This article is more than 5 years old. Information may no longer be current.
‘Lab-on-a-Disc’ reduces time to detect, identify bacteria in urine
Click Here to Manage Email Alerts
A cost-effective diagnostic device combining microfluidics and Raman microscopy detected and identified bacteria in urine samples in less than 70 minutes, according to a recent study.
“Compared to established, cultivation-based microbiological methods, which require 24 hours or more to identify the bacteria, an analysis time of slightly over 1 hour marks a huge step forward in fast, cultivation-independent analysis,” Ulrich-Christian Schröder, PhD student at Jena University Hospital and Leibniz Institute of Technology in Germany, and colleagues wrote.
The “Lab-on-a-Disc” platform is a centrifugally driven device that includes a spindle motor and microfluidic chips made of polydimethylsiloxane (Sylgard 184, Dow Corning). The diagnostic screening begins with microfluidic chips being stored in a vacuum for 30 minutes and spun for 20 minutes to remove air. Then, 5 mL to 10 mL of urine samples are loaded and spun at 25 Hz to capture and centrifuge bacteria in a V-cup-based platform within 45 minutes. The bacteria are analyzed using a Raman spectroscopic approach.
“Raman spectroscopy uses the way light interacts with matter to produce ‘unique scattering,’ the equivalent of a molecular fingerprint, which can then be used to identify the types of bacteria present,” Ute Neugebauer, PhD, also from Jena University Hospital and Leibniz Institute of Technology, said in a press release.
Up to four chips of bacteria can be analyzed simultaneously, allowing for parallel analyses that is desirable for precise results.
In their pilot study, Schröder, Neugebauer and colleagues used the device to detect Escherichia coli and Enterococcus faecalis pathogens in urine samples. They applied an algorithm to distinguish the bacterial Raman spectra of the samples using an extended multiplicative scatter correction and reported an excellent agreement of the calculated difference spectra, demonstrating a distinction between E. coli and E. faecalis.
“Compared to recent developments, which target the sensing of bacteria irrespective of the species level in urine, within even shorter intervals, the Lab-on-a-Disc approach ... sets itself apart by its high potential for bacterial classification and identification on a species level,” Schröder and colleagues wrote.
The researchers estimated that the process takes less than 100 minutes between the patient’s arrival and pathogen identification. If chips are already stored under vacuum, the total duration would be reduced to less than 70 minutes. The researchers concluded that the “golden age” of diagnostic testing is nearly attained using the approach.
“The next step will involve implementing antibiotic susceptibility testing and automating the sample pre-treatment steps,” Neugebauer said. “Our ultimate vision is to apply the concepts behind our device to enable diagnostics devices for use with other bodily fluids.” – by Stephanie Viguers
Disclosure: The researchers report no relevant financial disclosures.
Click Here to Manage Email Alerts