Surface-Templated Glycopolymer Nanopatterns Transferred to Hydrogels for Designed Multivalent Carbohydrate–Lectin Interactions across Length Scales

Abstract

Multivalent interactions between carbohydrates and proteins enable a broad range of selective chemical processes of critical biological importance. Such interactions can extend from the macromolecular scale (1−10 nm) up to much larger scales across a cell or tissue, placing substantial demands on chemically patterned materials aiming to leverage similar interactions in vitro.Here, we show that diyne amphiphiles with carbohydrate headgroups can be assembled on highly oriented pyrolytic graphite (HOPG) to generate nanometer-resolution carbohydrate patterns, with individual linear carbohydrate assemblies up to nearly 1 μm, and microscale geometric patterns. These are then photopolymerized and covalently transferred to the surfaces of hydrogels. This strategy suspends carbohydrate patterns on a relatively rigid polydiacetylene (persistence length ∼ 16 nm), exposed at the top surface of the hydrogel above the bulk pore structure. Transferred patterns of appropriate carbohydrates (e.g., N-acetyl-D-glucosamine, GlcNAc) enable selective, multivalent interactions (K D ∼ 40 nM) with wheat germ agglutinin (WGA), a model lectin that exhibits multivalent binding with appropriately spaced GlcNAc moieties. WGA binding affinity can be further improved (K D ∼ 10 nM) using diacetylenes that shift the polymer backbone closer to the displayed carbohydrate, suggesting that this strategy can be used to modulate carbohydrate presentation at interfaces. Conversely, GlcNAc-patterned surfaces do not induce specific binding of concanavalin A, and surfaces patterned with glucuronic acid, or with simple carboxylic acid or hydroxyl groups, do not induce WGA binding. More broadly, this approach may have utility in designing synthetic glycan−mimetic interfaces with features from molecular to mesoscopic scales, including soft scaffolds for cells.

Inkjet Printing of Nanoscale Functional Patterns on 2D Crystalline Materials and Transfer to Soft Materials

“…Previously, we have shown that the sPDA layers on HOPG can be transferred to soft materials including PDMS ,− and hydrogels, , taking advantage of the cross-linking reactions used to solidify the bulk polymer (Figure a). For instance, in polyacrylamide (PAAm) hydrogel cross-linking, the free radical polymerization reaction can utilize the PDA as a reactant, which creates a covalent linkage between the PAAm and the sPDA layer.…”

Phospholipid Epitaxial Assembly Behavior on a Hydrophobic Highly Ordered Pyrolytic Graphite Surface

“…The interaction between alkyl chains of phospholipids and HOPG is stronger than phospholipid molecule–molecule interactions. The Claridge research group’s series of studies utilized phospholipids as a surface chemical modification material for two-dimensional materials. − Through the Langmuir method, diyne PE and diyne PC established strips on the MoS 2 or HOPG. Subsequently, it was proved that the phospholipid strips were more stable after being ultraviolet polymerized .…”

Designing Interfacial Reactions for Nanometer-Scale Surface Patterning of PDMS with Controlled Elastic Modulus

“…Recently, we have demonstrated that it is possible to generate nm-scale chemical patterns in the surface chemistry of PDMS − and other soft materials. , Functionalization starts by assembling striped phases of diacetylene (DA)-modified amphiphiles on highly oriented pyrolytic graphite (HOPG). In the striped phases, the alkyl chain of the amphiphile lies flat on the HOPG substrate (Figure a), generating 1 nm-wide stripes of paired functional headgroups embedded in a stripe of exposed alkyl chains. − Photopolymerization of aligned DA groups (Figure a, bottom) produces polydiacetylene (PDA) backbones that tether together molecules within the layer.…”