In Today's Labs, Disposable Plastics Play A Supporting, But Essential, Role

SUPPLIERS OF PIPETTES, MICROCENTRIFUGE TUBES, AND OTHER PLASTIC LABWARE Action Scientific P.O. Box 765 Forest Hill, Md. 21050 Circle No. 062 on Reader Service Card Analtech Inc. P.O. Box 7558 Newark, Del. 19714 Circle No. 063 on Reader Service Card Ashton Pumpmatic 3306 Encrete Lane Dayton, Ohio 45439 Circle No. 064 on Reader Service Card Becton Dickinson/ Falcon Labware 1 Becton Dr. Franklin Lakes, N.J. 07417 Circle No. 065 on Reader Service Card Bel-Art Products 6 Industrial Rd. Pequannock, N.J. 07440 Circle No. 066 on Reader Service Card Bio-Rad Laboratories 2000 Alfred Nobel Dr. Hercules, Calif. 94547 Circle No. 067 on Reader Service Card Corning Costar Corp. 1 Alewife Center Cambridge Mass. 02140 Circle No. 068 on Reader Service Card DBM Scientific Corp. 28604 Avenue Stanford Building H Valencia, Calif. 91355 Circle No. 069 on Reader Service Card Drummond Scientific Co. 500 Parkway, Box D Broomall, Pa. 19008 Circle No. 070 on Reader Service Card Dynalab Corp. 350 Commerce Dr. P.O. Box 112 Rochester N.Y. 14601 Circle No. 071 on Reader Service Card Dynatech Laboratories Inc. 14340 Sullyfield Circle Chantilly, Va. 22021 Circle No. 072 on Reader Service Card Eppendorf North America Inc. 545 Science Dr. Madison, Wis. 53711 Circle No. 073 on Reader Service Card Evergreen Scientific 2300 E. 49th St. Los Angeles, Calif. 90058 Circle No. 074 on Reader Service Card Fisher Scientific Co. 711 Forbes Ave. Pittsburgh, Pa. 15219 Circle No. 075 on Reader Service Card Fisons Instruments 55 Cherry Hill Dr. Beverly, Mass. 01915 Circle No. 076 on Reader Service Card Hamilton Co. 4970 Energy Way Reno, Nev. 89508 Circle No. 077 on Reader Service Card ICN Biomedicals Inc. ICN Plaza 3300 Hyland Ave. Costa Mesa, Calif. 92626 Circle No. 078 on Reader Service Card INAMCO Chemicals & Lab Equipment 78-44 Parsons Blvd. Flushing, N.Y. 11366 Circle No. 079 on Reader Service Card Integrated Separation Systems 21 Strathmore Rd. Natick, Mass. 01760 Circle No. 080 on Reader Service Card Intermountain Scientific 420 N. Kays Dr. Kayesville, Utah 84037 Circle No. 081 on Reader Service Card Kimble/Kontes Glass 537 Crystal Ave. Vineland, N.J. 08360 Circle No. 082 on Reader Service Card SUPPLIERS OF PIPETTES, MICROCENTRIFUGE TUBES, AND OTHER PLASTIC LABWARE Lab Safety Supply Inc. P.O. Box 1368 401 S. Wright Rd. Janesville, Wis. 53547-1368 Circle No. 083 on Reader Service Card Labsystems Inc. 3000 Second Ave. Needham Heights, Mass. 02194-2818 Circle No. 084 on Reader Service Card Matrix Technologies Corp. 44 Stedman St., Unit 4 Lowell, Mass. 01851 Circle No. 085 on Reader Service Card Medical Systems Corp. 1 Plaza Rd. Greenvale, N.Y. 11548 Circle No. 086 on Reader Service Card Molecular Bio Products 9888 Waples St. San Diego, Calif. 92121 Circle No. 087 on Reader Service Card Nalge Co. P.O. Box 20365 75 Panorama Rochester, N.Y. 14602-0365 Circle No. 088 on Reader Service Card Narishige U.S.A. Inc. 404 Glen Cove Ave. Sea Cliff, N.Y. 11579-2107 Circle No. 089 on Reader Service Card Popper & Sons Inc. 300 Denton Ave. New Hyde Park, N.Y. 11040 Circle No. 090 on Reader Service Card Rainin Instrument Co. Inc. Mack Road Woburn, Mass. 01888 Circle No. 091 on Reader Service Card Sarstedt Inc. 1025 St. James Church Rd. Newton, N.C. 28658 Circle No. 092 on Reader Service Card Sigma Chemical Co. 3050 Spruce St. Catalog Department St. Louis, Mo. 63103 Circle No. 093 on Reader Service Card Spectrum Medical Industries 1100 Rankin Rd. Houston, Texas 77073 Circle No. 094 on Reader Service Card Stratagene Cloning Systems 11011 N. Torrey Pines Rd. La Jolla, Calif. 92037 Circle No. 095 on Reader Service Card Stoelting Co. 620 Wheat Lane Wood Dale, Ill. 60191 Circle No. 096 on Reader Service Card Thomas Scientific P.O. Box 99 Swedesboro, N.J. 08085-0099 Circle No. 097 on Reader Service Card TOMTEC Inc. 607 Harborview Rd. Orange, Conn. 06477 Circle No. 098 on Reader Service Card Tri-Continent Scientific Inc. 12555 Loma Rica Dr., Ste. 2 Grass Valley, Calif. 