Hemolytic activities, amphiphilic

It was found that unloaded PEBPBLA micelles cause no hemolysis, even at a level of 0.70 mg/mL. PECb-PBLA has an extremely low critical micelle concentration (Kwon et al., 1993), and thus, there is little monomeric PBEPBLA for the lysis of lipid bilayer membranes. In addition, PEO-bPBLA micelles may break apart slowly to monomers. The lack of hemolytic activity of PEO-bPBLA contrasts strongly with other amphiphiles used for drug solubilization and intravenous drug administration. Sodium deoxycholate causes 100% hemolysis at a level of 0.32 mg/mL. This is due to disruption of lipid bilayer membranes of red blood cells. 

Antimicrobial activity of cationic ROMP polymers has therefore been assessed (18, Figure 8.9) [106,107]. Amphiphilic polynorbornene (PNBE) derivatives were generated, and the antimicrobial and hemolytic activities evaluated to maximize the selectivity of the polymers toward prokaryotic cell disruption. A minimum charge density per polymer was required for antimicrobial activity, but when... 

The balance between hydrophilic and hydrophobic moieties was found to be a very important parameter for the preparation of antimicrobial amphiphilic polycations. On the one hand, the cationic part of the macromolecule is the main reason for electrostatic interactions with the anionic components of the bacterial cell surface.On the other hand, the mode of action of amphiphilic polycations calls for a certain hydrophobicity otherwise, the amphiphilic polycations would not be able to penetrate the bacterial cell membrane.However, it has been pointed out in various investigations that the higher the hydrophobic part, the higher the hemolysis rate will be. This means that there has to be an optimum value for an amphiphilic polymer system that offers maximum efficacy against bacteria and, simultaneously, minimal hemolytic activity. As pointed out by Palermo and Kuroda, there are mainly three different strategies used to tune the balance between the... 

Fig. 4 (a) Antimicrobial and hemolytic activity of three a,(3-peptides (1-3), compared to AMP magainin. (b) Axial view of predicted conformations of helical SMAMPs. Cationic residues are in red, hydrophobic residues are in black. SMAMP 1 is facially amphiphilic as an 11-helix (left column), SMAMP 2 is facially amphiphilic as a 14-helix (right column), and SMAMP 3 is facially amphiphilic in neither [65]... 

A synthesis of fluorolipopeptides by the modular methodology (Scheme 32) leads to the nonionic amphiphilic structures 38 [86,87]. Because derivatives 38 are poorly soluble in water, their surfactant properties have been determined in formamide [88]. Hemolytic tests carried out with some of these compounds indicate no activity toward red blood cells they show, however, a marked toxicity for hybridoma cells [89]. 

The antibacterial activity of grammistins is a consequence of their amphiphilic a-helical structure. They are active against Gram-positive and Gram-negative bacteria as a consequence of their membrane-lytic activity, but they are not all hemolytic and ichthyotoxic (Yokota, Naga-shima, and Shiomi, 2001 Sugiyama et al, 2005). 

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