Here is a quick update on some FoodSmartPhone ressearch.
The most direct system to make a smartphone based biosensor will be to use the camera to detect colour or colour intensity changes. These colour changes can be the result of a chemical reaction tailored to produce a colour only when the target (what ever that is) is present. Indeed, many different scientific papers have come out recently using optical smartphone based detection. However, each paper seems to use a different approach to quantify colour, get rid of background noise, make the system more reproducible etc etc. This plethora of methods makes it hard to choose how to approach the issue for a researcher that wants to develop such a system from scratch for a novel target.
For this reason we have recently conducted a very detailed comprehensive review on optical smartphone based sensing. The review looks at issues such as data treatment, background noise elimination, reproducibility and software development. I believe that the work is a very interesting read for anyone starting to develop a smartphone-based optical biosensor and hope it will bring so insights for novel development.
You can find the open access publication in Trend in Analytical Chemistry(TrAC)
Apart from reviewing the topic I have also actively been working on the development of a better way to analyse color based assays with a smartphone. For this I have been colaborating with another ESR, Yunfeng Zhao (Jack) who is a data scientist. Together we have developped a novel way to analyse colour data. The system is the first system to combine colour channels from various colour spaces together to optimise the analytical data. I believe it is a very promising system as it has shown to drastically reduce error created by using different phones. It also does not require the need of any ligh-shielding box and allows to get quantitative results within seconds. Moreover, the system has prooven to work for various commercial assays. This is great because it means that it can potentially be used with any existing strip test!
If you want to read more about this exciting work you can check out our paper about this in theJournal Analytical Chemistry
Finally, I want to talk a bit more about the title: Can we really detect anything with a smartphone? In other words, can we detect pathogens, toxins, pesticides, allergens, antibiotics and other chemical contaminants with a smartphone?
Can we use the smartphone for instance for the detection of SARS-CoV-2 the virus causing coronavirus?
The answer is yes we can, by using the right recognition element we can either detect antibodies made as an immune response against the virus or detect the DNA directly (see attachet image)
we need to have the right recognition element and develop the biosensor. Then we need to test if it works, optimise the parameters and finally start trying it out in real situations. This can take quite a while (up to several years).
Moreover, we will need to make sure the sensor is very robust and that the people are well informed regarding the limitations of such a device. For instance it will be impossible to get 100% correct identification of the virus. There will be false alarms (false positives) and also infections will sometimes go unnoticed (false negatives). Thus it is paramount that everyone is well aware of these limits before any device should go on the market.
That being said, at-home smartphone based testing of COVID-19 may very well be a great tool to increase the amount of testing done while at the same time freeing up hospital resourses and experts to attend to other issues which may become neglected due to the current crisis.
All in all I believe it would be a very interesting option, which is why I recently wrote an opinion article about this in The Conversation.
If you are interested in this posibility I invite you to find out more about it here .
Ok folks thats it for today,