Correlation between the Structure of Water in the Vicinity of Carboxybetaine Polymers and Their Blood-Compatibility

Abstract

The structure and hydrogen bonding of water in the vicinity of carboxybetaine homopolymer (poly[1-carboxy-N,N-dimethyl-N-(2'-methacryloyloxyethyl)methanaminium inner salt] (PolyCMB), and a random copolymer of CMB and n-butyl methacrylate, Poly(CMB-r-BMA), with various molecular weights were analyzed in their aqueous solutions and thin film with contours of O-H stretching of Raman and attenuated total reflection infrared (ATR-IR) spectra, respectively. The relative intensity of the collective band (C value) corresponding to a long-range coupling of O-H stretchings of the Raman spectra for aqueous solution of Poly(CMB-r-BMA) was very close to that for pure water, which is in contrast with the smaller C value in aqueous solution of ordinary polyelectrolytes. The number of hydrogen bonds collapsed by the presence of one monomer residue (N(corr) value) of PolyCMB and Poly(CMB-r-BMA) (CMB, 45 mol %) (M(w), 1.14 x 10(4) and 1.78 x 10(4), respectively) could be calculated from the C value. The N(corr) values were much smaller than those for ordinary polyelectrolytes and close to those for nonionic water-soluble polymers such as poly(ethylene glycol) and poly(N-vinylpyrrolidone). Furthermore, a water-insoluble Poly(CMB-r-BMA) with a large BMA content (M(w) = 347 kD, CMB 27 mol %) could be cast as a thin film (thickness, ca. 10 microm) on a ZnSe crystal for the ATR-IR analyses. At an early stage of sorption of water into the Poly(CMB-r-BMA) film, the O-H stretching band of IR spectra for the water incorporated in the film was similar to that for free water, which is in contrast with the drastic change in the O-H stretching band of water incorporated in polymer films such as poly(methyl methacrylate) (PMMA) and poly(n-butyl methacrylate) (PBMA). The theoretical vibrational frequency for water molecules hydrating a betaine molecule calculated by using a density functional method supported the experimental results. The adhesion of human platelets to Poly(CMB-r-BMA) films was much less than that to PMMA and PBMA. With an increase in the content of CMB residue, the number of platelets adhered to the Poly(CMB-r-BMA) film drastically decreased and then gradually increased, probably due to the increase in the roughness of the film surface. These results suggest that the carboxybetaine monomer residues with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules in both aqueous solution and thin film systems, resulting in the excellent blood-compatibility of the carboxybetaine polymers.

Bioprinting with pre-cultured cellular constructs towards tissue engineering of hierarchical tissues

“…Zwitterionic polymers, which have both anion and cation in a single molecule, are known as excellent bio-functional materials that prevent both cell adhesion and protein adsorption [17,18] , and are also useful for bio-patterning [19,20] . In this work, zwitterionic polymers were prepared using 1-carboxy-N,Ndimethyl-N-(2'-methacryloyloxyethyl)methanaminium inner salt also known as carboxymethyl betaine (CMB) was kindly donated from Osaka Organic Chemical Industry, Kashiwara, Japan, and n-butylmethacrylate (BMA) obtained from Wako, Osaka, Japan, at the rate of (CMB/BMA = 29/71; MW = 193 kDa and MW/Mn =1.92; 1 wt% ethanol solution), and utilized as a surface patterning material.…”

Effect of Zwitterionic Polymers on Wound Healing

“…15) CMB (6.19 g) and BMA (8.8 g) were polymerized using AIBN (7.3 mg) as an initiator in ethanol (75 ml) at 70°C for 24 h. The polymer product was dialyzed against methanol for several days (membrane, Spectra/Pro, Spectrum Laboratories, Inc.; exclusion limit, 3.5 kDa). After dialysis, the polymer was precipitated in n-hexane (12.4 g, CMB : BMAϭ3 : 7, MWϭ193 kDa).…”

“…30 mol%), has excellent blood compatibility properties such as suppression of platelet adhesion and complement activation on the polymer surface. 15) Platelet adhesion and complement activation on the polymer surface of poly(CMB-r-BMA) showed a minimum value around 30% of the mole ratio of CMB. Polymers containing zwitterionic moieties such as 2-methacryloyloxyethylphosphorylcholine (MPC) 16) and 3-sulfo-N,N-dimethyl-N-3Ј-methacrylamidopropylpropanaminium inner salt (SPB) 17) also have excellent blood compatibility.…”

Biological specific recognition of glycopolymer- modified interfaces by RAFT living radical polymerization

“…Glycopolymers have multiple OH groups, which could disturb the water structure by hydrogen bonding and induce nonspecific adsorption. 29 The hydrogen-bond formation of glycopolymers with proteins also induces nonspecific adsorption. In the case of the sugar monolayer, the surface was more hydrophobic, with a contact angle of 371, and not only the hydrogen bonding of sugar but also hydrophobic interactions contributed to nonspecific adsorption.…”