The Chemistry of Single Walled Carbon NanotubesApplications to nanotube separation and biomolecule detection

The Chemistry of Single Walled Carbon NanotubesThe Chemistry of Single Walled Carbon NanotubesApplications to nanotube separation and Applications to nanotube separation and biomoleculebiomolecule detection detection

Michael S. StranoDepartment of Chemical and Biomolecular Engineering

University of Illinois at Urbana-Champaign

Michael S. StranoMichael S. StranoDepartment of Chemical and Biomolecular EngineeringDepartment of Chemical and Biomolecular Engineering

University of Illinois at UrbanaUniversity of Illinois at Urbana--ChampaignChampaign

P. Barone, M. Usrey, D. Heller, E. Jeng, C. Lee, N. Nair, W. Kim, J. Choi

P. Barone, M. Usrey, P. Barone, M. Usrey, D. Heller, E. Jeng, C. Lee, N. Nair, W. Kim, J. ChoiD. Heller, E. Jeng, C. Lee, N. Nair, W. Kim, J. Choi

OutlineOutline

(n,m) selective, covalent chemistry of single walled carbon nanotubes

• Mechanism of electronic sensitive reactions

• Separation and sorting carbon nanotube by electronic type

Single walled carbon nanotubes as near infrared fluorescent biosensors

• Nanotube sub-cellular “molecular beacons”

• Tissue implantable biomedical devices

(n,m) Selective Chemistry on SWNT(n,m) Selective Chemistry on SWNT

e-

covalentreaction

ClNNF4B

Cl

Rate = f(n,m)+ R

R

Scalable (n,m) Separation Method

Exploitation of functional group for preparative scale (n,m) separation Metals

SemiconductorsFunc. Metals

SemiconductorsFunc. Metals

+

Semiconductors

On-chip Modification of SWNT FETs

SWNT FET Array

Functionalization carried out directly on SWNT array• ON / OFF current approaches 105

An, L., et. al. J. Am. Chem. Soc. 2004, 126, 10520.Balasubramanian, K., et. al. Nano Lett., 2004, 4, 827.Wang, C., et. al. J. Am. Chem. Soc. 2005. 127, 11460.

Before Rxn

After Annealing1st Rxn74% OFF state current

2nd Rxnzero OFF state current

Before Rxn

After Annealing1st Rxn74% OFF state current

2nd Rxnzero OFF state current

Semi-conductors

metals

M. S. Strano, C. Dyke, M. Usrey, el. al. Science 301 (2003) 1519-22

selective

UV-vis-nIR Absorbance190 to 1800 nmRaman Spectrometer

532 nm excitation

Stirred 3 neck flask70 mL of aqueous dispersed SWNT1% SDS/D2O ~ 10 mg SWNT/L

Peristaltic pump

Spectrophotometer

SampleRecirculation

Reaction Vessel at 25 oC

ClNNF4B

Reagent

0.25 mg/mlAdded in 100 μL aliquots

unreacted

reactedDisorder mode

Monitor Bond Formation

H2O dispersed

reacted in DMF

Monitor Charge Transfer

ML Usrey et al: JACS, 127 (2005) 16129-35.

Apparatus for Studying SWNT ChemistryApparatus for Studying SWNT Chemistry

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

300 800 1300 1800Wavelength (nm)

Abs

orba

nce

Ener

gy

1% SDS/D2O, 28 mg/L exposed to air

(9,1)(13,3)

Absorption Spectrum Allows Probing of Valence Electrons

Ener

gy

Density of States

Semiconductingv1→c1

v1

c1Semiconducting

v2→c2

v2

c2

v1

c1

Metallicv1→c1

0.45

0.55

0.65

0.75

0.85

400 600 800 1000 1200 1400 1600

Wavelength (nm)

OD

0.63

0.67

0.71

0.75

480 580 680

4 00

W a v e le n g th (n m)

0.02.13.95.69.111.8

aryl chlorideSide groups x 103

/Carbons

v1→c1 Metaltransitions

v2→c2 Semiconductor transitions

v1→c1 Semiconductor transitions

Low Concentration: Selective Reaction of Metallic Nanotubes

M. S. Strano, C. Dyke, M. Usrey, el. al. Science 301 (2003) 1519-22

ClNNF4B

Two Step Mechanism from Raman SpectroscopyTwo Step Mechanism from Raman Spectroscopy

0.9

0.95

1

1.05

0 1 2 3 4 5

Time (hrs)

