RE: The SonaTech fight back continues...26 May 2020 08:36
It’s not clear yet. They bind using antibodies or antigens.....sona are using antigens...and they can’t upscale consistently or rapidly.
Process...
“A lateral flow immunoassay, or immunochromatographic assay, is a rapid, convenient test that uses antibodies (or sometimes antigens) to detect specific macromolecules, such as antigens, drug substances, or other proteins.
One of the first steps in lateral flow rapid test development is the selection of the “right” materials, especially the nitrocellulose (NC) membrane. The NC is the heart of the lateral flow test, where the target molecule is bound and where the results are displayed.
A successful lateral flow immunoassay depends on a series of reactions. When selecting materials for immunoassay development, membrane properties and reagent properties must be considered together, as their interactions determine the outcome of test development.”
Full article..(note membrane is key)
https://www.cytivalifesciences.com/en/us/solutions/lab-filtration/knowledge-center/Considerations-for-membrane-selection-for-lateral-flow-immunoassays
the “Company”) is pleased to provide the following update on the development of its rapid-response, Covid-19 antigen test. The Company received confirmation from an independent laboratory that its test achieved a positive response to a recombinant whole spike protein control reagent specific to SARS-CoV2 and matched the limit of detection (LOD) achieved in its own labs. In-house analytical testing has indicated a very high level of specificity to COVID-19, with no false positives being generated.
https://sonanano.com/sona-nanotech-provides-covid-19-antigen-test-progress-update/
Ok here’s why it’s not in the bag....
Further testing will be conducted both in-house and independently using pre-treated viral samples after recent independent testing using virus samples that were de-activated by heat did not provide a response. Exposing a virus to high heat levels can modify its characteristics, making the treated virus sample an inappropriate proxy for a live sample. These findings, coupled with previous hospital-based experiments, have suggested that testing using a live viral culture and/or patient sampling will be required for ultimate confirmation of the effectiveness of the Sona test. The Company expects to confirm further third party validation testing, specific to its device needs, in the near future.
So issues with heat and stability, hence need to move to lab. They basically say between lines you need pcr type test to be sure..
Also from first link, this may also be key to avacta....Cytiva have 3 types of membrane but we don’t know yet if the Affimer is more or less susceptible to binding than the antigen on site. I would suspect that because we can bind to the whole and the detached spike protein that would mean greater sensitivity for Affimer. A guess though....
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