Sample Buffer Containing Guanidine-Hydrochloride Combines Biological Safety and RNA Preservation for SARS-CoV-2 Molecular Diagnostics

Diagnostics, 2022 · DOI: 10.3390/diagnostics12051186 · Published: May 10, 2022

Immunology Bioinformatics Research Methodology & Design

Simple Explanation

The COVID-19 pandemic has created a need for safe and effective ways to store and analyze infectious samples. This study introduces a storage buffer made with guanidine-hydrochloride. This buffer inactivates the SARS-CoV-2 virus while also protecting its RNA. The buffer's ability to preserve RNA was tested using RT-qPCR. The virus-inactivating properties were tested using a tissue culture infectious dose assay. The buffer is compatible with common RNA extraction methods and easy to produce, making it globally useful.

Study Duration

Not specified

Participants

18 individuals who had previously tested SARS-CoV-2-positive by RT-qPCR 5–7 days after symptom onset and SARS-CoV-2-negative individuals

Evidence Level

Not specified

Key Findings

1
The guanidine-hydrochloride-based storage buffer (SSB-4M) is compatible with commercially available and in-house GuHCl-based RNA extraction methods.
2
SSB-4M preserves SARS-CoV-2 RNA stability, even in the presence of 10 ng/mL RNAse A and in storage at room temperature.
3
A diluted form of the SSB-4M buffer efficiently inactivates SARS-CoV-2 viral particles.

Research Summary

The study addresses the need for a sample storage buffer (SSB) that inactivates SARS-CoV-2 while preserving viral RNA for reliable diagnostics and sequencing. The developed guanidine-hydrochloride-based SSB (particularly SSB-6M) demonstrated effective viral inactivation and RNA stabilization in various sample types, with compatibility across different RNA extraction platforms. The study highlights the importance of both virus inactivation and RNase inhibition for effective sample storage, suggesting the presented GuHCl sample storage buffer can support and improve SARS-CoV-2 laboratory diagnostics.

Practical Implications

Reduced Infection Risk

The buffer's ability to inactivate SARS-CoV-2 reduces the risk of infection during sample handling and analysis.

Improved RNA Stability

Enhanced RNA stability allows for longer storage times and more reliable follow-up analysis, such as variant sequencing.

Global Applicability

The uncomplicated manufacturing process and compatibility with common test systems make the buffer accessible and useful worldwide.

Study Limitations

1
The buffer has only been tested with GuHCl-based test systems.
2
Sampling methods might affect the findings, as viral load varies in different sample types.
3
Virus inactivation likely proceeded for a few minutes after SEC due to residual amounts of Triton X-100 and GuHCl.

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