Table 4.

The main strategies of microfluidic C. elegans sorting and their principles.

Sorting strategy	Principle	Applications	Reference(s)
Stimulus response-based	C. elegans have behavioral responses to external stimuli (e.g., current pulse, temperature)	Age synchronization, motion-based behavior analysis, drug screening, high-throughput search of biomolecules	[20–22,24,25,28,48,55,96,97,100,102,107,130,133]
CeMIC	Measure electrical impedance during worm flow and identify developmental stages by signals	Age synchronization, drug-evaluation studies, label-free quantification, phenotyping	[110,156]
Pressure-based	Control channel pressure through micropumps, microvalves, or adjustable filter structures	Age synchronization, culturing, stimulation, phenotyping, microsurgery	[49,51,56,61,73,74,92,135]
Continuous flow-based	Fill or perfuse the channel with a single fluid (e.g., culture medium aqueous solution)	Age synchronization, culturing, stimulation, high-throughput imaging	[46–48,54,93,111,112,122,131,132]
Droplet-based	Generate microdroplets (commonly aqueous droplets surrounded by oil) to wrap C. elegans for encapsulation	Individual separation, long-term behavioral observation studies, drug screening, high-resolution imaging	[32,90,91,157–159]
Fluorescence-assisted	Detect C. elegans fluorescent protein expression and other optical features	High-resolution imaging, genotype analysis, drug screening, biosensing development	[50,112,120,134,160,161]

CeMIC, C. elegans microfluidic impedance cytometry