Tuning Cell Adhesion and Growth on Biomimetic Polyelectrolyte Multilayers by Variation of pH During Layer‐by‐Layer Assembly

Abstract

Polyelectrolyte multilayers of chitosan and heparin are assembled on glass where heparin is applied at pH = 4, 9 and 4 during the formation of the first layers followed by pH = 9 at the last steps (denoted pH 4 + 9). Measurements of wetting properties, layer mass, and topography show that multilayers formed at pH = 4 are thicker, contain more water and have a smoother surface compared to those prepared at pH = 9 while the pH = 4 + 9 multilayers expressed intermediate properties. pH = 9 multilayers are more cell adhesive and support growth of C2C12 cells better than pH = 4 ones. However, pH 4 + 9 conditions improve the bioactivity to a similar level of pH = 9 layers. Multilayers prepared using pH 4 + 9 conditions form thick enough layers that may allow efficient loading of bioactive molecules.

Comparative Study of Osteogenic Activity of Multilayers Made of Synthetic and Biogenic Polyelectrolytes

“…The multilayer formation process was monitored by SPR. The resulting shift of the SPR resonance angle (m°) is proportional to the mass ( Γ SPR ) of adsorbed molecules on the surface . As expected, an increase in layer mass was observed for all PEM systems as the number of assembled layers increased, displayed in Figure .…”

“…The resulting change in the SPR angle shift (m°) is proportional to the mass ( Γ SPR ) of adsorbed molecules on the surface, whereby a shift of 122 m° corresponds approximately to 1 ng mm −2 . The MUDA‐modified gold sensors were placed into the flow chamber and equilibrated with degassed 0.15 m NaCl pH 7.4 to obtain a stable baseline. Thereafter, each PEL was injected with a flow rate of 3 µL s −1 for 10 min starting with PEI and followed by the different polyanion/polycation combinations mentioned above to form PEM with up to seven layers in total.…”

Effect of Immobilized Thiolated Glycosaminoglycans on Fibronectin Adsorption and Behavior of Fibroblasts

“…Further, the higher molecular weight of the tHA0.58 (64 kDa, Table ) compared to the other tGAGs could be a reason for higher surface coverage leading to a higher wettability of the system. Nevertheless, the tGAG surfaces were not as hydrophilic as expected since it was shown that substrata coated with native GAGs by adsorptive techniques as multilayers can have a WCA as low as 20°–40° . A reason for that could be the insertion of the small, hydrophobic cross‑linker DTPHY for thiolation of the GAGs.…”

Tuning cell adhesive properties via layer-by-layer assembly of chitosan and alginate

“…[2, 11–13] The overall properties of the film can be controlled simply by adjusting processing parameters: nature of polyelectrolytes, functional groups, molecular weight, charge density, concentration of the adsorption species, adsorption and rising time, pH, ionic strength, and humidity. [14–19]…”