Effect of functionalization of multilayered polyelectrolyte films on motoneuron growth.

We studied in vitro cell-substrate interaction of motoneurons with functionalized polylectrolyte films. Thin polylectrolyte films were built on glass by alternating polycations, poly(ethylene-imine) PEI, poly(L-lysine) PLL, or poly(allylamine hydrochloride) PAH, and polyanions, poly(sodium-4-styrenesulfonate) PSS or poly(L-glutamic acid) (PGA). These architectures were functionalized with Brain Derived Neurotrophic Factor (BDNF) or Semaphorin 3A (Sema3A). We used Optical Waveguide Lightmode Spectroscopy (OWLS) and Atomic Force Microscopy (AFM) to characterize the architectures. The viability of motoneurons was estimated by the acid phosphatase method, and morphometrical measures were performed to analyse the influence of different architectures on cell morphology. Motoneurons appeared to adhere and spread on all the architectures tested and preferentially on PSS ending films. The viability of motoneurons on polyelectrolyte multilayers was higher compared to polyelectrolyte monolayers. BDNF and Sema3A embedded in the films remained active and thereby create functionalized nanofilms.