A new detector using photonics to identify E. coli bacteria from a tiny drop of blood and produce a diagnosis in less than 30 minutes has been developed in a bid to reduce the mortality rate from sepsis by more than 70%.
The rapid ‘microarray’ detector looks at a small blood sample taken from a thumb or forefinger. The patient’s blood sample is then separated in a centrifuge so that a clinician can examine the plasma, the part of the blood sample where all the proteins are contained.
Programmed to detect proteins and E.coli the detector then uses light to look for specific biomarkers (the tell-tale signs or an indicator of a disease) that are as small as few nanometres in size, or 1 / 1,000,000th of the thickness of a single human hair.
Pre-clinical trials have already begun at the Vall d'Hebron University Hospital where the device has been in operation since 2018. Clinical trials are expected to take place at the end of 2019.
Current techniques for detecting sepsis can take hours or days to produce the results and diagnosis. While bacteria need to reproduce in large quantities before an accurate determination can be made, a patient can often be waiting more than one day before a course of treatment can be determined. If caught early enough, sufferers can be treated for sepsis with antibiotics.
Project coordinator, Dr Roland Terborg said: “The optical readout of the sample can be completed in one minute, allowing us to deliver results in thirty minutes from start to finish. This is much faster than methods currently in use. With a condition like Sepsis, where time is crucial this device looks set to prevent thousands of deaths every year that could easily have been avoided.”
Developed by the ‘RAIS’ project, (or ‘Scalable point-of-care and label-free microarray platform for rapid detection of Sepsis'), the project was coordinated by ICFO in Barcelona.
The plasma sample flows over a microarray, a collection of tiny spots containing specific antibodies on a nanostructured gold slide.
Two light beams are then shone through the full microarray, with one of them passing through the sample, while the other one goes through the clear part of the slide, acting as a ‘reference’.
The beams passing through the biomarker and the clear regions on the slide are then checked for any changes in intensity.
Dr Terborg added: “Depending on the amount and type of biomarker attached to each antibody, we obtain a unique image: a signature pattern if you like. The image patterns tell us what is present in the plasma sample, which we then record with a CMOS sensor, the same technology used in a digital camera that converts light into electrons.
“The low-cost point-of-care microarray platform will allow clinicians to identify sepsis early and therefore start patients on the right treatment quickly, potentially reducing the mortality rate by as much as 70-80%. The detector will have a significant impact on European industry, making it more competitive in the point-of-care medical market for detection of sepsis and other infectious diseases.”
The device could also be extended to perform on other types of disease screening or multiple simultaneous diagnoses, especially those requiring a rapid detection of large numbers of biochemical targets on a single microarray.
