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Microfluidics: Miniature Chemistry Labs 57

Posted by michael from the make-jello-using-one-third-vodka dept.
enkidu writes: "The NYTimes has a story (free reg, yaba yaba) about the rapidly emerging field of microfluidics and describes some of the methods used in making micro-valves, pumps and other components. In the future, you won't need to send your blood/urine sample to a lab, your doctor will put in his "lab-in-a-box" and hand you a printout before your leave."
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Microfluidics: Miniature Chemistry Labs More

Microfluidics: Miniature Chemistry Labs

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  • But the insurance companies won't allow it... (Score:5, Insightful)

    by printman ( 54032 ) on Tuesday January 01, 2002 @11:06AM (#2770228) Homepage
    A lot of doctors ran out an bought their own mini-lab test equipment when it first came out. Not only did it cost them less than sending it out to be processed, but they got results faster.

    *However*, the insurance companies have put a stop to that. My doctor has to send out my bloodwork and wait almost a week to check my cholesterol, instead of using his own equipment and getting me an answer within an hour or so... In the process, I end up paying *more* to my insurance company and they get to negotiate mass-quantity lab work with the lowest bidder.

    • Re:But the insurance companies won't allow it... (Score:1, Funny)

      by Anonymous Coward
      How dare you criticize the free market, implying that they are somehow trying to gouge you. The Free Market (tm) will not tollerate such heresy. The insurance companies are simply trying to make a profit which benefits all humanity. You are hinting that these individual doctors somehow know better than large, holy corporations.
    • Just tell the insurance companies to get outta town. Really, if enough people, at once, stood up against their bull crap, they would have to cave.

    • Re:But the insurance companies won't allow it... (Score:5, Insightful)

      by cplmd ( 92878 ) on Tuesday January 01, 2002 @01:24PM (#2770472) Homepage
      As a physician, it's not just the insurance companies to blame - if fact not them at all. It's how our wonderful federal government responds to a few of my unscrupulous colleagues.
      Specifically, Rep. Pete Stark in his three versions of Stark Acts have reduced how much a physician can do for you. Pharmacies, labs and x-ray cannot be owned or used by the doctor if he does have an interest in the facility. I don't have a problem with that given the kickbacks a few doctors got in the past.
      However, as always with federal regulation of individual/local problems, it has extended into areas that no longer make sense and actually make it worse for you as a patient. This office-lab in a box being a case in point.
      While on my soap box, it would be nice if the federal government limited and regulated the legal, esp. civil court system as much as the medical one. Given spiraling malpractice insurance costs and the actual closure of some rural hospitals due to legal liability and insurance costs, maybe as the federal government did with medicare/medicad in setting limits on what reimbursement would be to doctors and hospitals for a given disease, lawyers in this country should be limited in what they are paid for say a divorce, murder defense or malpractice / workman's comp. case.
  • *sigh* Now it will be easier for employers/cops/whoever to scan people for evil drugs.

  • sorry, your blood sample was declined (Score:1, Insightful)

    by Anonymous Coward
    blood testing in a handheld reminds me of Gattaca.
    shudder.
    • I wonder if the "handheld devices able to detect anthrax in a room" could be adapted to work like today's face-recognition camera systems, where a detector scans a room passively for traces of DNA that are known to be from a criminal, whose DNA is in a database. Possible?
  • I wonder if this could be a useful thing in cooling circuitry such as CPU's. Build a cooling system into the CPU itself. perhaps an ultra-efficient heatsink which pumps liquids through tiny channels in thin fins - anything to help heat dissipation.

    ...or combine the medical side of it and pump your own body fluids through your cpu - ooah. scary.

    • A man spontaneously combusted today while trying to cool his new Athalon25000 with his own blood.
    • Cooling a chip is great but,I wonder how many lives this will save by having portable labs available everywhere in the worlds.

    • Unlikely. The flow that you can get through a very small channel is absolutely tiny. Over a large range, the backpressure goes up as one over the square of cross-sectional area, so a large array of small channels can allow substantially less flow at a given pressure drop than a single large channel of the same area. Using channels the size that you can make using this kind of process you simply aren't going to be able to get enough flow to make much difference.

      (BTW, I do have some idea of what I'm talking about; I've worked in microfluidics and still work in a closely related field.)

    • "...or combine the medical side of it and pump your own body fluids through your cpu - ooah. scary."

      'OH NO! He's crashing!.. Code Blue!'

      takes on brand new meanings!

  • Won't this hurt accuracy? (Score:3, Interesting)

    by diamond0 ( 456988 ) on Tuesday January 01, 2002 @11:55AM (#2770297)
    Due to the small samples such a machine would process, the error margin is bound to be huge. This is elementary statistics, folks; if you want milligrams per deciliter of blood cholesterol, or any sort of statistic about a body fluid, the more of a sample available to the process, the more accurate it's going to be. Compare this to Nielsen surveying only twenty people, or Gallup only a hundred.

    I've been wrong before; maybe a biochemist could chime in and let us know how much blood or urine constitutes a true statistical sample?

