Table 2.

Microsensors for contraction force measurement in heart-on-a-chip

Mechanism	Structures	Materials	Cells	Applications	Measured values
Visible deformation	Biowires[62,63,9393] Cantilever[59,6464] Micropillars[57] Helical structure[56]	POMaC[62] PDMS[59] Hydrogel[57,64]	iPSC-CMs[62,63] Rat CMs[59,64] HCFs[63]	Cell maturation[57,62] Drug screening [57,59,62,63] Disease model[63]	Contraction force 2.89-5.09 µN[64] ~40 µN[62] Contractile stress ~15.4 kPa[59] ~1.7 kPa[57]
Electrical sensors	Piezoelectric[69] Crack sensor[74] Piezoresistive[12,67,68]	AlN[69] Pt-PDMS[74] CNTs-PDMS[68] CB:TPU[12]	Rat CMs[12,67,72,74] iPSC-CMs[68,69]	Drug screening[9,12,67-69]	Contraction force ~107 nN[74] Contractile stress ~2.34 kPa[68] 7-15 kPa[12]
Structural color	Cantilever[56] Biological-Crawling robot[66]	GelMA[66]	Rat CMs[66]	Drug screening[56,6666] Biological soft robots[66]	crawling speed 20 µm/s[66]