2004 04 22 nanomanipulator apps - uni-hamburg.de · 1 april 22, 2004 nanomanipulator apps advanced...

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April 22, 2004nanoManipulator Apps

Advanced Visualization and ControlUniversity of Hamburg, Russ Taylor, Summer ‘04 Slide 1

Science Experiments Enabled byThe nanoManipulator

Russell M. Taylor II



Administrative

• Course Textbook– One is in the library– The other is on reserve in room F-311

• Do not confuse with my office, which is F-331

• Project Teams and Ideas– Meet in the last several minutes of class– Meeting for all who can attend from 3-5 in F-331

• my office

– Schedule future meetings for Thursday afternoon or another time



2



Atomic Force Microscopy 101

Microscope Microscope TipTip

Tip or Sample Surface scanned back and forthTip or Sample Surface scanned back and forth

MirrorMirror

LASERLASERQuadrantQuadrant

PhotodiodePhotodiode

ComputerComputer

DisplayDisplay



E n d - O n - P u s hSliding

Tip contacts object

Tip on substrateLa

tera

l For

ce

AFM tip

Carbon Nanotube

AFM cantilever twists under “lateral” forces

Lateral Force Measurements during a manipulation

s (nm)

Atomic Force MicroscopyManipulation: Quantitative Nanometer-

Nanonewton Forces and Dynamics



nanoManipulator System

3



Materials Physics Experiments

• Gold Wires• Colloidal Gold Particles• Carbon Nanotubes

– Mechanical structure– Mechanical response– Electrical response– Electromechanical systems



Early AFM Experiment:nano-Repair of Gold Wire



Colloidal Gold Particles:“nanoWorld Cup”

• Form gap in gold• Push particle into gap

– Avoid obstacles– Avoid crushing– Avoid losing particle

• Measure conductance– Never got to this…– CNT came along

4



Graphite

Graphein: (Greek) to write

Diamond

Nanotube

Buckyball

The Forms of Carbon



MultiwallNanotubes:Concentric Shells

Single Wall

NanotubesBundles

Carbon Nanotubes



50 microns = 1/2 human hair0.25 micron

Electronic Circuit Wires vs Nanotubes

5



nanotubes poking out of fractured edge of polymer

composite

Application:Composite Materials



Nanotube Turture TestPopular press (The Economist)

view of a torture testThe Reality: AFM manipulation for

repeated bending stress



Bending and Buckling

6



D. Brenner, NCSU

Buckling reduces total strain energy

Red: stretchedBlue: compressed

Periodic Buckles in 2 cm Al tube!

Buckling:Macroscopic to Nanoscale



What Happens?hexagonal pencil twists- no rollinground pencil rolls, no twist, reorients

Macroscale Rolling and Sliding



0

0.1

0.2

0.3

0.4

0 0.2 0.4 0.6 0.8 1

x1 / L

Push Point

Push Point

Pivot Point

x1

x0

L

Pivot Point

Nanoscale Sliding

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84nm 84nm

Roll Direction

84nm 84nm

0 200

4 0 8 0 1 2 0 1 6 0

Nanoscale Rolling



60o

400 500 600 700 800 900100s(nm)

12

3

200 300 400 500 600 700 80s(nm)

1

2

3

a b

Lateral Force to rotate into and out of registry

Atomic lattices interlocking!

Why the different behaviors?• A clue from “bad” images



Atomic Lattice Interlock

8



•Different tubes•Different registration•Orientation Maintained through collision!

Lateral force measures collision

Nanotubes for Nanotechnology: Colliding tubes retain their lock-in angles!

-50

0

50

100

150

200

200 400 600 800 1000 1200 1400

s(nm)tip on

substratetip hits tube 1

tube1 hits tube2



a b

A B

C D

a

b

1

2

3

12

3

3

3

1 2

1

2

Stacking Carbon Nanotubes



The Data

What the scientist infers

CNT: Model & Experiment

Computed Centerline

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•Manipulate nanotube with electrical contacts•Reconnect broken tube•Simultaneous measurement of conductivity during manipulation

Nanotubes for Nanotechnology: Manipulation for Electrical Contacts in Nanoscale Devices

Ω= k 135R Ω> 710R Ω= k 500-150R

Time (sec)

Force and Resistance vs. time

100

300

Forc

e a

.u.

0 30

Res

ista

nce

(kΩ

)



Nanoscale Electromechanical Devices (NEMS)

AFM-Lithography onassembled tubes forElectromechanical

devices



Electrical Properties of Lattice Registration: Sense and actuate atomic interlocking

A

A

10



Electrical Effects:Contacts are critical

0 50

100

0 30 60 90 120 150 180

φ (degrees)

Res

ista

nce

(kΩ)

20 40 60 80 100

0

20

40

S RFriction

CNT/HOPG (Nardelli)Change R by 50 by rotating tube!Change R by 50 by rotating tube!



0 50

100

0 30 60 90 120 150 180

φ (degrees)

Res

ista

nce

(kΩ)

20 40 60 80 100

0

20

40

S RFriction•Changes Rcnt/hopg by >40•Compares with theory

CNT/CNT (Lu, Buldum)

CNT/HOPG (Nardelli)

Relative lattice orientation effect on resistance



Momentum (Direction) Conservation in a nanoContact

An artists view:Rajeev Dassani

The direction in which electrons move is critical

in contacts!

