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Poster Session

The role of material’s zeta potential on intracellular calcium ion signaling

Tuesday (18.06.2019)
20:02 - 20:03

Biomaterial surfaces for bone implants are modified to achieve a faster attachment of osteoblasts and thus a better osseointegration and regeneration of the surrounding tissue. In this, the material´s physico-chemical properties play an essential role as they are known to affect the cell physiology at the interface [1]. It has been found out that a positively charged, amino-group containing titanium (Ti) surface can amplify osteoblastic cell functions [2-4] such as the calcium ion (Ca2+) mobilization [5]. We hypothesize that surface charges play a crucial role in the material-cell interaction.To confirm this, we currently investigate the intracellular Ca2+ dynamic on Ti modifications with different surface charges.

We chemically modify plane silicon-Ti arrays (10x10 mm, ZfM, TU Chemnitz) by (i) amino functionalization via coating with the monomer allylamine by a pulsed plasma polymerization process (PPAAm) [5], (ii) polyelectrolyte multilayers (terminated with polydimethyldiallylammonium chloride using layer-by-layer assembly [6] and (iii) coatings with collagen-type I, Matrigel (basement membrane-like matrix) and the integrin adhesion peptide sequence Arg-Gly-Asp (RGD). We determine the surface charge by zeta potential measurements and the wettability by water contact angle measurements [5]. To evaluate the surface property-dependent mobilization of intracellular Ca2+, human MG-63 osteoblasts (ATCC) are stained with the calcium dye Fluo 3-acetoxymethyl ester and stimulated with adenosine 50-triphosphate to induce an immediate Ca2+ signal [5].

Our data have shown, especially for the positively charged PPAAm surface (zetapotential:+ 8.6 mV), a high increase of intracellular Ca2+ ions following an ATP stimulation (mean fluorescence intensity (MFI) level at 188–480 s: 89.1±1.9, mean±sem) compared to cells on uncoated Ti (MFI level at 188–480 s: 51.9±0.6, mean±sem) (n=3) [5].

Hence, we assume that the influence of a positive zeta potential on the cellular behavior dominates other surface properties like wettability. However, it is important to extend these studies to investigate which properties are favored by osteoblastic cells.

[1] Moerke et al, J Cell Sci 131: jcs207001, 2018

[2] Finke et al, Biomaterials 28: 4521-4534, 2007

[3] Rebl et al, Acta Biomater 8: 3840-3851, 2012

[4] Kunz et al, Eur Cell Mater 29: 177-189, 2015

[5] Staehlke et al, Cell Biosci 8(22), 2018

[6] Decher et al, CurrOpin Colloid Interface Sc 3(1): 32-39, 1998

Martina Gruening
Rostock University Medical Center
Additional Authors:
  • Sven Neuber
    University of Greifswald
  • Prof. Dr. Christiane Helm
    University of Greifswald
  • Dr. Katja Fricke
    Leibniz Institute for Plasma Science and Technology e.V. (INP)
  • Dr. Matthias Schnabelrauch
  • Dr. Birgit Finke
    Leibniz Institute for Plasma Science and Technology e.V. (INP)
  • Prof. Dr. Barbara Nebe
    Rostock University Medical Center