The post refers to an alternative method of testing for COVID-19 based on surface plasmon resonance that would have significant advantages, but unfortunately it provides absolutely no real substantiation that the test exists or works. The link about surface plasmon resonance goes to a generic Wikipedia page, the link about saliva is a small scale study that was conducted on RT-PCR not surface plasmon resonance, and the actual link to the team goes to a nothing more than splash screen with the company logo on it.
If there is substance to this then it would be massively in Paul's (and the company's) interest to better link to that in both the post and the company web site. At the moment, it looks like at worst vaporware or at best, something so early stage it's years out from viability.
Hi, Walker here, one of the PreDxion Bio co-founders. Heres a some more information on the technology underlying the test we are developing: https://pubmed.ncbi.nlm.nih.gov/25790830/.
Unfortunately, up until about a month ago us like many folks, were blissfully minding our business developing a rapid point of care cytokine detection platform for use in monitoring patients experiencing certain immune responses following cancer immunothereapies, you can read more here: https://pubmed.ncbi.nlm.nih.gov/31597044/.
Currently, we are very much focused on techical/clinical validation. We will have many more details to share on our approach, the technology, as we continue to move things forward.
I worked at Integrated Plasmonics in 2012–14, the major problem you will face is fluidics and sample handling not so much the sensor design. You should consider stochastic plasmonic features grown using dna self-assembly on the surface of a cmos sensor (lots more recent work on DNA-based plasmonic nanostructures). I worked on varieties of ways to characterize a chemical signal even from stochastically distributed plasmonic features by running calibration during manufacturing. We were able to use support vector regression to characterize known chemical reaction signals on a per sensor basis.
If you have to do that for every sensor the cost goes up a lot. Also, "stochastic plasmonic features" without knowing much more sounds like something that varies by time of day, wind currents in the lab, whether you hit it ten minutes ago with a socket wrench or didn't.
Thanks for engaging with the HN community. I'm a bit disappointed that the original article doesn't say if the author is associated with your company. At one point he says "We", but it's never clear. Did I miss something? Your comment doesn't address this issue at all. Investor? Employee?
What do you think of the article's claim that eliminating the cold virus would be a good thing? I think I read somewhere that early exposure to cold viruses reduces the chance of acute lymphoblastic leukemia, which makes me wary of trying to eliminate them completely...
There’s a lot of really interesting work left to be done in this area. In our company’s other life we’re involved in CAR-T research, which involves exploiting natural pathways in our immune systems to target them at cancer cells. It’s a super exciting area of research and is bleeding edge in terms of breakthrough therapies coming into the clinic. These therapies[0][1] cure upwards of 90% of what would otherwise be incurable cancers, but they also induce severe inflammatory responses (cytokine storm) which results in respiratory failure and neurological adverse events (that’s a nice clean clinical way of saying putting them in a coma).
OK, but what are you detecting? Antibodies? Viral proteins? RNA? The messages from Paul and your team have been contradictory. The message is confusing, and this makes people skeptical. It would be great if you could clarify the detection strategy.
At this point all our personal interests are to stay virus free as long as possible, given what we don't know might kill us. I really don't care why he's speculating about the things he is. Many of the things we postulate may be proven wrong simply by waiting long enough to get more data - i.e. it's not always necessary to formulate a test for disproving an idea, sometimes they evaporate on their own. (Software features for example frequently meet their ends this way).
I just found out about Covid Toes. What will come tomorrow?
I haven't been into an indoor shared space without it on for almost 3 weeks. You probably shouldn't use Gorilla Tape on it, because it might off gas something. Try surgical tape.
I gathered the same thing. Basically the gist is, if we can develop a cheap, fast, and effective test for COVID-19 then we can test everywhere and re-open everything.
Hasn't that always been everyone's argument? That's the crux of Pueyo's "dance" [1], that as long as you've contained the initial outbreak, you can pretty much go back to normal if you track movement and have the capacity to test everyone who comes in contact with an infected person.
This has been one major argument. The others have been: "flatten the curve - just extend the time until everyone gets it" (obvious problem, exponential growth can't work that way), "shelter in place 'till a vaccine appears" (not very practical) and "it's really not that bad, there are so many asymptomatic carriers that in the end it's not actually worse than the flu after all or at least there's nothing we can do." (not that plausible, not appealing, non-fatal cases still much worse than the flu).
