This page is a work-in-progress for how to build a "light cannon" for use in bacterial photography.
Please help make it better!
As part of their research and the 2004 Synthetic Biology and 2005 iGEM competitions, the good folks from UT and UCSF made the world's first camera that uses bacteria to take photographs. Let's call such photographs coliroids for now. Their early work was so cool that they published it as a paper in Nature. In order to take your own coliroids you need two things. First, the genetically engineered bacteria that respond to light. Second, a camera that can expose your bacteria to light. For unknown reasons, let's call the camera a Light Cannon. You can learn about how to make/get the bacteria (TBA). This page is about how to build Light Cannons!
In case you want to see if all the trouble will be worth it, check out these here coliroids. Build your own system and then add your pictures here!
Overview of Light Cannon
The following description is for building a light cannon as the one seen in the figure. However, light cannons exist in many forms and you should feel free to tweak, change, or abandon the following protocol.
- 100W mercury vapor lamp -or- 150W Sodium "grow" lamp
- Red bandpass filter (if using mercury vapor lamp). We get ours from Edmunds Optics. Description: FILTER INT 632NM 50.8MM SQ. Catalog number: NT43-185. http://www.edmundoptics.com/onlinecatalog/DisplayProduct.cfm?productid=1903
- 35mm slide containing desired image (can be custom made at by a photo imaging company such as Holland Photo)
- Height adjustable platform for 35mm slide
- Focusing lens (optional).
- 37C incubator with black walls, adjustable shelves, and a thermometer hole on top through which the image can be shone.
Instructions for Buildling
- Start by turning on Scott H. Biram's Lo-Fi Mojo at a slightly louder than reasonable volume.
- Continue by wallpapering the inside of a standard floor incubator with non glossy black construction paper. We also black out the internal glass door of our incubator (seen not blacked out in the figure above).
- Place a sheet of white paper on a rack ~1 foot from the top of the incubator directly below the thermometer hole.
- Clear the thermometer hole atop your incubator such that light can pass through unobstructed.
- Immobilize the lens in or atop the thermometer hole. This step is optional, but the use of a lens will obviously give you shaper images.
- Black out all remaining light-penetrable areas around the thermometer hole and lens, we use aluminum foil.
- Build some sort of device for holding the 35mm slide, such that the image on the slide is not obstructed. We find that a field goal post shaped flat thin piece of metal upon which the slide can rest works well.
- Connect the slide holding apparatus to some sort of height adjustable device. A simple method is to clamp it down with a ring stand. For greater control, we connect it to an actuator, which we hold in place with a ring stand. Set this system up such that the slide sits on the vertical axis which passes through the lens/thermometer hole. The height adjustability of the slide is critical as a focusing mechanism down the road.
- Similarly immobilize the bandpass filter ~3cm above the position of the slide (only if using a mercury vapor lamp). You can use the same ring stand for this.
- Build a simple apparatus (ours is made of book ends in case you haven't noticed) to hold the lamp above the bandpass filter. The light source on the lamp should end up being less than ~15cm from the bandpass filter (or slide in the case that you're using a sodium lamp).
- Turn on the lamp, adjust the x,y and z positioning of your 35mm slide such that a clear image appears in your incubator (like the Andy image in the figure above). If you need to adjust the focal length of your lens, do that at this point.
Engineering Escherichia coli to see light
Anselm Levskaya, Aaron A. Chevalier, Jeffrey J. Tabor, Zachary Booth Simpson, Laura A. Lavery, Matthew Levy, Eric A. Davidson, Alexander Scouras, Andrew D. Ellington, Edward M. Marcotte and Christopher A. Voigt
Nature 438, 441-442 (24 November 2005)
Scott H. Biram
Be sure to check out Scott H. Biram of Bloodshot Records. This page might not exist had it not been for Mr. Biram.
- End of Edited Content. Temporary Working Materials Follow
Anselm- The details on the filter are:
From Edmunds Optics description: FILTER INT 632NM 50.8MM SQ Catalog number: NT43-185 details on this website
> >Hey Jeff, > > > >could you tell me the details about the bandpass filter you use? > >HWFM and CWL or related. (or even just supplier and #) > >Just want to make sure I'll hit the same optimum window with some that > >I'm buying. > > > >Thanks alot! > > > >-Anselm
our thermometer hole is ~1.5 inches.
At 03:53 PM 12/15/2005, you wrote: One last annoying question. the hole in the top of the incubator, how big is it? I'm looking at a few different ones and can't decide if the standard thermometer port is large enough.
thanks for answering all these questions!
we've been using a 100W mercury vapor lamp, taken from a fluorescence microscope. with this light source we use a red bandpass filter (see the attached figure), that allows 660nm light to pass to the exclusion of far red light. we then place the image which is on a 35mm slide (the kind you would use for an old-style slide projector) below the filter, and focus the light through a double gauss lens. the whole apparatus sits outside of a 37C incubator, and the light image passes in.
one really nice feature that we have is an actuator to which 35mm slide is connected, which allows us to have pretty fine control over the focus.
we've also succesfully been using sodium "grow" lamps, which we don't filter usually.
as far as the agar preparation, it's still just 2-4% seaplaque agarose in LB+S-gal and Ferric Ammonium Citrate. We autoclave the media with everything in it before pouring, to get the solutes completely dissolved, then we keep it at 42 degrees, add the cells, mix and pour immediately.
we've actually thought about increasing signal to noise. one idea we had was to put a repressor of LacZ under the OmpF promoter. this will bring down total signal most likely but could also increase signal to noise. i'm sure there are lots of other good ways to do it as well...including mutating Cph8 and screening. good luck, let me know how it goes.
At 09:11 PM 11/2/2005, you wrote: Chris said that you guys have been using a smaller setup to develop your bacterial photos, could you tell me what kind of light sources and filters you've been using? I'd like to start taking some myself to see if I can improve the signal/noise ratio by modifying the construct. Also, if you've changed the agar preparation at all, I'd love to hear what's been optimized. All details are great as I'd like to just order the things needed.
By the by, I'll finally be starting some tests on a possible blue-light sensor soon.
thanks a lot! kick ass regarding the paper! -Anselm