Applications of graphene oxide nanomaterials on surfaces

Debora F. Rodrigues, Ph.D.Assistant Professor

Sustainable Nanotechnology Organization (SNO)

Nov. 3rd, 2013

Graphene Oxide

www.cnx.org; www.sciencebuzz.org

Iijima, S, Ichihashi, T. Nature 1993, 363, 603

Geim, A. K. Science 2009, 324, 1530.

Stankovich, S. , D. A. Dikin, G. H. B. Dommett, K. M. Kohlhaas, E. J. Zimney, R. D. Piner, S. T. Nguyen, R. S. Ruoff, Nature 2006, 442, 282.

High mechanical stiffness

Excellent electronic property

Good thermal stability

Anti-microbial

Anti-biofouling

Graphene Oxide

Graphene sheets with functional groups

Polymer nanocomposites with

Graphene

Polymer Conclusions observed for the resulting nanocomposites

Polydimethylsiloxane (PDMS) contact angle <130°

Polypyrole and polyaniline Increased electrocatalyticalability

poly (vinylidene fluoride) Exceptional thermal and mechanicalIntegrity

Natural polymers, chitosan Increased microbial compatibility and reduced cytotoxicity

poly vinyl alcohol and poly ethyleneglycol (PEG), poly vinyl alcohol hydrogel, Polysulfone

Hydrophilic surface

Poly-N-vinyl carbazole (PVK) Anti -microbial

Lin, Y, Allard, LF, Sun, YP. J Phys Chem B, 2004, 108, 3760.

Wang, Z, Liu, Q, Zhu, H, Liu, H, Chen, Y, Yang, M. Carbon 2006, 45, 285.

Brady-Estevez, AS, Kang, S, Elimelech, M. Small 2008, 4, 481.

Odaci, D, Timur, S, Telefoncu, A. Bioelectrochemistry, 2009, 75, 77.Beigbeder, A, Degee, P, Conlan, SL, Mutton, RJ, Clare, AS, Pettitt, ME, et al. Biofouling, 2008, 24, 291.www.nanopatentsandinnovations.blogspot.com; www.smalltech.co.uk; www.trendsupdates.com/

Santos, C. M., Tria, M.C., Vergara, R.V., Ahmed, F, Advincula, R. C., Rodrigues, D. F., Chem Commun, 2011, submitted.

Santos, C. M., Cui, K.R., Ahmed, F, Tria, M.C. De leon, A., Advincula, R. C., Rodrigues, D. F., Advanced Biomat, 2011, submitted.

Applications

PVK-GO nanocomposites

GO

PVK

Exfoliated PVK nanocomposite

(stable for 30 days)

Contains aromatic groups (pi-pi interaction)

Poly-N-vinyl carbazole (PVK)

Why PVK?

Presence of electro-active groups

(electrodeposition on any conducting/metal

surface)

Can form conducting polymer network (CPN)

Cui, K.R., Tria, M.C. Pernites, R., Binag, C., Advincula, R. C. ACS Appl. Mater. Interfaces, 2011.

PVK-GO 97:3 (wt %)

Objectives

Develop Environmental Engineering Applications for these

nanomaterials:

Develop anti-microbial surfaces with anti-corrosion properties

Develop membrane filters for water purification

Implications of new material

Reduce human cytotoxicity of the new materials

Reduce the amount of GO to make cheaper coatings

Maintain the same level of toxicity as pure GO to inhibit

microbial growth and potential microbial corrosion

Outline

Test the toxicity of these nanocomposites to human cells

and bacteria

Test the antimicrobial and anti-corrosion properties on PVK-

GO on metallic surfaces

Test the removal and inactivation efficiency of bacterial cells

on PVK-GO coated filters

Is the nanocomposite toxic to Humans?

Toxicity of Solution-based PVK-GO nanocomposites

MTT Assay

Isis E. Mejias, Catherine M. Santos, Xin Wei, and Debora F. Rodrigues, Nanoscale. 2012.

GO PVK-GO PVK Dead Cells0

20

40

60

80

100

% c

yto

tox

icit

ySamples

T25= 3 x 10 6

Grow the Human cells Remove media, add test

solution (sample)Incubate to desired time

(24 h)

Read OD 490 nm

Remove sample, wash with PBS (3x)Add MTS reagent

PVK-GO is less cytotoxic than GO

Is the nanocomposite toxic to Bacteria?

