Introduction: The Double Helix -a DNA Model With Lights

DNA models have been made from a lot of different things; candy, Styrofoam, KNEX, etc. I've even made a couple of models myself from beads, but surely there should be a model made from LEDs....

Step 1: What You Will Need:

Materials:

  • Base or stand -I used a dollar store jewelry box made of wood.
  • LEDs -5 different colours 20 total,8 white and 3 each of the other colours.
  • The appropriate resistors.
  • Power supply, with enough voltage to power the circuit (I used a 9v adapter).
  • Wires -white preferably
  • Electrical tape -white preferably
  • On/off switch.
  • Floral stem wire (18 gauge)
  • #6 plastic (polystyrene) -it is the clear plastic often used in takeout containers.
  • Clear vinyl tubing ~2 feet long, 7/16 inch diameter.

Tools:

  • Soldering iron, solder etc.
  • Scissors, and X-acto knife.
  • Drill, Dremel
  • Sandpaper
  • Glue (Weldbond)
  • Toaster oven, oven mitt and parchment paper

Step 2: Making the Basepairs

If you are fortunate to have access to a laser cutter, you could create the base pairs with more detail, since I'm not that lucky, I had to simplify them.

I used #6 (PS) plastic, cut out the shape and shrunk it in the oven, a cool trick I learned from the following instructable: https://www.instructables.com/id/Doodle-Earrings-Jewelry-Charms-by-Recycling-6-p/.

One important thing to note is that the plastic doesn't always shrink to the same degree. Before you start cutting out your base pairs, cut a small piece of the plastic, measure it (length and width), shrink it in oven and then measure the end product and use that to adjust the size of your template.

A) I wanted the base pairs to be 7cm in length, so I resized the template accordingly, and printed it out.

B) Using an X Acto knife, and the template (right click and save image below) as a guide, cut out a base pair.

C) With fine sandpaper, sand the base pairs (I left the hydrogen bonds unsanded).

D) Place the plastic base pair onto the parchment paper and into a toaster oven.

E) Set the oven to 250 F, and watch, first the plastic starts to curl, then it uncurls, then it shrinks.

F) With an oven mitt take out the parchment paper, if it is still a bit curled, place something heavy on top, such as a text book.

G) Make six of these, three A-T and three G-Cs.

Check out the above instructable for more information on shrinking #6 plastic.

Step 3: Making the Base

I found a wooden jewelry box at a dollar store which I used as the base or stand for my model, the dimensions are 13L X 9W X 4H (cm), with the lid removed.

  • First unscrew the hinges and remove the lid.
  • Mark on the back where the on/off switch is to go, and cut a slot in the wood using a drill and a Dremel.
  • Drill two holes about 0.5-1cm in diameter and about 4cm apart centred on the top of the base. These are for the wires to pass through.
  • Make a small notch on the bottom back of the base for the adapter wire to pass through.

Step 4: Wiring the Lights

I had a bit of trouble getting my circuit to work, I initially tried to string all the LEDs together in parallel with one resistor. This didn't work and I started to think that may be I should stick to doing cell biology. Fortunately, Instructables has an Answer section, where I posted my problem, and I got the help I needed to get my circuit to work (thanks to everyone who answered my question!)

What I needed to do was to keep the LEDs with different voltages on a separate parallel group with its own resistor. So in my case I had two branches of the white, blue and green (same voltage) LEDs in parallel with the appropriate resistor (as calculated with led calculator). And two branches of the red LEDs with the appropriate resistor. I need the two branches of each for the each strand of DNA. (You may be wondering what happened to the yellow LEDs, these would likely be grouped in with the red, that is if I had any, which I don't, so what I did was use white LEDs and coloured them with a yellow Sharpie.)

I've included the colour pattern below, the blue is paired with the red (3 pairs) and the yellow is paired with the green (3 pairs). These LEDs will light up the base pairs. The white LEDs light up the sugar-phosphate backbone (4 on each strand). These LEDs should be spaced 3-4cm apart.

The wires were then stuffed through the two holes in the wooden based and then soldered to the on/off switch and the 9v power supply.

Bend the LEDs for the base pairs (red, blue, green, and yellow) so that they are perpendicular to the wire, the white LEDs should be pointing upward.

