Low-cost microfluidics can be a sticky problem

May 12, 2006

A deceptively simple approach to bonding thermoplastic microchannel plates together with solvent could be used for low-cost, high-volume production of disposable "lab-on-a-chip" devices, according to researchers from the National Institute of Standards and Technology (NIST) and George Mason University (GMU).

Microfluidics is considered a highly promising technology for performing rapid and inexpensive chemical and biochemical analyses. The defining feature of microfluidics is the use of tiny channels less than a fraction of a millimeter wide to move samples and reagents through the device. For high-volume production, the channels likely will be molded or embossed in high-quality thermoplastic and then sealed with a cover plate. Bonding the two pieces together securely without blocking or altering the tiny channels is a key manufacturing issue.

One approach is to weld the two plates together by clamping them and heating the plastic to the point where the polymer chains begin to diffuse together. This requires just the right combination of time, pressure and temperature--which unfortunately has to be fine-tuned for each new lot of plastic. The other method is to weld the pieces with a solvent-type glue, like a model plane, but as model-builders will appreciate, the problem is keeping the glue where you want it and away from where you don't want it.

In a recent paper in Analytical Chemistry, a team from NIST and GMU suggest that the answer is simple: use the channels. They clamp the two plates together, inject a tiny amount of solvent at one end of the network of channels and apply vacuum at the other end. As the solvent is sucked through the channels, too fast to clog them, a minute amount is drawn between the plates by capillary action and welds them together. Total welding and incubating time: about 8 minutes. To demonstrate utility, the team successfully performed high-efficiency electrophoretic separation of 400-base single-strand DNA ladders, a typical microfluidics application, in the devices fabricated using the technique.

Citation: J.J. Shah, et. al., Capillarity induced solvent-actuated bonding of polymeric microfluidic devices, Analytical Chemistry 2006; 78(10) pp 3348 - 3353.

Source: NIST

Explore further: First circularly polarized light detector on a silicon chip

Related Stories

First circularly polarized light detector on a silicon chip

September 22, 2015

Invention of the first integrated circularly polarized light detector on a silicon chip opens the door for development of small, portable sensors that could expand the use of polarized light for drug screening, surveillance, ...

Physicists develop key component for terahertz wireless

September 14, 2015

Terahertz radiation could one day provide the backbone for wireless systems that can deliver data up to one hundred times faster than today's cellular or Wi-Fi networks. But there remain many technical challenges to be solved ...

Capturing cell growth in 3-D

August 14, 2015

Replicating how cancer and other cells interact in the body is somewhat difficult in the lab. Biologists generally culture one cell type in plastic plates, which doesn't represent the dynamic cell interactions within living ...

Recommended for you

A long look back at fishes' extendable jaws

October 8, 2015

When it comes to catching elusive prey, many fishes rely on a special trick: protruding jaws that quickly extend their reach to snap up that next meal. Now, researchers reporting in the Cell Press journal Current Biology ...

New protein cleanup factors found to control bacterial growth

October 8, 2015

Biochemists have long known that crucial cell processes depend on a highly regulated cleanup system known as proteolysis, where specialized proteins called proteases degrade damaged or no-longer-needed proteins. These proteases ...


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.