95945 Circle No. 099 on Reader Service Card Ulster Scientific Inc. P.O. Box 819 New Paltz, N.Y. 12561 Circle No. 100 on Reader Service Card USA Scientific Plastics P.O. Box 3565 Ocala, Fla. 34478 Circle No. 101 on Reader Service Card VWR Scientific Inc. 1310 Goshen Pkwy. West Chester, Pa. 19380 Circle No. 102 on Reader Service Card Wheaton 1501 N. 10th St. Millville, N.J. 08332 Circle No. 103 on Reader Service Card What is the most important piece of laboratory equipment, the one that no lab wants to be without? Depending on whom you ask, the answer to that question will vary. Molecular biologists or biochemists might name electrophoresis or chromatography equipment. A cell biologist would most likely consider a tissue-culture hood essential. Without a doubt, however, if you took away the disposable plastic pipettes and tubes used to handle minute liquid samples, the scientific studies of researchers in these fields would grind to a halt. Although not usually considered the marquee players in the laboratory, plastics such as pipettes, microcentrifuge tubes, or culture tubes are essential members of the scientific supporting cast. Perhaps the most indispensable are the plastic, disposable pipettes, which are available in dozens of generic and use-specific designs, in numerous shapes and sizes, and even in different colors. The polymerase chain reaction (PCR), used to generate copies of DNA sequences and considered by many to be the most important research tool of the 1990s, would not be feasible in a laboratory without plastics. In PCR, minute volumes of reactants are subjected to rapid changes in temperature-- from cool to very hot and back again--in a thermocycling device, which results in the sequential amplification of a specific sequence of DNA. This requires special microcentrifuge tubes with extra-thin walls to optimize heat transfer between the thermo-cycler and the reactants in the tubes. Also necessary are pipettes that can accurately measure minute volumes of liquid. In PCR, even a 1- or 2- microliter discrepancy can significantly change the reaction conditions. "A micropipettor equipped with a plastic tip that can accurately measure microliter amounts is an absolute requirement for setting up PCR reactions," says Denise McKeon, a microbiologist in the biology department at the State University of New York, Albany. Accuracy in volume measurement is a major consideration cited by many scientists who use plastic micropipette tips. "Accuracy is critical," says Michael Lapointe, a biophysicist in the department of physics and astronomy at Arizona State University in Tempe. Lapointe examines biological specimens such as protein and DNA at the atomic level using scanning tunneling microscopy, or STM. "We have to be exceedingly accurate when we prepare solutions to achieve the right electrochemical balance for STM," says Lapointe. Plastic pipettes come in all sorts of shapes and sizes. Some, like those used in PCR and numerous other biophysical or molecular biology applications, measure volumes less than 1 microliter. Others can be used to apportion larger volumes, in the milliliter range. Even the classic glass Pasteur pipette--a simple, ungraduated tube used to transfer samples, and historically the workhorse of the clinical lab- -now has plastic counterparts. "Because of the convenience, disposable pipettes of glass or plastic are very high-volume items," says Bob Bitgood, account manager for Dynalab Corp. in Rochester, N.Y., a supplier of laboratory plastics. "Sterilizing lab-ware takes time, and because plastic pipettes and tubes are low-cost and disposable, they have great appeal to investigators in both research and clinical labs." Convenience is a definite force driving the growing popularity of laboratory plastics. Micropipette tips, for example, are used once and then thrown away. This is a major improvement over the glass micropipettes that researchers in the 1960s and 1970s carried around, along with their own personal micropipette washers. In those days, an enzyme assay using perhaps dozens of micropipettes required a technician to draw--by mouth--on the end of thin rubber tubing attached to glass microcapillary-sized tubes to pull the liquid into the tubes. In addition, while using large numbers of miniature glass pipettes in such procedures, the technician could look forward to having to carefully wash and sterilize the tubes for reuse before running the next assay. With the plastic disposable micropipettes, one test can start where a previous test leaves off. Simply disposing of a plastic micropipette tip and using