ABOUT THE SPEAKER
Paul Rothemund - DNA origamist
Paul Rothemund folds DNA into shapes and patterns. Which is a simple enough thing to say, but the process he has developed has vast implications for computing and manufacturing -- allowing us to create things we can now only dream of.

Why you should listen

Paul Rothemund won a MacArthur grant this year for a fairly mystifying study area: "folding DNA." It brings up the question: Why fold DNA? The answer is -- because the power to manipulate DNA in this way could change the way we make things at a very basic level.

Rothemund's work combines the study of self-assembly (watch the TEDTalks from Neil Gershenfeld and Saul Griffith for more on this) with the research being done in DNA nanotechnology -- and points the way toward self-assembling devices at microscale, making computer memory, for instance, smaller, faster and maybe even cheaper.

More profile about the speaker
Paul Rothemund | Speaker | TED.com
TED2007

Paul Rothemund: Playing with DNA that self-assembles

Filmed:
471,278 views

Paul Rothemund writes code that causes DNA to arrange itself into a star, a smiley face and more. Sure, it's a stunt, but it's also a demonstration of self-assembly at the smallest of scales -- with vast implications for the future of making things.
- DNA origamist
Paul Rothemund folds DNA into shapes and patterns. Which is a simple enough thing to say, but the process he has developed has vast implications for computing and manufacturing -- allowing us to create things we can now only dream of. Full bio

Double-click the English transcript below to play the video.

