Surface Modification of Siliceous Materials Using Maleimidation and Various Functional Polymers Synthesized by Reversible Addition–Fragmentation Chain Transfer Polymerization

Abstract

A novel surface modification method was investigated. The surface of siliceous materials was modified using polystyrene, poly(acrylic acid), poly(N-isopropylacrylamide), and poly(p-acrylamidophenyl-α-mannoside) synthesized by reversible addition-fragmentation chain transfer polymerization. Thiol-terminated polymers were obtained by reduction of the thiocarbonate group using sodium borohydride. The polymers were immobilized on the surface via the thiol-ene click reaction, known as the Michael addition reaction. Immobilization of the polymers on the maleimidated surface was confirmed by X-ray photoelectron spectroscopy, infrared spectroscopy, and contact angle measurements. The polymer-immobilized surfaces were observed by atomic force microscopy, and the thickness of the polymer layers was determined by ellipsometry. The thickness of the polymer immobilized by the maleimide-thiol reaction was less than that formed by spin coating, except for polystyrene. Moreover, the polymer-immobilized surfaces were relatively smooth with a roughness of less than 1 nm. The amounts of amine, maleimide, and polymer immobilized on the surface were determined by quartz crystal microbalance measurements. The area occupied by the amine-containing silane coupling reagent was significantly less than the theoretical value, suggesting that a multilayer of the silane coupling reagent was formed on the surface. The polymer with low molecular weight had the tendency to efficiently immobilize on the maleimidated surface. When poly(p-acrylamidophenyl-α-mannoside)-immobilized surfaces were used as a platform for protein microarrays, strong interactions were detected with the mannose-binding lectin concanavalin A. The specificity of poly(p-acrylamidophenyl-α-mannoside)-immobilized surfaces for concanavalin A was compared with poly-l-lysine-coated surfaces. The poly-l-lysine-coated surfaces nonspecifically adsorbed both concanavalin A and bovine serum albumin, while the poly(p-acrylamidophenyl-α-mannoside)-immobilized surface preferentially adsorbed concanavalin A. Moreover, the poly(p-acrylamidophenyl-α-mannoside)-immobilized surface was applied to micropatterning with photolithography. When the micropattern was formed on the poly(p-acrylamidophenyl-α-mannoside)-spin-coated surface by irradiation with ultraviolet light, the pattern of the masking design was not observed on the surface adsorbed with fluorophore-labeled concanavalin A using a fluorescent microscope because of elution of poly(p-acrylamidophenyl-α-mannoside) from the surface. In contrast, fluorophore-labeled concanavalin A was only adsorbed on the shaded region of the poly(p-acrylamidophenyl-α-mannoside)-immobilized surface, resulting in a distinctive fluorescent pattern. The surface modification method using maleimidation and reversible addition-fragmentation chain transfer polymerization can be used for preparing platforms for microarrays and micropatterning of proteins.

Poly(l-lysine) Interfaces via Dual Click Reactions on Surface-Bound Custom-Designed Dithiol Adsorbates

“…The literature indicates that maleimide-modified surfaces with varying film thicknesses exhibit contact angles for water in the range of 41-57º; however, the lower value was observed for a monolayer in which the adsorbates contained an oligoethylene glycol segment. 15,46 In the current study, after the click attachment, the advancing contact angles of water on these surfaces were 44º for the N3BnDT SAM, 45º for the N3C11SH SAM, and 50º for the N3PrBnDT SAM. Considering the values found in the literature, 15,46 these contact angle measurements appear to indicate that the film formed from N3PrBnDT more effectively presents an ordered surface array of maleimide moieties than the other two SAMs.…”

A Comparative Study of Thiol‐Terminated Surface Modification by Click Reactions: Thiol‐yne Coupling versus Thiol‐ene Michael Addition

“…In the same year, Seto et al functionalized maleimide‐terminated siliceous surfaces with thiol‐terminated polystyrene, poly(acrylic acid), poly( N ‐isopropylacrylamide), and poly( p ‐acrylamidophenyl‐α‐mannoside). Immobilization of poly( p ‐acrylamidophenyl‐α‐mannoside) onto the surface provided a microarray for the detection of fluoresceinisothiocyanat labelled concanavalin A (FITC‐Con A) . One year later, in 2013, this group fabricated a streptavidin biosensor in an analogous manner using functionalization of maleimide‐terminated silicon and nickel surfaces with thiolated‐biotin .…”

Analysis of the Surface Coverage of a Self-Assembled Monolayer of Octadecyl Silane on a Si(100) Surface by Infrared External-Reflection Spectroscopy

“…6,7 The oxide layer provides hydroxyl groups on the silicon surface, which work as reaction points to make a covalent bonding. Nevertheless, the chemical bonding is not easily formed in comparison to that on a gold surface.…”