RNA separation and related techniques for determining viruses such as coronaviruses

#Certain aspects of the present disclosure generally relate to systems and methods for determining viruses such as coronaviruses.

#Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that are typically mild, such as the common cold, though rarer forms such as SARS, MERS and COVID-19 can be lethal.

#Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 27 to 34 kilobases. The name coronavirus is derived from the Latin corona, meaning “crown” or “halo,” which refers to the characteristic appearance of the virus particles: they have a fringe reminiscent of a crown or of a solar corona.

#Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:

#FIG. 1 illustrates an example device for determining a virus, in accordance with certain embodiments;

#FIG. 2 illustrates an example of a partitioning system for different viruses in one embodiment;

#Certain aspects of the present disclosure generally relate to systems and methods for determining viruses such as coronaviruses. For instance, some aspects are directed to systems and methods for determining viruses using a partitioning system. Within the partitioning system, free RNA or other nucleic acids may preferentially partition into one phase, while intact viruses may be present in the other phase or in both phases. Accordingly, in some cases, free RNA or other nucleic acids may be preferentially removed, e.g., as compared to intact RNA or other nucleic acids present within a virus. In some cases, the phase containing intact viruses can be determined to determine the infectiousness, e.g., of a sample arising from a subject. This may be useful, for example, for distinguishing subjects who are capable of spreading an infection from those who are not infectious.

#One aspect of the present disclosure is concerned with the detection of whole virus particles in biological samples containing a mixture of said whole virus particles, other virus components such as RNA (or other nucleic acids) that are recognized by a molecular detection system, e.g., RT-PCR, as belonging to the virus, and other biological or non-biological components that are not recognized by a molecular detection system as belonging to said virus. Some embodiments include techniques for distinguishing positive molecular detection of a whole virus particle and viral components using the same molecular detection system. This may provide for the determination of samples capable of further infection from those that are not, which may, e.g., be useful for clinically separating patients who are capable of spreading an infection from those who are sick but otherwise non-infectious.

#Certain embodiments rely on spatial separation of whole virus particles from other components of the same virus, e.g., RNA. While whole virus particles may be partitioned between aqueous phases of a partitioning system such as an aqueous multi-phase partitioning system, free nucleic acids such as RNA (e.g., not contained within a virus) can be partitioned preferentially to one phase, e.g., predominantly due to their net negative electrical charge. The aqueous multi-phase partitioning system can include two or more phases, e.g., as is discussed herein. In some cases, if a sample contains both free RNA from dead viruses and whole functional virions capable of further infection, that sample could be detected by simple molecular testing of the phase in which free RNA is not substantially present. If RNA is found in that phase, it may help to determine the presence of whole, functional virions in the sample.