In situ electrical stimulation for enhanced bone growth: A mini-review

The role of electrical stimuli in directing cellular activities during natural tissue healing and regeneration process has been well recognized. This observation has prompted the development and use of exogenous electrical stimulations in the treatment of delayed unions and non-unions of bone fracture in different parts of the human skeletal system. Considerable amount of clinical evidences has also been generated on the benefits of exogenous bone growth stimulators. However, the clinical efficacy and safety of these exogenous electrical stimulating methods are being argued to be inconsistent and inconclusive, due to lack of sufficient number of well-controlled, randomized clinical studies. As a result, there has been significant interest in the development of smart biomaterials, which can generate in situ electrical stimuli, for accelerated bone repair, healing and regeneration. These smart biomaterials are essentially either composite biomaterials containing electrically active materials or biomaterials that can be polarized. The primary objective of this mini review was to provide an overview of different exogenous electrical stimulation methods and biocomposites for in situ stimulation, which can be used for bone growth and healing. The first part is focused on exogenous stimulation methods, and the second part discusses the use of biocomposites containing electrically active materials such as piezoelectric materials and multiferroic materials for accelerated repair and regeneration of bone.