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I know I'm bumping but just to say thanks to OP (and his manservent for fetching ;-)).
I wouldn't have found this myself so show BB works and I get to be a child again as well.
I'm going to see if I can find their Zika LFD data
Praise be
Not a big orange clown waving a bible upside down
thanks for the bump. this has made my day. woohoo!
Oh go on then, one last bump for the evening crowd. If you haven’t already, I implore you to read this research paper... It’s a beaut.
Not long until the real game changer now. Gl all holders
https://avacta.com/how-a-lateral-flow-rapid-test-works/
So here is that reminder from Alastair as to how an affimer lateral flow test works.
CautiousOptimist - they've used antibodies in these assays because it's a little easier to set up with reagents. Also they only have one Affimer against each target, when it would be best to have two - a capture and a detection reagent. The detection Affimer is labelled with a gold nanoparticle and binds to the virus as it migrates up the strip, and the capture reagent is immobilised to the strip further up the strip. As the virus migrates through the strip it's the captured but the capture Affimer which accumulates the gold nanoparticle showing as a line on the strip. The control line just detects the detection Affimer and is used to show the saliva and detection Affimer has migrated along the strip - again this will be a detection antibody that binds to the Affimer or a tag on the Affimer. I hope that makes sense!
Thanks PL75 - i think pure right that the control line has yet another type of antibody. So the test has two types of antibody and one type of Affimer. My confusion was why all the antibodies when we’ve been told about the advantages of Affimers over them?
I think I’ve found my answer; in case of use to anyone else here it is... The difference is the antibodies used with Affimers on the test strip are polyclonal, as opposed to the monoclonal antibodies Affimers are designed to be used in place of. From wiki: “The technical skills needed to produce polyclonal antibodies is not as demanding (as monoclonal antibodies). They're inexpensive to make and can be generated fairly quickly, taking up to several months to produce. PAbs are heterogeneous, which allows them to bind to a wide range of antigen epitopes. Because PAbs are produced from a large number of B cell clones, they're more likely to successfully bind to a specific antigen. PAbs remain stable in different environments, such as a change in pH or salt concentration, which allows them to be more applicable in certain procedures. Additionally, depending on the amount needed, PAbs can be made in large quantities in relation to the size of the animal used.”
OK - I'm not going to go through all the calculations in detail but after reviewing some papers and doing a bit of maths, I think the LOD for COVID19 on a LFD is going to be 86,268 copies / ml which is way way less than they are when they first show as symptomatic. So pretty much what I guesses a couple of weeks ago when I said 1-2 days prior to showing symptoms.
Ophidian
Yes, there’ll be a control line, Zoe also mentioned using antibodies in her PHd paper. Like you’ve said I’d assume this is possible with affimers - they can be used in place of antibodies to capture a $100Bn market so why wouldn’t it be true on a strip as the control
Great job finding/pushing this, ab8dct and PL75! This is why I come here. :)
Onto a question... I thought I understood the LFA, but figure 6 has me mildly confused, and perhaps I’m not the only one? Appreciate if anyone smart can explain to this simpleton.
So, this is a positive read test, requiring two virus-binding reagents. Affimers get fixed on the detection strip, which bind to the virus. But the virus also has to bind to the red beads, and does that because the red beads are coated with rabbit antibodies? Anyone got any idea if it would be the same in the Cytiva test, and what might take the part of the rabbit antibodies? Two different types of Affimer?
No, I love you more
Stanman, great - I'm glad this has made you happy! It certainly pleased me when I spotted it.
ab8dct - Well now, you certainly made me happy. Cheers!
Bump, BB gold.
Amongst all the bragging and bleeding noise on the BB this is (imo) the most useful, informed and rational thread for some time.
Thanks, not got a specialist knowledge but appreciate those who do and share it.
Thanks TrekMadone - I’m happy as long as people see it. PL75 deserves credit for playing the game and bumping the message.
ab8dct
Take a bow! Great find mate!
My apologies I thought it was PL75 that made the find. He kindly helped out with copying the link over for us.
Anyways great sleuthing guys. I think that after today’s action i’ll soon be able to move this BB to a weekly look in rather than every day! Atb!
Trek
Yes, all Awacta IP - if you google affimer you'll only find references to Awacta. They supply affimers to Leeds Uni for precisely this kind of research to demonstrate it's incredible potential.
Fair play PL75 that's quite a find. No mention of Avacta here (unsure if all affirmer tech is ours?) but clinical evidence of an affirmer inhibiting a virus being able to spread.
Covid-19 is nasty enough but thank god nowhere near as nasty as that Congo-Crimean thing sounds...
Got me... damn, you lot are good...
No PL75 still on the list - clearly a ramper promoting this peer reviewed nonscientific absurd nonsense about Affimer reagents actually working in a relevant device and on a virus ;) haha
PS Am I allowed off 'The List' now?
I can't take any credit for the original find, but I will take credit for the continual pushing as it's stunning to read and everyone should experience some joy after the past few days
Looks like Avacta just may have the 'Holy Grail' of Covid19 tests....that could be worth a good market share.
Lol ST,
I must say totally agree with stanman, PL75 probably post of the month!
I was so lucky to take a slice at £2 to buy my car and now no pressure the rest can ride to £5 plus! Now they have ‘proven’ science fully funded! We are part of one amazing story.
This is a biotech equivalent to Microsoft or Facebook in the making. It really is gonna be that big!
Amazing potential here!
Trek
I missed the PHE link - well spotted @Ophidian.
It's great they're already aware of our Affimers and have used them in diagnostics previously. I just googled it and it looks like they evaluated Affimers as a potential LFA agent quite a few years ago. Very interesting......
Google - PHE Affimer from about page 24 in the doc
Trek,
In English you text simply says: "The damn thing works"! Pro. A. Smith
St