When I made sure everything worked, I wrapped up any exposed wires with white electrical tape.

Step 5: Wraping Wire

  • Wrap the floral stem wire with the white electrical tape, you will need two of these. I did this so that it looks nicer and ensures the metal doesn't contact the wires in the circuit.
  • Poke the floral stem wires through each hole in the base (as far as they will go). Then tape the two LED strands and the floral stem wire together with the white tape.
  • Since the bottom of the base(stand) is open, I put some tape across it so that the wires don't hang out.

Step 6: Basepairs and the Sugar-phosphate Backbone

  • Cut pieces of clear vinyl tubing so that they fit between the LEDs (base pairs).
  • Make a slit down the length of each tube so that they can easily be slipped around the wires.
  • Glue each plastic base pair in place (glue them right onto the LED). Make sure you are consistent; ie; red= thymine, blue= adenine, yellow=guanine, green=cytosine.

Step 7: Finishing Up

Once the glue has dried completely (I waited until the next day), gently grasp each DNA strand and twist. Although the double helix is really a double corkscrew shape, this is difficult to achieve and is often depicted as a twisted ladder instead, which is the look I'm going for.

Twist together the two ends of the floral stem wire so that they won't come undone and trim off the excess wire.

Cover ends with the vinyl tubing and you are done!

Comments

author
nluce7 (author)2015-03-18

This looks really hard and I only have a weekend to do it?do you think that I can do it? It's for an extra credit science project.

author
ChrysN (author)nluce72015-03-20

If you use a string of Christmas lights instead of wiring your own LEDs, it would save time. You could probably do it over a weekend.

author
david319q (author)2013-12-18

Can you believe my Science group hated this idea .

author
david319q (author)2013-12-13

No I meant quinlandavid319@yahoo.com . Sorry

author
david319q (author)2013-12-13

Can you email me the diagram davidquinlan319@yahoo.com

author
silvermoon929 (author)2012-01-13

what type of resistors do we need???? because im searching online and it turns out that there are a bunch of different types

author
ChrysN (author)silvermoon9292012-01-13

You need to calculate which one you need based on the voltage of the LEDs and power source that you need. You can calculate it on this site(http://ledcalc.com/ ).

author
lexkeepsitsimple (author)2012-01-11

This is amazing. You guys on this site are so bright and talented. I love instructables... I only wish I could make a lamp like this with no power tools or solder.

author
ChrysN (author)lexkeepsitsimple2012-01-11

Thanks, I see that you are new to the site, I'm glad you like it. I am actually really terrible at soldering and nearly gave up few times on this project. You may be able to make something similar with Christmas lights. As for power tools, I just use a Dremel, I don't really have the space to use anything bigger.

author
canucksgirl (author)2011-12-17

ChrysN this looks spectacular!

Penolopy Bulnick was wise to use your ible as the main image for "Teaching Tools: Biology Edition" as it sure got my attention. :D

Great job.

author
ChrysN (author)canucksgirl2011-12-17

Thanks!

author
mastermind007 (author)2011-12-02

congratulations, its nice but you forgot to include one major point in the watson-crick dna double helix model..
-there are 10 nitrogenous base pairing every one full turn of the double helix.
anyway, nice work.. :)

author
butcher_pro (author)2010-09-22

thankz a lot, i presented this as a skool project, absolute A !!!
well, in mexico that grade translates to 10 ; )
first pic is the chain, second pic shows nitrogened bases, and third pic is both at the same time, i putted 2 buttons to switch betwen ligths!
anywaz, thanks a lot man!!!

