New portable device enables RNA detection from ultra-small sample in only 20 minutes

Nov 07, 2012
Figure 1 shows the new power-free RNA detection microchip. Left: Fabricated microchip. Right: Microchannel design. Credit: RIKEN

A new power-free microfluidic chip developed by researchers at the RIKEN Advanced Science Institute (ASI) enables detection of microRNA from extremely small sample volume in only 20 minutes. By drastically reducing the time and quantity of sample required for detection, the chip lays the groundwork for early-stage point-of-care diagnosis of diseases such as cancer and Alzheimer's.

MicroRNAs (miRNAs) are small, non-coding that regulate in a wide range of biological processes including development, , differentiation and cell death (apoptosis). Concentration of certain in body fluids increases with the progression of diseases such as cancer and Alzheimer's, generating hope that these short RNA may hold the key to faster, more accurate diagnosis. Currently available techniques for sensitive miRNA detection, however, require days to reach a diagnosis and involve equipment operated only by trained personnel, making them impractical for use in many situations.

The research team set out to overcome these obstacles by developing a device that enables fast, easy-to-use point-of-care (POC) diagnosis from only a very small sample. In earlier research, the team developed a device in the form of a microchip which uses polydimethylsiloxane (PDMS), a silicone compound known for its air absorption properties, to pull reagents into a capture probe for analysis. This pumping technique simplified design by eliminating the need for external power sources, but the device required a quantity of sample too large for practical applications.

The new device also uses PDMS as an air pump, but drastically improves the method's sensitivity through a method called laminar flow-assisted dendritic amplification (LFDA). First, which bond to specific miRNA sequences are fixed to a glass surface along with the miRNA sample to be analyzed, and then sandwiched under a layer of PDMS with channels in it (Figure 1). Emptied of air in a vacuum, the PDMS layer induces a pump effect which pulls amplification reagents, inserted at the channel inlets, into the channels and into contact with the miRNA, creating fluorescence-labeled dendritic structures that grow over time and can be quickly detected.

The sensitivity of this technique drastically reduces the sample quantity required for diagnosis to only 0.25 attomoles (10-18 mole), a thousand-fold improvement over the team's earlier model. Together with its detection time of only 20 minutes, these properties make the self-powered device ideal for use in resource-poor environments, promising portable point-of-care diagnosis for millions in developing countries and around the world.

Explore further: Beer quality is no froth and bubble

More information: Hideyuki Arata, Hiroshi Komatsu, Kazuo Hosokawa, and Mizuo Maeda "Rapid and Sensitive MicroRNA Detection with Laminar Flow-Assisted Dendritic Amplification on Power-Free Microfluidic Chip". PLOS ONE, 2012, doi:10.1371/journal.pone.0048329

Related Stories

Everything flows in rapid diagnostic tests

Apr 12, 2012

(Phys.org) -- Our ability to detect pathogens has become quite good, but it usually requires complex laboratory techniques. Sometimes we need a quick result, or there is no laboratory nearby. Portable and ...

New protocols improve detection of microRNAs for diagnosis

Dec 07, 2011

MicroRNAs (miRNAs) that regulate processes including fertilization, development, and aging show promise as biomarkers of disease. They can be collected from routinely collected fluids such as blood, saliva, and urine. However, ...

A medical micropump

Nov 13, 2006

Using material similar to bathtub caulk, University of Utah engineers invented a tiny, inexpensive "micropump" that could be used to move chemicals, blood or other samples through a card-sized medical laboratory ...

Blood 'fingerprints' for cancer

Sep 03, 2008

Serum microRNAs (miRNAs) can serve as biomarkers for the detection of diseases including cancer and diabetes, according to research published online this week in Cell Research. The findings pave the way for a revolutionary ...

Recommended for you

'Global positioning' for molecules

Dec 19, 2014

In everyday life, the global positioning system (GPS) can be employed to reliably determine the momentary location of one en route to the desired destination. Scientists from the Institute of Physical and ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

PPihkala
1 / 5 (1) Nov 07, 2012
So what is the price of this detection device? It also needs to be correct for tech like this to be useful.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.