Neuron-ligand pathfinding on surfaces modified by laminin and laminin-derived peptides
Date
2006
Authors
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Publisher
University of Delaware
Abstract
Central nervous system (CNS) neurons, unlike those of the peripheral nervous system, are not able to regenerate their axons spontaneously following injury. Extracellular matrix (ECM) protein-modified substrates have recently emerged as a possible approach for promoting and guiding axon regeneration. In this study, LN and LN-derived peptides, SIKVAV and GYIGSR, were covalently immobilized to substrates by a GMBS heterobifunctional crosslinker method. Surface modification was verified by surface analytical techniques, such as contact angle measurement, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Patterned surfaces with alternating micron-scale cell-permissive (LN) and non-permissive (comb polymer) regions were produced by a microcontact printing technique and confirmed by ToF-SIMS imaging analysis. A kinetic study showed that the surface coverage of LN could be controlled by the amount of time that the surface was immersed in LN solution, and by the concentration of the solution. The interaction of neurons with surface-bound ligands was then quantitatively described by the length of axonal outgrowth. Both LN and LN-derived peptide-modified substrates supported significantly greater axonal outgrowth than control substrates, and the surface density of LN affected neurite outgrowth: the higher the LN surface density, the longer the axonal outgrowth. On patterned surfaces, neurons adhered to and extended neurites preferentially on LN regions, indicating that the patterned LN/comb surfaces were successful in spatially controlling the neuron attachment and neurite outgrowth.