Toxicity of Solution-based PVK-GO nanocomposites

Viability Assay

Sample incubated

in bacteria glass

slide

+

Microscope

Stained with fluorescent dyes:

SYTO 9 (green)- total bacteria

Propidium Iodide (red)- dead

bacteria

Sample bacteria

+

Incubate 37 C, 1 h,

40 rpm

Isis E. Mejias, Catherine M. Santos, Xin Wei, and Debora F. Rodrigues, Nanoscale. 2012

control (+) GO PVK-GO PVK0

20

40

60

80

100

% C

ell

Inactivation

sample

B. subtilis

E. coli

C. metallidurans

R. opaccus

Damaged cells > 90%

Disruption of cell wall

PVK-GO nanocomposites on Surfaces

Dip

coater

cellulose

nitrate filter

Santos, C. M., Cui, K.R., Ahmed, F, Tria, M.C. De leon, A., Advincula, R. C., Rodrigues, D. F., Nanotech 2012

PVK-GO

AFM (morphology) ATR (functional group)

1000 1500 2000 2500 3000 3500 4000

No

rmali

zed

Ab

so

rban

ce

Wavenumber (cm-1)

PVK/GO

PVK

(OH)

(C=O)

Electrodeposition

Dip coating

Anti-corrosion properties?

PVK-

GO/MWNT/S

WNT surface

wastewater

30 day

incubation EIS

Measurements*

CORROSION ASSAY

A: Steel (Working Electrode)

B: Platinum (Counter Electrode)

C: Ag/AgCl (Reference Electrode)

*Electrochemical Impedance Spectroscopy (EIS)

A B C

Determination of Corrosion

Anti-corrosion properties?

0 2x104

4x104

6x104

8x104

1x105

1x105

1x105

0

1x104

2x104

3x104

4x104

ITO

PVK

PVK-SWNT

PVK-GO-Z

im

ag

ina

ry (

-Z real (

Nyquist plots

PVK and PVK-GO have good anti-corrosion properties in

wastewater.

steel

Anti-microbial properties on surfaces?

Uncoated PVK-coated

GO-coated PVK-GO-coated

Grow bacterial cells with the coated anduncoated coupons for 24 h, then fix cells

and analyze

93% E. coli biofilm inhibition97% B. subtilis biofilm inhibition

Any potential for water purification applications?

Solutions of PVK

or PVK-GO

Dip

coater

cellulose

nitrate filters

Membrane coated by filtration

of solution of GO

FiltratePlate Count

Live-Dead Assay

Membrane Filter

PVK-GO (97-3)

GO

Unmodified filter (+)

Unmodified filter and PBS (-)

Experimental Design

Bacterial solution

(107 CFU/ml)

E. coli (Gram -)

B. subtilis (Gram +)

FILTRATE

TEST

FILTER

TEST

Plate Count

Live-Dead Assay

Filter Test (Live-Dead Assay)

FILTRATE

TEST

FILTER

TEST Filter membranes

after filtration with

bacteria

+Microscope

Stained with fluorescent dyes:

SYTO 9 (green)- total bacteria

Propidium Iodide (red)- dead

bacteria

Live-Dead Assay

B. subtilisE. coli

GO-containing samples

Plate Count

Live-Dead Assay

Filtrate Test (Plate Count Assay)

FILTRATE

TEST

FILTER

TEST

Spread plating

on TSA plates

Incubate at 37 C,

overnight

count CFU

Plate Count Assay

Log Removal compared to the control sample

PVK-GO GO0

1

2

3

4

5

6lo

g b

ac

teri

al re

mo

va

l

Filter membrane samples

E. coli

B. subtilis

• Coated surfaces with PVK-GO have:– anti-microbial properties

– anti-corrosion properties

• Potential applications for: – Coating medical devices/implants

– Coating of sewage and drinking water pipes to prevent microbial growth and corrosion

– Filtration devices

Conclusions

Acknowledgements

• NSF Career award: Nanohealth

• NSF I-Corps

• UH Faculty early career grant