by Keerthi Sindhu Harsha Ram, Applications Scientist II, Molecular Biology with Life Sciences and Lab Plastic Essentials at Thermo Fisher Scientific
Chemicals, radioactive substances, and biological specimens are all commonly utilized in research labs and, if mishandled, can cause harm. However, one of the most essential resources in the lab is likely not what people expect, but can be a deciding factor for contamination in your research – the labware used daily across nearly all experiments. If broken, glass can be tainted with harmful chemicals or infectious materials and could cause harm to lab personnel, turning a key lab instrument into a physical hazard. Some of the most common reportable accidents in the lab are often due to broken glass and people getting cuts, injuries, or exposure to chemicals. As a result, lab safety programs have become more and more critical as time goes by, and many labs are turning to reusable plastic instead of glass labware in the lab to reduce these risks.
Historical Use of Glassware in the Lab
Open any laboratory cabinet and it will contain a snapshot of science's past, with shelves filled with stacks of glassware. This is not surprising considering the influence of glass on science's evolution. Although much has changed throughout the years, glass remains the material of choice in the lab.
There are many reasons why glass has played a protagonist role in laboratories for many years and has been used as the primary material for labware. Glassware is transparent – it offers enhanced visibility of graduation marks; it is heat-resistant – it can be placed onto hotplates without breaking or melting. Glassware is washable and can be reused quite frequently. It is also chemically inert and allows for high chemical resistance against acids and any other solutions.
However, although glassware offers practical functions in the lab, it also has a few drawbacks worth considering. Glass is heavy, can be cumbersome to move around in the lab for larger vessels, and the likelihood of breaking is high, especially in busy labs with many users. In addition, glass is costly to replace and broken glass labware could lead to sample loss and exposure to potentially hazardous solutions or even injuries to the lab tech or scientist, therefore creating an unsafe laboratory environment.
Converting to Reusable Plastic for Lab Safety and Efficiency
Although glass has traditionally been considered the material of choice in the laboratory, there are better alternatives when it comes to lab safety that don’t compromise the utility of labware. Plastic laboratory ware, such as beakers, cylinders, and funnels, will not shatter or break like glass, making it a safer option in the lab. Furthermore, plastic is lightweight, durable, and strong, which supports efficient operations and movement throughout the lab.
There are a few primary considerations labs should take into account when trying to decide between glass or reusable plastic labware in the lab:
Safety: From a safety aspect, reusable plastic is safer and easier to handle in a busy lab. Researchers can move quicker and more freely without the fear of breaking a lab instrument. Working with large volume samples is already mentally preoccupying. Using glass labware adds to their mental strain considering the care lab researchers need to exert while working with glassware that's expensive or could crack and cause major harm. All these concerns are alleviated when opting for reusable plasticware. Furthermore, plastic labware can be the best option in the hands of an inexperienced lab researcher because it is more durable and creates a safer lab environment.
Ergonomics: Reusable plastic labware is more ergonomic to hold and manipulate than glassware due to its lightweight composition. Handling larger pieces of labware, like desiccators or carboys, from the balance to the oven to the bench top, or to and from incubators or storage racks, is easier when it is made of plastic as opposed to glass because plastic labware weighs drastically less. Overall, reusable plastic can make daily tasks more manageable and less painful while lowering the risk of repetitive motion injuries and muscle strain.
Durability: Like glass, several plastic labware pieces are reusable. There are those that can be washed, and also those that can be autoclaved the same way as glassware. However, unlike glass, reusable plastic is more durable and can last for up to 25 to 30 years with proper maintenance and usage. This is a huge cost saving for labs, especially considering that glassware can be damaged more easily and costs more than plastic to replace. Additionally, due to the supply chain process limitations, cost of manufacturing, and logistic challenges for glass, reusable plastic may be more readily available for replacement and stocking of new labs.
Even at the end of its life cycle, as long as plastic labware has been decontaminated appropriately, it can be recycled and easily disposed of, which is not the case for disposal of glass labware. Due to its potential for breakage, glass needs to be treated like a hazard and requires taking the more cautious approach that requires training staff on the safest disposal method.
Break it or Make it: Glass vs. Plastic in the Lab
With all the benefits of safety, shatterproof features, and ergonomics that reusable plastic offers, the question remains – why does glass labware continue to be prevalent? A few reasons are that using glass in the lab can offer better chemical resistance and is able to withstand a large range of severe temperatures when using tools like a hotplate, stirrer, or a Bunsen burner. In those cases, working with plasticware is not ideal.
