Team:IISER-Pune-India/Motivation
Our Motivation
After our interview with Dr Dionicia Gamboa, we realised that experts working in the field have a really hard time reaching remote areas due to the lack of infrastructure. This means that not only is it hard to study genetic variations in malarial parasites in these areas, but it is also more difficult to diagnose patients due to the lack of testing facilities.
Usually, to diagnose a malarial patient, a blood sample is collected and tested in a lab. The current gold standard for the diagnosis of malaria involves microscopy with visualization of Giemsa-stained parasites in a blood sample.[1],[2]
A species determination is then done based on the morphological characteristics of the four species of human malaria parasites and the infected red blood cells. This requires access to a lab with the technical expertise to identify malarial parasites and the presence of sophisticated microscopes to achieve the required 100x oil immersion magnification. [3]
The availability and application of conventional microscopy is difficult in remote or rural areas, where malaria is most prevalent. This is due to a variety of factors like high cost, the bulkiness of equipment, shortage or unavailability of skilled personnel, and the lack of the required equipment maintenance skills. [3]
We aim to design a tool that can bridge this gap. To do this, we are creating a portable diagnostics kit that allows healthcare workers to capture an image of a blood smear using a smartphone and test for the presence of malaria parasites using a Web API, making the diagnosis of the disease simple and efficient. We hope that this tool will dramatically contribute to efforts to eradicate malaria by enabling healthcare workers to easily test patients.
We have created a deep learning software based on Convolutional Neural Networks (CNN). This software will be able to identify the presence of malarial parasites from images of blood smears. The model has been trained to identify infected samples using a data set of twenty-seven thousand images of blood smears that have been identified by experts to be positive or negative for the presence of Plasmodium falciparum parasites. To capture the images of the blood smears, we plan to use a foldscope (an origami-based paper microscope) and a cost-effective centrifuge, developed by Dr. Manu Prakash.
Foldscope and Paper Centrifuge
While the entire cost of the parts to make a foldscope is less than a dollar, the foldscope is able to provide over 2,000× magnification with submicron resolution. It weighs about 8.8 g and is quite small (70×20×2 mm3) and so it can even fit in a pocket. The foldscope also does not require an external power source. Other important components of the foldscope include a spherical ball lens (or other micro-lenses), lens-holder apertures, an LED with diffuser or condenser lens, a battery, and an electrical switch.[4] The foldscope is made of three stages cut from paper - illumination, sample-mounting and optics and is assembled by folding.[4] Using a spherical ball lens provides an additional advantage of high-volume manufacturing, including reduced part count and simplified assembly due to rotational symmetry[6],[7],[8] . The foldscope allows for a wide range of magnification by changing the spherical ball lens, as magnification varies inversely with ball-lens diameter.[4] Thus the foldscope will enable healthcare workers to capture the image of the blood smears at the required magnification.
The paper centrifuge (called paperfuge) is a low cost, lightweight, and is human-powered. It was designed based on a theoretical model that was inspired by the mechanics of the fundamental concept of an ancient whirligig. The paper centrifuge is able to achieve speeds of about 125,000 r.p.m. [5] Studies have demonstrated that the paper centrifuge can separate pure blood from plasma and isolate malarial parasites in about 15 minutes. Carrigeable, human-powered centrifuges should pave the way to diagnostics in geographically remote settings.[5]
You can find the user manual for the Foldscope and paper centrifuge
here
We hope our envisioned system can make a meaningful and tangible impact on the eradication of malaria all around the globe.
References
[1] Malaria Diagnosis Using a Mobile Phone Polarized Microscope. Casey W. Pirnstill, Gerard L. Coté. Sci Rep 5, 13368 (2015). Doi: 10.1038/srep13368
[2] Imaging & identification of malaria parasites using cellphone microscope with a ball lens. Temitope E. Agbana, Jan-Carel Diehl, Fiona van Pul, Shahid M. Khan, Vsevolod Patlan, Michel Verhaegen, and Gleb Vdovin (2018). Doi: 10.1371/journal.pone.0205020
[3] Centers for disease control and prevention; Malaria Diagnostic Tests (February 19, 2020)
[4] Cybulski, J. S., Clements, J., & Prakash, M. (2014). Foldscope: Origami- Based Paper Microscope. PLoS ONE, 9(6), e98781. Doi: 10.1371/journal.pone.0205020
[5] Bhamla, M., Benson, B., Chai, C. et al. Hand-powered ultralow-cost paper centrifuge. Nat Biomed Eng 1, 0009 (2017). https://doi.org/10.1038/ S41551-016-0009. Doi: 10.1371/journal.pone.0205020
[6] Doushkina V, Fleming E (2009) Optical and mechanical design advantages using polymer optics. Advances in Optomechanics 74: 24–31.
[7] Lee C-C, Hsiao S-Y, Fang W (2009) Formation and integration of a ball lens utilizing two-phase liquid technology. IEEE 22nd International Conference on Micro Electro Mechanical Systems: pp. 172–175.
[8] Jeong K-H, Liu GL, Chronis N, Lee LP (2004) Tunable microdoublet lens array integrated with microfluidic network. Optics Express 12(11): 2494–2500.