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."

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;

There have been several notable events here at Biomicrofluidics in the past few months.

First up, congratulations are in order for Leslie Yeo, our newest editor. Dr. Yeo is at Monash University in Victoria, Australia, and he brings with him a lot of enthusiasm and great ideas for moving BMF forward. Take a look at Dr. Yeo's editorial for more info.

Speaking of new editorial members, the journal is also welcoming James Friend as an Associate Editor (both Drs. Friend and Yeo are part of the Micro/NanoPhysics Research Laboratory). Dr. Friend's appointment is especially newsworthy because he is helping the journal with its newest topical section: "Fabrication and Laboratory Methods." It is hoped that this section will provide a strong reference point for researchers interested in developing lab-on-a-chip or related technologies.

Another piece of good news: the first two issues of Volume 3 has published a great quantity of high quality articles from the 2009 Conference on Advances In Microfluidics and Nanofluidics, which was held at the Hong Kong University of Science & Technology last January. And in case it slipped your mind you can scroll down—or click here—to listen to and read several of the posters presented at that meeting. Thanks to the efforts of BMF's editors—Hsueh-Chia Chang and Leslie Yeo—Biomicrofluidics is publishing more high quality papers than ever before. Just try to stop yourself from reading "Electrowetting on a lotus leaf" or "Rapid on-chip genetic detection microfluidic platform for real world applications."

Finally, there have been a few changes to the website. There is now a gallery of all videos contained in published articles since the journal's inception. It may also interest those with a desire for updates that don't exceed 140 characters that AIP Publishing is now on Twitter. With each tweet, BMF has seen a notable increase in traffic.

Once again proving that the journal's content is amazing.

The prognosis, diagnosis, monitoring, or therapy of many diseases—melanoma, breast cancer, HIV detection, liver diseases—relies on the results of an ELISA (Enzyme-Linked Immuno Sorbent Assay) test. Typically, ELISA is time consuming and tedious and involves mixing, incubation, and washing, all carried out on a 96-well microtiter plate.

To spice up that musty old procedure, Hongyan He and his colleagues at The Ohio State University have built an integrated microfluidic device on a compact disk (CD), which automatically performs some of the more tedious tasks of ELISA. Each step of the ELISA procedure corresponds to a subtle yet precise change in the rotation speed of the CD, so that the centrifugal force of the fluid through the microfluidic channels is carefully controlled. Combined with microfluidic capillary forces, the flow sequence is accurately controlled for the different solutions involved in the ELISA process. Dr. He's paper—just published in the current issue of Biomicrofluidics¹—focuses on a microfluidic biochip that is used to detect a cytokine IFN-γ, and theoretically the device can be used for additional immunoassay applications.

Dr. He and his team have been using the CD technology as a basis for other applications for several years now, but the new CD-based ELISA design was just published online in Biomicrofluidics¹, and builds off of several years of CD-based microfluidic research by Dr. He's and Dr. James Lee's team at OSU.²

¹He, H., Yuan, Y., Wang, W., Chiou, N., Epstein, A., & Lee, L. (2009). Design and testing of a microfluidic biochip for cytokine enzyme-linked immunosorbent assay Biomicrofluidics, 3 (2) DOI: 10.1063/1.3116665

²Lai, S., Wang, S., Luo, J., Lee, L.J., Yang, S.-T., and, Madou, M.J. (2004). Design of a Compact Disk-like Microfluidic Platform for Enzyme-Linked Immunosorbent Assay Analytical Chemistry 76 (7), 1832-1837 DOI: 10.1021/ac0348322

Biomicrofluidics was lucky enough to be able to attend the first Advances in Microfluidics and Nanofluidics Conference at Hong Kong University, January 5-7, 2009.

Below are 15 posters that were part of the poster sessions, 5 of which include audio interviews with the poster's author.