However, different kinds of plastics have different chemical compatibilities and are able to withstand different temperature ranges. Therefore, depending on usage, lab personnel may be able to select a comparable plastic alternative, but may need to be informed on the properties of the plasticware chosen and its limitations to reap the benefits of reusable plastic.
Another make-it-or-break-it decision is knowing how to avoid leachables and extractables from the labware material itself. Borosilicate, glass labware, and even soda lime glass have a lot of metal ions associated with them. Therefore, in some cases, like tracing metals, opting for a metal-free plastic is the best choice. If lab personnel are concerned about trace levels of organic materials, using glass instead of plastic is an excellent option since there is less potential leaching. For the most part, good quality reusable plastic can offer a lower potential for leachables and extractables.
Researchers working with different chemicals, such as organic solvents, aqueous solutions, alcohols, plain reagents, etc., are likely to find a reusable plastic bottle, flask, or other pieces of labware comparable to just about any glass instrumentation. However, selecting the correct type of reusable plastic is essential.
Not All Plastics Are Created Equal
Not all plastics are created equal, and labs must choose the appropriate reusable plastic material and consider what type of chemical or heat source it will come into contact with and for how long. For example, will a graduated flask be used, washed, and autoclaved after briefly being in contact with a chemical? This is important since it is not a good idea to autoclave certain reusable plastics. Although some can withstand higher temperatures than the autoclave, other reusable plastics will melt approaching autoclave temperatures.
Another question to consider is how long the substance will be stored in the labware – for example, will a chemical need to be shelved for weeks, months, or even a year? Storing corrosive substances in certain bottles can destroy containers made from inadequate materials. Labs should also ask, what temperature range is this plastic labware going to see – will it be stored to freeze? Some reusable plastics are flexible in severe cold temperatures, while others get rigid and tend to break, so it’s important to note the material of the labware before use.
One other property to consider is that some plastics are sensitive to light. If plastic bottles are left on the top shelf, right under the fluorescent lights, or left on the countertop where they may receive UV light from outside, it will accelerate the aging process of plastic. Storing plastics and protecting them from UV radiation is always a good idea. Fortunately, similar to glass labware, one can opt for amber plastic labware to protect light-sensitive materials.
Selecting the Appropriate Reusable Plastic
Because plastic's physical characteristics and properties can vary and somewhat impact the results of an experiment, there are ways to select the appropriate reusable plastic for lab research using charts that show certain plastics’ chemical resistance, resin characteristics, and temperature range. These charts are easy to obtain and highly recommended to be visually available in the lab. To determine what type of plastic an experiment would require, most labware contains an identifiable code stamped or molded into the piece. This code indicates what type of plastic researchers are working with, whether it is HDPE, PP, or PC, and how best to use and care for the reusable plastic labware.
Finally, knowing what plastic to select requires knowing what reusable plastic labware supplier to contract. When using plastic labware, it is recommended to only source it from reputable manufacturers. Ensuring that the plastic labware purchased is made from virgin and laboratory-grade materials is crucial. Lab managers should feel encouraged to ask manufacturers if they use USP Class VI grade materials and request certificates for their products and documentation that back up their claims. Therefore, knowing who is manufacturing the reusable plastic labware and how and where it is being developed will add to success and safety in the lab.
Ultimately, when deciding whether to choose glass vs. reusable plastic labware, lab managers should consider safety, cost, ergonomics, and the research at hand. Weighing the advantages and disadvantages of each will ensure the selection of the appropriate material and the safety of the lab.
About the Author: Keerthi Sindhu Harsha Ram is an Applications Scientist with Thermo Fisher Scientific. She is a graduate of the University of Mysore, Mysore, India, with a Master’s degree in biotechnology and received her certification in biotechnology from the University of California, Santa Cruz.
She has worked in the field of sequencing for nearly 6 years and has extensive experience in sample preparation, nucleic acid extractions qPCR, and mammalian and bacterial cell culture. Currently, as part of the Applications Team, she conducts research to generate and publish data to support the development of applications for scientific products and the laboratory plastic essentials portfolio, including products for molecular diagnostics, laboratory consumables, and reusable plastic labware.