Rel

ativ

e In

tens

ity

1150 1350 1550 1750

Tangential mode after addition

Looks like A → B → C

Measures electron withdraw

Raman shift (1/cm)

Reagent addition

0

0.4

0.8

1.2

1.6

2

0 1 2 3 4 5

Time (hrs)

Rel

ativ

e In

tens

ity

Disorder mode after addition

Measures sp3 “disorder” ∴covalent bond formation

Reagent addition

B

C

Cl

N2+

(A)

(B)

(C)

k1

k-1k2

θ = θT – B[t] – C[t]

ClθA B C+

If coverage remains sparse, θ[t] >> (B[t] + C[t], k-1 ~ 0

k1

k-1

k2

0.9

0.95

1

1.05

0 1 2 3 4 5

Time (hrs)

Rel

ativ

e In

tens

ity

0

0.4

0.8

1.2

1.6

2

0 1 2 3 4 5

Time (hrs)

Rel

ativ

e In

tens

ity

Resolves outstanding problems:k1 = selective and delocalizedk2 = follows Pyramidalization

Disorder Mode “C”Tangential Model “B”

Understanding the Selective MechanismUnderstanding the Selective Mechanism

ML Usrey, ES Lippmann, MS Strano: JACS, 127 (2005) 16129-35.

Sodium dodecyl sulfate surfactant beads

Reagent is accessible

Sodium cholate:

closely packed adsorbed phase;steric hindrance

A → B → CX

0.8 nm

0.3

0.5

0.7

0.9

1.1

1.3

1.5

1.7

600 800 1000 1200 1400 1600Wavelength (nm)

OD

051520304060-150D

opin

g Ti

me

(min

)

\12-02-04 Cholate Doping 5sx5.HOL

1100 1200 1300 1400 1500 1600 1700

2000

4000

6000

8000

10000

12000

14000

16000

Raman Shift (1/cm)

Coun

ts

2468

10121416

Rel

ativ

e In

tens

ity

Raman Shift (cm-1)1100 1200 1300 1400 1500 1600 1700

\12-02-04 Cholate Doping 5sx5.HOL

1100 1200 1300 1400 1500 1600 1700

2000

4000

6000

8000

10000

12000

14000

16000

Raman Shift (1/cm)

Coun

ts

2468

10121416

Rel

ativ

e In

tens

ity

\12-02-04 Cholate Doping 5sx5.HOL

1100 1200 1300 1400 1500 1600 1700

2000

4000

6000

8000

10000

12000

14000

16000

Raman Shift (1/cm)

Coun

ts

\12-02-04 Cholate Doping 5sx5.HOL

1100 1200 1300 1400 1500 1600 1700

2000

4000

6000

8000

10000

12000

14000

16000

Raman Shift (1/cm)

Coun

ts

2468

10121416

Rel

ativ

e In

tens

ity

Raman Shift (cm-1)1100 1200 1300 1400 1500 1600 1700

D Peak

G Peak

Fluorescence

Disorder Mode – no change

Tangential mode adsorption step still selective

Rea

ctio

n Ti

me

Further Evidence: Blocking the Second StepFurther Evidence: Blocking the Second Step

ML Usrey, ES Lippmann, MS Strano: JACS, 127 (2005) 16129-35.

metallic

semi-conducting

surfactant/H2O25 oC

e-

ClNNF4B

metallic

semi-conducting

metallic

N2

metallic

semi-conducting

metallicSelective Reaction

thermal

annealing

restoredmetallic

Separationprocessp-hydroxy benzene diazonium

OH

R

R

Electrophoresis

OH

O-

pH ~ 11

H+

Usrey, M. A., Strano, M. S., in preparation (2006)

Chemistry for Sorting Carbon NanotubesChemistry for Sorting Carbon Nanotubes

00.14

0.480.34DiazoniumAdded (mM)

10001500 2000

25003000

Raman Shift (cm-1)

Inte

nsity

(A.U

.)

D Peak

G Peak

G’ PeakPL

Chemistry Controls Electrophoretic MobilityChemistry Controls Electrophoretic Mobility

(+) Cathode

(-) Anode

ν = (q/f ) E

wells

ν= electrophoretic mobilityq = net charge

f = hydrodynamic factorE = applied electric field

ν

(-)

(+)

(-)

(+)

MW Std 0.48mMol

0.34mMol

0.14mMol

0mMol

No rxnCompleterxn

RO-

RO-

OutlineOutline

(n,m) selective, covalent chemistry of single walled carbon nanotubes

• Mechanism of electronic sensitive reactions

• Separation and sorting carbon nanotube by electronic type

Single walled carbon nanotubes as near infrared fluorescent biosensors

• Nanotube sub-cellular “molecular beacons”

• Tissue implantable biomedical devices

0

2

4

6

8

10

400 650 900 1150 14000

0.2

0.4

0.6

0.8

1

Wavelength (nm)

Abs

orba

nce

(cm

-1)

Norm

alized Fluorescence

SWNT Fluorescence

Blood Abs.

