GenVault utilizes a nanoparticle matrix for room temperature storage of nucleic acid biosamples, Reversible Porous Matrix, for long-term maintenance of DNA and RNA integrity
GenVault’s latest, revolutionary dry-state, room-temperature biosample storage technology is the nanoparticle-based Reversible Porous Matrix, RPM. This bead technology allows you to store very small amounts to very large amounts of DNA and RNA at room temperature, with nearly 100% recovery from the storage matrix, when needed for downstream experimental use. These ceramic beads are inert and therefore do not interact with the chemistry of nucleic acids such as DNA or RNA. In addition, the RPM matrix is not carbon-based, therefore no life can grow in the storage medium. The matrix offers a unique level of protection to the biosample because the DNA or RNA strands actually sit between the beads, within the space created as many beads come together by drying to form a pellet. Almost 100% of the nucleic acid sample can be recovered from storage by adding water or a simple buffer solution. Once the water is added, conical tubes containing the re-suspended sample are spun down on the bench top to separate the purified nucleic acids from the beads. The nucleic acids can be concentrated to any desired level.
Review data generated by a collaborative effort between GenVault, the National Center for Forensic Science, and the University of Florida. The study demonstrates the use of RPM technology for storage of small amounts of RNA. RPM nanoparticles can also store purified genomic DNA.
Pores.
Pores are good for storing biosamples. They offer protection. But how is it possible to optimize the usage of pores? For example, how do you make pores occur when you need them and make them disappear when you don’t need them? GenVault’s latest technology, called RPM for Reversible Porous Matrix, does exactly that. The core material used to create the porous matrix is zirconium oxide, ZrO2, configured as a 27nm nanoparticle in the shape of a perfect sphere. Regardless of the size, but assuming all the spheres are of the same size in a bin, spheres will by nature pack together with other spheres of the same size in such a way that two-thirds of the space they occupy in the bin is due to their physical mass, and one-third of the space is a void created by gaps between the spheres. The void space is what creates the pores. Thus, randomly packed spheres of zirconium oxide come together to form an open porous structure that offers permanent stability, yet they can be disrupted anytime by suspension into a fluid sample, to be brought back to the original, unpacked form via simple air drying, thus reversing the suspension process.
What is a zirconium oxide nanoparticle?
The ZrO2 nanoparticle of RPM is roughly 27nm in diameter and a perfect sphere. The dimension of the interstitial pores formed by random nanoparticle packing scales exactly with the diameter of the sphere. Thus, an assembly of randomly-packed 27nm diameter ZrO2 nanoparticles will form pores that are about 13nm wide. The diameter of a DNA duplex is 2nm and that id single stranded RNA is 1nm. Thus, the RPM pores are large enough to accommodate these relatively large biological molecules, but in an environment that is highly constrained on all sides, due to the fact that, during drying, the nanoparticles assemble around the DNA and RNA molecules to form pores that are far too small to have been occupied by diffusion.
In addition, the nanoparticles are coated with a negatively charged chemical which repulses DNA based on its phosphate negative charge. Thus, this charge repulsion allows the surface of the zirconium oxide nanospheres to become passive, so that DNA or RNA will not be lost by binding to the nanosphere surface.
Use.
Nucleic acid biosamples are added to the RPM medium as an ordinary fluid solution, at a volume that is determined by the total volume of the container and the amount of nanoparticle spheres present (typically 20uL). Upon pipette mixing, the nucleic acid and the nanospheres form a uniform suspension, which is then air dried. The water evaporates, leaving a clearly defined nanoparticle pellet, with the nucleic acid encapsulated in the pores formed between the spheres.
Three levels of protection.
- The non-porous ceramic ZrO2 nanospheres, by forming nooks and crannies for the DNA and RNA molecules to reside in, offer robust physical protection to the biosample.
- Because the nanoparticle chemistry is inert, the biosample is protected from experiencing any chemical changes due to ageing of the matrix.
- Additional amounts of the inert chemical that coats the spheres is added to further tightly pack the biosample. This is analogous to the “peanuts” one uses for shipping contents in a box. Once a fluid sample is added to the conical RPM storage tube, then air-dried, the ZrO2 nanoparticles assemble around the DNA or RNA and any remaining space in the pores is completely encapsulated by the extra packing material.
Even though very dense, these nanospheres are very small, and thus settle very slowly. When a sample + RPM suspension is placed in a drying box, the water evaporates and particles remain in suspension throughout the drying process.
