Nanotrap particles can enhance present sequencing workflows of SARS-CoV-2

Researchers from Ceres Nanosciences, USA, have offered a nanotrap enrichment workflow for capturing and concentrating extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) particles from diagnostic and contrived samples.

This method enhances each column and magnetic bead-based RNA extraction protocols, offering important enhancements in sequencing outcomes on the Oxford Nanopore applied sciences (ONT) MinION sequencing platform. Sequencing output demonstrated considerably extra mapped viral reads, and 20-80% improved sequence protection from diagnostic samples with low virus titers.

Study: Nanotrap Particles Improve Nanopore Sequencing of SARS-CoV-2 and Other Respiratory Viruses. Image Credit: Unitone Vector/ShutterstockResearch: Nanotrap Particles Enhance Nanopore Sequencing of SARS-CoV-2 and Different Respiratory Viruses. Picture Credit score: Unitone Vector/Shutterstock

The group additionally demonstrated the identical method to complement two different respiratory viruses particularly Influenza A virus and respiratory syncytial virus, highlighting its potential to enhance real-time PCR and sequencing outcomes for respiratory viruses apart from SARS-CoV-2.


Steady genetic evolution of SARS-CoV-2 highlights the necessity to always determine and monitor the emergence of recent viral variants, and thus particularly calls for for quickly deployable correct sequencing applied sciences.

Right here, the ONT MinION sequencer comes into focus. Being a conveyable and comparatively cheap detection technique, it may be used for speedy on-site detection and characterization of viral variants within the subject. Nevertheless, the usefulness of those moveable sequencing instruments is proscribed by the base-calling accuracy points that come up in samples with inadequate nucleic acid focus.

The group from Ceres Nanosciences, of their latest analysis printed on the preprint server bioRxiv*, has addressed this limitation through the use of an affinity-based magnetic hydrogel particle enrichment know-how (Nanotrap particle enrichment know-how) that may focus viral particles, resulting in improved detection of many viral brokers together with SARS-CoV-2. With superior base-calling, bioinformatic instruments can confidently distinguish the genetic mutation within the variant from machine error.

What did the researchers do?

The group developed three workflows to exhibit the robustness and the ease-of-use of Nanotrap particle know-how: a handbook methodology with a column-based RNA extraction (Nanotrap Particle Workflow 1), a handbook methodology with a magnetic-bead-based RNA extraction (Nanotrap Particle Workflow 2), and an automatic methodology with a magnetic-bead-based RNA extraction (Nanotrap Particle Workflow 3).

These workflows have been carried out in SARS-CoV-2 contrived (spiked with 1:10 serial dilutions of heat-inactivated SARS-CoV-2 ranging from 106 TCID50/mL to 102 TCID50/mL) viral transport media (VTM) in addition to remnant diagnostic VTM samples. The Nanotrap particle workflows (+NT) have been in contrast towards the workflows with none Nanotrap particles (-NT).

Extracted RNA was ready for sequencing utilizing the ARTIC nCoV-2019 sequencing protocol and sequenced on the ONT Mk1C sequencing platform, adopted by information evaluation.

Moreover, real-time RT-PCR was carried out on RNA extracted from all three workflows to determine a possible correlation between the 2 assays and make sure the presence of SARS-CoV-2.

Nanotrap particles enhance sequencing outcomes

With Nanotrap Workflow 1, Nanotrap particles considerably improved sequencing outcomes at varied virus concentrations when in comparison with the workflow with out Nanotrap particles. A 6.0X enhance in reads mapped to SARS-CoV-2 was noticed at 106 TCID50/mL and a 2.0X enhance was seen at 105 TCID50/mL. These enhancements have been statistically important. Viral detection in real-time qPCR was additionally considerably improved by two PCR Cycle thresholds (Ct) throughout the primary 4 serial dilutions.

As column-based RNA extractions are extra applicable when working with much less variety of samples, the group tried to evaluate the Nanotrap particles’ potential to enhance on sequencing when utilizing RNA extracted through magnetic beads (Nanotrap Workflow 2). Right here, an enchancment of 1.9X in SARS-CoV-2 mapped reads was noticed at 106 TCID50/mL and an enchancment of 1.4X at 105 TCID50/mL. Moreover, real-time qPCR detection of SARS-CoV-2 was enhanced, offering a median 1.5 Ct enchancment at 106-102 TCID50/mL.

“RT-PCR outcomes confirmed Nanotrap particle enrichment was efficacious for decrease focus samples for each workflows, doubtlessly suggesting that on another sequencing platform with higher general sensitivity, Nanotrap particles may additionally enhance sequencing of those decrease titer virus samples”, the group highlights.

