Cornell NEMS device Weighs a Single DNA Molecule

karvind writes "Cornell researchers have refined their NEMS device to detect a single DNA molecule and can even count the number of DNA molecules attached to a single receptor by noting the difference in mass. The researchers used the Cornell Nanoscale Facility to create arrays of tiny cantilever oscillators 3 to 5 microns long and 90 nanometers thick on silicon chips. The principle underlying the mass-detection devices is that the frequency at which a solid object vibrates varies with its mass. In the reported experiments, the change in mass of 1 attogram was enough to shift the frequency of vibration by 50 Hz or more, depending on the size of the oscillator. This allowed the researchers not only to detect the binding of DNA molecules, but also to count the number of molecules attached to a single receptor by the total frequency shift. Results are reported in the latest issue of Nano Letters. " (Here's an earlier Slashdot story about weighing molecules by Caltech Researchers.)

Comments

Re:Question

[karvind]

Like any scientific endeavor, the journey is as important as the final goal. Many new techniques and ideas come along to put the whole picture together. So even if a practical realization of this technique may not be feasible, the learning (from the experiments and theory) will be useful.

PhysOrg (Article on Caltech's work on weighing molecules) has comment about the possible applications:

The new method might ultimately permit the creation of microchips, each possessing arrays of miniature mass spectrometers, which are devices for identifying molecules based on their weight. Today, high-throughput proteomics searches are often done at facilities possessing arrays of conventional mass spectrometers that fill an entire laboratory and can cost upwards of a million dollars each, Roukes adds. By contrast, future nanodevice-based systems should cost a small fraction of today's technology, and an entire massively-parallel nanodevice system will probably ultimately fit on a desktop.

uses of weighing molecules

[Anonymous Coward]

This same technique has been used with AFM (Atomic force microscopy) for a few years. The idea for a sensor is that you introduce a sample and you can tell if your target analyte is present. Specificity is achieved by using an antibody or other type of probe on the oscillator tip... These are a very common type of sensor, but usually a bunch of molecules are required to get a measurable frequency shift. Different ways of measuring frequency, including laser deflection, piezoresistors, and other assorted optical techniques, can be used. Nano-and even micro cantilever technology is cool because it facilitates label and reagent free sensors, with the holy grail of biosensors being a real time, label free, robust, multianalyte sensor with great sensitivity and selectivity over a huge dynamic range. O yeah... and cheaper and faster than Mass Spec. This type of sensor could theoretically do all of these things.

-Adam