Do Your Work Cleanly With Gloveboxes

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Gloveboxes are used in laboratories across the sciences. This article will focus on the use of gloveboxes in the life sciences—especially in those laboratories housed in academic institutions, government institutions, biotechnology companies, and pharmaceutical companies. Purchasers of gloveboxes for these types of settings must consider a number of factors. First, does the application call for isolation (in which case, an isolation box would be used) or containment (i.e., a biosafety cabinet)? In other words, is the purpose of the box to protect a sample against some environmental condition in the external environment (isolation) or to protect operators from a hazard that is inside the box (containment)?

Gloveboxes as cleanrooms

Because the box is airtight, any samples being worked on within the box are protected from contamination by particulates in the external environment. The internal environment of the box is also important because it creates a specific, “clean” environment for the work being performed within it. In fact, some types of gloveboxes are also referred to as cleanrooms, isolators, or sterile gloveboxes. “Clean” refers to the fact that the entire environment—air and surfaces—inside the box is sterile, that is, they are free of microbial particulates. The internal environment might also consist of inert gas, low oxygen, a specific temperature or level of humidity, and more. There is no specific glovebox for life science. All kinds of flow boxes can be used in a life science laboratory.

The isolation box: creating the cleanroom

A filter inside the box handles removal of particulates. There are many choices among filtering systems, the most common of which is the HEPA filter. A HEPA-filtered glovebox, the Protector^® from Labconco (Kansas City, MO), is shown in Figure 1. The operator should choose the HEPA filter that will work best to remove the size and type of particulate of concern, so that the box will contain clean air internally.

Another consideration is whether or not the box should include a processed gas. Often, this means a purged box, which is probably the most common in an isolation application. These boxes are simply purged with a processed gas. For sterile gloveboxes, the most important gas in this category is vaporized hydrogen peroxide (VHP), which is necessary to sterilize the inside of the box.

Applications for gloveboxes

A typical life science application for an isolation box is the preparation of a drug formulation by a pharmaceutical manufacturer.

In this application, the manufacturer is looking to sterilize the inside of the box using a validated VHP sterilization process. The United States Food and Drug Administration (FDA) requires that sterilization of the box be confirmed by taking hundreds of swab samples that, when processed, show no growth of any microorganism in an incubator. A pharma manufacturer will want to assemble a drug cocktail within the box to ensure that the drug compound is sterile for use in animals or in humans.

Although gloveboxes are primarily unregulated, their sterilization can create an internal standard known as the ISO5. Determined by an international organization for standards, the ISO5 sets the standard for air particle levels inside the box. Once this standard is set, introducing a nonsterile item into the box will destroy the cleanroom standard. If this occurs, only conducting the VHP process again will reestablish the ISO5 standard.

In addition to sterility, other conditions inside the box can be controlled. For example, some research and industrial applications require low oxygen concentrations. Very low oxygen requirements inside the box are accommodated by incorporating an oxygen scavenger system, vacuuming out ambient air from the inside of the box, and then backfilling the box with a processed gas.

Containment: The class III biosafety cabinet

A class III or biosafety cabinet for life science laboratories is a glovebox for containment of the deadliest organisms known to mankind, for example hanta virus. Those types of organisms are what the U.S. Centers for Disease Control and Prevention (CDC) calls its select agents. For example, these boxes can be used to work with smallpox virus, and all the laboratory equipment needed to perform DNA identification of the bug, for example, must be inside this box. These boxes are primarily used in biosafety level IV laboratories and only for non-weaponized organisms. These types of gloveboxes often have a doubledoor autoclave chamber, and the only way to transfer any equipment or biological materials into or out of the box is through the autoclave.

Glovebox design and price points

Figure 2 - Series 600 stainless steel glovebox. Courtesy of Terra Universal.

Gloveboxes can be made of many types of materials, including plastic or stainless steel; the application(s) being performed inside the glovebox determines which material is most appropriate. Box design must accommodate the need for frequent sterilization. Rounded corners can minimize any possibility for cracks or crevices where germs could colonize, thus helping to maintain sterility. Stainless steel allows for easier sterilization than plastic. However, stainless steel boxes are more expensive than plastic ones. Although plastic boxes are less expensive, their durability varies according to the type of material used to fabricate the box. On the higher price end is polypropylene, which resists alcohol and a fairly wide range of harsh chemicals, including biocides. On the lower end is acrylic, which is not as chemically resistant and cannot even be cleaned with alcohol because doing so would eventually cloud and crack the surface. The Series 600 stainless steel glovebox from Terra Universal (Fullerton, CA) is shown in Figure 2.

The price point depends on the level of customization. For Terra Universal, a base model of a nitrogen purged box is under $1000. The purchaser can build on the purged equipment by a having other process control components added to the box. With this model, the user can have a functional system for under $3000. This price point is for the plastic systems. Other companies, such as Labconco, have a multipurpose turnkey type of system with prices starting at $8000–$10,000. Stainless steel glove boxes are much more expensive.

 James Netterwald, who has a Ph.D. in Microbiology and Molecular Biology and a B.S. in Clinical Laboratory Science, is a freelance biomedical writer and editor; e-mail: james.netterwald@ yahoo.com.

Please check out our glove box section for more information or to find manufacturers that sell these products.