I think this is the best position, however but it still needs to be argued for since it's not the only position.
Edit: Also, it looks like the US has plateaued at this point but in a situation with a fairly dysfunctional testing arrangement. It is going to be hard to argue for people to sit tight until tests are in place so I'm not terribly optimistic.
> "flatten the curve - just extend the time until everyone gets it" (obvious problem, exponential growth can't work that way)
Just to nitpick a little here, it's more like "flatten the curve - stretch the time while everyone gets it, so we don't overwhelm hospitals". Even with exponential growth, you would rather deal with it over a longer period than have a massive spike where all services are overwhelmed.
The characteristic of exponential is that things tend to come all once. In the final double period, you get as many cases as all the other doubling periods combined.
Which is to say, you can stretch out exponential growth a lot and still not have enough. If you exponential growth from 1,000 to 1,000,000 cases over a year, the last month will overwhelm your services entirely and constitute the bulk of both cases and death.
There's a reason all those early graphs showed parabolas, not actual exponential curves, you can't even give plausible visual representation of this process, because it isn't plausible.
""flatten the curve - just extend the time until everyone gets it" (obvious problem, exponential growth can't work that way)"
Huh? One goal is to flatten the curve so that we don't have exponential growth. Another is to flatten the curve so much that, even if might still be exponential growth, the growth is slow enough for our health care systems to absorb the peak.
One goal is to flatten the curve so that we don't have exponential growth
The aim of mitigating measures is reducing the growth rate of the disease. But the mechanism of the disease is that you generally have a basic situation where X people infect at time t results R*X people at time t+1. That's fundamentally exponential process (even though you can extra factors, the process doesn't change 'till you get close to having infected everyone). If we can make R small enough, this become exponential decay, a good thing but still an exponential process. But when you do exponential growth. you have a doubling and on the last double, you get more cases than all the cases combines. So the peak is just MUCH higher than the rest of the curve and you can "flatten" a lot and still wind-up overwhelmed in the end if the growth process continues.
"Flatten the curve" and "shelter in place" aren't mutually exclusive with a necessity to ramp up testing or develop a vaccine, they are just things that laypeople can be doing in the mean time to mitigate the negative effects of the virus while those other solutions are prepared.
Is this what you're looking for? Scientists at NTNU St. Olav's Hospital has made a test that can check 150,000 patients per week for Corona infection [1]. (Yes, it's the same uni that used the USA as an example in warning students abroad against poorly developed health systems lol.) Already testing is a lot more frequent in Norway because of it, and they're cautiously re-opening some businesses and services, the first of which are kindergartens and hair dressers.
The Norwegian health authorities also published an app that can be voluntarily downloaded, that tracks and warns about infected, while also collecting research data for future use. [2] The app has garnered some criticism for leaking user data, and for discharging the battery too quickly. The retort is that it's of course voluntary and anonymous, and that it's actually tracking less data than Facebook or Google.
The relevant quote actually concerned the collective infrastructure in the US, including health insurance. The actual quality of care in the US is great, particarly for specialty cases... for the few that can comfortably pay for it.
Relevant part of their tweet:
"This applies if you are staying in a country with poorly developed health services and infrastructure and/or collective infrastructure, for example the USA. The same applies if you do not have health insurance."
As well as a message, now apparently removed but archived by others, on their website:
"This also applies for countries with poorly developed collective infrastructure, for example the USA, where it can be difficult to get transport to the airport if you don’t have a car. The same applies if you don’t have health insurance."
Yeah but maybe we shouldn't. We have the technology to compartmentalise our society WAY more than it currently is, at relatively little cost. COVID-19 is a fantastic dress rehearsal for the next disease, which will be far scarier and will come relatively soon. Humanity is a monoculture and like all such, is very vulnerable to pathogens. We need to start building social distancing into our culture the same way we built protection for sex into our culture.
Ever since 2000, we've have a pandemic once every decade. The next one will occur soon, but it's not certain whether it'll be as scary as COVID-19.
> We need to start building social distancing into our culture the same way we built protection for sex into our culture.
