Side-Chain Spacing Control of Derivatives of Poly(2-methoxyethyl acrylate): Impact on Hydration States and Antithrombogenicity

Abstract

A series of variants of antithrombogenic poly­(2-methoxyethyl acrylate) with controlled side-chain spacing were prepared via regio-selective ring-opening metathesis polymerization. In general, understanding the hydration state and its dynamics at the polymer/water interface is important for the development of biomaterials. To determine how the chemical design of polymeric materials can control the hydration state, we systematically investigated the effect of side-chain spacing not only on the hydration state but also on thrombogenicity. The hydration state of novel polymers was determined by evaluating the thermodynamic behavior at low temperatures using differential scanning calorimetry measurements. Under physiological ionic conditions in phosphate-buffered saline [PBS(−)], the amount of intermediate water (IWPBS), which is the fraction of hydration water showing cold crystallization near the homogeneous nucleation temperature, decreased monotonically with increasing side-chain spacing. Thrombogenic properties were evaluated by the human platelet adhesion test, quartz crystal microbalance measurements, and enzyme-linked immunosorbent assays. All thrombogenic reactions were activated with the expansion of the side-chain spacing except for albumin adsorption. The present study revealed a clear correlation of IWPBS with antithrombogenicity and the possibility of controlling IWPBS by simply changing the side-chain spacing of the polymers.

Periodically Functionalized Linear Polyethylene with Tertiary Amino Groups via Regioselective Ring-Opening Metathesis Polymerization

“…9,35 The regioregularity of P(3DR-CHE)s was slightly decreased compared to that of P(3DR-COE)s. Only two papers have reported regio-/stereoregular ROMP of poly(allyl-functionalized CHE), and the results were consistent with our results. 10,14 Because of the scarcity of reports on the ROMP of 3R-CHEs, we investigated the effect of the reaction conditions on the regioregularity of the resulting polymers (Table 2). Notably, as the catalyst loading increased, the two monomers showed different trends in conversion, increasing for 3DM-CHE but slightly decreasing for 3DE-CHE; 3DR-COE showed the same trend as 3DM-CHE.…”

“…In a previous work, similar behavior was observed for analogous polymers having 2-methoxyethoxycarbonyl groups on every fourth polyethylene backbone carbon, although the other analogues having the same functional group with high or low density showed no such behavior. 14 If the spacing is too narrow, solvation with a nonpolar solvent is unfavorable. Conversely, when the spacing is too wide, intramolecular interactions are more favorable than solvation.…”

“…As we discussed in the previous report, understanding the polymer hydration behavior will be the key for the development of high-performance materials utilized in aqueous environments. 14 The polymer design applied in this study is expected to help clarify the hydration effect on the polymer properties and to control the solvation state to accomplish the objective properties, e.g., biocompatibility of medical devices, ion conductivity in the fuel cells, and antifouling property on marine coatings.…”

“…The shape and temperature of the peaks were very similar to those of the HP(3DR-COE)s with no specific interaction (e.g., hydrogen-bonding or electrostatic interactions) among the functional groups in the side chain. 9,13,14 Therefore, the observed peaks for the hydrated novel HP3(DR-COE) might be the melting peak of the polyethylene unit of the polymer main chain. The similarity of T m and ΔH m to the reported data for saturated poly(3-methoxy-1-cyclo- octene) supports the crystallization of the polyethylene units.…”

“…Coating Stability Evaluation. The obtained novel polymers were coated on the Au model surface by a spincoating method with 10 mg/mL toluene solution at 3000 rpm for 30 s. To compare the effect of the tertiary amino group on coating stabilization, two previously prepared samples, which are analogous polymers having a 2-methoxyethoxy carbonyl group on every seventh and eighth carbons of the polyethylene backbone (HP7 and HP8), 14 were also evaluated as controls. Although all the polymer layers were smooth in the dried state, obvious differences were observed upon immersion in PBS, as shown in Figure 7.…”