Water Abs.

Semi-conducting single walled carbon nanotubes

• fluoresce in near infrared• very photostable• sensitive to environment

D. A. Tsyboulski, Nano Lett., Vol. 5, No. 5, 2005

Advantages for Optical SensingAdvantages for Optical Sensing

Single nano-particle spectroscopy = single molecule sensor

(+ -) (+ -)Analyte

Scheme for β-d-Glucose SensorScheme for β-d-Glucose Sensor

Step I: Immobilization of binding site (GOx) on SWNT

+ (GOx)Self assembly Colloidally stable

Nanotube-Glucose oxidasecomplex

Glucose oxidase

Glucose + O2 + H2O H2O2 + 1,5-gluconolactone(GOx)

Step II: Coupling to electron transfer

2[Fe(CN6)]3- + H2O2 2[Fe(CN6)]4- + 2(H+) + 2e- + O2

Ferricyanide Ferrocyanide

A nanotube redox couple:

+ e- [ ]- Decrease influorescence intensity

Two Step SynthesisTwo Step Synthesis

PW Barone, S Baik, DA Heller, MS Strano: Nature Materials 4 (2005) 86-92.

Cryo-TEM of individual nanotubes

Band-gap fluorescence

50 nm

Step I: Immobilization of GOx EnzymeStep I: Immobilization of GOx Enzyme

Add1:200

Glucose Oxidase

SurfactantDialysis

440 nm

GOx-SWNT4.5 nm1

0123456

0 200 400 600 800Translation (nm)

Heig

ht (n

m)

1. Saal, K. et al. Bio. Eng. 19, 195-199 (2002).

02468

10

870 920 970 1020

Wavelength (nm)

Inte

nsity

(a.u

.)In

tens

ity (a

.u.)

Start

GOx

Energy shift with Binding

Glucose oxidase (GOx)

β-D-glucose

excitation

N-IR fluorescence= surface bound Fe(CN)6

-3

= adsorbed H2O2

0.00

0.20

0.40

0.60

0.80

0 5 10Glucose concentration (mM)

Norm

aliz

ed F

luor

esce

nce

0.20

0.50

0.80

1.10

0 10 20

Time (min)

1.4 mM

2.4 mM4.2 mM

Rel

ativ

e In

tens

ity

Rel

ativ

e In

tens

ity

Time (min)

Step II: Functionalization with FerricyanideStep II: Functionalization with Ferricyanide

(6,5)

PW Barone, S Baik, DA Heller, MS Strano: Nature Materials 4 (2005) 86-92.

Tissue Implantable Biomedical SensorsTissue Implantable Biomedical Sensors

Porous dialysis capillary13 kDa MW cutoff

Enzyme/SWNTsolution

200 μm

Rel

ativ

e In

tens

ity5

4.5

4

3.5

3

2.5

2

1.5

1

0.5

0

105

1 cm

EpidermalTissue

Sample

nIR image of filled capillary beneath tissue sample

Photodiode Laser InGaAs Array

Excitation

Emission

ImplantedCapillary

Tissue

PW Barone, RS Parker, MS Strano: Analytical Chemistry 77 (2005) 7556-62.

DNA Wrapped Carbon Nanotube HybridsDNA Wrapped Carbon Nanotube Hybrids

2 nmalternating guanine/thymine pairs – 20 mer

Raw material

ds(GT)15oligomers

Ultra-sonication3 W, 4 oC

Centrifugation

Synthesis I: Sonication

M Zheng, A Jagota, MS Strano, et al. Science 302 (2003) 1545-48.

