Characterization of Protein Adsorption at the Phosphorylcholine Incorporated Polymer−Water Interface

Abstract

We have studied the adsorption of a number of model proteins onto the surface of a cross-linkable hydrogel polymer incorporated with phosphorylcholine (PC) groups and dodecyl chains (PC 100B). The structure of the coated thin polymer film was determined by neutron reflection combined with spectroscopic ellipsometry. No measurable change in the thickness of the polymer film was detected within the experimental time scale of minutes when immersed in water, showing a fast water solubilization process. The polymer film at the solid−water interface was modeled using a single layer of 51 ± 3 Å with 40 ± 5% water, suggesting a uniform distribution of water across the polymer film. This film structure is in sharp contrast with the uneven swelling of the film formed from a different hydrogel polymer (PC 100A) which had a similar molar ratio of dodecyl chains and PC groups but did not contain any silyl groups as cross-linkers. The results hence suggest that the uniform structure of the PC 100B film is rendered by the formation of the silyl cross-linking network. The effectiveness of the PC 100B film at reducing protein adsorption under different solution conditions was subsequently characterized. Both neutron reflection and spectroscopic ellipsometry showed substantial reduction in protein adsorption on PC 100B. At the bulk protein concentration around 1 g dm-3 the surface excess was found to be less than 1 mg m-2 for lysozyme and fibrinogen at pH 7 and BSA at pH 5, while under the same solution conditions, the surface excess at the hydrophilic silicon oxide−water interface was 3.6 ± 0.3 mg m-2 for lysozyme, 6.0 ± 0.3 mg m-2 for fibrinogen, and 2.5 ± 0.3 mg m-2 for BSA. Despite the structural difference between the two coated polymer films, the residual level of protein adsorption was found to be comparable between the two PC polymer surfaces. The insensitivity of spectroscopic ellipsometry to the presence of a diffuse protein layer on the surface of the coated polymer films is also discussed.

Surface adsorption of zwitterionic surfactants: n-alkyl phosphocholines characterised by surface tensiometry and neutron reflection

“…For example, our previous work and others have indicated that when incorporated in synthetic polymers PC helps to reduce protein adsorption and provide surface biocompatibility [5][6][7][8][9][10][11][12][13][14][15][16][17]. PC biomaterials are generally benign and non-thrombogenic in vitro and in vivo.…”

Surface Modification of Polyacrylonitrile-Based Membranes by Chemical Reactions To Generate Phospholipid Moieties

“…For the phospholipid modified membranes, the surfaces with the zwitterionic moieties were hydrophilic and electrically neutral in an aqueous environment, which can effectively inhibit the adsorption of protein and the adhesion of platelets. [41][42][43][44] Conclusions Phospholipid moieties could be introduced onto the PANCHEMA membrane surface by the reaction of hydroxyl groups with COP followed by a ring-opening reaction with trimethylamine. Therefore, the density of phospholipid moiety on the membrane surface could be controlled by varying the content of HEMA in the copolymer.…”

Hollow poly(MPC-g-PEG-b-PLA) graft copolymer microcapsule as a potential drug carrier

“…Resistance of protein adsorption is one of the most important factors to develop a prolonged drug carrier. Many researchers have reported that MPC polymers could effectively reduce non-specific protein adsorption and cell adhesion (Murphy et al, 2000;Chen et al, 2005;Iwasaki and Ishihara, 2005). In fact, this property is crucial for the long circulation of the nanoparticles in blood.…”