A process for making and using a tissue preservation gel. The gel is comprised of water, reticulated acrylic acid, water soluble short-chain paraben, isopropyl alcohol and either triethanolamine or propylene glycol. To use the gel, a tissue to be preserved is first bathed in hypertonic sodium chloride, then soaked in a wash in multiple increasing concentrations of isopropyl alcohol and then preserved indefinitely in the tissue preservation gel.

The invention refers to a composition for the fixation of histological preparations, comprising a solution of glyoxal, wherefrom acids, normally present in the commercially available glyoxal, have been removed. The composition of the invention provides an optimal fixative for the preservation of structure, antigenic components and nucleic acids in tissues. The acid-free glyoxal has limited toxicity, is not considered as a carcinogenic agent and represents a valid alternative to formalin for the fixation of tissues and cells.

A process for making and using a tissue preservation gel. The gel is comprised of water, reticulated acrylic acid, water soluble short-chain paraben, isopropyl alcohol and either triethanolamine or propylene glycol. To use the gel, a tissue to be preserved is first bathed in hypertonic sodium chloride, then soaked in a wash in multiple increasing concentrations of isopropyl alcohol and then preserved indefinitely in the tissue preservation gel.

Disclosed herein are compositions for fixing tissue for cytologic, histomorphologic, and/or molecular analysis (e.g., DNA, RNA, and/or protein analysis). In some embodiments, the fixatives are aldehyde-free fixatives, for example, formaldehyde- or formalin-free fixatives. Particular disclosed compositions include buffered ethanol. The buffer is a phosphate buffer or phosphate buffered saline (PBS) in some examples. In further embodiments, the fixative includes additional components, such as glycerol and/or acetic acid.

Aspects of the disclosure relate to a fixative containing carboxylic acid, preferably acetic acid, for parasitological samples. In some aspects the disclosure relates to an aqueous fixative solution for parasitological samples comprising: a) a C.sub.2 to C.sub.6 carboxylic acid (preferably acetic acid) at a concentration of 0.5M or greater; and b) a C.sub.2 to C.sub.6 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 pg/ml menthol and 350 pg/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 are compositions for fixing tissue for cytologic, histomorphologic, and/or molecular analysis (e.g., DNA, RNA, and/or protein analysis). In some embodiments, the fixatives are aldehyde-free fixatives, for example, formaldehyde- or formalin-free fixatives. Particular disclosed compositions include buffered ethanol. The buffer is a phosphate buffer or phosphate buffered saline (PBS) in some examples. In further embodiments, the fixative includes additional components, such as glycerol and/or acetic acid.

The present invention leverages the techniques for expansion microscopy (ExM) to provide improved high-throughput super-resolution whole-organ imaging methodology to image protein architectures over whole organs with nanoscale resolution by using high-throughput microscopes in combination with samples that have been iteratively expanded more than once, in a method referred to herein as “iterative expansion microscopy” (iExM). In the ExM method, biological samples of interest are permeated with a swellable material that results in the sample becoming embedded in the swellable material, and then the sample can be expanded isotropically in three dimensions The process of iteratively expanding the samples can be applied to samples that have been already expanded using ExM techniques one or more additional times to iteratively expand them such that, for example, a 5-fold expanded specimen can be expanded again 3- to 4-fold, resulting in as much as a 17- to 19-fold or more linear expansion.

A smear preparation machine includes: a slide loading mechanism (2) configured to load a slide; a sample applying mechanism (3) configured to apply a blood sample to the slide; a smearing mechanism (4) configured to smear the blood sample on the slide to prepare a smear; a dripping and staining mechanism (5) configured to drip a staining reagent and a buffer solution to the smear; an air blowing mechanism configured to blow air to the staining reagent and the buffer solution on the smear for blowing mixing, such that the staining reagent and the buffer solution are mixed and cover the smear, thereby staining the smear once.

A process for making and using a tissue preservation gel. The gel is comprised of water, reticulated acrylic acid, water soluble short-chain paraben, isopropyl alcohol and either triethanolamine or propylene glycol. To use the gel, a tissue to be preserved is first bathed in hypertonic sodium chloride, then soaked in a wash in multiple increasing concentrations of isopropyl alcohol and then preserved indefinitely in the tissue preservation gel.

A smear preparing apparatus includes: a smear unit that prepares a smear slide by smearing a sample on a slide; a buffer solution preparation unit that prepares diluted buffer solution by diluting a highly-concentrated buffer solution; a diluted staining solution preparation unit that prepares diluted staining solution by diluting a highly-concentrated staining solution with the diluted buffer solution; and a stain unit that stains the smear slide prepared by the smear unit with the diluted staining solution.