Cell membranes, interaction synthetic polymers

Interaction of Synthetic Polymers with Cell Membranes and Model Membrane Systems Pyran Copolymer ... 

In this paper, we examine the Interactions of pyran copolymer with model biomembranes of two kinds 1) the human red blood cell membrane (or red cell "ghost") and 11) multilamellar suspensions (liposomes) of dlpalmltoylphosphatldylchollne (DFPC), a pure synthetic phospholipid. Each of these systems offers advantages In studies of polymer-cell surface Interaction The red cell membrane, idille complex. Is still the most readily Isolated and best understood of the membranes of nonnal human cells, and Its molecular architecture Is, In a general way at least, typical of such membranes. The pure phospholipids provide a much simpler biomembrane model, with the prospect of yielding more complete Interpretation of experimental observations. 

Borden KA, Eum KM, Langley KH, Tirrell DA. Interactions of synthetic polymers with cell membranes and model membrane systems. On the mechanism of polyelectrolyte-induced structural reorganization in thin molecular Aims. Macromolecules 1987 20 454-456. 

In general, the properties of a biosystem and a synthetic polymer as well as the nature of the biological medium dictate the degree and type of interaction between a biostructure and a polymer. The biocompatibility of synthetic polymers depends on their chemical nature, physical state, and macroscopic form, which can be modified by functionalization of the polymer skeleton. Many biopolymers, such as proteins and nucleic acids, are natural poly electrolytes. Similarly, the outer cell membrane of living cells has charged groups. The biological medium is an electrolyte with an aqueous phase. Therefore, electrostatic... 

Synthetic carbohydrate polymers, so-called glycopolymers, also exhibit specific interactions with lectins and proteins. Thus, synthetic polymers containing sugar units can mimic functions similar to those found in biological interactions of natural carbohydrates. Figure 5.18 schematically highlights possible interactions of glycopolymer architectures with cell membranes. 

Much of the literature uses simpler synthetic mimics of cell membranes, consisting of vesicles (also known as liposomes) and occasionally flat bilayers supported on a substrate. Most contain no protein in order to focus on polymer-lipid interactions. Membranes meant to mimic mammalian membranes generally consist of PC and may include some cholesterol. Red blood cells (RBCs) also serve as a model system, as they do not divide. Gram-positive bacteria mimics generally consist of PC and cardiolipin, while gram-negative bacteria mimics have PE and PC. 

Another specifity of in vivo conditions is given by the compartmental nature of the body discussed above, Pinocytosis or phagocytosis represent a transport of the polymer in the interior of the cell only in the geometrical sense because the polymer remains physiologically isolated from the cytoplasma by the lysosomal membrane. There are techniques which can open the membrane for macromolecules, e.g. osmotic manipulation or fusing with liposomes However, as far as we know, they have not yet been employed in the study of the effects of synthetic polymers in the cell interior. Although all in vitro studies of the direct interaction of synthetic polymers with nucleic acids, mitochondria, intracellular enzymes, etc., are of undeniable theoretical importance, they yield little information on the effect of these polymers in vivo. 

Such complexation is important to the interaction of synthetic polymers with biological cell membranes, since complex formation has the potential of increasing membrane fluidity or inducing molecular aggregation. 

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