A method relating to preparation of a biological sample for analysis by flow cytometry including contacting a drawn blood sample with a protective agent that is substantially free of formaldehyde and analyzing the white blood cells of the contacted sample for protein epitopes after at least about twenty-four hours after contacting.

The invention provides a method termed protein retention ExM (proExM), in which proteins, rather than labels, are anchored to the swellable gel, using a cross-linking molecule. This proExM strategy can be used to perform nanoscale imaging of immunostained cells and tissues as well as samples expressing various FPs as fluorescent signals from genetically encoded fluorescent proteins and/or conventional fluorescently labeled secondary antibodies and streptavidin that are directly anchored to the gel are preserved even when subjected to the nonspecific proteolytic digestion.

The present disclosure provides compositions and methods for using fixed biological samples in partition-based assays. In at least one embodiment, the disclosure provides a composition comprising a fixed biological sample and an un-fixing agent contained in a partition, such as a discrete droplet. In some embodiments, the disclosure provides un-fixing agent compounds capable of catalytically cleaving crosslinks in fixed biological samples, particularly crosslinked nucleic acids, such as RNA.

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 refers to a formal-in-free fixative composition, suitable for the fixation of cells in particular in liquid samples, the use of said fixative for the treatment of biological samples, a method for the treatment of cell-comprising liquid samples, a kit comprising said fixative and a method for diagnosis of cell-comprising biological material samples.

Aqueous solutions that include: (A) an organic polyol having from 2 to 20 carbon atoms and having a flash point of at least 93 C.; (B) a base; (C) a surfactant; and (D) water, where the aqueous solution does not include an organic solvent having a flash point below 23 C. and a boiling point of at least 38 C.

A clearing agent and mounting solution for microscopy is disclosed comprising at least trichloroethanol and/or derivatives thereof, where the refractive index of the solution is greater than or equal to about 1.3810. Also disclosed are methods of preparing specimens for microscopy.

The present disclosure provides methods for carrying out Romanowsky-type stains, specifically Wright-Giemsa and May-Grnwald stains, quickly and efficiently. The methods greatly reduce the overall amount of time required to complete a Wright-Giemsa stain or a May-Grnwald stain of sufficient quality on a biological sample. The subject methods can be applied to both manual and automated staining procedures.

The present disclosure relates to a fixative composition for preparing a biological sample smear. The fixative composition according to an aspect ensures that, in a solid-gel-based staining method, a biological sample is completely fixed onto a slide even after gel patch staining and an image of cells having clear boundaries without cell damage may be obtained. Accordingly, the fixative composition may be useful for smear examination of biological samples.

The invention provides a medium. The medium comprises a fibrous matrix and silica microparticles immobilized in the fibrous matrix. The fibrous matrix may comprise glass fibers, polyolefin fibers, polyvinylidene fluoride (PVDF) fibers, polytetrafluoroethylene (PTFE) fibers, polypropylene fibers, polyethylene fibers, aramid fibers, natural cellulosic fibers, or a combination thereof. A composition comprising the medium is provided. A device comprising the medium or the composition is also provided. Further provided are methods for preparing a proteomic sample from a biological sample on the medium. The biological sample comprises cells or proteins. The method may comprise a treating step, a digesting step, a reducing and alkylating step, and an eluting step. All of these steps may be performed on the medium. The proteomic sample comprises the eluted peptides. The proteomic sample may be desalted. The peptides prepared from the biological sample may be suitable for qualitative or quantitative analysis, for example, mass spectrometric analysis.