AsianScientist (Mar. 16, 2017) – Researchers from Ulsan National Institute of Science and Technology have developed an integrated centrifugal microfluidic platform that can isolate extracelluar vesicles (EV) from urine. Their results, published in ACS Nano, could be used in clinical settings to test urinary EV-based biomarkers for cancer diagnostics.
EVs are cell-derived nanovesicles (40-1000 nm in size), present in almost all types of body fluids, which play a vital role in intercellular communication and are involved in the transport of biological signals for regulating diverse cellular functions.
Despite the increasing clinical importance of EVs as potential biomarkers in the diagnosis and prognosis of various diseases, current methods of EV isolation and analysis suffer from complicated procedures with long processing times. For instance, even ultracentrifugation, the most commonly used method for EV isolation, requires time-consuming steps involving centrifugation and collecting large sample volumes, and the results suffer from low yield and purity.
To overcome these limitations, Professor Cho Yoon-Kyoung and his team developed a new lab-on-a-disc platform for rapid, size-selective, and efficient isolation and analysis of nanoscale EVs from raw biological samples, such as cell-culture supernatant or cancer-patient urine.
“The Exodisc is composed of two independent filtration units (20nm and 600nm in size) within a disk-shaped chip to enable the processing of two different samples simulateously,” said study first author Mr. Woo Hyun-Kyung. “Upon spinning the disc, the urine sample is transferred through two integrated nanofilters, allowing for the enrichment of unirary EVs within the size range of 20 to 600nm.”
The hole sizes in nanoporous filters mounted on the Exodisc were set to separate the nanoscale vesicles from germs or unnecessary proteins. The direct detection of urinary EVs from patients with bladder cancer was validated using on-disc enzyme-linked immunosorbent assay (ELISA).
“Using Exodisc, it is possible to isolate EVs from raw samples within 30 minutes,” said Cho. “The process of passing the filter through centrifugal force is automatically carried out, effectively recovering the enriched EVs.”
In the study, the research team examined clinical samples by analyzing urinary EVs from bladder cancer patients, using a tabletop-sized centrifugal microfluidic system. As a result, fully automated enrichment of unirary EVs in the size range of 20-600 nm was achieved within 30min quantitative tests.
“On-disc ELISA using urinary EVs isolated from bladder cancer patients showed high levels of CD9 and CD81 expression, suggesting that this method may be potentially useful in clinical settings to test urinary EV-based biomarkers for cancer diagnostics,” said study co-first author Dr. Vijaya Sunkara.
“We are currently conducting further studies to determine various diseases, including cancer by analyzing the collected nanoparticles,” added Cho. “We hope this device can contribute significantly to the advancement of studies related to tumor biology and acceleration of the practical use of EV-based liquid biopsies for personalized medicine in clinical settings.”
Source: Ulsan National Institute of Science and Technology.
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