Prototype
Marketing Research
Current point-of-care:
BD Veritor™ system
1
cobasliat
2
Disadvantages of current design:
Special machine is needed to show the results
Validated samples sources are restricted: only nasopharyngeal washes/aspirates and nasopharyngeal swabs
The advantage of our design:
Only heater/heat plate is needed
Even if no heater is available, incubated at room temperature for 12 hours can still show the result
Result is reported by colour changes, no special demonstrator is required
Throat swab is possible, increasing choice of sampling
Another benefit of our design is the involvement of subtyping test. None of the current commercial point-of-care kits is able to subtype the suspected samples, so subtyping mainly is handed over to analyzing laboratory, providing an efficient way for frontline staff, such as immigration department and Agriculture, Fisheries and Conservation Department.
Consideration Criteria
1. Reliability
Almost all respondents prioritize reliability (ie. sensitivity and specificity) in the first place, no matter from local or international surveys.
2. Easy-to-use
Our ultimate goal is that non-professional can also handle. For the sake of easy observation of the results, we utilized chromoprotein as the reporter so that no special reporter machine is needed.
3. Time
Ordinary and typical diagnosis procedure always spend an entire day long. After the conversations with two medical experts, it is known that shorter the diagnosis time, quicker for patients to undergo medical treatment. Thus, we aim to shorter the detection time. Also, we have considered that heater/ heat plate is not common, or even unavailable in the suburb, remote districts or some developing countries. The reporter chromoprotein can still be expressed under room temperature, however, its disadvantage is that users need to wait around 12 hours. But still, it provides convenience to people living in regions with limited resources.
4. Prices
according to the result in Hong Kong, they mostly accepted the additional price ranging from HKD41 to HKD60 for quick detection, in which we are confident the price of the kit will be much lower than it. However, the acceptable price range of our another target group, people in developing countries, such as Bangladesh, Vietnam is only 1 USD approximately. If we want to promote our kit as far as possible to the above-mentioned countries, which is suffering from the influence of influenza, we need to further cut down our cost.
5.Others
According to the result of surveys in Hong Kong, size and ethic consideration got lesser votes, when we asked for the reasons behind, they agreed that smaller size of the product will be better, but the size should not have a high priority in the process of design. As for ethic consideration, despite fears were expressed by interviewees when we mentioned that E.coil is utilized during the productions of toehold switches, they felt more acceptable after full explanation on the whole flow of manufacture and further recommend us to add such kind of explanations inside the kit (ie, protocol) to allay users’ worries.
However, this design is criticized by Prof Chan as the pellet may be not condensed at the bottom of test tube during freeze-drying by reasons of improper transportation, etc. In view of this, we try to condense the cell-free solution at the bottom, for example, use a smaller tube rather than the 15ml tube so that it is easier to make the pellet condensed at the bottom. Also, the cell-free system will be freeze-dried and stored in the test tube prior to distribution to market. Thus, during shipping, low-temperature environment maintenance should be ensured, preventing them from melting and not dispersed around.
He also agreed to the advice of our supervisors that cell-free system in solution form will be more practical, and appreciated to the design of chromoprotein, allowing simpler detection process, nevertheless, he cast his doubt on the subtyping, another track other than medical diagnosis: since the cell-free system can only reveal the result in yes-or-no form, there is no big problem in the medical track since not many tubes will be consumed, however, when applied in subtyping path, it seems redundant and many tubes will be used at the same time in only one sample (for example, when we want to test a suspect from verifying whether it is H5N1 or H7N9, 4 tubes are needed in total).
Design 3 (Tablets package)
In response to the concern raised by Prof Chan, we designed another design and the appearance is tablet package alike. As the bottom is curve-like shape, even if the freeze-dried cell-free system melt and spread around, or cannot condense totally at the bottom, the curve-shape can help settle down the cell-free solution. During the use, tear off the firm firstly, and add a certain amount of water by dropper. After hydration, similar to previous design, add the sample by cotton wool. The procedures afterward (eg the verification) are equivalent to previous design.
Apart from smaller size when compared to the previous design, fewer materials are used, which is more environmental-friendly. For the medical track, as mentioned above in procedure section, there are 7 wells (with freeze-dried cell-free system) in one plate and every patient will only consume 1 plate. (Two versions of our design are introduced below)
For the sake of convenience, especially on-site mass-screening detection carried by immigration or agriculture department, a larger plate with more wells is prepared, allowing mass detection at the same time.
Prototype of detection kit applied in medical diagnosis
In spite of appreciation of tablet design by Prof Chan, he commented that RNA may degrade during sampling, also the amount of sample is not standardized, which may interfere with the result. Such concerns render further improvement on next design.
Design 4 (Modification of tablets package)
During the conversation with Prof. Sung, we inquired him the problems faced in the last prototype. He suggested adding the samples to small amount of PBS before transferring to the detector, the cell-free system and it can help stabilizing the RNA inside the samples.
Therefore, new distribution and allocation of wells inside the detection plate are changed: For medical track, each user/patient will consume 2 plates, one is the detector with freeze-dried cell-free system, another is only plate with water for sample stabilization; For subtyping, the plate is advanced by the referral from medical experts by adding more subtype detection. According to the latest information from the Centers for Disease Control and Prevention
3 (lastly updated on 19 April 2017), there are 18 known HA subtypes and 11 known NA subtypes up to now and many different combinations of HA and NA proteins are possible. Thus, a plate with two rows, HA and NA with 31 wells in total (18 for HA, 11 for NA and 2 for controls, positive and negative).
Reference
1. http://www.bd.com/en-us/offerings/capabilities/microbiology-solutions/point-of-care-testing/veritor-system
2. https://www..com/point-of-care-influenza-test/
3. Influenza Type A Viruses, Centers for Disease Control and Prevention
https://www.cdc.gov/flu/avianflu/influenza-a-virus-subtypes.htm