*4.1.1 Electrical stimulation*

Electrical stimulation can enhance MSCs' adhesion, alignment, division, proliferation, migration, and differentiation [41, 42]. Electrical stimulation can be applied invasive, semi-invasive, or non-invasively. In the invasive method, the DC stimulator electrodes are implanted in the bone injuries and will remove at the end of the regeneration procedure. In the semi-invasive method, the cathodes were placed percutaneously. In the non-invasive method, stimulators were inserted on the skin [43]. Two main mechanisms possibly direct the response of the cells to electrical fields. The first mechanism includes the downstream activation as a consequence of asymmetric redistribution/diffusion of electrically charged surface cell receptors and the other mechanism is attributed to the voltage-gated Ca2+ channels activation and the following cellular responses [42].


*Recent Advances, Challenges and Future Opportunities for the Use of 3D Bioprinting in Large… DOI: http://dx.doi.org/10.5772/intechopen.111495*



**7**
