Enhancement of Intracellular Calcium Ion Mobilization by Moderately but Not Highly Positive Material Surface Charges

Martina Gruening; Sven Neuber; Peter Nestler; Jutta Lehnfeld; Manuela Dubs; Katja Fricke; Matthias Schnabelrauch; Christiane A Helm; Rainer Müller; Susanne Staehlke; J Barbara Nebe

doi:10.3389/fbioe.2020.01016

Enhancement of Intracellular Calcium Ion Mobilization by Moderately but Not Highly Positive Material Surface Charges

Front Bioeng Biotechnol. 2020 Sep 8:8:1016. doi: 10.3389/fbioe.2020.01016. eCollection 2020.

Authors

Affiliations

¹ Department of Cell Biology, Rostock University Medical Center, Rostock, Germany.
² Soft Matter and Biophysics, Institute of Physics, University of Greifswald, Greifswald, Germany.
³ Colloid and Interface Chemistry, Institute of Physical and Theoretical Chemistry, University of Regensburg, Regensburg, Germany.
⁴ Department of Biomaterials, INNOVENT e.V., Jena, Germany.
⁵ Leibniz Institute for Plasma Science and Technology e.V. (INP), Greifswald, Germany.
⁶ Department Science and Technology of Life, Light and Matter, Faculty of Interdisciplinary, University of Rostock, Rostock, Germany.

Abstract

Electrostatic forces at the cell interface affect the nature of cell adhesion and function; but there is still limited knowledge about the impact of positive or negative surface charges on cell-material interactions in regenerative medicine. Titanium surfaces with a variety of zeta potentials between -90 mV and +50 mV were generated by functionalizing them with amino polymers, extracellular matrix proteins/peptide motifs and polyelectrolyte multilayers. A significant enhancement of intracellular calcium mobilization was achieved on surfaces with a moderately positive (+1 to +10 mV) compared with a negative zeta potential (-90 to -3 mV). Dramatic losses of cell activity (membrane integrity, viability, proliferation, calcium mobilization) were observed on surfaces with a highly positive zeta potential (+50 mV). This systematic study indicates that cells do not prefer positive charges in general, merely moderately positive ones. The cell behavior of MG-63s could be correlated with the materials' zeta potential; but not with water contact angle or surface free energy. Our findings present new insights and provide an essential knowledge for future applications in dental and orthopedic surgery.

Keywords: amino polymer; calcium ion signaling; human osteoblasts; polyelectrolyte multilayer; surface charge; titanium surface modification; wettability; zeta potential.