(click image for full size)

"Instability and Thermal Behavior of Droplet in PDMS Membrane Electrowetting Studied by High Speed Camera and Thermal Imager"
Jiang-Tao Feng, Zi-Qian Wang, Ya-Pu Zhao
State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China

download the audio interview (mp3)

(click image for full size)

"Hydro-electronic Voltage Generation based on Water-Filled SWCNT"

Quanzi Yuan, Ya-Pu Zhao

State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China

download the audio interview (mp3)

"Shearing of Mesoscopic Liquids in a Narrow Gap"
Chan Chia-Ling
National Central University, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China

download the audio interview (mp3)

Presented in Mandarin: "Shearing of Mesoscopic Liquids in a Narrow Gap"
Chan Chia-Ling
National Central University, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China

download the audio interview (mp3)

(click image for full size)

"The One Dimensional Dynamics and Transport of DNA Molecules in a Quasi-Two-Dimensional Nanoslit"
Po-Keng Lin¹, Keng-hui Lin^1,2, Chi-Cheng Fu³, K-C Lee³, Pei-Kuen Wei², Woei-Wu Pai⁴, Pei-Hsi Tsao⁵, and Y.-L. Chen^1,2
1Institute of Physics, ²Research Center for Applied Sciences, and ³Institute of Atomic and Molecular Science, Academia Sinica, Taipei, Taiwan, People's Republic of China
⁴Center for Condensed Matter Sciences and ⁵Department of Physics, National Taiwan University Taipei, Taiwan, People's Republic of China

download the audio interview (mp3)

(click image for full size)

"Simulate Micro-Channel Flows with Super-Hydrophobic Surfaces Using an Atomistic-Continuum Hybrid Method"
Qiang Li and Guo-Wei He
Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China

download the audio interview (mp3)

Dielectrophoresis (DEP) is a phenomenon in which a force is exerted on a dielectric particle when it is subjected to a non-uniform electric field. DEP can be used to manipulate, transport, separate and sort different types of particles. There are a lot of opportunities to exploit this method in the field of bio-related microfluidics, since biological cells already have dielectric properties.

The growing interest in DEP was evident at the recent 2009 Conference on Advances in Microfluidics and Nanofluidics in Hong Kong (Jan. 5-7). In fact, the editor of Biomicrofluidics was ecstatic, commenting, "We are in DEP heaven!"

A noteworthy work by Daniel Ou-Yang's group at the Physics department of Lehigh measures the DEP mobility of nanocolloids with an optical tweezers technique, as seen in his invited article in BMF¹. Note that he measures not just the cross-over but the mobility as a function of frequency. You will note in his last two figures the anomalous scalings that defy the Clausius-Mossotti theory.

Other notables right now include Elaine Zhu and Jiang Zhao who are working on molecular DEP—AC induced dipolar effects on polyelectrolyte conformation and hybridization with fluorescence correlation spectroscopy (FCS) techniques. Elaine just published a paper with Peter Hoffmann and Prasad Sarangapani in Langmuir² on binary nanocolloid phase separation by DEP and with Victoria Froude in an upcoming J. Phys. Chem. paper on DEP of liposomes. There are beautiful images and a very good characterization of surface conductance effect in Victoria's paper!

Another notable DEP paper is one on how DNA hybridization of nanocolloids changes their cross-over, by Zachary Gagnon and Senapati³, and was fast-tracked and featured on the cover of the December issue of Electrophoresis.

¹Ming-Tzo Wei, Joseph Junio, H. Daniel Ou-Yang (2009). Direct measurements of the frequency-dependent dielectrophoresis force Biomicrofluidics, 3 (1), DOI: 10.1063/1.3058569

²Peter D. Hoffman, Prasad S. Sarangapani, Yingxi Zhu (2009). Dielectrophoresis and AC-Induced Assembly in Binary Colloidal Suspensions Langmuir, 24 (21), DOI: 10.1021/la8013392

³Zachary Gagnon, Satyajyoti Senapati, Jason Gordon, Hsueh-Chia Chang. Dielectrophoretic detection and quantification of hybridized DNA molecules on nano-genetic particles Electrophoresis, 29 (24), DOI: 10.1002/elps.200800528

If you've been anywhere near any kind of research publication in the past couple of years, you've no doubt run across at least one open access (OA) journal. Biomicrofluidics is an open access journal; at least I think it is. The confusion lies in the definition. From Wikipedia:

Open access is free, immediate, permanent, full-text, online access, for any user, web-wide, to digital scientific and scholarly material, primarily research articles published in peer-reviewed journals. OA means that any individual user, anywhere, who has access to the Internet, may link, read, download, store, print-off, use, and data-mine the digital content of that article. An OA article usually has limited copyright and licensing restrictions.

My concerns lie with the usage of the terms "permanent" and "limited copyright and licensing restrictions." It's tough for a publisher to look at this definition and see the potential for profit. Luckily, Biomicrofluidics is published by a not-for-profit—the American Institute of Physics. But it still takes time and money to put the journal together, and I'm not sure how a journal can get published if no one is "paying the bills," so to speak. Plus, physicists get antsy when you say something is "permanent," what with the imminent heat death of the universe and all. And while it may make good business sense to give away your product, it's harder to make the case that it's good business sense to give away your copyright and licensing of that product. Questions abound. Time and experimentation are needed to sort things out. As technology lurches forward, so should publishers.

