Selecting a Reliable Supplier for Quality Laboratory Plastics

PCR is a highly sensitive molecular biology technique, so the quality of your PCR plates and tubes can really impact your results. When selecting a PCR plate or tube on which to standardize a process, it is important to choose a laboratory consumables supplier that can consistently deliver high-quality molecular biology-grade plastics that meet your specifications.

Consider these guidelines when selecting PCR plastics or qPCR plastics for a large or ongoing project:

• Consider large laboratory consumables suppliers with experience in precision manufacturing of scientific plastics using high-quality raw materials.
• Check to see if the supplier verifies every lot as DNase/RNase-free as well as performance of the plate in PCR reactions.
• Confirm that the manufacturer has tested the fit of the PCR plate into your machine. Get a sample and test it before committing to a large order.
• Verify that they are certified to the relevant ISO quality standards.

Laboratory plastics such as microplates are produced on an industrial scale by melting plastic resin and injecting it into highly complex molds. A well-established and highly controlled manufacturing process results in PCR plates and tubes that are consistent both within and across lots. Reliable laboratory plastics manufacturing requires:

• Establishment of manufacturing clean rooms to prevent contamination by air particulates.
• Mold designs that optimize resin flow into the mold as well as easy release of the finished product.
• Precise control over resin temperature, flow speed, and molecular composition.

Laboratory consumables manufacturers with an ISO 9001 and ISO 13485 certified quality management system will carry out these steps consistently and reliably.

Most PCR tubes and the wells of PCR plates are made from virgin polypropylene plastic resin due to its inertness and excellent heat transfer capacity. Some PCR plate frames are made from polycarbonate, which is well suited for automated PCR plate handling.

Because it is in direct contact with the reaction components and subjected to repeated temperature extremes, the purity and quality of polypropylene is highly important for achieving good performance in molecular biology reactions. PCR plates and tubes made from lower quality polypropylene may leach compounds that inhibit enzymes, or light-absorbing materials that interfere with spectrophotometric analysis [1–3]. For these reasons, it’s recommended to work with laboratory consumables suppliers who use medical or molecular-grade virgin plastic and have tested their products for inhibitory activity.

Given the risks that contamination poses to PCR success, do confirm that your PCR plate/tube supplier certifies its products as nuclease free; ideally, they should also be certified free of human DNA. Contaminating human DNA and nucleases can result in false positives and false negatives respectively, creating inefficiency and the need for re-work. Good laboratory consumables suppliers will test each lot and make a Certificate of Analysis available.

Physical fit of the PCR plate or tube into your (q)PCR equipment is critical for maximum amplification as well as avoiding damage to the reaction. Besides myriad design options (e.g., cap style, well volume, skirt type) that affect compatibility, the precise dimensions of the thermal blocks in PCR and qPCR instruments can vary slightly among manufacturers; even the smallest mismatch between your instrument and the PCR plate or tube can reduce the contact between the two, diminishing control over the reaction temperature and potentially reducing amplification efficiency.

PCR plates made for specific instruments are great for optimizing fit and performance. For example, each Applied Biosystems thermal cycler and qPCR instrument is verified for performance with specific Applied Biosystems PCR plastics.

When sourcing PCR plates from someone other than the instrument manufacturer, make sure that the consumables vendor has tested the fit of their product in your model of thermal cycler. An online PCR plastics selection tool can making finding compatible PCR plates and tubes much easier.

Thermo Fisher Scientific produces its own PCR plates and tubes with a commitment to high quality molecular biology manufacturing standards. Moreover, they can supply your whole workflow including pipet tips, PCR reagents, and DNA purification kits.

The Thermo Scientific PCR portfolio includes a huge variety of PCR plates and tubes verified for fit in third-party thermal cyclers and qPCR instruments.

In addition, Applied Biosystems PCR plastics and PCR reagents are validated with Applied Biosystems instrumentation (PCR and qPCR) as a complete system. This validation helps provide an additional level of confidence that the chosen components are well suited for producing reliable results.

By investing some time up front to find a reliable vendor and the right consumables for your workflow, you can avoid many problems and keep your project on track.

1. Chen H, Blanchaert B, Shinde AB, et al. (2016) Abl1 inhibitory contaminants leach from plastic tubes. Journal of Enzyme Inhibition and Medicinal Chemistry, 31:2, 340-343, DOI: 10.3109/14756366.2015.1022171 
2. Chua EW, Miller AL, Kennedy MA. (2015) Choice of PCR microtube can impact on the success of long-range PCRs. Analytical Biochemistry. 477; 115–117. DOI: 10.1016/j.ab.2015.02.023  
3. Lewis LK, Robson M, Vecherkina Y, et al. (2010) Interference with spectrophotometric analysis of nucleic acids and proteins by leaching of chemicals from plastic tubes. Biotechniques. 48(4);297–302. doi: 10.2144/000113387