In vitro study of partially hydrolyzed poly(2-ethyl-2-oxazolines) as materials for biomedical applications

Abstract

Polymers based on 2-oxazoline, such as poly(2-ethyl-2-oxazolines) (PETOx), are considered to be a type of ‘pseudopeptide’ with the ability to form novel biomaterials. The hydrolysis of PETOx was carried out to evaluate its use in biomedical applications. In the present work, PETOx samples with a range of molar masses were prepared by living cationic polymerization. Hydrolysis was carried out at time intervals ranging from 15 to 180 min to prepare copolymers with different amounts of ethylene imine units. 1H NMR spectroscopy was used to identify the structure of the hydrolyzed polymers. The dependence of in vitro cell viability on the degree of hydrolysis was determined using three different model cell lines, namely, mouse embryonic 3T3 fibroblasts, pancreatic βTC3 cells, and mouse lymphoid macrophages P388.D1. It was demonstrated that increasing the degree of hydrolysis decreased cell viability for all cell types. Fibroblast cells displayed the highest tolerance; additionally, the effect of polymer size showed no observable significance. Macrophage cells, immune system representatives, displayed the highest sensitivity to contact with hydrolyzed PETOx. The effect of polymer hydrolysis, polymer concentration and the incubation time on cell viability was experimentally observed. Confocal laser-scanning microscopy provided evidence of cellular uptake of pyrene-labeled (co)polymers.

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Acknowledgments

Authors from the Polymer Institute of the Slovak Academy of Sciences are thankful the Slovak Grant Agency, VEGA, for financial support of Projects No. 2/0151/12 and 2/0163/12. Authors from the Centre of Polymer Systems are thankful for the support of the Operational Program Education for Competitiveness co-funded by the European Social Fund (ESF) and the national budget of the Czech Republic, within the framework of the Advanced Theoretical and Experimental Studies of Polymer Systems (reg. number: CZ.1.07/2.3.00/20.0104) Project, including partial support from the Ministry of Education, Youth and Sports of the Czech Republic (Project No: ME-LH14050).

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Correspondence to Juraj Kronek.

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Shah, R., Kronekova, Z., Zahoranová, A. et al. In vitro study of partially hydrolyzed poly(2-ethyl-2-oxazolines) as materials for biomedical applications. J Mater Sci: Mater Med 26, 157 (2015). https://doi.org/10.1007/s10856-015-5485-4

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Keywords

  • High Performance Liquid Chromatography
  • Molar Mass
  • Lower Critical Solution Temperature
  • Cationic Polymer
  • Cationic Polymerization