1) 2) 3)

cholateDNA Probe 12-14kDa dialysis membrane

100kDa dialysis membrane

0

0.2

0.4

0.6

0.8

1

1.2

850 900 950 1000 1050 1100

wavelength (nm)

Nor

mal

ized

Inte

nsity

DNA-SWNT

Cholate SWNT

-17.6 meV

Fluorescence

Sodium cholate ssDNA

Synthesis II: Dialysis

E. Jeng, M. Strano, Nano Letters, ASAP (2006)

Selective Detection of DNA HybridizationSelective Detection of DNA Hybridization

Jeng, E.S., Strano, M.S. Nano Letters ASAP (2006) Graduate Student Esther Jeng

-0.5

0

0.5

1

1.5

2

2.5

0 500 1000 1500

[cDNA or nDNA] (nM)

ΔE

(meV

)

nDNA

cDNA

0.85

0.95

1.05

987 992 997

wavelength (nm)N

orm

aliz

ed

Inte

nsity

0nM879nM

cDNA2meV

hν1

hν1

hν3

hν2

Selective response to complement

cDNA = 5’- GCC TAC GAG GAA TTC CAT AGC T – 3’

5’ – TAG CTA TGG AAT TCC TCG TAG GCA – 3’

nDNA = 5’- TCG ATA CCT TAA GGA GCA TCC G -3’

Sensor: SWNT decorated with ss-DNA

cDNA

nDNA

300nm

Thicker sections denote DNA adsorbed on SWNT

Fluorescence energy : E = E11 + Eb

E11 = Energy of V1 – C1 transition

Eb= Exciton binding energy

Eb scales with effective environmental dielectric constant (ε)

Perebeinos, et. al. PRL, 92 (2004)

Binding energy relation:

Eb≈ Rn-2mn-1 ε-n

R = nanotube radius m = nanotube effective massn = scaling value of 1.4

Optical Transduction: Dielectric ModulationOptical Transduction: Dielectric ModulationOne dimensional structure confines exciton that forms on photo-absorption

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 2 4 6 8 10

v1

c1

v2

Density of Electronic States

Ener

gy

c2

conduction

valence

E11fluorescence

E22absorption

( ) waterDNA ε1εε αα −+=Nanotube fluorescence linked to analyte adsorption via surface area (α)

Effective medium approximation

3.4 Å

4.6 Å

M2+cations

0.8

0.9

1

1.24 1.25 1.26Energy (eV)

0 mMHg2+84 mM

Hg2+

Nor

mal

ized

Int.

Divalent metal ions added to DNA-SWNT cause red shift in nanotube fluorescence

1.240

1.245

1.250

1.255

0.001 1 1000 1000000 1E+09Concentration (μM)

Ener

gy (e

V)

Mg2+

Ca2+

Co2+

Hg2+

Heller, D. A. et. al., Science 311 (2006)

Same relative sensitivity to divalent ions

Conformational polymorphism of nanotube-bound DNA

Detecting Changes in DNA Conformation

Detecting Changes in DNA Conformation

(6,5) SWNT PL50 mW, 785 nm

C0 a βB/ βZ NDNADNA-SWNT

70.8 µM 0.118 1.04 30102 µM 0.118 1.21 5

Hg2+ Concentration (μM)

Ener

gy (e

V)

[Θ]-5

(deg

-cm

2 /dm

ol)

DNA in solution

DNA on SWNT

1.240

1.244

1.248

1.252

0.0001 0.1 100 100000

-5.5

-3.5

-1.5

0.5

2.5

Hg2+ Concentration (μM)

Ener

gy (e

V)

[Θ]-5

(deg

-cm

2 /dm

ol)

DNA in solution

DNA on SWNTDNA on SWNT

1.240

1.244

1.248

1.252

0.0001 0.1 100 100000

-5.5

-3.5

-1.5

0.5

2.5

Compare CD and PL: common midpoints – Δ(ΔGibbs) ~ 0 thermodynamically similar transitions

Slopes at the inflections are different for SWNT-DNA and free DNA

Thermodynamic Comparison of DNA

Transitions on and off SWNT

Thermodynamic Comparison of DNA

Transitions on and off SWNT

1−

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛⎟⎟⎠

⎞⎜⎜⎝

⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛=

aN

oZ

B

aN

o CC

CCK

ββ

K = fraction of transitionC0 = DNA length-independent conc. a = binding sites/DNA length βB/ βZ = ratio of nucleation rates N = effective oligonucleotide length

Pohl F., Jovin, T, J. Mol. Biol. 67 (1972) Pohl, F., Cold Spring Harbor Quant. Biol. 47 (1982)

B-form Z-formB-formB-form Z-formZ-form

Shorter effective length

Probing the Effects of Nanotube DiameterProbing the Effects of Nanotube Diameter

21 −−→Δn

tn

ZB

rE

μ

Scaling from 1-D ExcitonSimulations1

Nanotube radiusEffective

mass

(6,5)

(7,5)(7,6)

(10,2)(9,4)

(9,5)

