The Schistoscope 3B

What it does

Schistoscope 3B helps diagnose and map the disease schistosomiasis haematobium across Africa, where more than 90% of the world’s schistosomiasis cases are found. There is a lack of knowledge on the disease’s prevalence, a solution to which is this device.

Your inspiration

Schistoscope 3B is an iteration of the development of a smart optics-based diagnostics device, called the Schistoscope, which started under the ‘Diagnostics for All’ research program at TUDelft. The requirement was to create an automated microscope that can be manufactured and used in remote areas of Africa by local health care workers. During our research, we found that there were no high throughput devices currently in use that can be taken on the field, and use it to diagnose, as well as map the disease across a region. This inspired us to create a device that can scan six samples simultaneously and store data for later analysis.

How it works

Raspberry pi 4 is used to control the device. The idea is to take multiple photographs of a sample (snake scan) and stitch them together, so each egg is clearly visible. Six standard microscope glass slides are used to hold six different urine samples and are assembled onto a specially designed tray that holds the slides on the top and doubles as a rack at the bottom. When inserted into the device, the teeth of the tray mesh with a pinion below, which is driven by a motor. This motor is used to control the side to side movement of the tray. When the tray is moved to the desired location, a lens positioned just above the sample is moved into place with a motor attached to a lead screw. The lens can be moved back and forth along the longer axis of the glass slide. When the lens is in the right position, another motor controlling its focus ring is activated. A picture is now taken and stored. The sample is moved to the next position, and the process is repeated.

Design process

Since we decided on making the device usable on the field, as well as for mapping, it was only logical to design a device with high throughput (scan multiple samples). The biggest challenges we faced were ‘how to scan multiple samples at once while keeping the device portable?’, ‘how to lower patient waiting time (from the time sample is received to the time results are given to the patient) if multiple samples are being scanned?’, ‘how to design for local manufacturability and repairability?’. Brainstorming, and many sketches later, it was decided that the device would be most portable if the scanning unit was small, while the sample unit, which can be long due to multiple samples, can be inserted into the scanning unit when needed. Portable A4 scanners were taken as an analogy here. The paper would be the samples in this case. It was also concluded that six samples would be ideal for the device. This is because it was approximated that the sample collection, preparation and scanning of six samples takes approximately 45 minutes, which would be a reasonable waiting time for each patient. 3D printing was chosen to be the method of production as there are many makerspaces in Africa. Creating CAD parts that were both 3D printable and allowed for accurate movement was challenging.

How it is different

The main distinction for this device is its ability to scan six samples in one scan cycle. All previously designed devices were designed to scan only one sample at a time. Scanning six samples gives the health care worker time to interact with the patients or attend to other duties in the meantime. We interviewed three researchers from Leiden University Medical Center (LUMC) for feedback on the device, and they all said the multiple sample scanning feature would be very useful. Another distinction is its simplicity and ease of use. All operations within the device can be controlled with a single rotating knob by scrolling to the desired option and pressing on the knob to select it. This will be a very useful feature especially for those who operate the device in a field setting, while managing patients and preparing samples. The chances of making errors is much less when compared to devices with multiple buttons or touchscreen.

Future plans

Future plans will include validating the tray and lens movements, making the device dust and waterproof to a rating of IP55, incorporating a GPS module, and using printable barcodes to associate samples to patients.

Awards

We have just completed this project as a part of the course 'Advanced Embodiment Design', and the James Dyson Award will be our first entry.