The influence of laminin-derived peptides conjugated to Lys-capped PLLA on neonatal mouse cerebellum C17.2 stem cells

Chemical guiding cues are being exploited to stimulate neuron adhesion and neurite outgrowth. In this study, an amino-functioned PLLA, lysine-capped PLLA [K-(CH2)n-PLLA (n = 2, 5, 8)], was synthesized with different length of linking spaces between lysine molecule and PLLA backbone. Drop-cast films were fabricated from K-(CH2)n-PLLA/PLLA blends (10/90, w/w) and amino groups were detected on the surfaces of the resultant films. More amine groups were detected on the surface and the hydrophilicity of the films was obviously improved by annealing the films in water. The representative atomic force microscopy (AFM) images indicated that incorporation of lysine-capped PLLA into PLLA matrix increased the roughness of the films and resulted in a phase separation with distinct two nano-domains which may correspond to the hydrophilic and hydrophobic domains. Furthermore, the laminin-derived peptides, CYIGSR (Cys-Tyr-Ile-Gly-Ser-Arg) and CSIKVAV (Cys-Ser-Ile-Lys-Val-Ala-Val), were jointly tethered to the amine groups of lysine-capped PLLA by a linking reagent sulfo-succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (Sulfo-SMCC). The neonatal mouse cerebellum C17.2 stem cells were seeded on the peptides-grafted K-(CH2)n-PLLA/PLLA (n = 2, 5, 8) films and pure PLLA films were used as controls. Improved viability and longer neurites were obtained on the peptide-grafted films than PLLA film over the cultivation period, especially for K-(CH2)5-PLLA/PLLA, which had the highest peptide density of 0.28 ± 0.03 μg/cm2. This study highlights the potential of using the lysine-cappeded PLLA with laminin-derived peptides for promoting nerve regeneration.