iGEM Calgary 2014: B.s. Detector, A Multiplexed Rapid Diagnostic Device

Abstract

Febrile diseases such as meningitis, dengue fever, and typhoid fever are symptomatically similar to malaria and are thus often misdiagnosed in developing countries which lack the resources to maintain suitable healthcare infrastructures. Failure to accurately diagnosis such diseases within a patient is of particular concern as misdiagnosis prevents the appropriate treatments from being administered in a timely manner or often at all, which results in unnecessary human suffering and a significant financial burden on the patient’s respective health care system (Mabey, Peeling, Ustianowski, & Perkins, 2004). To address this global healthcare issue, the 2014 Calgary iGEM team (International Genetically Engineered Machine) has engaged with various stakeholders including researchers and end-users in developing countries with the hopes of mitigating the frequency of misdiagnosis.

Using synthetic biology, we aim to develop a novel, nucleic acid-based, point-of-care device capable of diagnosing multiple infectious diseases simultaneously. Specifically, we are engineering Bacillus subtilis to generate a chromophoric reporter protein in response to pathogenic genetic markers indicative of said diseases. This engineered strain of B. subtilis will lie dormant as a collection robust bacterial spores in a portable, handheld device until ready to be activated and used. In theory, by sporulating the B. subtilis, we can effectively increase the shelf-life and durability of the device as it is transported to the end-user in the developing world.

Our device will use a transcriptionally-regulated genetic circuit, in conjunction with the innate mechanism of homologous recombination found within B. subtilis, to detect and report the presence of multiple species of pathogens within the patient. Using only a minute sample of blood, the final device will enable users to differentiate between diseases based on a colorimetric output. Specialized training or outside resources will not be necessary to use the device and interpret its results. The strength of this diagnostic method lies in its modularity and high level of customization. Ultimately, our system is a platform technology which can be adapted to detect a wide variety pathogens by modifying the genetic markers to which our engineered B. subtilis binds to.