Accès à l'homopoly(amino sérinate), un polyester aliphatique aminé chiral et son aptitude à former des complexes polyélectrolytiques dégradables

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Degradability of poly(L-lysine) and poly(DL-aminoserinate) complexed with a polyanion under conditions modelling physico-chemical characteristics of body fluids

International audiencePoly(L-lysine), (PLL), and poly(DL-amino serinate), (PSA), are respectively enzymatically and hydrolytically degradable polycations. This work was aimed at investigating their degradability when they are complexed with polyanions, namely poly(acrylic acid) and poly(L-lysine citramide), taken as simple models of DNA in polyplexes. Comparison was made with degradation characteristics of the same polycations in solution in the absence of polyanion on the basis of size exclusion chromatography and capillary zone electrophoresis. Complexed PLL remained enzymatically degradable by trypsin, an endopeptidase, but was no longer degradable by aminopeptidase, an exopeptidase. Trypsin yielded a mixture of trilysin and tetralysin. Complexed PSA remained hydrolytically degradable in aqueous media. The hydrolysis of PSA led to DL-serine. However, traces of anionic species were also detected that were identified as residues of constituting repeating units issued from the N-benzyloxycarbonyl polyaminoserinate precursor (PSAZ)

Complex impedance spectroscopy to investigate degradable chondroitin-poly(amino-serinate) complexes

International audienceSodium chondroitin-4-sulfate and poly(amino-serinate) bromide can interact to form a degradable polyelectrolyte complex. The structure of each polymer and of their complex before and after degradation is investigated by complex impedance spectroscopy. Poly(amino-serinate) bromide and sodium chondroitin-4-sulfate exhibit dc conductivity and dielectric relaxation phenomena in the 102–106 Hz range. On the contrary, no dc conductivity and dielectric relaxation are observed in the polyelectrolyte complex before degradation. After degradation, the released chondroitin-4-sulfate is re-complexed with additional poly(amino-serinate) bromide. Contrary to the original parent complex the restored complex exhibits both dc conductivity and dielectric relaxation phenomena. This difference is assigned to structural defects due to the presence of residual poly(amino-serinate) oligomers which compete with the newly added poly(amino-serinate) to complex the released chondroitin-4-sulfate. This outcome is interpreted assuming the displacement of the low molecular by higher molecular weight chains in contrast to the behavior usually reported for this type of polymeric systems