Hydration Mechanism in Blood-Compatible Polymers Undergoing Phase Separation

Abstract

Interactions involving intermediate water are crucial for the design of novel blood-compatible materials. Herein, we use a combination of atomic force microscopy, quartz crystal microbalance measurements, and soft X-ray emission spectroscopy to investigate the local hydrogen-bonded configuration of water on blood-compatible poly­(2-methoxyethyl acrylate) and non-blood-compatible poly­(n-butyl acrylate) grafted on a gold substrate. We find that the initially incorporated water induces polymer-dependent phase separation, facilitating further water uptake. For the blood-compatible polymer, tetrahedrally coordinated water coexists with water adsorbed on CO groups in low-density regions of the grafted polymer surface, providing a scaffold for the formation of intermediate water. The amount of intermediate water is determined by the type of functional groups, local polymer configuration, and polymer morphology. Thus, blood compatibility is governed by the complex water/polymer interactions.

Polydioxanone Derivative Bearing Methoxy Groups toward Bio‐Functional Degradable Polymers Exhibiting Hydration‐Driven Biocompatibility

“…These interacting water molecules are believed to be actively involved in the prevention of platelet adhesion and the adsorption and denaturation of related serum proteins. [ 18–23 ] Compared to the results in previous reports, [ 24,25 ] the exotherm at ≈−40 °C in the cooling scan appeared to reflect the water interacting with methoxy side groups. Those at ≈−25 °C may correspond to water interacting with ether bonds in the main chain and ester groups in the main and side chains (Figure 6b).…”

“…As mentioned in the Introduction, the blood compatibility of polymers correlates with the hydration properties, [19][20][21] which can be evaluated by differential scanning calorimetry (DSC) and water contact angles. The DSC profiles of polymer 1 showed a glass transition temperature (T g ) of −30 °C in the dry state (Figure 6a).…”

“…[10,17] Poly(2-methoxyethyl acrylate) (PMEA; Figure 1) is a bloodcompatible polymer and is clinically used as a coating material for oxygenators. [18,19] The high blood compatibility of these polymers is believed to be related to surface hydration. [20,21] The concept of hydration-driven biocompatibility facilitates recent developments and applications of various etherfunctionalized polymers, [22,23] including aliphatic polycarbonates, mimicking the side-chain structure of PMEA.…”

“…[ 10,17 ] Poly(2‐methoxyethyl acrylate) (PMEA; Figure ) is a blood‐compatible polymer and is clinically used as a coating material for oxygenators. [ 18,19 ] The high blood compatibility of these polymers is believed to be related to surface hydration. [ 20,21 ]…”

Surfactant-free suspension polymerization of hydrophilic monomers with an oil-in-water system for the preparation of microparticles toward the selective isolation of tumor cells

“…9 This indicates that the specific surface area of PMEA, whose outermost surface swells more easily than that of the polymer in the bulk state, increased upon forming microparticles and this promoted hydration. 30,31 Subsequently, differential scanning calorimetry (DSC) measurements of the polymer microparticles were performed under wet conditions. We have previously reported that the PMEA homopolymer and its derivatives form cold-crystallizable water, called intermediate water (IW), at approximately À40 1C, which plays a key role in the blood compatibility of polymer surfaces.…”