Lysine-based polymers

Wang W, Tetley L, Uchegbu I F (2001). The level of hydrophobic substitution and the molecular weight of amphiphilic poly-L-lysine-based polymers strongly affects their assembly into polymeric bilayer vesicles. /. Colloid Interface Sci. 237 200-207. 

Uchegbu and coworkers have studied the complexation and delivery of DNA using a unique poly(amino acid)-based polymer vesicle. A polymer of either poly (L-lysine) or poly(L-omithine) was functionalized with methoxy-poly(ethylene glycol) (mPEG) and hydrophobic palmitic acid chains to synthesize an amphiphilic triblock of either mPEG-6-poly(L-lysine)-6-palmitoyl or mPEG-Z>-poly(L-omithine)-6-palmitoyl. Vesicles formed from these polymers were complexed with DNA and showed improved transfection in vitro over poly(amino acid) complexed with DNA or DNA alone [82]. 

Fig. 2. Lysine-based dendron 1 of 2nd generation and a similar dendron 2 of 4th generation with PEG as soluble polymer support [8,9]...

Lee and Wang [80] investigated the effects of lysine-based diisocyanate (LDI) as a coupling agent on the properties of biocomposites from PLA, poly (butylene succinate) (PBS) and bamboo fiber (BF). They observed that the tensile properties, water resistance, and interfacial adhesion of both PLA/BF and PBS/BF composites were improved by the addition of LDI, but thermal flow [81] was hindered due to cross-linking between polymer matrix and BF. Enzymatic biodegradability of... 

Encapsulation and delivery of DNA has also been investigated with poly(amino acid) (poly(AA)) based polymer vesicles. Brown and coworkers synthesized an amphiphilic triblock copolymer from methoxy-poly(ethylene glycol) (mPEG), hydrophobic palmitic acid chains in block segments along a poly-L-lysine (PLL) or... 

Poly(L-lysine-fllt-isophthalamide) polymers were prepared with leucine side chains varying in mole fraction between 10% and 75% (Figure 13). The base polymer, whose MW was 17.9 kDa and PDI was 2.0, was used for all leucine modifications. The pH solubility of these copolymers was measured using turbidity at 480 nm and Imgml" of polymer. Copolymers containing 10% leudne showed an onset of pre-dpitation at pH = 4.7, very similar to the parent polymer, which inaeased to pH = 5.7 for the 75% leudne sample. The pyrene assay was employed and showed that the 10% leudne polymer appeared as an expanded coil at pH a 5.3 and collapsed to a globule below pH = 4.2. As typically observed, the... 

Thus, as shown in Figure E.7, a remarkable control of pharmaceutical release is possible. Furthermore, the pharmaceutical can vary all the way from a simple bare cation or anion to a protein or nucleic acid. Under favorable circumstances, as with carboxylate groups, the vehicle disappears as the pharmaceutical releases. With a cationic polymer such as a lysine-containing protein-based polymer, the chloride ion can displace the pharmaceutical to lessen the zero order release. Significantly, with elastic protein-based polymers, no fibrous capsule forms around the adequately purified polymer such that this does not affect the release process. 

Preparation of chemically cross-linked fibers Chemical cross-linking was achieved by extrusion of solutions of E- and K- pairs of polymers at equal concentrations of functional groups into a saturated solution at 50 C of water soluble carbodiimide (EDC, l-(3-dimethy-laminopropyl)-3-ethylcarbodiimide) to form amide bonds between the carboxyl of glutamic acid (E) residues and the e-amino groups of lysine (K) residues. When in an adequately hydrophobic elastic protein-based polymer, the charged carboxylate and amino functions experience a driving force for ion-pairing. The force... 

Cationic amino acid-based polymers possess limited transfection efficacies due to their high toxieities. To solve this problem. Pun and colleagues prepared poly(L-lysine) (PLL) and poly(hydroxypropyl methacrylate) (PHPMA)... 

Susuki, M. Owa, S. Shirai, H. Hanabusa, K., Poly(dimethylsiloxane)-Based Polymer Organogelators with L-Lysine Derivatives as an Organogelation-Causing Segment. J. Polym. Sd., Part A Polym. Chem. 2006,44, 3817-3824. 

Wiggins,J.S. and Storey, R. (1992) Synthesis and characterization of l.-lysine based poly(ester-urethane) networks. Polym. Preprints., 32, 516-517. 

T.T. Reddy, A. Kano, A. Maruyama, A. Takahara, Synthesis, characterization and drug release of biocompatible/biodegradable non-toxic poly(urethane urea)s based on poly(E-caprolactone)s and lysine-based diisocyanate, J. Biomater. Sci. Polym. Ed. 21 (2010) 1483-1502. 

Liu K, Zhang X, Tao X, Yan J, Kuang G, Li W, Zhang A (2012) Lysine-based dendronized polymers with preferred chirality. Polym Chem 3(10) 2708-2711. doi 10.1039A32PY20510F... 

Historically, after the development of oligopeptide-based vesicles, several groups developed and characterized vesicles using polypeptide hybrid systems consisting of polypeptide and synthetic polymer blocks [17-19]. Soon thereafter, vesicles formed entirely from polypeptides, such as poly(L-lysine)-h-poly(L-leucine) and poly(L-lysine)-h-poly(L-glutamate), were developed [20, 21]. This review will focus on recent developments in the formation of vesicles composed of polypeptide hybrid or polypeptide systems, as well as the potential promise of these systems as effective dmg delivery vehicles. A specific example of a polypeptide-based vesicle is shown in Fig. 1, where the hydrophobic segment is a-helical and the hydrophilic segment is a random coil. 

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