An example of a LFA
CovidLFA Logo
How it will be processed by the smartphone

The potential for a 2 Euro COVID-19 Test

Inspiration

Covid-19 testing takes too long: >1 hour (on average 2-4 hours) and it is way too inaccessible to common people. Only Hospitals can execute the RNA based test on nasopharyngeal swabs.

Indirect Covid-19 tests antibodies, based on antibodies (early IgM and late IgG) can detect the ongoing (IgM) and the happened infection (IgG). They are cheap and rapid also based on LFA or ELISA. The problem is that the earlier IgM detection are appearing in the blood after 8-10 days from the infection and the can give “false negatives”. False negatives can go around transmitting the virus freely.

Our CovidLFA kit will provide a quick, cheap and easy solution for people that will be able to test themselves at home and all the times. It has been used before in other crises and is easily reproducible.

Our CovidLFA test is based on the direct detection of the Covid-19 Spike protein immunologically and the results can be read by smartphones in terms of minutes (2-5 min.) max.

Using fluorescence enables it to gain higher accuracy.

What it does

It detects the Covid-19 Spike protein (present in the outside part of the virus envelope) by using immunological techniques coupled to fluorescent detection. In brief, a nasal swab or a saliva/tear sample is taken, mixed with an extraction solution, that is loaded then into a premade lateral flow strip made of nitrocellulose. The sample is passing through a conjugate pad containing primary antibodies catching the virus spike protein. The virus, if present is finally sandwich captured into the test line by secondary antibodies (that also recognize the virus spike protein in another epitope) and at the end the excess of primary antibody is captured by the control line. Two red lines positive to Covid-19. One control top red line negative. Since the level of virus can be very low this system can visualize the positive by fluorescence by the use of a smartphone equipped with a device 3D printed in development. The image is processed by an Androip App (CovidLFA App) and by the algoritme return the final negativity or positivity, showing also the results quantitatively..

How I built it

Recombinant insect cell produced Covid-19 spike protein has been commercially available and used as antigen to produce rabbit polyclonal antibodies. Two antibodies have been purified by affinity chromatography from the pool of the polyclonal for two epitopes that have been used in the production of the nitrocellulose strips. The primary antibody (epitope 1) have been conjugated with custom made nanoparticle harboring red visual and fluorescent dye. A nitrocellulose based paper strip is layered by microfluid printers (different vendors) with a Test line (containing the secondary antibodies for Covid-19 Spike protein epitope 2) and the Control line, containing the goat anti-rabbit IgG. In the Control line the goat anti-rabbit Antibodies are detecting the unreacted antibodies raised against the Covid-19 spike protein epitope 1 that are conjugated with nanoparticles coated with fluorescent dyes. The smartphone LFA fluorescent reader skeleton will be printed with 3D printer and will be equipped with two filters and a lent to focus on the Test/Control line area. An Android App has been written for controlling the image acquisition and processing: standard curve calibration, etc. Positive control will be included in the kit. An iOS/PC app will come soon.

Challenges I ran into

The sensitivity of the immunological LFA is given by two factor: 1) how good are your antibodies; 2 ) how sensitive is the conjugate detection system used for the visualization of the results. The antibodies can be upon scaling up be produced as monoclonal in order to lower down of a magnitude of 10 the sensitivity and by now they are sensitive respect the Abs present in the market so far. Furthermore, the magnetic-fluorescent silica nanoparticle are custom made by the nanomaterials companies and not on the shelf as default. Hence, the choice of those was quite challenging to go down in sensitivity required for this very small virus (diameter of Covid-19 is 100 nm), which according to the classification can be called itself a nanoparticle. The price optimization for the scale up cost should be in the range of 1 EUR per strip test. The smartphone reader upon scale up production can become very cheap as well (max 5 EUR).

Accomplishments that I'm proud of

Production and purification of monospecific antibodies for Covid-19 immunodetection. Setting up LFA printing arrays. Choose of the most sensitive and cheap detection method. Meet the right partner for smartphone App development.

What I learned

The present method can be applied to many other practical applications. The use of smartphone can be a cheaper solution instead of Point-of-Care (POC) instrument that nevertheless are "mobile", are very expensive. Video editing; smart-collaboration; mentoring; visibility of the project.

What's next for CovidLFA

We search investors for finishing this project and going for scale up mass production if not financed by the Hackathon.

This provides great value for testing for COVID-19 because it is highly economical, so it can be done many times on a single person to continuously ensure one does not have COVID-19.

Presentation to learn more

https://docs.google.com/presentation/d/1jitJmrhcvqmLjNkcO4HTwgy7hdQ1F7hjtMv8Ys3D3X0/edit?usp=sharing

Attached is what we currently have for our Android application code. http://github.com/vdaita/CovidLFAAndroid This is merely an App prototype of what the application could be like. Screenshots are inside the Youtube video.