Keeping all of this in mind, BMF is dropping author charges. The articles will still be freely available, and so AIP is busily exploring other paths for financing the journal. We can move forward with this experiment because, like the Public Library of Science, we've got little to lose and a lot to gain if we strike upon a successful model.

It's apparent to me that BMF provides needed and interesting research to a growing and interested community. (It may be appropriate here to again mention that the journal is hosting its first conference—Advances in Microfluidics & Nanofluidics—in Hong Kong, January 5-7, 2009, and the journal will be publishing invited reviews and papers from that meeting.)

Essentially, the journal is looking for a proper way to adapt to a changing economy. Do we give away everything? How can we increase the positive image of AIP in the scientific community? Does it work best as a so-called sharing economy? The best strategy may be to just stay agile and open to new ideas... all the while keeping our common sense intact.

Biomicrofluidics is sponsoring the 2009 Conference on Advances in Microfluidics and Nanofluidics in Hong Kong on January 5-7, 2009.

The first annual conference is an international and interdisciplinary conference with special focus on research activities in the Pacific Rim. It will be held at the beautiful campus of HKUST by the bay.

The objective of the conference is to provide a forum for researchers in this interdisciplinary subject area to disseminate recent theoretical/methodological developments and technological applications as well as a platform for fostering closer networks and collaborative ties. It is anticipated that this inaugural conference will be the first of a series or regular conferences along this theme.

The organizing committee is therefore inviting submissions of abstracts falling within the broad scope of micro/nanofluidic science and engineering. Authors of selected abstracts will be invited to submit a full contribution of their work for review and publication in one of two special issues of Biomicrofluidics.

The last decade has seen exponential growths in microfluidic and nanofluidic research in Asia, driven by robust funding with expectation that it will spur a large Asian biotechnology industry.

The intent of this conference is to bring researchers of different disciplines and nationalities together, which is necessary for the Asian community to advance to the next level. It is also an opportunity to expose Asian research achievements to leaders in the field and for Asian students to interact with them. Biomicrofluidics, an American Institute of Physics journal, will be the affiliated journal to facilitate the missions of this conference, and subsequent follow-up conferences.

The invited speakers are leading microfluidics and nanofluidics researchers in Physics, Chemistry and the various engineering disciplines. It is the hope of the organization committee that this will be the first of a regular Pacific Rim conference on the topics.

We cordialy invite you to join the conference and look forward to see you in Hong Kong from January 5th to 7th, 2009.

The charm of the open access model has been discussed quite a bit recently. Harvard just decided to make all of their own research papers free—anything associated with their own researchers or students can be downloaded at no charge. There are other models for open access worth mentioning. Of course, how could I not mention AIP's own Biomicrofluidics (disclaimer: I am an AIP employee).

There is the Public Library of Science, run rather successfully by former bio researchers. In addition, any research funded by the National Institutes of Health will (supposedly) be made free on their PubMed site. An older model of open-access that was developed for physicists is arXiv.org. I like to think that physicists are always a little bit ahead of the curve (disclaimer: I have a physics degree). It should be noted that some stuff on arXiv.org is pre-publication, meaning that it hasn't been peer-reviewed and shouldn't be considered the final version of the researcher's vision, but there are a lot of published papers. As a sidenote, the Institute of Physics has developed a supposedly friendlier interface for arXiv.org, it's called eprintweb.org, and allows you to create online bookmarks for arXiv.org articles that you like, along with a few other features.

Anyway, it's a nice thought to come across articles on arXiv that someone might not be able to read otherwise. A couple days ago, I found a neat article on droplet traffic in microfluidic networks. The article was published in Physics Review Letters on January 28, 2008, but was submitted to arXiv.org on December 20, 2007.

Once we get past all of the gobbledygook (pardon the technical language), we can actually talk about the content of the article. The authors—Drs. Schindler and Ajdari from the Laboratoire de Physico-Chimie Théorique in Paris—have built what they call "microfluidic dual networks" which they use to analyze the traffic of microfluidic droplets. The researchers hope to stimulate further experiments with passive microfluidics, and present a "simple yet efficient fast numerical tool" for this analysis.