(8,4)

(11,1)

(8,6)(8,7)

Rel

ativ

e In

tens

ity

0

1

Emission Energy (eV)

Exci

tatio

n En

ergy

(eV)

2.3

(8,3)

3D plot of fluorescence maxima in excitation/emission space

3D plot of fluorescence maxima in excitation/emission space

0

1(6,5)

(7,5)(7,6)

(10,2)(9,4)

(9,5)

(8,4)

(11,1)

(8,6)(8,7)

Rel

ativ

e In

tens

ity

Emission Energy (eV)

Exci

tatio

n En

ergy

(eV)

Exci

tatio

n En

ergy

(eV)

2.3

(8,3)

0.009

0.013

0.017

0.021

0.025

0.029

0.35 0.40 0.45 0.50 0.55Nanotube Radius (nm)

(6,5)

(7,5)

(8,4)(7,6)

(10,2)(8,6)

(11,1)(9,5)

(8,7)

(8,3)

(9,4)21 −−→Δn

tn

ZB

rE

μ

52 mMHg2+

1. Perebeinos, et. al. PRL, 92 (2004)

Modeling Conformational Polymorphism on SWNT

⎟⎟⎠

⎞⎜⎜⎝

⎛−=Δ −−

→ nB

nZ

nt

nZB rAE

εεμ 1121

Exciton binding energy difference of B and Z forms modeled on change in dielectric constant (ε)

( ) DNAiOHii εαεαε +−= 21

Effective medium model accounts for changing ε using DNA surface area coverage on the nanotube

εDNA = 4.0 and εH2O = 88.1α = surface area

A, n, = empirical parametersµ = SWNT reduced effective massr = SWNT diameter

b

r

w

The surface area of the absorbed DNA helix is described by 3 parameters:

r = radius w = strand widthb = pitch

Heller, D. A. et. al., Science 311 (2006)

Equilibrium values of radius and pitch in B and Z DNA:

r0 b0

B form 1 nm 3.32 nmZ form 0.9 nm 4.56 nm

Transduction is Modeled using DNA Geometry

(Eb,b – Eb,z) for each nanotube:

0.009

0.013

0.017

0.021

0.025

0.029

0.35 0.40 0.45 0.50 0.55

21 −−→Δn

tn

ZB

rE

μ

Nanotube Radius (nm)

(6,5)

(7,5)

(8,4) (7,6)

(10,2)(8,6)

(11,1)(9,5)

(8,7)

(8,3)

(9,4)

0.009

0.013

0.017

0.021

0.025

0.029

0.35 0.40 0.45 0.50 0.55

21 −−→Δn

tn

ZB

rE

μ

Nanotube Radius (nm)

(6,5)

(7,5)

(8,4) (7,6)

(10,2)(8,6)

(11,1)(9,5)

(8,7)

(8,3)

(9,4)

Unchanging ε

ΔEb based on DNA geometry

Endocytosis of DNA-SWNT “sensors” within live cellsEndocytosis of DNA-SWNT “sensors” within live cells

1 μm

Fluorescence Mapping

Transmission Electron Micrograph

Nuclear envelope

EndosomeBound SWNT

Myoblast stem cells

Peri-nuclearSWNT

DA Heller, MS Strano, Advanced Materials 17 (2005) 2793-99

0.85

0.95

1.05

1.228 1.238 1.248

0 µM1000 µM

10000 µM

Energy (eV)

785 nm laser excitation and collection optics

Endosome-bound SWNT

3T3 fibroblast cell in media

20 µm

Hg2+ ionsperfused in

buffer

Applications for Metal Ion Detection Applications for Metal Ion Detection

1.237

1.242

1.247

1.252

0 10 1000 100000

Peak

Ene

rgy

(eV)

Hg2+ Concentration (µM)

Tissue

Black Ink

Whole Blood

Model from expt. in buffer.

Near infrared fluorescence through tissue

Whole blood

Heller, D. A. et. al., Science 311 (2006)

The Strano Group at University of Illinois

Post doctoral Researchers:

Seunghyun Baik (now Assist. Prof. at Sungkyunkwan

University, Korea)Jiang Zhang (not shown)Woo Jae Kim (not shown)

Jong Hyun Choi (not shown)

Graduate students: P. Barone D. HellerE. Jeng

M. UsreyC. Lee

R. GraffN. Nair (not shown)H. Jin (not shown)

R. Sharma (not shown)

E. Jeng D. HellerM. Usrey

P. Barone

S. BaikC. Lee

R. Graff