Centrifuge Sample Handling Puts a Renewed Focus on Integrity

Adam Dickie, PhD, is a science writer at Separation Science. He can be reached at [email protected]

Centrifuges have long been unsung workhorses of biology and chemistry labs, but these machines are increasingly coming into the spotlight with recent advancements that have enabled researchers to investigate nanoscale systems, improve production of drug delivery vesicles, and more.

But as centrifuges implement new features, how are handling systems keeping pace? In this article, we review some trends impacting centrifuge sample formats.

Most labs have foregone glass centrifuge tubes in favor of the cost and convenience of plastic consumables typically made from polypropylene—but recent research indicates that chemical leaching from such sample holders may be an underestimated problem in life science applications. A 2021 report by industry giant Eppendorf revealed that a common type of centrifuge incubation—a half-hour at 95°C, spinning at 600 rpm—could contaminate ultrapure water samples in microcentrifuge tubes.1 Analytical methods found part-per-million level quantities of water-soluble leachables, such as additives, in the samples. Organic solvents extracted even more contaminants from microcentrifuge tubes, sometimes to part-per-thousand concentrations.

To combat against leachables and extractables, centrifuge tube manufacturers recommend several different approaches. Materials such as polycarbonates offer enhanced chemical resistance, while design changes such as thicker tube walls can resist centrifugal forces. Vendors are also taking closer looks at polypropylene supply chains, presenting products from virgin resin sources or with improved traceability.

Continuous innovation in centrifuge sample handling is driven by the need to couple improved performance and automation with stricter control over sample integrity.

For users who prepare and store biomaterials such as cells inside centrifuge tubes, critical problems occur when plastic surfaces react with samples. Historically, typical solutions for minimizing protein adsorption onto polypropylene tubes included silicone coatings or adding bovine serum albumin to sample assays. Recent improvements in polypropylene synthesis, however, have enabled vendors to offer centrifuge tubes specially designed to repel proteins and nucleic acids. Others come with cleanroom sterility specifications and certified free of DNase/RNase contaminants.

Some vendors offer solutions to ensure integrity when working with higher-capacity formats as well. For instance, there are single-use and sterilized centrifuge bags available to minimize cross-contamination during harvesting and purification of components from bioreactors.

Continuous innovation in centrifuge sample handling is driven by the need to couple improved performance and automation with stricter control over sample integrity. Lab managers can enhance data quality and streamline processes by adopting similar strategies in their workflows.

References:

1. “Extractables and Leachables in Microcentrifuge Tubes – Extensive HPLC/GC/MS Analysis.” https://www.eppendorf.com/product-media/doc/en/625557/Consumables_Application-Note_417_Microcentrifuge-Tubes_Extractables-Leachables-Microcentrifuge-Tubes-Extensive-HPLC-GC-MS-Analysis.pdf.