Table 1 Challenges and strategies for flexible/stretchable devices to measure the physiological signals on human body accurately.

 Low SNR

EEG

Building conformal and biocompatible neural interfaces

^{55,96,97,98,99,100,101,102,104,105}

Sweat composition

To improve the electrochemical activity of sensors by porous/hybrid electrode

^56,57

 Weak relevance

Non-invasive blood glucose

Extract glucose from interstitial fluid or blood to the surface of the skin through the method of Electrochemical channels

⁵⁸

 Dynamic deformation

Body temperature

Composite materials with zero gauge factor

⁶¹

Rigidity programmable substrate

²⁵

 Temperature noise

Sweat composition

Temperature sensor as reference

⁵⁹

 Ambient light noise

Blood oxygen

Opaque encapsulation layer and intimate contact

^60,62

 Device internal interface

EMG

Root inspired interlocking layer

³⁰

 Human-device interface

Sweat composition

Tattoo-inspired electrochemical sensor to realize intimate contact with the skin

^{63,64,65,66,67,68}