Project Lead(s): Ratmir Derda
The development of point-of-care devices is a rapidly growing topic of research; but not well developed in low-income countries.
One of the requirements for onsite production of such tests is the identification of simplified alternatives to well-engineered techniques: liquid transport, liquid measurement and dilutions, micro-patterning, weighing and densitometry, centrifugation, etc.
This would enable tests to be produced onsite to diagnose diseases such as malaria, HIV or tuberculosis.
The project team sought to demonstrate that a functional, portable device for the growth of bacteria or amplification of bacteriophage could be created using simple materials (tape, paper, ink and a polydimethyl siloxane membrane).
The division time of E. coli and the amplification of the phage M13 in this device are similar to the rates measured on agar plates and in shaking cultures.
The growth of bacteria with a fluorescent mCherry reporter can be quantified using a flatbed scanner or a cell phone camera.
Permeating devices with commercial-viability dye can be used to detect low-copy numbers of E. coli and visualize microorganisms in environmental samples.
The platform, equipped with bacteria that carry inducible mCherry reporter, could also be used to quantify the concentration of the inducer.
The same platform can be used to perform more complex tests, such as detection of resistant bacteria or detection of low concentrations of bacteria, in a short time (two to three hours) using bacteriophage-based detection.
The project team managed to optimize the different components necessary to develop a working prototype of a multiplex, point-of-care device.
They showed that identical culture platforms can, potentially, be used to quantify the induction of gene expression by an engineered phage or by synthetic transcriptional regulators that respond to clinically relevant molecules.
The majority of measurement and fabrication procedures were replicated by low-skilled personnel (high-school students) in a low-resource environment (high-school classroom).
The fabrication and performance of the device was tested in a low-resource laboratory setting by researchers in Nairobi, Kenya.
These findings suggest that the platform – a combination of paper based culture platform and bacteriophage-based detection – can be used as both an educational tool and as a diagnostic tool in low-resource environments worldwide.
The team organized an international diagnostic workshop in Kenya. The venue attracted more than 30 presenters and 126 participants (39 international and 87 African). The organizers and 17 other presenters demonstrated production and use of culture platforms and other diagnostic devices onsite in Nairobi. The attendees of the hands-on workshop developed and published a policy proposal in PLOS Neglected Tropical Diseases that proposes steps towards accelerated development of new types of diagnostic devices.
A video was also produced at the workshop in Kenya, demonstrating the theoretical use of point-of-care diagnostic tests, which can be used for learning purposes.