Even though the research is now published in a highly-respected journal, they're practically giving their idea away on arXiv.org. The extent to which this one article can be freely obtained presents researchers with important options for accessing research, even if it's not published yet. The biggest challenge, though, probably belongs to publishers. Some of whom probably see the situation as a real obstacle to overcome. Others, though, probably hope to be able to employ these open-access ideas with some success. These kind of questions are probably outside the scope of Biomicrofludics, although BMF's publishing model may have an influence on what's to come. It's impossible to predict how the public and publishers are going to respond to all of this gobbledygook.

Biomicrofluidics means more than just biological stuff flowing at a micron-scale. The focus of this blog has probably been a bit too narrow and it could stand to expand slightly. A strict discussion of things that only fall under the umbrella of "bio + micro + fluidics" is too restricting. For example, it's more interesting to be able to consider the whole array of diagnostic applications that arise from applied physics and biology research, even if they're not taking a lab-on-a-chip or microfluidic approach.

To start things off, these crafty researchers at the Wellman Center for Photomedicine at Massachusetts General Hospital and Harvard Medical School are using flow cytometry to detect cancerous cells flowing through blood. With the new method, which researchers used to detect multiple myeloma in mice, doctors could one day skip the messy blood samples and just shoot some light in your eye to find cancer.

Flow cytometry is not discussed very much in the public sphere of science and I think that's a shame. Bridging optics with biology and medicine, flow cytometry has been in use since the middle part of the 20^th century, although finding a reliable account of the history is tough.

Cytometry is a field of study borne from scientists interested in research across disciplines of science. The engineer and inventor Wallace Coulter helped devise complicated measuring instruments and procedures for cytometry. Along the way, he convinced biologists (specifically hematologists) to use the tools to study blood and cancer in greater detail. The field blossomed and both biology and optics quickly expanded. From studies like the one above, it's easy to imagine that there is great potential for cytometry to help unravel biological complexity.

In the current issue of Biomicrofluidics, an article about building tiny structures out of nanometer–sized droplets of biomaterials appears. The movie version of the article might sound vaguely like this: a nanodroplet voyages from a nozzle to a substrate—its structure and path are guided along the way by a benevolent electric field. Finally, the droplet is laid down, becoming part of a giant micro-structure that was conceived in the mind of some great unseen force. It's all very dramatic.

Several descriptions of scientific concepts have, in the past, been presented with the help of movies, television shows, or other works of fiction. I am reminded of a lecture I once attended as an undergraduate entitled, "The Economics of The Simpsons." The lecture was so popular that it was repeated every semester, and I happened to go more than once. Not surprisingly, the lecture was consistently filled to capacity with more Simpsons fans than economics enthusiasts. Despite my lack of interest in economics, I did learn a few things about supply and demand.

It's helpful to students new to a concept—as I am to biomicrofluidics—to be presented with a common concept that helps describe how the concept works, even if that concept is something as alien to microfluidics as a cartoon family.

These sorts of interpretations aren't just there for the satisfaction of rabid fans, but are clever learning tools (created by rabid fans) to engage otherwise apathetic students. They take advantage of the plot twists and unexpected actions of fictional characters to help explain complex situations, for example, how a saturated market responds to a price increase, as predicted by the deeds of J. Montgomery Burns.

Professors are getting students excited about economics with the help of a prime-time cartoon. What fictional comparisons can be made to help students understand and explain the complex behavior of fluids on a microscopic scale? What sort of wacky–and–popular–culture–filled account can we use to describe the actions of the nanodroplets from the article above?

It seems that in the strange world of biomicrofluidics, comparisons become more relevant and interesting if you consider an obtuse fictional work. Samuel Becket claimed:

To find a form that accommodates the mess...

I'd like to think that the absurdist plays of Beckett may have more to do with biomicrofluidics than American Idol, but I could be wrong. After all, in one of the oldest biological fluid flow systems of mammals, one sperm struggles against millions of other competitors to achieve conception. Replace "sperm" with "singer," and "conception" with "fame and fortune," and students might begin to understand the difficult task the sperm is given.

Let me know when someone comes up with a good microfluidics pop culture interpretation. Who knows, maybe it'll have something to do with The Terminator.

Welcome to the blog page of Biomicrofluidics. We would like to use this website to foster closer networking among micro-fluidic researchers and users. Informal exchange of opinions, announcement of upcoming conferences/work shops, reactions to a recent publication, requests for information, collaborators and technologies, advertisement for post-doc/internship positions, new funding opportunities etc would all be appropriate activities.