FT-IR characterization and hydrolysis of PLA-PEG-PLA based copolyester hydrogels with short PLA segments and a cytocompatibility study

Abstract

Telephone: + 61 7 334 63860; Facsimile: + 61 7 334 60330 Keywords 2 Structure-property relations, hydrolytic degradation, infrared spectroscopy, in-vitro cytocompatibility, poly(PEG-co-lactide) hydrogel AbstractA series of the biodegradable copolyester hydrogels was prepared using a redoxinitiated polymerization with a constant 1:9 mole ratio of the Boltorn-based acrylate and diacrylate triblock comacromonomers. The Boltorn® macromonomer was derived from the hyperbranched polyester Boltorn H20, which was functionalized at each terminus with poly(ethylene glycol) acrylate, and the diacrylate triblock macromonomer was poly(lactide-b-ethylene glycol-b-lactide) diacrylate. The hydrolysis of the copolyesters at pH 7.4 in a phosphate buffered saline solution at 37 °C was studied using ATR-FTIR spectroscopy. It was found that the presence of the Boltorn, the PEG and lactide block lengths both play vital roles in determining the structure-property relationships in these materials. The ATR-FTIR studies showed that with increasing lactide segment length, the rate of ester hydrolysis increased due to the increased concentration of the hydrolytically-sensitive PLA ester groups in the network. However, incorporation of Boltorn into the PLA-PEG-PLA copolymer did not significantly change the kinetic rate constant for hydrolysis of the PLA segments.The cytocompatibility of a typical one of these materials in the presence of its degradation by-products was assessed using cultured osteoblasts from the rat. The hydrogel was degraded for 28 days and found to be cytocompatible with osteoblasts over days 23 to 28 of the hydrolysis period.

Interaction and quantification of thymol in active PLA‐based materials containing natural fibers

“…The carbonyl (>CO) stretching peak at 1746 cm −1 is due to the carbonyl group in the lactic acid ester moiety of PLA . The deformational vibrations of CH in the methyl group of PLA are also observed in the range of 1300 to 1500 cm −1 . The peak at 1180 cm −1 is due to the stretching vibration of COC and another asymmetric stretching vibration of COC is observed in the range of 1150–1060 cm −1…”

“…The absence of the OH stretching band in the spectrum of the neat PLA confirms that this particular grade of PLA (7001D) is hydrophobic. The carbonyl (>CO) stretching peak at 1746 cm −1 is due to the carbonyl group in the lactic acid ester moiety of PLA . The deformational vibrations of CH in the methyl group of PLA are also observed in the range of 1300 to 1500 cm −1 .…”

Efficient functionalization of magnetite nanoparticles with phosphonate using a one-step continuous hydrothermal process

“…40 Moreover, PHA molecules have aliphatic chains, the adsorption energy of which can be responsible for the decrease in the diameter of Fe 3 O 4 -PHA NPs as reported in the case of the use of ammonium base (R 4 NOH with R = CH 3 , C 2 H 5 , C 3 H 7 ) during iron oxide NP synthesis. 42,43 Measurements by XPS presented in Fig. The presence of phosphorus, carbon and oxygen elements which compose PHA is confirmed in Fig.…”

“…The same effects have been observed in the case of citric acid on iron oxide NPs obtained by coprecipitation. 42 A broad band between 3500 cm −1 and 3000 cm −1 is detected and corresponds to water molecules and OH vibrations from the carboxylic groups are discerned at 1556 cm −1 and 1404 cm −1 (asymmetric and symmetric stretching of CO 2 − groups). 41 Spatial conformation of PHA molecules on NP surfaces FTIR spectroscopy and XPS confirm the grafting of PHA on Fe 3 O 4 NPs.…”

“…Regarding the carboxylate group of PHA (without interaction with other elements or functional groups), absorption bands are usually observed around 1620 cm −1 . This corresponds to COO − asymmetric and symmetric stretching respectively 42,44 and can be attributed to an interaction between the NP surface and COO − groups. 8.…”