a different one to measure out the next volume in an assay is a considerable advantage in itself. Also, when sample purity is essential to an experiment's success, disposables are the only way to go. "Any contaminant, even ones the size of an atom, show up on STM," says Arizona's Lapointe. "Using disposables in our preparations helps to minimize the chances of something getting into the sample." There are plastic pipettes to perform virtually any application requiring either small or large volumes of liquids. Plastic and disposable serological pipettes have found a definite niche in laboratories that would otherwise generate large numbers of dirty pipettes needing cleaning. They are indispensable in teaching laboratories, in which students might use 100 serological pipettes in a single laboratory class. "It is much less expensive and more time- efficient to use presterilized plastic pipettes than to wash and sterilize glass," says McKeon at SUNY-Albany. Currently, the largest market in laboratory plastics appears to be in micropipette tips and disposable microcentrifuge tubes, according to Dynalab's Bitgood, although many other disposable plastic products are also available. In micropipette tips alone there are dozens of different designs. Some can be used in standard applications that simply require the accurate measurement of microliter volumes. Others are designed with a specific application in mind. For loading protein electrophoresis gels or DNA-sequencing gels, there are tips that taper to a thinly elongated end that slips neatly between the glass plates of an electrophoresis apparatus. With this type of capillary micropipette tip, a protein or DNA sample can be loaded directly into the bottom of a sample well, which decreases the possibility that a sample will spill over into an adjacent well. PCR applications, in particular, benefit from the wide array of plastic tips available for liquid handling. In PCR, a primer that is complementary to a particular sequence of DNA is added to a sample, where it binds and starts off a round of amplification steps. Keeping contaminating DNA out of PCR samples is critical to ensure that the DNA being amplified is from the desired source exclusively. To protect against contaminating aerosols derived from sample aspiration in PCR amplification reactions, micropipette tips with an aerosol barrier keep the pipetted liquid in the plastic tip and away from the nose cone of the micropipettor. This eliminates contamination of a PCR sample with airborne DNA from a previous sample. Tips with aerosol barriers are also useful in assays requiring radioactivity. The barrier keeps radioactive particles from contaminating the micropipetting device, saving the investigator a phone call to his or her institution's environmental safety office. Cell biologists also enjoy a large assortment of plastic products from which to choose. Plastic, presterilized, and specially treated disposable pipettes, culture tubes, and tissue-culture flasks are the backbone of the cell-culture laboratory. A selection of micropipette tips is even available in individually wrapped and irradiated packages. For instance, Bio-Rad Laboratories, based in Hercules, Calif., sells 13 different types of individually packaged sterile plastic tips that fit most commonly used micropipette apparatus. For laboratory tests performed in the wells of microtiter plates, multichannel pipetting devices make liquid handling a bit easier. Many are ergonomically designed to prevent hand and wrist fatigue. Using a multichannel pipette, an investigator can fill an entire 96-well microtiter plate quickly, accurately, and with a minimum of effort. The tips for these pipettors come packaged in racks that match the microplate spacing to save even more time. Approaching the logical limit in multichannel pipettors may be a 96-channel device that fills (or empties) all of the wells of a 96-well plate with a single push on a 35 ml disposable plastic syringe. This unit, called the Vaccu- Pette/96 from Bel-Art Products in Pequannock, N.J., is individually packaged and irradiated to assure sterility. Bel-Art makes the Vaccu-Pette/96 in two models: one that is disposable after a single use, and another that can be cleaned and resterilized by autoclaving, making it reusable. Disposability is