Neurite Outgrowth on a DNA Crosslinked Hydrogel with Tunable Stiffnesses


Mechanical cues arising from extracellular matrices greatly affect cellular properties, and hence, are of significance in designing biomaterials. In this study, a DNA crosslinked hydrogel was employed to examine cellular responses of spinal cord neurons to substrate compliances. Using DNA as crosslinkers in polymeric hydrogel formation has given rise to a new class of hydrogels with a number of attractive properties (e.g., reversible gelation and controlled crosslinking). Here, it was demonstrated that by varying length of crosslinker, monomer concentration, and level of crosslinking, DNA gel stiffnesses span from ∼100 Pa to 30 kPa. Assessment of neurite outgrowth on functionalized DNA gels showed that although primary dendrite length is not significantly affected, spinal cord neurons extend more primary dendrites and shorter axons on stiffer gels. Additionally, a greater proportion of neurons have more primary dendrites and shorter axons on stiffer gels. There is a pronounced reduction in focal adhesion kinase (FAK) when neurons are exposed to stiffer substrates, suggesting its involvement in neuronal mechanosensing and neuritogenesis in response to stiffness. These results demonstrate the importance of mechanical aspects of the cell–ECM interactions, and provide guidance for the design of mechanical properties of bio-scaffolds for neural tissue engineering applications.

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This study was supported by a grant from the New Jersey Commission on Spinal Cord Research (Grant # 05-3041-SCR-E-0) and partially supported by National Institute of Health (Grant # EB004919-01) and grant from the New Jersey Commission on Spinal Cord Research (Grant # 07A-019-SCR1). This work was performed towards the partial fulfillment of the Ph.D. requirements of the first author. A first year fellowship awarded to F.X.J. from the Department of Biomedical Engineering of Rutgers University is also acknowledged. Suggestions and advice from Drs. David Shreiber and Rene Schloss are appreciated. We thank Dr. David Lin for assistance in DNA design and gel preparation, Dr. Yangzhou Du for assistance in spinal cord cell culture and study of DNA degradation, Dr. Baogang Li for assistance in experiments, Dr. Penelope Georges for comments. Discussions from members of both Langrana and Firestein laboratories have been very helpful and are also acknowledged.

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Correspondence to Noshir A. Langrana.

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Jiang, F.X., Yurke, B., Firestein, B.L. et al. Neurite Outgrowth on a DNA Crosslinked Hydrogel with Tunable Stiffnesses. Ann Biomed Eng 36, 1565 (2008).

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  • Neuron
  • Spinal cord injuries
  • Material design
  • Crosslinking
  • Crosslinker length
  • Focal adhesion kinase
  • Mechanosensing
  • Neural tissue engineering