Table 4.

Electroactive biomaterials that can potentially be utilized for promoting bone healing and regeneration under various disease conditions

Electroactive biomaterials	Category/Type	Advantages	Disadvantages	Key references
Piezoelectric biomaterials	Synthetic piezopolymers	High flexibility and low stiffness	Low biodegradability	Ribeiro et al.[ 155 ] Kalimuldina et al.[ 156 ] Rufato et al.[ 157 ] Capuana et al.[ 158 ] Williams[ 159 ] Goonoo et al.[ 160 ]
	Synthetic piezoceramics	Similar mechanical properties to natural bone tissue, such as high hardness and friction coefficients	Very brittle	Li et al.[ 163 ] Chen et al.[ 164 ] El‐Rashidy et al.[ 165 ] Felice et al.[ 166 ] Ziglari et al.[ 167 ]
	Naturally‐occurring piezoelectric materials in polymeric or ceramic form	Good biodegradability, excellent biocompatibility, and negligible cytotoxicity	Higher inter‐batch variability than synthetic biomaterials	Shin et al.[ 168 ] Rico‐Llanos et al.[ 169 ] Arcos & Vallet‐Regí[ 170 ] Baldini et al.[ 171 ] Osorio et al.[ 172 ] Jayakumar et al.[ 173 ] Aguilar et al.[ 174 ]
Electroconductive biomaterial	Carbon‐based biomaterials	Good mechanical properties High electrical conductivity Large specific surface area for loading of bioactive factors	Low biodegradability Some degree of cytotoxicity	Shadjou et al.[ 179 ] Tanaka et al.[ 180 ] Aoki et al.[ 181 ] Peng et al.[ 182 ] Liu et al.[ 183 ]
	Metal/metal oxides	Good mechanical properties High electrical conductivity	Low biodegradability Some degree of cytotoxicity	Wang et al.[ 185 ] Li et al.[ 186 ] Wang et al.[ 187 ]
	Conductive polymers	High electrical conductivity	Rigid and brittle Low biodegradability	Liang and Goh.[ 188 ] Rajzer et al.[ 189 ] Guex et al.[ 190 ]
Electrostimulation scaffolds/devices with implantable energy harvestors (IEH)	Piezoelectric nanogenerators (PENGs)	Generate electrical stimuli without an external power source by harvesting energy from the human body	Most of these technologies not yet mature, and face various challenges such as poor biodegradability, cytotoxicity and insufficient miniaturization	Kao et al.[ 194 ]
	Triboelectric nanogenerators (TENGs)			Li et al.[ 195 ]
	Mass imbalance oscillation generators (MIOG)			Zurbuchen et al.[ 196 ]
	Enzymatic biofuel cells (EBFCs)			Haque et al.[ 197 ]
	Endocochlear potential (EP) collectors			Mercier et al.[ 198 ]
	Photovoltaic cells (PVC)			Long et al.[ 199 ]
	Pyroelectric nanogenerators (PYENGs)			Ryu & Kim[ 200 ]
Electroresponsive biomaterials	Drug‐delivery	Enable precisely‐timed drug release via electrical stimuli	Requires direct electrical stimulation, which maybe difficult to apply to implants embedded deep within the human body	Sirivisoot et al.[ 201 ] Kiaee et al.[ 202 ]
	Modulation of cell function – adhesion, proliferation and differentiation	Enable precise control of cellular function via electrical stimuli		Lashkor et al.[ 203 ] Zhang et al.[ 204 ] Tang et al.[ 205 ]
	Mechanostimulation	Enable precisely‐timed mechanostimulation via electrical stimuli		Shang et al.[ 206 ] Rahimi et al.[ 207 ]