4π/3a

Towards the nanoRheostat

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Topography and Conductance

• Michael Stadermann



Biological Experiments

• DNA• Virus particles

– Tobacco Mosaic Virus (TMV)– Adenovirus

• Fibrin (blood clotting)



AFM topographic imageDNA/mica

in liquid

Lateral Force Trace

Cutting strength of DNA…

12



DNA: Model & Experiment• Simulated AFM scanner

– Scanned surface vs. model surface– “What should I be seeing?”– Ongoing collaboration with chemists

(Dorothy Erie) to produce a model of what happens when proteins/DNA are scanned with an AFM



Tobacco Mosaic Virus:Adhesion vs. Stiffness



Cantilever base position (nm)

Late

ral F

orce

(nN

)La

tera

l For

ce (n

N)

Push 1

Push 2

1.2 104

1.4 104

1.6 104

1.8 104

2 104

2.2 104

2.4 104

2.6 104

0 200 400 600 800

1.2 104

1.4 104

1.6 104

1.8 104

2 104

2.2 104

2.4 104

2.6 104

0 100 200 300 400 500 600 700

Viral Transport from Manipulation

• Break from Substrate

• Not re-stuck!

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Adenovirus and Gene Therapy

• Causes respiratory infections and conjunctivitis

• Structure and infection cycle understood as well as any unenveloped virus

• Being used as possible vector for gene therapy ~25% of trials

80 nmQuestions• Basic Science of Infectivity• Basic Science of Delivery



Imaging Adenovirus

• Use Villarrubia’s algorithm (NIST)• Does blind reconstruction of tip shape• Uses reconstructed tip to erode surface

• Enhanced Adeno Facets



Adenovirus85 nm

Icosahedral

AFM Images

virus ps sphere

TEM

Color by slope:Flat=dark

Steep=bright

Specular highlightsthrough

Directional illumination

Adenovirus: Imaging icosahedralshape with advanced rendering

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How does the DNA release from the Capsid?

• pH, Selective binding?



Image/ManipulationOf Adenovirus in solution on silicon

Quantify lateral force recorded during manipulation:Adhesion and Friction

Adenovirus: Quantify surface binding through manipulation



Adenovirus: Measure elasticity, modulus and hardness at precise location

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70

Inde

ntat

ion

(nm

)

Z Piezo Position (nm)Force (nN)

Inde

ntat

ion

(nm

) Adenovirus in water

Adenovirusin air

PS beadsin air

Position tip on virusPress down and measure

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Autocorrelation of Ad on Si Lateral Force Trace

??

One revolution contacts 10 facets.

Virus diameter = 75 nm, C=235nm and a 23.5nm spacing between peaks.

Flow of mucus across epithelium produces enough shear force to produce rolling – Increases number of binding sites contacting surface



Image: Manfred Kaga/Peter Arnold; Voet&Voet, “Biochemisty”, Wiley & Sons, NewYork, 1990

• Fibrin fibers: major structural component of clots

• Biomedical importance:• wound healing• heart attacks and strokes

• Disorders are associated with fibrinogen mutations• Some lead to excessive bleeding• Others lead to excessive clotting• Clot morphology is different from wild-type

Tools in Bioscience: Fibrin Fibers



+

Lateral aggregation

thrombin

fibrinogen fibrin Protofibrilformation

Fibrin Fiber Questions:What are the biochemical/structural What are the biochemical/structural

factors that determine clotting quality?factors that determine clotting quality?

•• Measure fiber Measure fiber strength during strength during growthgrowth

•• Compare wild Compare wild type and type and mutant/drug mutant/drug treatedtreated

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Tip hits fiber

Partial surfaceDetachment

Rupture

Tip

fiber

Ft

Fs

Fr

Late

ral f

orce

Tip position

B

TranslocationDeformation

0

0.5

1

1.5

2

2.5

3

0

1000

2000

3000

4000

5000

6000

0 1000 2000 3000 4000 5000 6000s(nm)

Late

ral f

orce

(nN

)

800 nm

Measurements on Individual Fibers



21 DcFR ⋅=

DcFR ⋅= 2

Solid cylinder:

Thin-walled cylinder:

4.1=b3 ⋅= RcF bR

Best exponential fit:

Young’s modulus

E = 0.4 GPa,Steel: E = 200 GPa

DNA: E = 0.1 GPa

Diameter (nm)0.1

1

400

6008001000

3000

50007000

10 100

Rup

ture

forc

e (n

A) R

upture force (nN)

1 .2

1.4

1.6

1.8

2

2.2

2.4

2.6

2.8

3350 3400 3450 3500 3550

Late

ral F

orce

(nA

)

s (nm )

Quantify fiber strength/structure



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Credits for non-UNC Inclusions

• The Forms of Carbon: Images from the Internet

• Composite Materials: Stanley Tools• Nanotube strong-man: The Economist• Atomic-scale simulation of bent nanotube:

Don Brenner, NCSU

2004 04 22 nanomanipulator apps - uni-hamburg.de · 1 april 22, 2004 nanomanipulator apps advanced...

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