Table 4.

Measurement methods and characteristics of micro-force sensors.

Type	Detection Principle	Advantages	Disadvantages	Precision	References
Piezoelectric sensor	Piezoelectric effect of piezoelectric materials	• Wide band • High sensitivity • High signal-to-noise ratio • Simple structure	• Poor output direct current response • Unsuitable for static measurement	μN–sub μN	[142]
Piezoresistive sensor	The relationship between force and resistance	• Proven detection method and good frequency response	• Modest signal-to-noise ratio • Complex structure • Temperature-sensitive	mN–sub mN	[143,144]
Capacitive transducer	The relationship between force and capacitance change between plates	• Simple structure • Good stability • High sensitivity	• Highly nonlinear strain	μN–sub μN	[66,69]
Strain gauge	The relationship between the shape variable and stress	• Simple structure	• Modest detection accuracy	mN	[145]
Polyvinylidene fluoride force transducer	Piezoelectric effect	• High linearity • High signal-to-noise ratio • Suitable for dynamic force induction	• Cannot work under high temperature	sub μN	[146,147,148]
Polydimethylsiloxane (PDMS) patch force transducer	Deviate from PDMS posts	• Easy to fabricate and can be used to study different types of cell characteristics	• Difficult to prepare	nN	[68,149]
Cantilever-based force sensor	Beam deflection	• Easy to fabricate and allows vision-enabled measurement of structural deformation	• Low sensitivity and precision • Difficult to detect static forces	nN	[150,151]
Cantilever force transducer with an indentation probe	Beam deflection	• Simple structure • High resolution, can be used to study the force response of cells under large deformation	• Complex mechanical structure	nN–pN	[71,152,153,154]
Miniature camera-based force sensor	Change in diffraction efficiency	• High resonance frequency	• Difficult to fabricate • Complex optical setup	N/A	[38]
Magnetic effect-based sensor	The compressive magnetic effect of magnetic materials	• High measurement accuracy	• Prone to be affected by the surrounding magnetic field	nN	[155]
Vision-based sensor	The relationship between stress and image deviation	• Non-contact measurement	• Strict requirements for image processing precision	mN–μN	[156,157]