Roundtable Discussion; The Future of Mineral Sands. Watch the video here.
All LFT manufacturers have the buffer evaporating over time in the capsule, so they'll be less left to go the LFT once processed - this is one of the things that determines the expiry date of the buffer capsule. None of them as far as I'm aware have anounced publicly they're looking into it, though are probably investigating it.
Ethylene oxide is used as a sterilisation method for the swabs (and many medical devices) during production as you don't want the chance of anything alive/being able to replicate in you going up your nose etc. If you don't use EO i guess you'd have to use some other equally nasty thing.
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Its now the 2nd from the top under the Rapid tests section.
Some of us weren't able to watch it last night, a spoiler alert would have been nice!
*your
Its Wetherby....
But hopefully our point still stands
What Ndn said!
Isn't this Affimer's whole USP over antibodies, that you don't have to inject your mouse/goat/camel/rabbit/rat with your antigen, wait for the immune system to do its thing then bleed them, purify the antibodies and find the best one. Look up phage display which there are many papers on and Avacta have said they use. They already have the genetic 'instructions' for making the new Affimer, it would be a matter of repeating the phage display to pick out a new one specific to the new variant.
With regards to better binding, there's nothing stopping the right Affimer (out of the billions in their phage display library) bind the S protein better than antibodies, its simply a numbers game to find the best ones. Affimer's size should mean you're able to get a higher density of binding sites on the LFD anyway
"Now, Kent variant comes along, it has 18 changes in its sequence. It does not matter how many changes it has, we know the entire sequence of the Kent variant. So we take this Kent variant S protein gene sequence and email a DNA synthesis company and ask them to produce it, which you can then use to express in the bacterial system and produce your new protein. Notice what has happened - you did not need to use the moecular biology scissors to cut out the S gene from the virus.
All the variants of concern have mutations that lead to amino acid changes, which is why they are variants of concern. They have changed physical and chemical properties to render the vaccine less effective. Avacta would have had to change the purification process to accommodate the test against Kent variant. Are you saying that Avacta processes are cumbersome that its not easily changed to accommodate new variant protein? I had assumed this part Avacta should be able to do without fuss, but you are suggesting otherwise. If that is the case then that is a real concern for Avacta technology and how quickly it can adapt to changing landscape."
I know the molecular biology, its basic biochemistry, my masters and the last 5 years of my career. The point I was trying to make was Avacta will have optimised their protein expression/purification systems for Affimers, its unlikely they will make the S1 protein themselves, they'll buy the target from another company like sino biological or R&D systems. I am saying that its the like of these supply companies who will have to potentially reoptimise purification and Avacta have to wait for this to be done to allow them to buy the new variant S1 protein and test it in their system.
Sorry delay in it posting
"As a man of science, you should know that it does not need the whole virus, it just needs the S protein. Since we know the reference sequence and the mutations, we can design the whole S protein with synthetic dna and express and produce it. I went over this topic few weeks ago here. There is no reason why they should not be designing tests for the impending storm."
And how long does it take from identifying a new mutant to express, purify to >95%, and characterise sufficiently so that companies such as Avacta believe that it is a S1 protein with the mutation. Then consider the lead times to prepare enough S protein and I presume Avacta will do their own QCs when it enters the door (I know I would), this is all before Avacta even test their Affimers on it to confirm it still binds.
Some mutations can change the amino acid sequence enough that it causes a big change in physical and chemical properties, making it so you have to reoptimise the purification process.
"As a man of science, you should know that it does not need the whole virus, it just needs the S protein. Since we know the reference sequence and the mutations, we can design the whole S protein with synthetic dna and express and produce it. I went over this topic few weeks ago here. There is no reason why they should not be designing tests for the impending storm."
And how long does it take from someone identifying a new mutant by sequencing for a company to express, purify to >95% and characterise it sufficiently so companies such as Avacta can be confident the S1 protein is what they say it is ie with the new mutation? Then think about what the lead times might be and I presume Avacta will want to do their own QCs on it arriving in the door (I know I would), before Avacta even get to testing it on the Affimers.
Rx typically means reagents ie the Affimers that go into various kits
For the Lfds, it's all about the binding reagent and which particular part of the virus it sticks to. If the particular part mutates, then the 3D structure will also change and that may decrease (or increase) the binders affinity, whether that is Affimer, antibody or aptamer.
MS would be able to tell you any non-silent (ie affects amino acid of protein rather than being a different RNA triplet for the same amino acid) mutation that occurred if you new what you were starting from. Because BAMS uses an affinity reagent to pull the virus out of solution onto the bead, concentrating it, I guess it too is limited by the area the Affimer immobilised on the bead binds to.
There is a website somewhere that tracks all the different lineages of SARS-COV-2 out there, most are a single nucleotide different and don't make any functional difference.
"I know the current PCR tests are confident that they can cover the new variants too but does also not mean that they can't distinguish between them too?"
CS, different PCR manufacturers use different primers (short stretches of DNA) to initiate the replication stage of PCR. My understanding is that some primers overlap where the mutations are happening on the gene for the S protein and labs are using whether all of primer a, b or c bind or only 2 of 3 (for example) has bound and amplified that segment of viral RNA. The primer that has not been able to bind can give an indication of where the mutation has occurred. The sample can then be sent off for full genome sequencing to verify this.
Far a long long way to run
Ndn, strictly speaking he's a physicist, but the point possibly still stands
That is a biiiiig leek