Team:Oxford/Applied Design

Introduction

iGEM encourages all teams to take their projects beyond the lab and to take a holistic approach to design. The question “What is our real world problem?” has been a key consideration from the beginning, and has guided our project throughout the summer.

To put our diagnostic device into context, we considered various aspects including safety, accessibility and socioeconomic factors in Latin America. Many design iterations were built upon over the course of the summer, influenced by discussions with experts from a range of disciplines, including blood coagulation, microfluidics and general diagnostic devices.

Having thoroughly examined and evaluated various design options, we propose a final design for our system which fulfils our criteria for a suitable diagnostic device.

What diagnostics for Chagas disease currently exist?

Diagnosis of Chagas disease is difficult, as the disease is mostly asymptomatic in the acute phase and for the majority of the chronic phase.

We spoke to Dr Carol Lole Harris, who advised us on the practical and social considerations involved in the application of our diagnostic in Latin America, based on her experience working in Paraguay. We discussed the current tests available for Chagas and Carol emphasised that a spot test would be by far the best option for a multitude of reasons.

Following further reading, we created a table of our findings to highlight the lack of a rapid and feasible diagnostic for congenital Chagas disease.

Table 1: Main diagnostic methods currently used to diagnose Chagas disease

Test	How it works	Benefits	Limitations	Suitable for newborns
Whole parasite microscopy	Preparation of Giesma blood smears Visualised using light microscopy	Established method Carried out by already trained professionals	Not suitable for the when there is little T. cruzi in the blood Not always possible to differentiate between T. cruzi from T. rangeli, which does not cause disease in humans.	Yes
Polymerase Chain Reaction (PCR)	Molecular detection of T. cruzi DNA is performed using a combination of three real-time PCR assays. Acceptable specimen types are EDTA blood, heart biopsy tissue or cerebrospinal fluid.	Allows high sensitivity in the acute phase Allows the presence of T.cruzi to be accurately distinguished from T. rangeli Allows direct detection of infection and easy interpretation of results	High variation in accuracy and lack of international quality controls High cost and complexity means it is not practical to use in a clinical practice Further validation is needed to prove whether PCR is suitable to diagnose the chronic phase of Chagas	Yes
Serological tests	Detection of antibodies against T. cruzi Includes techniques such as indirect fluorescent antibody (IFA) test, a commercial enzyme immunoassay (EIA) and immunochromatographic tests	Can be used for acute phase and chronic phase High specificity and sensitivity Commercialised and approved for use by WHO Low-cost formats are available	Cross reactivity can occur with diseases, such as leishmaniasis and schistosomiasis Performance of these tests is lower than reported by their manufacturer, especially against specific strains of T. cruzi Not suitable for immunocompromised patients and newborns	No

We also spoke to Professor Dias Borges Lalwani is professor of epidemiology at the Faculty of pharmaceutical sciences at UFAM, whose contact details were forwarded to us by the AQA Amazonas team. We were fortunate enough to be able to arrange a Skype meeting with Jaila, which helped us contextualise the problem of Chagas highlighting the difficulty of seeking diagnosis given non-specific early disease symptoms.

Why congenital Chagas disease?

We spoke to Dr Alonso-Vega of the University of San Simón, Cochabamba who ran the National Congenital Chagas Disease Programme in Bolivia from 2004-2009, and is an expert in congenital Chagas. Dr Alonso-Vega’s Chagas Disease Program recommended the need for a new congenital diagnostic. She gave us specific guidance for implementation of our diagnostic device in Bolivia and confirmed the suitability of our congenital test in Bolivian hospitals, where most deliveries occur.

We first contacted Professor Yves Carlier early on in our project to gain more information about the pathology of congenital Chagas disease. Professor Carlier is a researcher in infectious diseases and clinical immunology at the Université Libre de Bruxelles. He re-emphasised the need for a diagnostic for neonates, strengthening our resolve to focus on congenital Chagas disease. He also informed us about the benefits of diagnosing Chagas disease in neonates, such as that treatment with benznidazole cures around 100% of babies if given before one year of age but not later in life.

We also learnt that Chagas treatment for under 15’s is free, giving us confidence that our diagnostic would be accessible and impactful in containing Chagas if provided in a hospital setting. Our discussion with her further emphasised the requirement for a rapid point of care test that would allow treatment of infected newborns to begin before they left the hospital.

How did we develop our design?

Based on our findings from the OpenPlant conference, we established a set of criteria for our applied design - the 4 E’s (‘Effectiveness’, ‘Ease of use’, ‘Economics’ and ‘Environment & Safety’).

Prototyping involved extensive consideration of various design iterations. We progressed from paper to cardboard to 3D printing - at each stage of this process, we were able to iron out flaws in our design and to incorporate new features from our evaluations.

What is our solution?

Our current kit meets our criteria established from our 4E’s framework: it is effective, easy-to-use, economically viable and environmentally safe. Furthermore, it incorporates many of the recommendations provided to us by the experts we contacted. Our solution is a rapid, point-of-care diagnostic for congenital Chagas disease which can easily be used by any healthcare professional.

Following extensive design and development, we produced a 3D prototype version of our kit. We spoke to Tim Ring, the vice president of safe-tec sales and marketing who generously sent us MICROSAFE® pipette samples so we could test the compatibility of these with our kit design. These pipettes are advantageous for blood collection and allowed us to test our applied design more rigorously.

Our 3D prototype design was refined by the healthcare professionals we contacted for evalutation. The insights from Sarah Dragonetti (Registered Nurse) and Dr. Ben Riley (General Practice doctor) were hugely useful in assessing and refining the practicality of our diagnostic kit, consequently improving our applied design.

How will we implement our design?

We consider integration of our device into existing healthcare systems and current infrastructure a key challenge, and therefore a fundamental aspect of our applied design considerations.

We received invaluable advice from David Sprent, an expert in International Supply Chain, and Juan Solano and Alfons Van Woerkom, representatives of the Global Fund who advised us on evaluating costs of manufacture, transport and taxation of a kit for end use by the Bolivian healthcare system.

We consulted with HeLEX, (Centre for Health, Law and Emerging Technologies) and with InSIS (Institute for Science, Innovation and Society). InSIS researches and informs key contemporary and emerging issues and processes of social, scientific, and technological change. The insights from both HeLEX and InSIS were highly useful in evaluating the ethical and social issues related to our project, and heavily influenced our applied design.

Professor Keith Pardee has worked on cell-free technologies, and he informed us how cell-free systems could solve a lot of issues around safety and cost.

Dr Piers Millett is a Senior Research Fellow at the Future of Humanity Institute, and he introduced us to the concept of platform technologies and how this could be applied to our project. This provides a good way of fast tracking future developments because the platform will already have met regulatory approval, therefore allowing the device to be more rapidly adapted for other diseases.

References

Carlier, Y. and Truyens, C. 2017 Maternal-fetal transmission of Trypanosoma cruzi. Second Edition, American Trypanosomiasis Chagas Disease: One Hundred Years of Research: Second Edition. Second Edition. Elsevier Inc. doi: 10.1016/B978-0-12-801029-7.00024-1.

Cencig, S. et al. 2012 ‘Evaluation of benznidazole treatment combined with nifurtimox, posaconazole or AmBisome?? in mice infected with Trypanosoma cruzi strains’, International Journal of Antimicrobial Agents. Elsevier B.V., 40(6), pp. 527–532. doi: 10.1016/j.ijantimicag.2012.08.002.