:D

091010205148.jpg091010205212.jpg091010205235.jpg
author
ChrysN (author)butcher_pro2010-09-22

Excellent, thanks for posting your pictures!

author
eulaliaaaa! (author)2010-09-10

GO DIOXYRIBONUCLEIC ACID!!!!

author
butcher_pro (author)2010-09-09

thanks for the project and the explanation, i was dying to find out how to do it, i didnt follow as planned cuz in mexico u cant find the right leds, but i did my best and it went so good, thanks again for uploading!!!

author
ChrysN (author)butcher_pro2010-09-09

Glad you liked it, feel free to post a picture of yours.

author
its2l8men (author)2010-08-03

i like to have dis for my science project, my classmates are gonna freak out with this one its so beautiful

author
kykypy3o (author)2009-10-16

The  CAT !!! )))

author
LoboNR (author)2009-10-15

ey man congratulations for the art DNA model
it's really very nice
could you send me the diagramm that you used to the conections??
i'm just learning about leds and i'm not very good.
however i wanna try to make this project

thank you and congrutalations again


my e-mail adress is  lobo.alirog13@gmail.com

author
lamyae (author)2009-08-30

Excuse me, i just want to know plz is there a possibility to contact u plz, i need to do the DNA model in the next weeks and i loved ur model, and i want to know some steps more detailed than u wrote:) can u plz contact me on my email stoonat@hotmail.com plz, and thank u

author
Demoni0 (author)2009-07-09

Really good!! is time to make art!!! thank you.

And want your cat is beautyfull , ;)

author
mrdepo96 (author)2009-06-23

Looks amazing! (Your cat has no legs!)

author
mrdepo96 (author)mrdepo962009-06-23

sorry if your cat actually has no legs*

author
ChrysN (author)mrdepo962009-06-23

Now that you mention it, it does look like they are missing. He does have legs though, they are tucked under him somewhere.

author
Carlos Marmo (author)2009-06-18

Wonderful Work! Congratulations!

author
ChrysN (author)Carlos Marmo2009-06-18

Thanks!

author
theophrastus (author)2009-06-18

very artistic, but you do know that DNA is a normally a right-handed helix, (as opposed to the left-handed one depicted)? ah well, it's still very shiny!

author
ChrysN (author)theophrastus2009-06-18

Oops, I guess that would make it a Z-DNA model.

author
verticalfuzz (author)2009-06-10

what an excellent project!! accurate down to the hydrogen bonds! was this done for a school project, or are you genuinely interested in genetics?

author
ChrysN (author)verticalfuzz2009-06-10

I'm a little old for school projects, but I do work in a Cytogenetics lab where we deal with chromosomes and DNA.

author
Istarian (author)ChrysN2009-06-18

You should adjust this so you can use controllable rgb leds, then you can color code for DNA bases and be able to make it a lit up of a given string of DNA. It would be a bit pricey, but very cool.

author
ChrysN (author)Istarian2009-06-18

That sounds really cool.

author
Sparkplug (author)ChrysN2009-06-15

dang i wish i could have seen this one a couple of months ago. My Bio teacher was offering extra credit for anyone who made a DNA model, especially one that lights up.

author
ChrysN (author)2009-06-17

I'll PM you.

author
Serial-Cricket (author)2009-06-14

That is very cool. 5*

author
ChrysN (author)Serial-Cricket2009-06-14

Thanks!

author
Serial-Cricket (author)ChrysN2009-06-15

Yw

author
wupme (author)2009-06-14

the cat looks like "this better be worth my time" lol. Anyway nice idea, and i think next month i'm gonna make something like that for my roomfountain, but only if i got enough spare money :(

author
ChrysN (author)wupme2009-06-14

Yeah, my cats always jealous when I'm spending to much time on my projects.

author
TheTrustedOne (author)2009-06-13

Please done use electrical tape, it's horrible for electronics, ironically, use heat shrink tubing to ensure a neat permanent bond

author
ChrysN (author)TheTrustedOne2009-06-13

Thanks, I'll have to remember that for future projects.

author
kelseymh (author)2009-06-10

That is really amazing. It's rare to see DNA models built with the actual molecular bond shapes. The writeup and the science orientation are a welcome addition! Someone beat me to the Feature flag, but at least I got to rate it :-)

I wonder how hard it would be to wire up the hydrogen-bonds with small pin connectors (like Burndy's) so that the LEDs would only illuminate when complementary bases were joined. This would make a really cool kit...

author
ChrysN (author)kelseymh2009-06-10

That sounds like a cool idea, turn it into a teaching tool.

author
ravebot (author)2009-06-10

very nice i like the smooth look you get when your done

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Bio: I like sewing and crafts,and trying new things. I'm vegetarian and always looking for new recipes. My cat's name is Mirko and ... More »
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