Mineralised tissues were demonstrated to be highly innervated by sensory neuronal population, which is one of the main peripheral regulators for bone development and mass accrual. Therefore, particular interest has been shown in the involvement of sensorial neuropeptides in the regulation of bone tissue due to the effect of soluble factors, produced by nerve fibres, associated with changes in the activity of bone cells. Nonetheless, the intercommunication between the bone and peripheral nervous system is scarcely understood. Therefore, given the importance of nerve fibres in bone microenvironment and the lack of adequate tools to study such crosstalk, we used the compartmentalised microfluidic platforms to recapitulate the in vivo bone sensorial innervation. Microfluidic compartmentalised devices allow the separation of the somal and axonal fraction of neurons and, more interestingly, the separation of different cell types. We have benefit from these proprieties and developed microfluidics-based co-culture systems comprising dorsal root ganglion and osteoblasts, in 2D/3D chemically functionalised hydrogels, to mimic the properties of naturally occurring tissue extracellular matrices providing more accurate mechanical and biochemical signalling factors. Additionally, we have also developed a computational application of a mathematical algorithm, available online for the scientific community, which improved the systems readout by enabling the automatic quantification of neurite outgrowth within non-neuronal cells in these platforms. Together the entire system emerges as a potential new tool to be explored for modelling of innervation processes and pharmacological screening with an automated and non-subjective tool for the system readout. We believe that this system can be further translated to study the innervation of different peripheral tissues in physiological or pathological conditions.
Disclosure: The authors declared no competing interests. This work was supported by FEDER funds through the COMPETE and by Portuguese funds through FCT in the framework of the projects PEst-C/SAU/LA0002/2013 and PTDC/BIM-MED/1047/2012. EN is recipient of PhD fellowships SFRH/BD/81152/2011.