In vitro cytotoxicity testing of AB‐polymer networks based on oligo(ϵ‐caprolactone) segments after different sterilization techniques

Abstract

Recently developed versatile biodegradable polymeric biomaterial offer new therapeutic options in numerous medical fields. Biocompatibility is a crucial requirement for the biomedical application of biomaterials, including the sterilization of these materials with the use of accepted protocols. Ethylene-oxide (EO) and low-temperature plasma (LTP) sterilization are frequently used low-temperature sterilization technologies for heat-sensitive materials. The agarose diffusion assay is a recommended cell-screening test to assess the cytotoxicity of biomaterials in vitro. The sensitivity of the agarose assay can be increased by using a modified computer-based image-analysis system. The influence of EO and LTP sterilization on the cytotoxicity of a versatile polymer system of shape-memory polymer networks based on oligo (epsilon-caprolactone) dimethacrylate and n-butyl acrylate was investigated. Statistically significant differences in the rate of cell lysis after EO and LTP sterilization of the polymer samples were detected by using this modified quantification system. The influence of the different sterilization techniques on the cytotoxicity of the polymeric material, as well as the clinical relevance of the described differences, are discussed.

Shape-Memory Polymer Networks from Oligo[(ε-hydroxycaproate)-co-glycolate]dimethacrylates and Butyl Acrylate with Adjustable Hydrolytic Degradation Rate

“…Table 3 also shows the thermal properties of macrodimethacrylates depending on M n and the glycolate content. T g of the macrodimethacrylate DMAC-CG (14) shows no systematic dependency on the molecular weight. The values for T g of the functionalized oligomers are about 7 to 8 K higher in comparison to T g of the macrodiols.…”

“…The results of the 1 H NMR analysis of the macrodimethacrylates DMAC-CG for the determination of the degree of methacrylation are shown in Table 1 Swelling Behavior of the Copolymer Networks. The values determined for Q and G of the copolymer networks N-CG (14) in chloroform with varying M n of chain segments are shown in Table 2. Q of the copolymer networks N-CG (14) increases with increasing M n of chain segments of the oligomers from 440 to 960%.…”

“…In the case of AB-copolymer networks an additional T g is observed, which can be correlated to the additional amorphous domains provided by oligo(butyl acrylate) segments. The results of the thermal analysis of copolymer networks N-CG (14) by DSC are shown in Table 2. While T g of copolymer network N-CG(14)-3 is -56°C, the values for T g of the copolymer networks with higher chain segment M n are at -53°C.…”

“…Second, to simulate conditions relevant for medical application in the body, the strain recovery of samples, which are programmed in air, is performed in water. Figure 3 shows the programming of the temporary shape in the fifth cycle of a strain-controlled, cyclic, thermomechanical tensile test of copolymer networks N-CG (14). Divergent from the standard program due to the limit in R , the tests are performed using a maximum elongation of 75%.…”

Biodegradable, Amorphous Copolyester‐Urethane Networks Having Shape‐Memory Properties

“…[4] The blocks that determine the switching segment may display T trans as either a melting temperature or a glass transition temperature. In biodegradable shape-memory polymers previously described as thermoplastic multiblockcopolymers [3] or photoset AB polymer networks [2,5] T trans is the melting point of crystallizable oligo(e-caprolactone) segments. Hydrogels with hydrophobic and crystallizable side chains as molecular switches also can show a thermoresponsive one-way shape-memory effect.…”