Thermogelation of amphiphilic poly(asparagine) derivatives

Abstract

Thermoresponsive sol–gel transition polymers based on biodegradable poly(amino acid) were synthesized by the reaction of poly(succinimide) with dodecylamine and amino alcohols. The introduction of the hydrophobic amine into the thermoresponsive poly(amino acid)s induced the sol–gel transition in phosphate buffer saline. The effects of the side chain structure, molecular weight, concentration of the polymer, and the additives (inorganic salts and urea) in the solution on the thermoresponsive behaviors were systematically investigated. A relationship between the lowest critical solution temperature (LCST) in the dilute solution and the viscosity reduction of the concentrated solution upon heating was observed. The present poly(amino acid)s showing a thermoresponsive sol–gel transition in aqueous solutions possess immense potential as an injectable biodegradable hydrogel system for various biomedical applications. Copyright © 2009 John Wiley & Sons, Ltd.

Temperature/pH Responsive Hydrogels Based on Poly(ethylene glycol) and Functionalized Poly(e-caprolactone) Block Copolymers for Controlled Delivery of Macromolecules

“…The slower release of the TMRD 40 KDa compared to the 10 KDa is perhaps due to the its larger size resulting in slow diffusion, and/or better interaction of TMRD40 KDa with the polymeric network of the gel. For drugs with the molecular size comparable to or larger than the gel pore size, further release will most likely be achieved by erosion/degradation of the polymer network, which does not appear to be happening in this case during the time line of the study (150 min) (26). In fact the results of our degradation study confirms this hypothesis (24).…”

Tuning the gelation of thermoresponsive gels

“…39 In a study by Tarasevich et al the T gel decreased and the gel strength increased while increasing the MM (5300 to 6400 g mol -1 ) of graft polymers where the backbone consisted of D,L-lactide (DLLA) and glycolide (GA), and the side chains consisted of EO. 40 In a contradictory study on amphiphilic thermoresponsive poly(N-substituted α/β-asparagine) derivatives, where polycondensation was used to prepare the polymers, with MMs ranging from 1100 to 5400 g mol -1 it was observed that the polymer with the lowest MM did not demonstrate thermoresponsive behaviour while the rest of the polymers demonstrated similar T gel s. 44 However this observation is ambiguous as the polymers were synthesised with polycondensation and they had a very broad MMD.…”

Biodegradable Polymers Derived From Amino Acids

“…Takeuchi et al synthesized thermoresponsive sol‐gel transition polymers based on biodegradable poly(amino acid) by the reaction of poly(succinimide) with dodecylamine and amino alcohols 55. The introduction of the hydrophobic amine into the thermoresponsive poly(amino acid)s induced the sol‐gel transition in phosphate buffer saline.…”