The functional and structural effects of an amphipathic pH responsive biopolymer: A comprehensive study in osteosarcoma cells

• Cytotoxicity of an amphipathic biopolymer, PP-50, was evaluated in osteosarcoma cells.
• Cellular metabolic activity, membrane integrity and morphology were analysed.
• PP-50 was shown to have no negative effects on cell viability.
• A robust method to determine cellular viability effects of polymers was established.

The use of amphipathic pH-responsive polymers to transport sugars across cell membranes has been shown to improve the cryopreservation of mammalian cells. However, the effect of these polymers on cell viability and morphology has not yet been thoroughly analysed. In this study, the objective was to investigate the functional and structural effects of an amphipathic polymer, PP-50, upon an osteosarcoma cell line (SAOS-2). Cellular growth curves confirmed similar doubling times in PP-50 treated cells and untreated cells. PP-50 concentrations (10–2000 μg/ml) were well tolerated by cells after 2, 24 and 48 h of incubation, as measured by mitochondrial enzyme activity and Lactate Dehydrogenase release. Analysis by flow cytometry demonstrated that PP-50 did not induce any additional apoptosis or necrosis in polymer treated cells compared to untreated cells. Phase contrast, confocal and transmission electron microscopy analysis of PP-50 treated cells revealed no signs of morphological changes, with cells maintaining their nucleus size and membrane integrity after treatment. PP-50 was shown to have no negative cellular effects, which is a critical characteristic of polymers towards use in cryopreservation and biomedical applications. In addition, the methodology and protocols established in this work provided a robust and comprehensive analysis of PP-50’s cellular effects, thus making them well suited for determining these effects in mammalian cells exposed to other polymers intended for biological applications.

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