A fixative contains carboxylic acid, preferably acetic acid, for parasitological samples. An exemplary aqueous fixative solution for parasitological samples comprises: a) a C2 to C6 carboxylic acid (preferably acetic acid) at a concentration of 0.5M or greater; and b) a C2 to C6 carboxylate salt or halide salt at a concentration of 0.02M or greater, preferably 0.04M or greater. An optional composition comprises 1.3M acetic acid, 12 mM sodium benzoate, 0.9% calcium chloride, 0.9% calcium bromide, 100 g/ml menthol and 350 g/ml thymol. The fixative is free of formaldehyde or other hazardous compounds, and exhibits good killing and staining properties when used with parasitological samples such as ova and helminths.

Disclosed herein, inter alia, compositions and methods for efficient transfer and analyses of cellular material, tissue samples, such as tissue sections, using tissue transfer hydrogel devices.