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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