    • Re:Won't this hurt accuracy? (Score:5, Informative)

      by baz00f ( 520771 ) on Tuesday January 01, 2002 @01:08PM (#2770430)
      Speaking as a pedigreed biochemist, you are correct in the extreme of vanishingly small samples. But these devices are still working with enough volume such that an analyte of interest at a substantial concentration (glucose, cholesterol, etc.) is effectively present at the same concentration at nearly all sample volumes.

      Things DO fall apart (as you intuit) when the concentration of the analyte gets vanishingly small. We see this routinely when we try to quanitate DNA using PCR (Polymerase Chain Reaction) methods. PCR is sensitive enough that we can detect ONE copy of a DNA molecule in a volume of sample. So if you have say, one copy in 1ml of volume, and you sample .1 ml and do your PCR, your test would come up negative upon repeats (on average) 9 out of 10 times. With small numbers of copies you can use Poisson statistics to calculate your hit rate. With higher concentrations your Poisson distribution collapses to a gaussian that gets narrower and narrower, which is the regime that most normal wet analytical techniques work. For example, fasting blood glucose is about 100 mg/dl, which is about 5 mM. Assuming your device can work with 1 nanoliter sample size (this is about 100x smaller than a volume about the size of the proverbial period at the end of a sentence) you would have 3x10^12 molecules of glucose in it. Assuming your technique is sensitive enough to register the presence of this "small" number of molecules, you are still far away from seeing sampling errors on repeats of the same sample due to random fluctuations of the number of molecules (the "concentration") in any given sample.

      Paul Yager at U. Washington (Seattle) has a good introduction to microfluidics:

      Microfluidics Tutorial and Prognostication [washington.edu]
    • I posed this question to a friend who does work with testing body fluids in a lab, and her response was that since there -are- minimum sample sizes, one small test on a tiny scale could certainly have errors on a different scale to current tests.

      My guess is by looking at the relative complexity (in number of components) of the pumps/mixers/detectors compared with a several hundred million transistor CPU, that an array of perhaps millions of separate testers could be easily built, one which would run millions of simultaneous tests.

      Only comparing those results with known working ones would show if the results were comparable - certainly one more type of testing can't hurt, and if it only proves extra accuracy in a few cases, they may be ones with a great impact.

    • Analytical volumes are in the mL range to ease handling and to minimize cumulative error. In most modern techniques, microlitres are taken up by the test instruments; the actual amount of 'stuff' that is actually analysed is minute. Good test design and bench technique give good results.

      It's not the sample volume I'd be questioning, but calibration, standarization, and QA procedures. These are the root of inaccurate (and imprecise) test results.

      --
    • I really wish people wouldn't assume that they can spot an elementary error in published science upon five minutes thought. You'll invaribaly find that they have already thought of and dealt with your show-stopper.

      It's widely believed that climate change models "don't account for water vapor", too. It amazes me that people can convince themselves that scientists can work on a project for years and still miss things that are obvious to amateurs.

      There's plenty wrong with science these days, but still it's just about impossible to be transparently wrong in the hard sciences. Subtly wrong, sure, nut not obviously wrong.

      This posting was basically a nice question, but something about the way it was asked bothers me a lot.

      ----
    • This is absolutely truth.
      For the best results doctors should take no less than five liters of the patient's blood for testing.

  • Incredible Shrinking Labs (Score:1, Informative)

    by Anonymous Coward
    http://www.ornl.gov/ORNLReview/meas_tech/shrink.ht m
    A small blurb on Dr ramseys work.

    http://www.chipcenter.com/columns/bmcginty/col01 2. html
    Another article on fludic chips.[check the links at the bottom]
  • next time my doctor needs to take a blood sample maybe they'll be able to take a small enough quantity of blood that I won't faint. It's not a problem if they only need to run one test, but when they need four or five tests this will be a major improvement.
    • The amount of blood taken for normal analysis isn't enough to give you direct physiological symptoms. The psychosomatic issues are generally the cause of dizzyness and fainting ( your brain, quite rightly, doesn't want you to have holes in vessels, or to give up any blood. Dropping your blood pressure to reduce blood loss is an evolutionary good thing).
      A fingerprick will give enough volume for microsampling, but the number of fainters will diminish, not disappear. I volunteer at Red Cross blood drives, and I've seen a high-school football player faint from the fingerprick. I've also seen non-donors have issues (bring a friend for "moral support", watch THEM collapse!)
      Anyone who tries to give blood is a hero, and those who are uncomfortable with the proccess, but donate anyway are bigger heros...
    • I'm wondering if this also means that blood samples can be taken via different routes? No need for blood from the vein if a finger-sitck will do.
  • I'm supposed to be researching microfluidics before I get back to meet my advisor after vacation. I wonder how one would reference Slashdot in a footnote... ;-)
  • It's interesting to see Dr. Stephen R. Quake's [caltech.edu] name cropping up again in one of these stories. His group [caltech.edu] is working on some amazing stuff, mostly working with one molecule at a time—although, admittedly, they're moby molecules.

    No, I wasn't going to comment on his framerate.
  • I find the use of a lab for routine blood work lucridous. It takes a half hour to run a routine spectrum of blood work manually.
    My own physician finds it lucridous that the HMO he is affiliated with will not allow him to draw his own blood nor do his own routine tests. Hell the lab charges $145.00 for a CBC that he could have done in his office for $35.00

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As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality. -- Albert Einstein

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