Biointerfacial analysis of HEK293 cells in contact with hydrogels based on Poly-N-Isopropylacrylamide and Copolymers

Abstract

Several researches have demonstrated that synthetic hydrogels can mimic the mechanical and physicochemical properties of native extracellular matrices and act as cell-scaffold. The biointerface can influence over tissue activities such as adhesion, signaling, cell–cell communications, and proliferation. In this work, the behavior of human embryonic kidney cells (HEK293) in contact with hydrogel surfaces based on poly-N-isopropylacrylamide (PNIPAM) and copolymers is studied. Ionic and neutral hydrogel surfaces are synthesized by free radical polymerization and characterized by Fourier-transform infrared spectroscopy, swelling capacity, and wettability at culture conditions. Viability, proliferation, and bioadhesive capacity are analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Neutral Red assays, [3H]-thymidine technique, Acridine Orange and Hoechst dye. Noncytotoxic and proliferative effects are observed in all cases. HEK293 cells are mainly adapted and adhered on neutral and low ionic charge surfaces showing typical cell morphology, and normal mitotic rates. While, lower adhesion, abnormal nuclear and cytoplasmic morphologies with mitotic/fragmentation processes are observed after contact with high ionic surfaces. The cellular cycle after cultive on PNIPAM, assessed by flow cytometry, is not affected regarding control surfaces (polystyrene). Therefore, hydrogel surfaces with neutral and low ionic charges can be apt to in vitro tissue development and possible applications of biomedical treatments.