Featured Research

from universities, journals, and other organizations

Bioanalysis: Microbeads are easily fixed

Date:
April 10, 2014
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
A passive method for sorting and fixing microbeads of different sizes could lead to cheaper and more functional biological assays, researchers report. Biological assays are an integral part of the researcher's toolkit in the fields of biomolecular chemistry and genomics. Microfluidic microbead systems, which consist of arrays of beads coated with an assay-specific reagent, have revolutionized biological assay technology by allowing the high-throughput detection of target molecules from small sample volumes. Fabrication of the microbead systems, however, requires great care and various ancillary devices.

Microscopy image of a microtrap array showing the capture of large 16-micrometer-diameter beads in surface traps. Smaller 8-micrometer-diameter beads accumulate in the underlying dispersion gap.
Credit: Copyright : 2014 A*STAR Institute of Microelectronics

A passive method for sorting and fixing microbeads of different sizes could lead to cheaper and more functional biological assays

Biological assays are an integral part of the researcher's toolkit in the fields of biomolecular chemistry and genomics. Microfluidic microbead systems, which consist of arrays of beads coated with an assay-specific reagent, have revolutionized biological assay technology by allowing the high-throughput detection of target molecules from small sample volumes. Fabrication of the microbead systems, however, requires great care and various ancillary devices.

Chee Chung Wong and colleagues from the A*STAR Institute of Microelectronics have now developed a passive and robust method for manufacturing sorted arrays of multiple microbead types.

The preparation of microbead systems conventionally involves the use of a pump to introduce a bead-carrying fluid into a microfluidic circuit. The beads then adsorb to the walls of the microchannels with little control over position or sorting. The resultant microbead-coated channels can be used for targeted molecule detection, but the beads can be easily dislodged by flow.

Recognizing the limitations of conventional systems, Wong and his colleagues set out to develop a passive, pumpless method for preparing more robust microbead arrays. "There are no pumpless bead sorting strategies currently available," notes Wong. As a result, "we had to research and study three-dimensional trap architectures that could efficiently perform size-based bead sorting."

The researchers used semiconductor fabrication technologies to create a trap architecture consisting of a top surface with larger micrometer-sized holes and an underlying diffusion gap. When a drop of fluid containing microbeads is placed on the top surface, the beads become trapped in the micrometer-sized holes while the fluid is free to flow through the diffusion layer and out of the array. This structure has the advantage of allowing beads of different sizes to be trapped and permanently fixed in different parts of the device as the fluid evaporates (see image).

"We studied how a droplet of liquid evaporates and how this affects the flow field," says Wong. "Based on simulations and experiments, we were able to optimize our microtrap architecture for efficient size-based sorting of a range of different bead sizes."

The researchers expect their fabrication method to alleviate ease-of-use issues associated with current bead sorting assays, but also to significantly speed-up throughput by allowing multiple molecular targets to be detected in one device. "The additional dimension of bead size would directly increase the number of analytes that can be detected," says Wong. "They could increase from two, for a conventional two-color system, to six for a system with three bead sizes in different trap regions."


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Chee Chung Wong, Yuxin Liu, Karen Yanping Wang, Abdur Rub Abdur Rahman. Size based sorting and patterning of microbeads by evaporation driven flow in a 3D micro-traps array. Lab on a Chip, 2013; 13 (18): 3663 DOI: 10.1039/C3LC50274K

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Bioanalysis: Microbeads are easily fixed." ScienceDaily. ScienceDaily, 10 April 2014. <www.sciencedaily.com/releases/2014/04/140410160243.htm>.
The Agency for Science, Technology and Research (A*STAR). (2014, April 10). Bioanalysis: Microbeads are easily fixed. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2014/04/140410160243.htm
The Agency for Science, Technology and Research (A*STAR). "Bioanalysis: Microbeads are easily fixed." ScienceDaily. www.sciencedaily.com/releases/2014/04/140410160243.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins