Synthesis of novel polyampholyte comb-type copolymers consisting of a poly(L-lysine) backbone and hyaluronic acid side chains for a DNA carrier.
The polyampholyte comb-type copolymers consisting of a poly(L-lysine) (PLL) main chain, a DNA binding site, and hyaluronic acid (HA) side chains, cell-specific ligands, have been prepared as the DNA carrier targeting sinusoidal endothelial cells of liver. The reducing end of HA and epsilon-amino groups of PLL were covalently coupled by reductive amination to obtain the resulting comb-type copolymers (PLL-graft-HA). The chain length of HA was controlled by the enzymatic hydrolysis of high-molecular weight HA. Since HA formed polyion complexes with PLL, the coupling reaction was carried out with high-ionic strength media to suppress polyion complex formation. The reaction proceeded in a homogeneous system, leading to a high efficiency of coupling (>70%) of HA onto the PLL backbone. By using the enzymatic hydrolysis of HA and the reductive amination reaction between HA and PLL with high-ionic strength media, it is possible to prepare the various comb-type copolymers with a defined density and a defined length of HA side chains. Furthermore, we also find that these polyampholyte comb-type copolymers vary their assembling structure in water in response to two kinds of environmental factors, i.e., ionic strength and pH. Finally, a 1H NMR study reveals that the PLL backbone efficiently interacts with DNA molecules despite the presence of HA side chains having negative charges.
Asayama
S
S
Department of Biomolecular Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8501, Japan.
Nogawa
M
M
Takei
Y
Y
Akaike
T
T
Maruyama
A
A
D002240:Carbohydrate Sequence; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA / Q000737:chemistry; D006820:Hyaluronic Acid / Q000138:chemical synthesis* / Q000737:chemistry; D008969:Molecular Sequence Data; D011107:Polylysine / Q000138:chemical synthesis*; D011108:Polymers / Q000138:chemical synthesis*
D011108:Polymers; D011107:Polylysine; D006820:Hyaluronic Acid; D004247:DNA