Structural Transition of pH-responsive Poly(l-lysine) Hydrogel Prepared via Chemical Crosslinking

Abstract

Poly(l-lysine) (PLL) undergoes structural change from α-helix to random coil in response to a change in pH in an aqueous solution. By chemical crosslinking of PLL with ethylene glycol diglycidyl ether (EGDE), we prepared pH-responsive hydrogels that undergo a change in volume and conformation between α-helix and random coil in response to a change in pH. The difference in transition pH between a PLL linear polymer and a PLL hydrogel revealed that chemical crosslinking stabilized the helical structure of PLL chains in hydrogel networks.

Water solubilization of paclitaxel using polypeptides for cancer therapy

“…26 These fascinating properties of HSVM encouraged us to develop polypeptide-based water solubilization methodologies because of their excellent biocompatibility, biodegradability, and functionality. [28][29][30][31] In this work, we report the water solubilization of the hydrophobic anticancer drug paclitaxel (PTX) using polypeptides, including poly-L-lysine (PLL), poly-L-g-glutamic acid (PGA), and collagen (Col), for cancer treatment (Fig. 1).…”

NIPAm-Based Modification of Poly(L-lysine): A pH-Dependent LCST-Type Thermo-Responsive Biodegradable Polymer

“…As it is well known, PLL adopts various secondary structures depending on pH and temperature [ 15 , 21 ]. At pH 10.6, the nearly uncharged PLL adopts mainly an α-helix secondary structure, i.e., about 80%, which becomes 100% above pH 11.5 [ 22 ]. Upon heating an α -helix-to- β -sheet conformational transition is expected above a critical temperature which depends on molecular weight, i.e., the lower the molecular weight the higher the transition temperature [ 23 ].…”

pH-Responsive Polypeptide-Based Smart Nano-Carriers for Theranostic Applications

“…Nano-micelles designed based on poly( l -lysine-4-azepan-1-yl-butyric)- b -PEG- b -poly(leucine) were able to response to different pHs. Chemical cross-linking of PLL with ethylene glycol diglycidyl ether yields a pH-responsive hydrogel, which can change its volume and conformation from α-helix to random coil with change in pH (Figure 2) [54]. Recently a pH-responsive asymmetric dendron-like polypeptide-based polyampholyte was reported by Chen et al Poly( l -lysine) 4 - d 2 - b - d 1 -poly( l -glutamic acid) 2 [(PLL) 4 - d 2 - b - d 1 -(PLGA) 2 ], where D 1 and D 2 are the first and the second generation poly(amido amine), was synthesized by the combination of ring-opening polymerization and click chemistry.…”

“…Illustration of the structural change of poly( l -lysine) from α-helix to random coil in response to pH change. Reproduced with permission from [54]. Copyright 2015, The Chemical Society of Japan.…”