decidedly the feature of laboratory plastics most scientists emphasize. But what about all those discarded plastic pipettes and tips that now make up the bulk of discarded laboratory waste? With landfills closing and worries increasing about the long-term effects of plastics buried underground, the problem of what to do with all of the discarded laboratory plastic will have to be addressed, scientists say. "The problem of laboratory waste disposal is a growing one," says Vincent Franconere, director of environmental health and safety at SUNY-Albany. Like most research institutions, the university generates tons of plastic waste each year. Under applicable laws, pipettes and other types of laboratory plastics are not currently considered regulated medical waste--terminology used to refer to syringes, needles, or other waste items generated by medical research projects and that may be contaminated with human blood. Because of this, the plastic items are allowed to be shipped out in the regular garbage to be landfilled or incinerated. Even so, concerns remain about this type of laboratory waste. There are unanswered questions of what happens to the chemical components of the decomposing plastics buried underground. Do they leach into the soil, for example, creating toxic substances with the potential to contaminate groundwater? Or, will plastics that are specifically designed to be durable and strong ever degrade in a landfill? Unless a microbiologist fortuitously detects a resin-eating microbe, it is likely that some used laboratory plastics will remain in the ground in solid form for the indefinite future. Laboratories that generate large amounts of non-reusable plastics are increasingly finding themselves at the center of a politically volatile environmental debate. "Environmentally, purists will say we should go back to using glass in the laboratory, because it's reusable," says Franconere. "But you have to consider the practical side of operations. The volume that is being generated just doesn't allow us to go back to glass because of the [diminishing] resources we have available to us. When you examine all of the costs and the time involved, disposal is the only viable option." However, disposal as ordinary trash is becoming a less acceptable way to discard plastic pipettes and other plastics like petri dishes and culture tubes. There is a possibility that in some states contaminated disposable pipettes and petri dishes may soon come under one of the most highly regulated category of medical waste--"sharps." (The plastics themselves may not be sharp, per se, but this dangerous type of medical waste includes needles contaminated with HIV-infected blood and other pathogens, for example.) If that happens, disposal costs will skyrocket for research institutions that contract with commercial waste-management companies to haul away their regulated medical waste. "Categorizing these items as sharps would increase our output of regulated medical waste by five or six times, and that type of waste is not cheap to deal with," says Franconere. Another problem is that a given landfill may decide against accepting further laboratory waste at any time. And with environmental concerns growing over the use of incineration as an option for solid-waste disposal, the alternatives are reduced further. Manufacturers, distributors, and users of disposable plastic appear to have adopted a wait-and-see stance as far as disposal is concerned. "At the distribution level, there are no aggressive programs looking into reclamation or other practical and environmentally safe disposal alternatives," says Dynalab's Bitgood. "It is possible to shred the plastic and then chemically decompose the material and reuse the resin," he adds, although he concedes that the practice may be economically unfeasible. "It might cost more to dispose of the plastic than to acquire it." According to Franconere at SUNY-Albany, the situation will have to be resolved soon: "The plastics issue is a mini- crisis waiting to happen." Holly Ahern is a freelance science writer based in Albany, N.Y. She teaches cell and molecular biology at the State University of New York, Albany.

In Today's Labs, Disposable Plastics Play A Supporting, But Essential, Role

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