Spinning our Way to Success--how Pall’s viral concentration devices are aiding with COVID-19 detection
Centrifugal ultrafiltration devices reliably recover virus particles from wastewater to track COVID-19 outbreaks
April 8, 2021
As COVID-19 cases surge, so too do efforts to track and contain the virus. Wastewater based epidemiology is gaining ground as a promising method of detecting COVID-19 outbreaks early, sometimes before hospitals can confirm positive case counts. While testing community wastewater to track disease outbreaks is not new in and of itself, scientists only recently developed the capability to accurately screen for the COVID-19 virus.
Early detection of SARS-CoV-2, the virus that causes COVID-19, is critically dependent on viral concentration methods.  Viral RNA detection methods must be sensitive and accurate, to safeguard against the risk of false positive or false negative results. Because human wastewater is a complex substrate, accurate detection would not be possible without a concentration method that can reliably recover viral particles from a complex mixture with minimal sample loss.
Pall centrifugal ultrafiltration devices are currently being used to concentrate SARS-CoV-2 virus in wastewater, using technology that has proven effective at viral recovery . Centrifugal devices are available in a wide variety of volume formats and MWCO membranes, adding flexibility to research workflows (Fig 1.).
Figure 1 demonstrates the basic workflow used to concentrate and screen for the presence SARS-CoV-2 viral RNA in human wastewater samples. High speed centrifugation is used to spin viral RNA particles through MWCO membrane into the filtrate receiver, while larger particulates and proteins remain behind in the sample reservoir.
The following concentration steps are used to optimize recovery of SARS-CoV-2 viral RNA particles:
1. Preliminary centrifugation of the wastewater sample to obtain a supernatant.
2. Supernatant is transferred to the ultrafiltration device and further centrifuged at 3500 g through a MWCO membrane.
3. Filtrate is collected for RNA extraction and RT-PCR.
Pall centrifugal filter devices can rapidly concentrate volumes ranging from <50 µL to 60 mL and are compatible with several different RNA extraction kits.
The large volume JumbosepTM centrifugal filter device is reusable, making it an economical and environmentally sound choice compared to single-use devices. Both the sample reservoir and filtrate receiver can be put through a simple decontamination process to remove any trace of COVID-19 viral RNA. Internal studies have shown that decontamination is completely effective at eliminating residual RNA, allowing the device to be reused multiple times without risk of carryover or loss in effectiveness.
Download our technical bulletin: Decontamination of Jumbosep™ Centrifugal Devices used for Concentrating Viral Particles in Testing of Wastewater Sample
Following concentration, viral RNA is extracted from the filtered sample, and Real-time RT-PCR is used to amplify any existing RNA signal. Scientists are then able to verify whether a wastewater sample is positive or negative for the SARS-CoV-2 virus.
At Pall, we are proud to be part of the fight against COVID-19. Visit our Covid-19 workflow information to learn more.
1. Lu D., et al. Primary concentration – The critical step in implementing the wastewater-based epidemiology for the COVID-19 pandemic: A mini-review. Science of the Total Environment. (747) 2020.
2. Ahmed W. et al. Comparison of virus concentration methods for the RT-qPCR-based recovery of murine hepatitis virus, a surrogate for SARS-CoV-2 from untreated wastewater. Science of the Total Environment. (739). 2020.