Creative uses of LEDs (papers)
Bryan Bishop
I used to think that playing around with blinking LEDs all the time
was boring :-). It's more than safe to say that I was wrong. There may
be a few really awesome papers that I am forgetting to mention (like
micromolding of LEDs in capillaries, or ink-jet printable polymer
organic LEDs (OLEDs)), but overall I think this is a neat
representative sample for anyone wanting to read up on interesting
uses of LEDs.
A scalable method for multiplex LED-controlled synthesis of DNA in capillaries
http://heybryan.org/books/papers/A%20scalable%20method%20for%20multiplex%20LED-controlled%20synthesis%20of%20DNA%20in%20capillaries.pdf
(240 nt/day @ $277 (for reagents), in 2006)
In that last paper, they were using a foam matrix to make it dark
enough around the LEDs so that the majority of the light went into the
capillary.
Violet diode-assisted photoporation and transfection of cells (gene transfer)
http://heybryan.org/books/papers/Violet%20diode-assisted%20photoporation%20and%20transfection%20of%20cells.pdf
Whole blood pumped by laser driven micropump
http://heybryan.org/books/papers/Whole%20Blood%20Pumped%20by%20Laser%20Driven%20Micropump.pdf
Diode-laser generated ultrasound for human blood cell lysis
http://heybryan.org/books/papers/Diode%20laser%20generated%20ultrasound%20for%20human%20blood%20cell%20lysis.pdf
Piezoelectric-generated ultrasound (Controlled deposition of picoliter
amounts of fluid using an ultrasonically driven micropipette)
http://heybryan.org/books/papers/Controlled%20deposition%20of%20picoliter%20amounts%20of%20fluid%20using%20an%20ultrasonically%20driven%20micropipette.pdf
^ but no reason to not think about that method with diode-laser
generated ultrasound (like the previous reference)
Maskless photolithography using UV LEDS
http://heybryan.org/books/papers/microfluidics/Maskless%20photolithography%20using%20UV%20LEDs.pdf
Not related to LEDs, but two items still sufficiently cool that I
recently came across-
Single cell transfection using plasmid decorated AFM probes
http://heybryan.org/books/papers/Single%20cell%20transfection%20using%20plasmid%20decorated%20AFM%20probes%20-%2030%20percent%20efficiency.pdf
(30% efficiency)
Bacterial cell curvature through mechanical control of cell growth
http://heybryan.org/books/papers/Bacterial%20cell%20curvature%20through%20mechanical%20control%20of%20cell%20growth.pdf
JonathanCline
LED's are also used as photodetectors, in 2 ways.
1. Emit light from color LED, detect with photodiode or light
dependent resistor. (Many papers here) This is how several DIY
spectrophotometers operate.
2. Emit light from "white" (flat spectrum) LED, detect with color LED
which is driven in "sensing" mode. (A papers here)
Nanodrop uses colored LEDs as #1 above, for example, in a few of it's
measurements.
With connections to an LED foundary, it wouldn't be a big deal to
create a fully solid-state/all-digital spectrophotometer or
fluorometer with 10-nm resolution, by varying color in LED lenses for
fine-tuned wavelength overlap, for #2 above.
## Jonathan Cline
## jcl...@ieee.org
## Mobile: +1-805-617-0223
########################
Bryan Bishop
> Nanodrop uses colored LEDs as #1 above, for example, in a few of it's
> measurements.
I thought that nanodrops were using fiber optics?
Anyway, I was reading about atomic force microscopes (AFM) the other
day. I must have had them confused with scanning tunneling microscopes
(STM) because I didn't realize before how conceptually simple they
are: very sharp tip and a cantilever that bends due to force somewhat,
and then an LED and photodiode strip or megapixel camera to detect
changes in the bending of the cantilever due to small forces. So,
there's another neat use of LEDs-- atom-resolution microscopes, if you
can make a sharp-enough tip. These are used to image biological
samples in room temperature and in ambient air conditions, which makes
that single cell transfection with plasmid-coated AFM tip all the more
interesting (in the other post).