The Flow

Imagine my delight when I searched YouTube for "microfluidics" and got 275 results. Go ahead, I'll wait while you conjure up a picture of me grinning madly...

Anyway, the field is obviously growing rapidly, but I was surprised to see that the multimedia is being dispersed across the web. I can't decide whether this video explosion is due to the field's popularity or whether young researchers are actually finding that YouTube is useful tool for dissemating their research. Granted, most of the comments are along the lines of "Cool!" or "Science is great," so it may just be that bored people are stumbling across some pretty pictures—don't get me wrong, though, that's fantastic.

Well, regardless, here are two interesting microfluidics videos:

This one actually contains a lot of great information, including formulas, although I wouldn't go so far as to call it self-contained. The user who posted this doesn't seem like a company or research group, so it's not really a promotion item, which I can appreciate. He's just a nice fellow who happens to do research that he's proud of so he put it on youtube. Better than posting a video of yourself lip-synching to AC/DC, right?

This one is a little different because of the C. Elegans. There's nothing better than watching an animal work its way through a maze. Here, the Wheeler Lab has posted their group's research. I can definitely appreciate the quality and content here. Great job!

To quote the impassioned Dr. Steve Brule, "...go make some computer technologies of your own! Get out of the house and go do it!"

Each of our bodies respond differently to stimuli. For example, I could go outside and lay down in a patch of Poison Ivy (Toxicodendron radicans) and be fine, but my mom will break out in grisly red bumps. A more apt example might be that I could take NyQuil for my cold, fall asleep and wake up rested, whereas a friend could take the same dose and lie awake in a restless state all night long.

The microfluidic chip above is manufactured by Fluidigm, and will be used to simultaneously perform more than 9,000 reactions to try and predict a patient's response to a particular treatment for prostate cancer. Credit: Fluidigm

There are genetic reasons some drugs produce different responses for different people. So, what's the solution? Test each patient's genes and run about 9,000 simultaneous reactions to analyze the differences in how a patient's genes are expressed, rather than the specific genetic structure. This is an important distinction—sequencing genetic code is not yet a good indication of what will ultimately be expressed. Expression is a complex system that relies on many many genes to decide what ultimately happens inside your body. So this is exactly what Howard Scher, chief of the Genitourinary Oncology Service at Memorial Sloan-Kettering Cancer Center, has proposed in a new clinical trial for prostate cancer. The trial will take a look at rare tumor cells and analyze them using a microfluidic chip—the results will allow the researchers to decide how well the patient will respond to a certain drug. Essentially, the researchers are "building a profile" for the patient's tumor, which they can then use to decide what the best treatment will be. The chip—manufactured by Fluidigm, a South San Francisco biotech company—uses only a few nanoliters of reagent, and is combined with DNA through a series of valves and channels. One chip costs about $300. Emily Singer wrote a lovely and concise article about the upcoming trial in MIT's Technology Review.

Using lab-on-a-chip technology for DNA detection and analysis is one specific goal many researchers are inching toward. Researchers have now offered a way to align DNA strands to allow for analysis within a nanofluidic channel. The difficulty and cost of creating nanochannels is an impediment, but new research, published in Biomicrofluidics, offers the use a cost-effective material that could garner long term results in DNA analysis.

Nanochannels offer a way to align and analyze long biopolymer molecules such as DNA with high precision at potentially single basepair resolution. In the article "Complementary metal oxide semiconductor compatible fabrication and characterization of parylene-C covered nanofluidic channels with integrated nanoelectrodes," published today in Biomicrofluidics, Chih-kuan Tung, Robert Riehn, and Robert H. Austin, present a novel method of fabricating nanochannels with parylene, while measuring impedance characteristics with 25 nanometer thick electrodes. Parylene-C is a cheap and robust material, which is typically used for coating printed circuit boards as well as stents, defibrillators, pacemakers, and other implanted medical devices.

The researchers believe that this technology will open up opportunities for electronic detection of charged polymers, and that "with techniques to fabricate nanoelectrodes with nanochannels, it should be possible to include integrated electronics with nanofludics, allowing the electronic observation of a single DNA molecule at high spatial resolution."

There is something oddly calming about dulcet and jazzy music mixed with microject visuals. Both move fluidly and calm the senses.

Ming K. Tan, James R. Friend, and Leslie Yeo reported in the July 10 Physical Review Letters a way to induce a fluid jet to burst from an isolated droplet. The method uses surface acoustic waves (SAWs) to excite the fluid. The amplitude of the SAWs are just a few nanometers and the frequency is 30 megahertz, creating the surface acceleration seen here and leading to eruptions that sent droplets 1 to 2 centimeters in the air.

This year's combined 13th International Conference on Surface and Colloid Science of the International Association of Colloid and Interface Scientists, and the 83rd Colloid and Surface Science Symposium was held at Columbia University in New York City. Now that I've gotten the giant name of this conference out of the way, I'd like to talk about some highlights.

This year's even drew over 1100 attendees—a good turnout in most of the attendees' opinions. Because Biomicrofluidics was sponsoring the "Electrokinetics & Microfluidics" sessions, here are a couple of highlights from that session:

Monday morning, Howard A. Stone began the session to a crowded room with his lecture on "Multiphase Flows in Confined Systems." Dr. Stone explored the idea of using microfluidic approaches in multiphase hydrodynamics in confined systems and cellular-scale hydrodynamics.

Other highlights from the day included a lecture on "Droplet Breakup in Flow-Focusing Geometries," by Carnegie Mellon's Shelley Anna—who was also the co-organizer of that morning's session. The other organizer—Leslie Yeo, Monash University and editor of Biomicrofluidics—spoke next about "Microfluidic Interfacial Destabilization and Atomization," in which he described a "10 nanometer earthquake wave" with an acceleration at the surface reaching 10⁷ g's. He spoke briefly about some of the future applications for the research, including drug delivery and encapsulation, chip-based spectrometry, and "soft" molecular printing.

Tuesday afternoon's session started off with the keynote lecture from Hseuh-Chia Chang, from Notre Dame and editor of Biomicrofluidics. Dr. Chang, entitled "AC Polarization of Nanocolloids and Their Impedance Signatures in Strong Electrolytes." Dr. Chang described a method for open-flow nanocolloid assays that had several advantages to traditional methods: fast (less than 1 minute), label-free, sensitive (down to picoMolar concentrations) to hybridization, selective (down to 3 base pairs), and portable.

The real highlight for the journal came on Tuesday evening, when several good friends of the journal gathered to discuss their own research and whatever else popped up over a glass of wine.

BMF dinner attendees (left to right): Zhengdong Cheng, Texas A&M University; Sumit Gangwal, North Carolina State University; Hseuh-Chia Chang, Notre Dame; Ehud Yariv, Technion-Israel Institute of Technology; Kevin Dorfman, University of Minnesota; Peng He, Texas A&M University; Ahmet Can Sabuncu, Old Dominion University; Leslie Yeo, Monash University; Guiren Wang, University of South Carolina;