Funky bioelectronics

I'd been meaning to look into this more ever since reading about it in the quarterly tech review in The Economist, back in Dec.

There are folks who are creating nanoscale structures of pores and
particles, combining them with extremely sensitive detection tools, and
creating new breeds of macromolecule detectors.

A hard drive for GMR
One of them uses the same tech as in hard drives, used to detect magnetic particles. They are called called Giant Magnetoresistive Sensors (a gnarly review for you hard-core geeks).

As Shan Wang from Stanford says,

Wicked.

And Wang has an example of how this can be used, in this case, in the detection of Human Papiloma Virus.

Pores and beads
The other methond is the sequencing of DNA by passing it through a nanopore. Because, like beads on a string, as DNA passes through a pore each base has a slightly different (and detectable) electrostatic effect and one can read out the sequence as the strand goes through the pore. The only person I found actually playing with this was Aleksei Aksimentiev from whom I took the image above.

Surface issues
When I was doing biochemistry, I used a ton of specialized equipment to measure enzymatic activity. But one that I never got a chance to use was a gizmo from Pharmacia that took advantage of a funky effect called "surface plasmon resonance." The only way I can describe it is an effect by which mass on one side of a surface affects the refraction of light on the other side of the surface (Wikipedia is not any clearer). In that way, you can have something binding on one side of a chip that is then detected spectroscopically on the other side of the chip, with great sensitivity and in real time. From that, you can calculate the on and off rates for molecules binding, which is what a lot of the biochemistry I did was about.

In any case, it's always interesting when hard-core physics meets biology. While I start getting glazed eyes when getting too close to physics, the best parts of my training were when physics and physical chemistry helped explain a phenomenon we were studying. I would say the strength of my training was the mix of physics, chemistry, and biology that made me see systems at many interacting levels, each contributing to the model and experiments.

And, as in most multi-disciplinary endeavors, these folks, above, mixing hard-core physics and biochemistry are also adding to a richness that either disciplines on their own could not.

Exciting.