Phospholipid coatings for the prevention of membrane fouling

Abstract

The aim of the present work was the development of phosphorylcholine-based treatments for biofiltration membranes and the demonstration that such treatments prevent or inhibit protein fouling. Microfiltration membranes of cellulose triacetate, polyether sulphone and polyvinylidene fluoride were etched with oxygen in a plasma chamber to generate surface hydroxyl groups and were then treated with the monomer 2-methacryloyloxyethyl phosphorylcholine. These membranes were evaluated with water, buffer, bovine serum albumin (BSA), yeast fermentation broth, beer and orange juice. The treatment of cellulose triacetate membranes reduced both the initial flux and the extent of water fouling. In terms of the integrated flux, these factors tended to cancel each other out. For protein, the membranes gave similar or higher fluxes but worse fouling. The cellular feed (yeast) reacted more favourably to the coating than the BSA. The polyether sulphone was scarcely affected by the coating; fouling remaining high with most 'real' feeds. There was lower initial flux but less flux decline with water and beer. Washing with water and cleaning with Tergazyme did not restore the initial flux. Polyvinylidene fluoride membranes gave the most positive results. In most cases, the coating both increased initial flux and decreased the rate of fouling. The coating was particularly effective for BSA and for beer and orange juice, where fouling is probably caused by a polysaccharide rather than by a protein. Electron microscopy showed, nonetheless, that fouling by proteins was accompanied by protein adsorption primarily on the upper surface of the membrane and that coated membranes showed less deposition and in different places than did untreated membranes.

Biomimetic Principles to Develop Blood Compatible Surfaces

“…Early studies on material surface modifications were performed with single zwitterions, but macromolecular approaches have gained increasing importance mainly because polyzwitterions provide a more robust coating and are more efficient at blocking original surface ions (44, 45). This finding has received strong support by adsorption experiments of fibrinogen and cells such as fibroblasts or platelets on surfaces with different coverage of pSBE or pCB brushes, where the capability to prevent fouling correlated with the degree of grafting (46–48).…”

Approaches and Challenges of Engineering Implantable Microelectromechanical Systems (MEMS) Drug Delivery Systems for in Vitro and in Vivo Applications

“…Over time the biomolecules within the body will react with the materials of the device, possibly leading to the passivation and reduced functionality of the device [68,69]. For example, the accumulation of proteins in the pores of the material around the drug output port eventually obstructs it [70]. To prevent biofouling, various types of coatings in addition to the device packaging are used.…”

Nanoporous materials for biomedical devices

“…The thickness of these fouling layers has been estimated to be in the range of 20 nm to 0.5 m. 29 In-vivo microdialysis, in-vitro cell, and protein fouling studies have confirmed that membrane biofouling results in decreased sensor signal strength. 30,31 5 m Figure 2. A scanning-electron micrograph of PEGylated, platinum-coated nanoporous alumina membrane after exposure to human platelet-rich plasma.…”