Cationic hydrogels

Fig. 5. Expansion (swelling) of a cationic hydrogel due to ionization of pendent groups, at specific pH values.

Brannon-Peppas and Peppas [13, 14] have derived models to describe this ionic contribution term for both anionic and cationic hydrogels. Here the... 

Podual, K. Doyle, F.J., III Peppas, N.A. Dynamic behavior of glucose oxidase-containing microparticles of poly(ethylene glycol)-grafted cationic hydrogels in an environment of changing pH. Biomaterials 2000, 21, 1439-1450. 

Vinogradov SV, Bronich TK, Kabanov AV. Nanosized cationic hydrogels for drug delivery Preparation, properties and interactions with cells. Adv Drug Deliver Rev 2002 54 135-147. 

By radical copolymerization of poly(A/-isopropylacrylamide-co-N,iV-dime-thylaminoethyl methacrylate) [poly(NIPAM-co-DMAEMA)] macromonomer with the monomers NIPAM and DMAEMA, comb-type cationic hydrogels with poly(NIPAM-co-DMAEMA) backbone networks and grafted poly(NIPAM-co-DMAEMA) side chains can be successfully prepared. Within the comb-type hydrogels the grafted chains have freely mobile ends, which are distinct from typical network structures of normal-type crosslinked hydrogels, as shown in Figure 5.7. The obtained hydrogels show both temperature and pH sensitivity. They all deswell with an increase of temperature and/or pH, and exhibit a lower critical solution temperature (LCST) at about 34 °C and a p a value at about pH 7.3. 

The aim of this chapter is to give a brief selective overview of typical biomedical areas where cationic polymers can be employed. The use of cationic polymers in tissue engineering is a high priority topic in this chapter and several aspects on this phenomenon are given related to this is the potential of cationic hydrogels for medical and pharmaceutical applications. The importance of cationic polymers and copolymers as non-viral vectors in gene therapy is described, as well as how micelles and vesicles based on cationic polypeptides can form nanostructures by self-assembly. The potential of cationic polymers for drug delivery applications is also elucidated. 

In the paragraph above, we have discussed hydrogels of chitosan and cationic hybrid gels, based on chitosan, with potential for biomedical applications. However, there are also other cationic hydrogels that can be useful for medical and pharmaceutical applications. Jia et al. designed a... 

Cationic polymer-based nanogels are nanosized swollen cationic hydrogel particles composed of chemically or physically crosslinked polymer net-works/ The highly hydrated properties and tightly crosslinked core makes these systems superior in colloidal stability. These properties make these nanogels suitable for encapsulation of therapeutic nucleic acids in the core for carrier systems for delivery, in comparison to macroscopic hydrogels or nanoparticles. ... 

Cationic hydrogel swelling behavior at low pH the drug is released due to the swelling of the polymer network. (Source-. Reprinted and adapted from Reyes eta ., 2013, copyright 2013, with permission from Elsevier B.V.)... 

Farmer,T. G., Edgar,T. F. and Peppas, N. A. (2008) In vivo simulations of the intravenous dynamics of submicrometer particles of ph-responsive cationic hydrogels in diabetic patients . Industrial Engineering Chemistry Research, 47, 10053-10063. 

Schwartz, L.M. and Peppas, N.A. (1998) Novel poly(ethylene glycol)-grafted, cationic hydrogels preparation, characterization, and diffusive properties. Polymer, 39, 6057-6066. 

Pang, X., Wu, J., Chu, C.C., Chen, X., 2014. Development of an arginine-based cationic hydrogel platform synthesis, characterization and biomedical applications. Acta BiomateriaHa 10,3098-3107. 

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