Biohawk Frequently Asked Questions

Is it possible to quantify the BioHawk assay analysis?

Yes. What you do is challenge the coupon with a range of concentrations of the target analyte, and in that way obtain a response curve. While the unit will not compute concentrations directly, the data can be downloaded and the data compared with the response curve. If you had a customer that was going to buy a large number of units, we could provide custom software (hopefully, paid for by the user) that allowed you to load a response curve into the BioHawk (or RAPTOR) and which would provide a numeric output. Users generally prefer to stay away from numeric outputs, as field operators usually are more interested in and capable of understanding presence/absence, rather than actual concentration.

Once a virus is detected should I discard the waveguide probe?

The waveguides are coated with a target-specific antibody. If the target is not present in a sample, the coating is still good, and is available for further sample challenges. The coating is stable for up to 24-48 hours, depending on temperature, the presence of chemicals that might cause the antibodies to become damaged, or bacteria that might like to eat the antibody coating. The secondary fluorescent reagent is stored and reused, so its life is long as well. It does not attach to the waveguide unless the target substance is present in the sample, so it is not depleted except through dilution. cause by mixing with water fillets in the coupon's waveguide portion.

Once one of the waveguides has captured some of its targeted substance, that particular waveguide is compromised, but the other waveguides (assuming they target something else) would still be unaffected. Subsequent assays may show a small positive response on that channel, even if there is no targeted substance present in later samples, due to the fact that the secondary antibody reaction is not 100% effective at labeling each captured target on the first use. This is a conscious choice on our part. By not going to equilibrium on the step where the waveguide is soaked in the secondary antibody, the assay time is significantly shortened.

Please define "detection", "monitoring", "confirmatory analysis", and "classification".

Detection means that something is being found present. It is a broad term, and doesn't say anything by itself, as to the concentration, etc. A simple example might be your nose detecting an odor. You may or may not know what the odor corresponds to, but there is enough odor for your nose to 'detect' it. A biotrigger might for example detect the presence of some type of spore in the air, while a bioidentifier will not only detect the spore, but tell you what type of spore it is.

Monitoring means that something is being continuously done, as in monitoring the speed of your car. Most biotriggers monitor for a class of material, such as organic vs inorganic, or bacteria vs spores, by continuously drawing air through a detection volume. Most of these devices use an ultraviolet light beam that responds in a specific way to the classes they can distinguish. Our bioidentifier's air sampler also continuously monitors, that is, it draws air in and places the particulates in a small amount of water. It differs from a typical trigger in that specific pathogens or toxins can be identified in about 15 minutes after a sample has been taken from the collector's water inventory. So our bioidentifier in essence keeps a record of what particles it has seen because they continue to circulate in the sampler's water until you pull some of it off either for analysis; for transfer to the onboard bottle for a confirmatory analysis; or you wash the sampler out.*

Confirmatory Analysis means an analysis that uses another method for detecting a pathogen or toxin. All portable instruments are considered to be warning devices, and the presence of a partricular target is usually confirmed later by using some widely accepted microbiological method, such as culturing in a petri dish. If a portable detector does not have a way of saving a sample for later analysis, it is usually considered deficient. Any secondary analysis method that does not use the same detection principles as the portable bio-identifier will be considered a 'confirmatory analysis.' For example, bioassay tickets do not use the same assay method as the BioHawk, so a 'second opinion' with a ticket analysis would be, for some cases, an adequate confirmatory method. However, purists always want to grow the bugs in a petri dish at some later point. In the case of the SBS, it's air sampling rate is so low that you have to question its ability to gather a large enough sample from any cloud it passes through, to provide a good confirmatory analysis.

Classification means, in the present context, that the device helps to sort out what kind of material is present in the air, at whatever detection limits it has, but it will not identify specific pathogens or toxins. As an example, air quality indexes on television typically give you pollen count. In this case, the device that gives you pollen count does not tell you what type of pollen it is- just the total. That is the same situation with biotriggers, which are classifiers. They only give you a reading related to the total quantity of each target type.they can differentiate between- not pathogen versus non-pathogen, for example. Most triggers that cost less than $100K primarily give a response that tells you the amount of organic material suspended in the air as opposed to inorganic material (such as sand). The idea is to give a warning that some type of bio-identification should be done. A big problem with them is that if the total concentration of a particular class stays roughly the same, no alert is given.

In a buffer, will salts re-aerosolize at the same rate as in water?
Can BioHawk detect chemicals like Sarin?
What is difference between an array, a coupon and a recipe?
What are the detection parameters for BioHawk?
How do you calculate coupon life cycle? And how do you define the start and an end of a reaction?
Can one coupon hold different classes of target reagents simultaneously?
Is BioHawk able to detect and identify the H1N1 flu virus?
How large an area can BioHawk cover for sampling?
Can we expect extended coupon life over 24 hours after hydration if no bio-assay is done?
If there are flurophore floating in the room during the assay, will it affect the result?
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