Guide to floating mouse cages

The floating mouse cage is a critical component of every Mobile HomeCage® system. For the mouse to experience effortless, self-directed movement, the cage needs to meet three key criteria:

• Lightweight – If the mouse struggles to move the cage, it ruins the illusion of smooth, autonomous locomotion.
• Rigid base – Ensures even flotation, keeping things stable.
• Grippy floor – Prevents slipping, ensuring balance and comfort.

In 2024, we redesigned our small cages (180 mm diameter) to better meet the above criteria—and to make them more user-friendly. Here’s what’s new:

• Light but sturdy: Made from carbon fiber-reinforced plastic for effortless movement and smooth flotation.
• Easy to clean: You can rinse them under warm water or disinfect with a 70% ethanol solution—quick and efficient.
• No more doors: We’ve eliminated the cage door, which could unintentionally cue the animal and impact behavioral studies.
• Embedded magnets: Neodymium magnets in the base allow for precise locomotion tracking without the need for tracking mats. Magnets are invisible, minimize rotational inertia, and help the mouse move naturally.
• More cost-effective: We now provide two cages with each Mobile HomeCage® system at no extra charge. Individual cages are available for sale in the webshop.
• Adjustable wall heights: Choose between 20, 40, or 60 mm high walls to suit your specific needs.

Choosing the right cage

When selecting a cage, consider the height of the walls based on your research:

• 60 mm walls: Ideal for imaging, as they shield the mouse from external stimuli, reducing stress.
• 40 mm walls: Best for using micromanipulators at an acute angle.
• 20 mm walls: Perfect for visual stimulation, side video recording (e.g., pupil dilation), and patch-clamp recordings, as the clamp won’t touch the cage wall. Mice may feel more exposed in these lower-wall cages, so extra training may be required.

For visual stimuli or gait research, our transparent cages (40 or 60 mm) are a great option. They allow unobstructed video recording from the side, though they come at a higher price due to being hand-made.

When possible, we recommend using the 60 mm wall cages to minimize stress. They mimic the security of a standard laboratory home cage, shielding the mouse from external lights and noises. You can enhance this comfort with familiar toys or light bedding, such as wood shavings.

Cage care and maintenance

Proper care will ensure your cages last and perform optimally:

• Keep away from metal surfaces to avoid magnet damage.
• Avoid exposing the cages to temperatures above 60°C (100°F), as this can alter the properties of the magnets.
• Do not autoclave, machine-wash, or use aggressive cleaning agents/abrasives.
• Do not use cleaning products without strong, lasting odors, as these may repel the mice.
• After each use, rinse with warm water and mild detergent, then disinfect with 70% ethanol.

Floating mouse cages for the Mobile HomeCage Large

There is more to large cages than meets the eye. The cages have a sandwich bottom which consists of a layer of foam squeezed between two layers of carbon fiber film. The cages that are used for locomotion tracking also have magnets built into the bottom. Unfortunately, it is not possible to manufacture large carbon fiber cages in the mold. Each cage is hand-made, which means that it is easier to customize but more difficult to manufacture at a low cost. These are the most common sizes:

• diameter: 325 mm; wall height 70 mm (see below, right)
• diameter: 325 mm; wall height 40 mm (see below, center)
• diameter: 325 mm; wall height 20 mm (see below, left)
• diameter: 290 mm; wall height 70 mm
• diameter: 290 mm; wall height 40 mm

The wall height has important implications for managing stress. Whenever possible, we recommend using the high wall (70 mm), which shields the mouse from external lights and noises and comes closest to recreating a “natural” environment of a standard laboratory homecage. To further enhance the perception of safety, add familiar toys or light bedding, for example, wood shavings to the carbon fiber cage.

We can make any large mouse cage with transparent walls at no extra cost. The largest diameter cages (325 mm) are the best choice for behavioral monitoring. Unfortunately, even some large-frame two-photon microscopes don’t provide the needed space for this cage’s flotation. This is the reason why we offer smaller-diameter cages as well. Read our guide to compatibility to learn more about horizontal space requirements for optimal cage flotation.

No tracking mats are required for the large cages: we build the magnets directly into the cage’s bottom. The magnets are not visible: do not place the cage on metal surfaces. The magnets will attach to a magnetic surface, and disattaching them may damage the cage.

Foam cages and mazes for the Mobile HomeCage Large

Finally, we also make mouse cages and mazes from foam and plastic. Do not use these cages and mazes between different mice, because it is not possible to disinfect the foam base. However, it is possible to use the same cage multiple times for the same mouse. Besides that, we sell the foam cages and mazes in sets of fifteen at consumables prices.

Making the cages out of foam and plastic allows implementing a greater variety of designs. Currently, we offer these options:

• round cage (top row, left);
• square cage with straight corners (top row, center);
• square cage with rounded corners (top row, right);
• T-maze (bottom row, left);
• donut maze or circular track (bottom row, center);
• sociability cage (bottom row, right).

All foam cages and mazes have 40 mm walls.

Cleaning and storing the large mouse cages

Carbon fiber cages

Clean the cage with a soft cloth soaked in water and mild detergent. Alternatively, use a 70% ethanol solution. Other disinfectants have strong lasting smells that repel mice.

Do not machine-wash or autoclave, and do not use abrasive washing materials.

While using large carbon fiber cages, do not leave any liquid in the cage for a long time. The liquids may penetrate through the carbon fibers and damage the foam layer of the cage’s bottom.

Carbon fiber cages are sensitive to extreme heat. Storing temperature must not exceed 40 degrees Celsius (roughly 100 degrees Fahrenheit). Magnets built into the bottom for locomotion tracking may de-magnetize at high temperatures.

Foam cages and mazes

To prolong the use, wipe out the liquids with paper towels. Use damp paper towels to clean the base. The plastic walls can be washed and disinfected – remember to disassemble them before cleaning.

We recommend using each foam cage or maze for only one mouse. Label the cages or mazes for repeated use.