While I agree with the general gist of your comment, I should emphasize that what we need is physical-distancing, not social. Humans are social beings at core, and depriving them of social interactions is as deadly as the virus itself. What we should be practicing more than ever before is washing our hands, minding our coughs, and in general, being responsible to the society. The individualistic lifestyle - which is pretty much dominant in the West - shouldn't stop us from caring about our community as a whole and our duties towards other people. Technology can only help us get so far; the rest depends on how much we - as responsible social beings - take care of ourselves and each other.
> while finding ways to connect remotely with the people who are important to us
Good stop-gap, but not remotely viable long-term. Humans aren't made for isolation, even if video calls help take the edge off soon. FaceTime and Zoom have a significant cognitive load, too. As long as we're talking about how society should adapt to this sort of risk, we can't just go to living in individual hermetic pods with internet connections. The mental health cost will be monstrous.
I don't know why or how, but I can confirm that remote connections have a significantly higher cognitive load than in-person interactions. Perhaps it's the same reason as why talking on the phone while driving is much more dangerous than talking to the passenger in the seat next to you.
According to my biochem-undergrad kid, surface plasmon resonance is a thing; it had come up in classes. "It's like doing an ELISA with no secondary antibody". Someone here will know what that means. I don't!
A regular ELISA/immunoassay is: surface->Ab->protein<-Ab+signal. In school these are taught as "sandwich-assays". Basically you have one antibody to bind your molecule of interest to your substrate, and then another second which binds the bound molecule... which has been bound to the surface. This second antibody is decorated with an enzyme which will do something fancy (color-change) or a fluorescent protein to light-up if we shoot it with a laser. SPR is a label-free approach which results in an optical response in real-time as molecules associate with the SPR sensor. Detection is then a function of how long you need to let things bind to the sensor before your ability to detect the signal optically.
Sounds like your undergrad kid has been paying attention in class...
It's a very sensitive detection technique that uses some cool properties of light. We used it 20+ years ago in grad school (they were very expensive machines that were extremely hard to master; everything from calibration to routine operation was significantly more challenging than most devices I worked with) and I think it has quite a history before that. Never heard of it being used for rapid detection in a public environment; my experience is that things that work in a lab setting often don't externally unless somebody comes up with a good technology improvement (think vacuum tubes -> transistors -> small radios).
It’s a thing, but doing a saliva test with limited sample prep (which you need to be beat PCR, otherwise you might as well just make more known to work qPCR machines) is not something anyone has accomplished with it for any virus. It’s a promising technology; but not for having a widely deployable test before we have boring old ELISA antigen tests. Which we have developed for plenty of viruses, and which some individual companies alone can manufacture at a rate of several per second with existing production capacity.
I’m glad more money is being put towards research in this tech (I used to study plasmonics from the physics side), I don’t think it’ll make a difference for COVID specifically before it’s too late to matter.
Test complexity (sample prep, test workflow) is a real challenge to achieving testing scales at orders of magnitude above what is presently available.
We should hopefully have boring old ELISA antigen tests shortly, thanks to Abbott and many of the other folks we've all heard from. The real challenge is scaling testing beyond what can be reasonably implemented from central lab facilities.
ELISA tests don’t need to be done at central lab facilities; there are plenty of machines on the market with varying levels of automation (and many already in hospitals, even in ones that aren’t particularly outstanding). I’m curious what barrier to scaling those with COVID (either by making more of these machines, or repurposing other test capacity) you’ve identified that makes bringing a totally new machine to market more attractive, from a scaling perspective.
> The real challenge is scaling testing beyond what can be reasonably implemented from central lab facilities
The SPR machines I’m familiar with are not inexpensive. Are there machines appropriate for these tests that are less expensive such that it could be rolled out widely? Sample cost is low, but a warehouse shift change of several thousand people isn’t going to need only one machine for screening as the load on the machines will be very bursty.
If one is clever, one can use SPR to interrogate a surface: monitor the surface and you can “see” the surface changing when stuff is sticking to it. If you have something with specific binding properties on that surface, like an antibody (as is used in an ELISA), with some additional effort you can maybe have an assay that detects something binding to that antibody.
If there is substance to this then it would be massively in Paul's (and the company's) interest to better link to that in both the post and the company web site. At the moment, it looks like at worst vaporware or at best, something so early stage it's years out from viability.