To check the efficacy of Nanotrap particles with actual scientific samples, the group evaluated the Nanotrap particle workflows utilizing 10 diagnostic remnant scientific swab samples with reported qPCR Ct values starting from 24 to 35. The group quantified each whole viral mapped reads and the related % genome protection at 30x depth of the processed samples.

Nanotrap Particle Workflow 1 resulted in a big 7X enchancment in whole viral reads mapped throughout all 10 diagnostic remnant samples, which additional resulted in a median viral genome protection enhance of 52% over samples processed with out Nanotrap particles. RT-PCR confirmed the presence of SARS-CoV-2 with a median enchancment of 4 Ct over no Nanotrap particle samples.

Automated Nanotrap Particle Workflow 3 methodology on automated KingFisher Apex System additionally demonstrated improved outcomes, with a median enchancment of 42X in whole viral mapped reads that corresponded to a median 51% enhance in viral genome protection relative to (-NT) samples. Once more, qPCR confirmed the presence of SARS-CoV-2 for all 10 samples with a median 3.7 Ct enchancment.

Determine one: Nanotrap Particle Workflow 1 Improves Sequencing of Diagnostic Remnant SARS-CoV-2 Samples. 10 SARS-CoV-2 constructive diagnostic remnant samples have been processed utilizing Nanotrap Particle Workflow 1 [+NT] or the RNEasy Equipment alone [-NT]. Samples then underwent sequencing on a ONT MinION R.9 circulate cell and have been analyzed by Viral Mapped Reads to SARS-CoV-2 (A), Viral Genome Protection at 30x depth (B), or RT-PCR (C). [+NT] have been in comparison with [-NT] by paired t-test in an effort to assess significance of elevated viral detection (D),(E). ***p<0.001.

Enhanced detection of different respiratory viruses

To substantiate the enriching potential of Nanotrap particles for different viruses and never simply SARS-CoV-2, the group equally examined RNA extraction with workflow 1 on contrived VTM samples spiked with Influenza A (H1N1) virus and RSV. Noticeably, Nanotrap particles have been capable of enhance sequencing outcomes for each viruses. As with SARS-CoV-2, Nanotrap particles elevated viral mapped reads by 4X for each Influenza A and RSV in comparison with the samples processed with out Nanotrap particles. Moreover, Nanotrap particles considerably improved the detection of viral RNA with qPCR. Primarily based on this experiment, the group means that Nanotrap particles can be utilized to determine and enhance sequencing outcomes of a number of viruses in VTM samples.

Sequencing library preparation protocol includes using varied enzymes that may be negatively impacted by the presence of detrimental organic materials current in the actual human-derived diagnostic samples. Pre-processing with Nanotrap particles allows the seize of viral materials whereas decreasing host cell particles and different contaminating materials. The group thus means that workflows with out Nanotrap particles usually tend to be impacted by inhibition.


Because the viral genome protection was tremendously elevated and was virtually improved by 80% within the majority of diagnostic samples, the group means that utilizing Nanotrap particles can permit for the lodging of extra scientific samples in a single run.

The group highlights the necessity for a easy and speedy workflow in an effort to obtain a excessive pattern throughput in a public well being setting and subsequently recommends the automated Nanotrap Workflow 3 for such settings.

It’s price noting that this automated methodology would allow the processing of 96 samples in 1 hour, which is considerably quicker and way more person pleasant than the manual-column extraction methodology, making this a lovely proposition for medium- to high-throughput laboratories”

Moreover, Nanotrap particle workflows can be utilized for the advance of broad-scale viral detection by sequencing as demonstrated from the sequencing experiments carried out on Influenza A and RSV.

General, the observations recommend that Nanotrap particle enrichment permits for sequencing of decrease titer scientific samples in VTM utilizing the ONT MinION Sequencer, which in any other case might not have been appropriate for sequencing.

A Nanotrap particle concentrating methodology paired with a ONT sequencing platform permits for a robust sequencing software that might doubtlessly be deployed in an space with lack of entry to extra conventional sequencing or pattern processing gear” the group concludes.

Determine two: Nanotrap Particle Workflow 3 Improves Sequencing Output of Diagnostic Remnant SARS-CoV-2 Samples. 10 SARS-CoV-2 constructive diagnostic remnant samples have been processed utilizing Nanotrap Particle Workflow 3 [+NT] or the MagMAX package alone [-NT]. Samples then underwent sequencing on a ONT MinION R.9 circulate cell and have been analyzed by Viral Mapped Reads to SARS-CoV-2 (A), Viral Genome Protection at 30x depth (B), or RT-PCR (C). [+NT] have been in comparison with [-NT] by paired t-test in an effort to assess significance of elevated viral detection (D), (E). * p<0.05, ** p<0.01.

*Vital discover

bioRxiv publishes preliminary scientific experiences that aren’t peer-reviewed and, subsequently, shouldn’t be thought to be conclusive, information scientific apply/health-related conduct, or handled as established data.

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