An Ebola outbreak in West Africa has killed more than 11,000 people since 2014, with new cases occurring recently in Guinea and Sierra Leone. The current gold standard for detecting the Ebola virus relies on a method called polymerase chain reaction (PCR) to amplify the virus's genetic material for detection.
UC Santa Cruz researchers' have now developed a chip-based technology that enables reliable direct detection of Ebola virus and can help doctors contain future outbreaks. The newly developed system uses direct optical detection of viral molecules and can be integrated into a simple, portable instrument for use in field situations where rapid, accurate detection of Ebola infections is needed to control outbreaks.
Laboratory tests using preparations of Ebola virus and other hemorrhagic fever viruses revealed that the system has the sensitivity and specificity needed to provide a viable clinical assay.
The currently used PCR works on DNA molecules and Ebola is an RNA virus. The reverse transcriptase enzyme is used to make DNA copies of the viral RNA prior to PCR amplification and detection.
Senior author Holger Schmidt, "Compared to our system, PCR detection is more complex and requires a laboratory setting. We are detecting the nucleic acids directly, and we achieved a comparable limit of detection to PCR and excellent specificity. The system combines two small chips, a microfluidic chip for sample preparation and an optofluidic chip for optical detection."
For over a decade, the research team has been developing optofluidic chip technology for optical analysis of single molecules as they pass through a tiny fluid-filled channel on the chip. This microfluidic chip for sample processing can be integrated as a second layer next to or on top of the optofluidic chip.
Schmidt said, "The team has not yet been able to test the system starting with raw blood samples. That will require additional sample preparation steps, and it will also have to be done in a biosafety level 4 facility."
The study is published in Nature Scientific Reports.