Table 3.

Sample mounting for enhanced optical clarity.

Methoda	Sample Preparation	Clearing Reagents	Size Fluctuations	Fluorescence
organic solvents RI ~ 1.52–1.57	none	methyl salicylate [209]	shrinkage	NO
	Ultramicroscopy [27]	BABB	shrinkage	Y/N»
	3DISCO iDISCO	dibenzyl ether	shrinkage	Y/N
amides RI ~ 1.38–1.44	ClearT, ClearT2 [24]	formamide ± PEG	none, n/db	Y/N
	Sca/eA2, Sca/eS, CUBIC, FRUIT	urea	slight -moderate expansion	YES
polyol and concentrated sugar or sugar alcohol solutions RI ~ 1.43–1.50, tunable	CLARITY, PACT, PARS	glycerol	slight expansion	YES
	SeeDB [21,102]	fructose	minimal	YES
	FRUIT	fructose + thioglycerol + urea	slight expansion	YES
	Sca/eA2	glycerol + urea	moderate expansion	YES
	CUBIC	sucrose + urea + triethanolamine	moderate expansion	YES
	Sca/eS, PARS, PACT	sorbitol, sRIMS	slight - moderate expansion	YES
aqueous contrast media RI ~ 1.46, tunable	CLARITY	Focus Clear: Diatrizoic acid	slight expansion	YES
	PACT, PARS, RIMS	RIMS: Histodenz	acute shrinkage, gradual expansion	YES
aqueous mounting media RI ~ 1.33–1.52, tunable	TDE [34]	2,2’-thiodiefhanol [83]	none	YES

^aOptical clarity, or reduced light scattering through tissue, may be enhanced via homogenizing the refractive indices throughout heterogeneous tissues and at all material interfaces between the sample and objective lens

^bY/N = signal decay may necessitate prompt imaging upon sample mounting