Aerospray Gram

Microscope slides smeared with samples containing microorganisms are stained to differentiate between Gram positive and negative microorganisms. Slides ready for the microscope in minutes.

The Aerospray Gram automated slide stainer will stain biological samples to differentiate between Gram positive and negative organisms. Only fresh reagents are applied to the slides so there is no chance of slide-to-slide cross-contamination. The reagent consumption is very low and throughput is high using either a 12- or 30-slide slide carousel. The slides are dry and ready for the microscope in five minutes, giving superior results. With the addition of the optional Cytopro® Cytocentrifuge Rotor, the Gram is also able to deposit cells onto microscope slides.

Scope: Microbiology

Manufacturers: Wescor Inc.,


The Aerospray® Gram automated slide stainer is a dual-purpose microprocessor-controlled slide staining and cell preparation system.

Atomizing spray nozzles apply reagents onto microscope slides prepared with microbiological specimens. Slides are mounted in a rotating 12- or 30-slide carousel.

Specimens can be heat fixed and stained directly, or the automatic alcohol fixation cycle can be used to provide a convenient and reproducible specimen fixation. Once slides are fixed, they are sprayed with crystal violet, a positively charged (basic) dye which rapidly penetrates microbial cells and stains them dark blue to purple. The excess stain is then removed by centrifugation and washed away with deionized water to prevent precipitate formation outside the stained cells.

Iodine reagent is then sprayed onto the slide. The iodine penetrates the cells and forms a precipitate (“mordant”) with the crystal violet dye. Excess iodine is spun off and rinsed from the slide with deionized water.

Decolorizer is then applied to remove the crystal violet-iodine complex until only the gram-negative organisms are decolorized. Safranin or fuchsin (added to the decolorizer) simultaneously stains the gram-negative cells red. With other staining methods, counter-staining is performed separately.

Decolorization is the critical step in proper gram differentiation and unless carefully controlled can lead to errors. The Aerospray Gram stainer provides a choice of decolorizing cycles ranging from 1 to 9, allowing the operator to compensate for thick specimens, changes in reagents, and possible instrument variations.

A high-speed spin cycle rapidly dries the stained slides in the Aerospray stainer. A properly executed gram stain yields a clean specimen in which the gram-positive organisms are blue to purple and gram-negative organisms are pink to red.

This method of staining is rapid, precise, and results in exceptionally clean fields. After just a five minute stain cycle, the slides emerge from the carousel dry and ready for the microscope.

The Aerospray Gram applies only fresh reagents precisely metered to the slides so there is no chance of slide-to-slide cross-contamination of specimens.

The Aerospray Gram is easily programmable with nine decolorizer settings and three adjustable settings for crystal violet and iodine. The instrument is highly responsive to a wide range of staining requirements.

The Aerospray Gram includes an operator initiated clean cycle that reduces maintenance to a minimum. As part of the regular maintenance, nozzles are easily disassembled for easy cleaning.

The Aerospray Gram has a lid interlock system which locks the lid during carousel rotation. A rotation indicator is located on the front panel that will light up if the carousel or rotor is rotating. The stainer also monitors the levels of the reagents and will warn the user if reagent levels are low.

With the optional Cytopro® cytocentrifuge rotor, the Aerospray Gram becomes a superb cytocentrifuge with eight-slide capacity. It allows you to efficiently spin sample cells and sediment them onto microscope slides for staining without purchasing an additional instrument.
The user programs the speed, time, and acceleration settings to protect cell morphology. Up to nine memory settings can be stored for quick access to frequently used settings.