Functionalization of Cationic Polymers

Copolymerizing DMAEMA with monomers that possess primary amino, imidazole or carboxylic functionalities has been investigated as well, in order to enhance the endosomal escape, but all of the researched copolymers showed limited transfection/  

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Functionalization of Cationic Polymers for Drug Delivery Applications... 

One solution to this problem is to create new copolymers of lignin which have the appropriate functional groups to perform effectively in a given environment. One such class of new materials with the right parts to function where anionics fail is the class of cationic polymers. Data from such a copolymer will now be presented. 

These contain redox-active centers able to switch on/off cation or anion complexation when treated with redox reagents or electrochemical stimulation. Examples include some ferrocenyl-containing macrocycles, such as (159), or donors with an anthraquinone fragment, as in (160).252 The functionalization of electroactive polymers by monocyclic polyethers has been used for the building of cation-responsive electrodes. 

Figure 6.39 Separation factors as a function of the number of methylene units between ionic sites of cationic polymers used in the formation of polyion complex membranes (pervaporation of 90% aqueous ethanol solution at 30 °C). Polyion complex membranes prepared by ion complex formation between k-carrageenan (anionic polymer) and poly[l,3-bis(4-alkylpyridinium)propane bromidejs (cationic polymer) with different numbers of methylene units between ionic sites.

FIGURE 16.10 Yield functions of cationic fragments desorbed from a plasma-polymerized FP under LEE impact. (Polym. Degrad. Stab., 93, Massey, S., Cloutier, R, Hale, P. et al.. Low-energy electron and x-ray degradation of biomedical plasma-fluoropolymer, 383-391, Copyright 2008b, with permission from Elsevier.)... 

This is also the reason why in recent years a variety of modifications to commonly applied cationic delivery systems have been made and the continuing research in multidisciplinary areas of cationic polymers will surely lead to further improved designs, which is only achievable by understanding the possibilities and limitations of conjugation and functionalization chemistry. 

The cytotoxicity of cationic polymers is seen as a major limiting factor in their success as drug or gene delivery vectors. Mechanisms of cytotoxicity caused by polycations is not yet fully understood however, mechanisms are thought to be influenced by different properties of the polymers, such as (i) MW, (ii) charge density and type of the cationic functionalities, (iii) structure and sequence, such as block, random, linear and branched, and finally (iv) conformational flexibility. ... 

Effect of Cationic Polymers on the Functions of Mesenchymal Stem Cells... 

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