Preparation of ‘click’ hydrogels from polyaspartamide derivatives

Abstract

Lately, copper‐assisted azide–alkyne cycloaddition (CuAAC) has become a very interesting tool for synthesizing biocompatible polymer‐based materials such as hydrogels or microgels, which can be used as biomaterials for tissue engineering and drug delivery. Novel poly(2‐hydroxyethyl aspartamide)s (PHEAs) functionalized with pendent acetylene or azide groups were prepared from polysuccinimide, which is the thermal polycondensation product of aspartic acid, through successful ring‐opening reactions using propargylamine, 1‐azido‐2‐aminoethane and ethanolamine. The composition of the prepared copolymers was analyzed using 1H NMR spectroscopy. Clickable PHEA derivatives were crosslinked by mixing together in water with a catalyst system of Cu(I) and N, N, N′, N′, N″‐pentamethyldiethylenetriamine, a type of Huisgen's 1,3‐dipolar azide‐alkyne cycloaddition. The reaction of the polymers resulted in a chemoselective coupling between alkynyl and azido functional groups with multiple formation of triazole crosslinks to give hydrogels. The triazole linkages in the hydrogels are highly stable and may also play a role in swelling behavior. PHEA‐based hydrogels were also obtained by the crosslinking of azide‐ or alkyne‐modified PHEA with a small‐molecule crosslinker. The hydrogels prepared using these two methods were characterized by their degree of swelling and the morphology of the hydrogels was confirmed using scanning electron microscopy. The approach we describe here presents a promising alternative to common chemical hydrogel preparation techniques, and these hydrogels seem to possess structures having potential for a variety of industrial and biomedical applications. © 2012 Society of Chemical Industry

Temperature and pH responsive hydrogels based on polyethylene glycol analogues and poly(methacrylic acid) via click chemistry

“…prove that the PMOH/PMAA hydrogel was prepared by click chemistry. By comparing spectrum (a) with (b), an obvious peak for the azide group stretching vibration at 2050 cm −1 can be observed in spectrum (b), which confirms the successful attachment of azide groups to PMOH . Alkyne groups on the alkyne‐PMAA are confirmed by comparing spectra (c) and (d).…”

Preparation of novel hybrid gels from polyaspartamides and natural alginate or hyaluronate by click reaction

“…The reversible swellingdeswelling of Gel III occurred faster with larger swelling amplitudes compared to Gel IV. The hybrid hydrogels showed higher swelling degrees with improved physical strength compared to previously reported hydrogels [24,26]. Polyaspartamides are versatile and the modification by conjugation of various functional and bioactive moieties onto the pendant is facile.…”

“…The synthetic procedure and characterization of PHEA-N 3 have been described in our previous communication [26,27].…”

“…9 Swelling curves of click Gel III and Gel IV in different solutions solvent) and the amount of crosslinker compound. An increase in concentration leads to a decrease in gelation time [26,27]. As shown in Table 1, 'click' Gel I and Gel II were rapidly formed at room temperature; gelation happened particularly quickly when a 40 % wt/v solution was used.…”

“…The synthesis of AEA was described in our previous report [26]. One gram of PSI was dissolved in 10 mL of DMF in a flask; 0.177 g (20 % mol) of AEA in 5 mL of DMF was also added.…”