00:26
There's an ancient and universal concept that words have power,
0
1000
4000
00:30
that spells exist, and that if we could only pronounce the right words,
1
5000
4000
00:34
then -- whooosh -- you know, an avalanche would come
2
9000
2000
00:36
and wipe out the hobbits, right? So this is a very attractive idea
3
11000
5000
00:41
because we're very lazy, like the sorcerer's apprentice,
4
16000
2000
00:43
or the world's greatest computer programmer.
5
18000
2000
00:45
And so this idea has a lot of traction with us.
6
20000
2000
00:47
We love the idea that words, when pronounced --
7
22000
2000
00:49
they're just little more than pure information,
8
24000
2000
00:51
but they evoke some physical action
9
26000
1000
00:53
in the real world that helps us do work.
10
28000
1000
00:54
And so, of course, with lots of programmable computers
11
29000
3000
00:57
and robots around this is an easy thing to picture.
12
32000
3000
01:00
So how many of you know what I'm talking about?
13
35000
2000
01:02
Raise your right hand. OK. How many of you
14
37000
1000
01:03
don't know what I'm talking about? Raise your left hand.
15
38000
3000
01:06
So that's great. So that was too easy.
16
41000
3000
01:09
You guys have very insecure computers, OK?
17
44000
3000
01:12
So now, the thing is that this is a different kind of spell.
18
47000
5000
01:17
This is a computer program made of zeros and ones.
19
52000
1000
01:18
It can be pronounced on a computer. It does something like this.
20
53000
3000
01:21
The important thing is we can write it in a high-level language.
21
56000
2000
01:23
A computer magician can write this thing.
22
58000
3000
01:26
It can be compiled into this -- into zeros and ones --
23
61000
3000
01:29
and pronounced by a computer.
24
64000
1000
01:30
And that's what makes computers powerful:
25
65000
1000
01:32
these high-level languages that can be compiled.
26
67000
2000
01:34
And so, I'm here to tell you, you don't need a computer
27
69000
3000
01:37
to actually have a spell. In fact, what you can do
28
72000
3000
01:40
at the molecular level is that if you encode information --
29
75000
3000
01:43
you encode a spell or program as molecules --
30
78000
2000
01:46
then physics can actually directly interpret that information
31
81000
3000
01:49
and run a program. That's what happens in proteins.
32
84000
2000
01:52
When this amino acid sequence gets pronounced as atoms,
33
87000
2000
01:55
these little letters are sticky for each other.
34
90000
2000
01:57
It collapses into a three-dimensional shape that turns it into
35
92000
3000
02:00
a nanomachine that actually cuts DNA.
36
95000
2000
02:02
And the interesting thing is that if you change the sequence,
37
97000
3000
02:05
you change the three-dimensional folding.
38
100000
2000
02:07
You get now a DNA stapler instead. These are the kind of
39
102000
3000
02:10
molecular programs that we want to be able to write,
40
105000
2000
02:12
but the problem is, we don't know the machine language of
41
107000
2000
02:14
proteins. We don't have a compiler for proteins.
42
109000
2000
02:17
So I've joined a growing band of people that try to make
43
112000
2000
02:19
molecular spells using DNA. We use DNA because it's cheaper.
44
114000
3000
02:23
It's easier to handle. It's something that we understand really well.
45
118000
2000
02:25
We understand it so well, in fact, that we think we can actually write
46
120000
4000
02:29
programming languages for DNA and have molecular compilers.
47
124000
3000
02:32
So then, we think we can do that. And my first question doing this --
48
127000
4000
02:36
or one of my questions doing this -- was how can you make
49
131000
1000
02:38
an arbitrary shape or pattern out of DNA? And I decided to use
50
133000
3000
02:41
a type of DNA origami, where you take a long strand of DNA
51
136000
3000
02:44
and fold it into whatever shape or pattern you might want.
52
139000
3000
02:47
So here's a shape. I actually spent about a year in my home,
53
142000
3000
02:50
in my underwear, coding, like Linus [Torvalds], in that picture before.
54
145000
3000
02:54
And this program takes a shape, spits out 250 DNA sequences.
55
149000
3000
02:57
These short DNA sequences are what are going to fold the long strand
56
152000
3000
03:00
into this shape that we want to make. So you send an e-mail
57
155000
3000
03:03
with these sequences in it to a company, and what it does --
58
158000
3000
03:07
the company pronounces them on a DNA synthesizer.
59
162000
1000
03:09
It's a machine about the size of a photocopier. And what happens is,
60
164000
3000
03:12
they take your e-mail and every letter in your e-mail,
61
167000
2000
03:14
they replace with 30-atom cluster -- one for each letter,
62
169000
3000
03:17
A, T, C, and G in DNA. They string them up in the right sequence,
63
172000
3000
03:21
and then they send them back to you via FedEx.
64
176000
1000
03:23
So you get 250 of these in the mail in little tubes.
65
178000
1000
03:25
I mix them together, add a little bit of salt water,
66
180000
3000
03:28
and then add this long strand I was telling you about,
67
183000
2000
03:30
that I've stolen from a virus. And then what happens is,
68
185000
2000
03:33
you heat this whole thing up to about boiling. You cool it down
69
188000
3000
03:37
to room temperature, and as you do,
70
192000
1000
03:38
what happens is those short strands, they do the following thing:
71
193000
2000
03:41
each one of them binds that long strand in one place,
72
196000
3000
03:44
and then has a second half that binds that long strand
73
199000
2000
03:47
in a distant place, and brings those two parts of the long strand
74
202000
3000
03:50
close together so that they stick together.
75
205000
2000
03:52
And so the net effect of all 250 of these strands is to fold
76
207000
3000
03:55
the long strand into the shape that you're looking for.
77
210000
4000
03:59
It'll approximate that shape. We do this for real in the test tube.
78
214000
3000
04:02
In each little drop of water you get 50 billion of these guys.
79
217000
3000
04:05
You can look with a microscope and see them on a surface.
80
220000
2000
04:08
And the neat thing is that if you change the sequence
81
223000
1000
04:09
and change the spell, you just change the sequence of the staples.
82
224000
4000
04:13
You can make a molecule that looks like this, and, you know,
83
228000
3000
04:16
he likes to hang out with his buddies, right.
84
231000
2000
04:19
And a lot of them are actually pretty good.
85
234000
1000
04:21
If you change the spell again, you change the sequence again.
86
236000
2000
04:23
You get really nice 130 nanometer triangles. If you do it again,
87
238000
4000
04:27
you can get arbitrary patterns. So on a rectangle
88
242000
3000
04:30
you can paint patterns of North and South America, or the words, "DNA."
89
245000
5000
04:35
So that's DNA origami. That's one way. There are many ways
90
250000
4000
04:39
of casting molecular spells using DNA.
91
254000
3000
04:42
What we really want to do in the end is learn how to program
92
257000
3000
04:45
self-assembly so that we can build anything, right?
93
260000
3000
04:48
We want to be able to build technological artifacts
94
263000
2000
04:50
that are maybe good for the world. We want to learn
95
265000
2000
04:52
how to build biological artifacts, like people and whales and trees.
96
267000
4000
04:57
And if it's the case that we can reach that level of complexity,
97
272000
2000
04:59
if our ability to program molecules gets to be that good,
98
274000
3000
05:03
then that will truly be magic. Thank you very much.
99
278000
3000
05:06
(Applause)
100
281000
1000

▲Back to top

ABOUT THE SPEAKER
Paul Rothemund - DNA origamist
Paul Rothemund folds DNA into shapes and patterns. Which is a simple enough thing to say, but the process he has developed has vast implications for computing and manufacturing -- allowing us to create things we can now only dream of.

Why you should listen

Paul Rothemund won a MacArthur grant this year for a fairly mystifying study area: "folding DNA." It brings up the question: Why fold DNA? The answer is -- because the power to manipulate DNA in this way could change the way we make things at a very basic level.

Rothemund's work combines the study of self-assembly (watch the TEDTalks from Neil Gershenfeld and Saul Griffith for more on this) with the research being done in DNA nanotechnology -- and points the way toward self-assembling devices at microscale, making computer memory, for instance, smaller, faster and maybe even cheaper.

More profile about the speaker
Paul Rothemund | Speaker | TED.com