Table 5.

Comparison between approaches for artificial tactile sensing: fully-synthetic, bio-hybrid and fully-biological tactile sensing. Advantages and disadvantages of each approach.

Artificial tactile sensing
Approaches	Types	Advantages	Disadvantages
FULLY-SYNTHETIC tactile sensing	Capacitive sensors Piezoelectric sensors Piezoresistive sensors Inductive sensors Optoelectric sensors Strain gauge sensors	Physical robustness Greater sensitivity	Non self-healing properties Biocompatibility
BIO-HYBRID tactile sensing	Silicon-based bio-hybrid sensor with microfluidics and conductivity sensors Silicon-based MEMS sensors with tissue engineered skin Polymeric substrate with bio-hybrid skin-like electrode	Bio-mimicry Bio-inspiration Self-healing Greater softness and compliance	Conservation of living cells
FULLY-BIOLOGICAL tactile sensing	Hydrogel-based artificial skin Gelatin-containing artificial skin Tissue engineered skin Merkel cells	Bio-mimicry Bio-inspiration Self-healing Wettability Regeneration of tissues Greater softness and compliance Biocompatibility Biodegradability	Conservation of living cells Rejection