switchable Binding of Proteins and Bacteria.

The synthesis of carbohydrate-functionalized thermosensitive poly(-isopropylacrylamide) microgels and their ability to bind carbohydrate-binding pathogens upon temperature switch are reported. It is found that the microgels' binding affinity is increased above their lower critical solution temperature (LCST), enabling thermo-triggerable capture of pathogens. Here, a series of microgels with comparatively low mannose functionalization degrees below 1 mol % is achieved by a single polymerization step.

Hydrogel Microparticles as Sensors for Specific Adhesion: Case Studies on Antibody Detection and Soil Release Polymers.

Adhesive processes in aqueous media play a crucial role in nature and are important for many technological processes. However, direct quantification of adhesion still requires expensive instrumentation while their sample throughput is rather small. Here we present a fast, and easily applicable method on quantifying adhesion energy in water based on interferometric measurement of polymer microgel contact areas with functionalized glass slides and evaluation via the Johnson⁻Kendall⁻Roberts (JKR) model.