Keeping mice and rats clean and safe benefits the animals and lab personnel. Often, that requires an animal transfer station (ATS) or biological safety cabinet (BSC). To understand the uses of these tools and how to pick the most ergonomic options, I talked with Scott Christensen, vice president of global sales at NuAire (Plymouth, MN). Here’s what I learned.
ATS Options
“Animal transfer stations are used to safely transfer clean mice and rats from a dirty cage into a cage with fresh bedding, feed, water, etcetera,” Christensen says. “Sterility for the animals is provided through vertical laminar airflow of HEPA filtered air through the work zone.” He adds, “Users are protected from allergens by an exhaust HEPA filter in the base of the transfer station.”
In moving animals, an ATS must meet a range of requirements, and two key ones are efficiency and ergonomics for the technician. “Think of it like your office cubicle where you want everything needed to do your work within easy reach to maximize your productivity,” Christensen explains. “In terms of an animal transfer station, technicians are going to want different shelf configurations to hold supplies, a magnifying glass to take a close look at a mouse tail or cage tag, hand-sanitizer dispenser, cage-top holder to secure cage tops and perhaps a forceps holder.” A lab manager shopping for a new ATS can also consider other options, including light timers or a red light, which can be used to keep transfers from interrupting the sleep cycle of the animals.
Beyond the options on an ATS, Christensen says, “Facilities should also consider how their technicians will be working with the animal transfer station.” As an example, he says, “If they will be moving the transfer station around the holding room up to the ventilated racks, then they will want a transfer station that they can access from any side; if on the other hand, they will leave the transfer station parked in a single location and move the racks over to the transfer station, then they may want their unit configured with access on a single side to better contain a mouse that gets loose.”
The footprint of an ATS should also be considered. “Since space in animal-holding rooms is always critical, the animal transfer station should be available in a variety of sizes to maximize the available space in the room,” Christensen says.
From an ergonomic perspective, a scientist should keep other ATS features in mind. “Since most technicians stand at an animal transfer station, the most critical ergonomic factor is that it be height adjustable to accommodate a wide variety of people—short or tall, and those who may wish to be seated versus standing,” Christensen says. “Options such as cage-top holders and hand-sanitizer dispensers should be within easy reach or freestanding so that they can be positioned in close proximity of the technician.” To reduce eye strain and make an ATS more energy-efficient, a scientist should consider an ATS with LED lighting.
BSC Basics and Beyond
In some lab situations, scientists need more than an ATS to move animals. “Whenever an animal has been exposed to potential bio-hazards, or where the status of the animal is unknown, they need to be handled in a Class II Bio-safety Cabinet that is configured for handling mice or rats in animal cages,” Christensen says.
Not just any BSC, however, will work for animal handling. “To accommodate the movement of cages in and out of the work zone, the access opening along the front of the BSC should be a minimum of 12 inches for mouse cages and ideally 13 to 14 inches or taller for rat cages,” Christensen suggests. “To ensure product protection—sterility—for the animals and personnel protection of the researcher, the BSC needs to be rated as a Type A2 cabinet with an air inflow velocity of 105 feet per minute and downflow of HEPA filtered air through the work zone of at least 60 feet per minute.” Those parameters keep animals and personnel safe, even with frequent movements in and out of the BSC.
When a BSC will be used for procedural work, some specific features come in handy. As Christensen notes: “There are a number of options to consider to ensure that the cabinet is configured to meet the intended procedural work to be done inside the cabinet.” These options can include an ultraviolet light and service valves for air, oxygen and vacuum, and flex hoses on the valves allow a BSC to still be height adjustable. To make a BSC a better fit for procedural work, a manufacturer can also add a heated work surface to keep the animal warm during surgery, feed hoppers, sidewall pass-throughs, a magnifying glass and more. Christensen adds, “Bio-safety Cabinets used for procedures involving gnotobiotic mice require customization so that these germ-free mice can be transferred into and out of the work zone effectively without exposure to any potential contamination.”
Other features also make a BSC easier to use and more effective in transferring animals. One thing to keep in mind is how a BSC will be cleaned—and that is often, because of animal hair and dander, plus bedding. Consequently, Christensen notes, “there needs to be a good pre-filtration system in place to collect these particles that is easily accessible for inspection and cleaning.” He points out that “a backwall pre-filter is an ideal location.” More features can be utilized to simplify cleaning. “The work tray itself should be equipped with a kickstand that allows it to be propped up at a 45-degree angle so that users can clean underneath the work surface without lifting it out of the cabinet,” Christensen explains.
To make the animal-transfer process as ergonomic as possible for lab personnel, a BSC needs more modifications or features. “The entire cabinet should be sitting on a motorized base stand with castors to allow for height adjustment for a variety of users—short or tall, seated or standing,” Christensen explains. “While seated at the cabinet, users should be able to rest their arms and elbows on an armrest along the front access opening, and there should be ample room for their legs so they can roll a chair up to the cabinet to do procedural work.”
From an ATS to a BSC, many features must be considered for animal transfers and procedural work. As Christensen shows us, many features can improve a technician’s comfort, which matters with ongoing transfers.