Hardware

ViTEST PROTOTYPES

A simple, fast and field-based diagnostic toolkit to detect grapevine diseases.

ViTEST Mk I

Diagnostics

User Manual

ViTEST Mk II

Sample collection

User Manual

“If I had asked people what they wanted, they would have said faster horses.”

–- Henry Ford

OVERVIEW

Our ultimate goal is to create user friendly toolkits which enable winegrowers to test their infected grapevines whenever they want. And grant them some time to treat the contagion once identified. Thus we designed our first prototype ViTEST Mk I which allows winegrowers to test the infected plant on site. However, during our research, we found that collecting samples and extracting DNA using the conventional way is quite troublesome and time consuming. As we are able to extract DNA in an easy and efficient way, we came up with our next prototype ViTEST Mk II, which integrates sample collection and DNA extraction together. Winegrowers can either choose to send the ready-for-test DNA solution to the lab or perform it on their own using our first prototype.

"Every great design begins with an even better story."

-- Lorinda Mamo

INSPIRATION

We got our first inspiration from a field-based detection toolkit for Buruli Ulcer developed by Kumasi Center for Collaborative Research at KCCR. They use RPA as their amplification method, which is the same method we've chosen. The suitcase will provide everything we need for diagnostics, like heat blocks, pipettes, test solution and standard color card to verify the results.
However, users will need to perform most of the task we did in the lab, including using gloves to stamp the leaves for DNA extaction, pipetting the right amount of RPA reaction into test tube, separate it into three tubes and pipette again for the PURE reaction. In the end, draw the results by comparing the liquid color with the standard color card.
The whole procedure can be hard to control and results may vary or be ambiguous. We need something easier to use, and give standard results.

“Simplicity is the ultimate sophistication.”

– Leonardo da Vinci

DESIGN

In order to simplify the process, we divided our task into two parts:
DNA extraction & RPA amplification
Toehold expression & signal generation
In the end, the winegrowers should be able to perform only few steps to finalize a result on their suspected disease.

DNA extraction & RPA

Our sample collection and DNA extraction have the potential to be integrated as one. Using micro-needle patches allows us to extract DNA directly in the vineyard. Therefore, there's no need to collect the leaves or follow contagion transportation protocols. Additionally, as DNA is more stable, the sample can preserve for a longer period without refrigeration. Our RPA reaction is carried out by rehydrating the freeze-dried pellets, the solution we collect can be used directly as the rehydration buffer and the template.

DESIGN I

01.Open micro needle protection lid, stamp the leaf with micro-needle patch.

02.Open the plastic lid for the capsule dip micro needle patch inside for several times.

03.Open protection lid for the puncher, punch through the second lid let the solution flow into the bottom chamber.

04.The RPA reaction will start right after the pellet gets rehydrated.

Toehold expression & signal generation

The goal in the inpiration part was to express the signal in a liquid-based reaction which needs tubes and pipettes to help to standardize the concentration and create uniform signals. But it increases both the price and the complexity of the test. Therefore, a paper-based reaction is more favorable. And instead of pipettes we chose syringes which are cheaper and controllable.

DESIGN II

01.Cut open the bottom of the RPA capsule. Gently pour the RPA product into the syringe with tip closed.

02.Distribute the RPA products into the three wells of paper discs, once the trigger DNA is present in the RPA product, toehold will be activated and express our report protein CDO and change the colour of the disc from white to yellow.

FINAL DESIGN

By combining the two ideas together, we come up with another design which make it has less components.

01Extraction

Stamp the leaf with micro-needle patch.

02Installation

Connect syringe to the micro-needle capsule.

03RPA

Open the lid of RPA capsule, inject the DNA sample inside.

04Incubation

Wait for 20 minutes till the RPA reaction is finished.

05Signals

Tear open the bottom of the capsule, squeeze one drop of the solution on each paper disc If the disc turns yellow, it means the according gene is present.

“Design is thinking made visual.”

– Saul Bass

PROTOTYPE FABRICATION COST

3D STRUCTURE DOWNLOAD SECTION

ViTest Mark I

ViTest Mark II

“Design is not just what it looks like and feels like. Design is how it works.”

– Steve Jobs

TUTORIAL

Team:EPFL/Hardware