Table 3.

List of biomaterials used as a substrate in wearable sensors.

SN	Category	Substrate Material	Chemical Structure	Properties	Reference	Notes
1.0	Synthesis	PDMS	[C2H6OSi]n	High stretchability. Non-toxic, non-flammable, and hydrophobic. Acceptable Processability: ○ Soft lithography through plant leaf or piece of silk or micromachined silicon wafer. ○ Various fabricated patterns such as Groove, Pyramids, Hemispheres (e.g., Bumpy Design), Rods, and random-distributed channels with different sizes.	[229]	• Lack of biodegradability.
		Ecoflex® Silicone Elastomer	-	High stretchability. Skin-safe silicone with lower modulus.	[230]	• Lack of biodegradability.
		PET	[C10H8O4]n	Acceptable transparency (i.e., >85.0%). High creep resistance and excellent printability.	[231]	• Relatively high modulus of elasticity (about 2~4 GPa).
		PI	C35H28N2O7	Acceptable flexibility. Acceptable creep resistance and tensile strength.	[232]	• Lack of biodegradability.
2.0	Natural	Cellulose Paper	[C6H10O5]n	Inherently flexible. Porous, inexpensive, and recyclable. Biodegradable and biocompatibility.	[176,233]	• Durability and stability are still amongst the biggest challenges for enhancing its properties.
		Smart Textile *	-	• Flexible, inexpensive, and biocompatible.	[234,235,236]	Low-level integration. Can be further developed by: Increasing conductivity/ sensitivity Making conductive materials absorbed into porous fibers and textiles. They include Cotton-Ag dipped and repeatedly dried in Ag NWs solutions for a high-performance pressure sensor.

* This includes silk and cotton where sensing chips are integrated into these textiles to realize a clothing-like sensing system.