Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

Vanadium pentoxide nanoparticles mimic
vanadium haloperoxidases and thwart
biofilm formation
V2O5 NW
MetalLayer
Bacterial Attack HOBr Production Anti-fouling Activity
NoBiofilmformation
Presented By:
Madhulika Sinha
Green Chemistry Report
Dept. Of Chemistry
National Tsing Hua University

 History
 Introduction
 Synthesis and Activities
 Result & Discussion
 Conclusion
 Why I chose this paper?
 References
NATURE NANOTECHNOLOGY | VOL 7 | AUGUST 2012 530 |
2013.05.06

2013.05.06 3
NATURE NANOTECHNOLOGY | VOL 7 | AUGUST 2012 530 |
“And arsenic and sulphur have been well mixed with Chian oil
and the mixture evenly applied to the vessel’s sides that she
may speed through the blue waters freely and without
impediment.”
-Translation from the Aramaic of papyrus dated 412BC
“All ships’ bottoms were covered with a mixture of tallow and
pitch in the hope of discouraging barnacles and teredo and
every few months a vessel had to be hove-down and graved on
some convenient beach”
-Christopher Columbus
Worldwide problem in marine systems, costing US Navy alone an
estimated $1 billion per annum (2002).
Fouling leads to hull roughness & hydrodynamic drag; more energy
required to propel the vessel through water; increased fuel
consumption & Green house gas emission4.
Tributyltin-free and Silicon elastomers A/F coatings– Not suitable
results(1-4).
“fleet generates
emissions
equivalent to
nearly 190 million
cars
–or all of the
vehicles in the U.S”
Marine biofouling- Small marine microorganisms Colonization,
adhesion of barnacles, macroalgae and microbial slimes4.

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NATURE NANOTECHNOLOGY | VOL 7 | AUGUST 2012 530 |2013.05.06
INTRODUCTION
−V2O5 NW
t = 0
−V2O5 NW
t = 60 days
Production of functional recombinant V-HPOs5 & isolation of naturally occurring V-HPOs6
done- withstands organic solvents, but commercial production expensive7.
a)Vanadium bound to Schiff base complexes8
Functional inorg. V-HPO’s developed
b) Peroxovanadium complexes9
Advantages- efficient, selective in various oxidation states8
Disadvantage- low stability and solubility, optimal working conditions (ex: organic solvents,
extremely low pH) [8-10]
Other Antibacterial NP’s like Ag, Cu, ZnO, Fe2O3 are either expensive or toxic to marine biota.
Wolfgang et al

5
Vanadium Pentoxide Nano Wires(V2O5 NW) mimic naturally occurring Vanadium
Halo peroxidase (V-HPO) enzyme, prevents bio film formation. V2O5 wires in
presence of Br-, Cl- etc. and H2O2 (both present in sea water) behaves like V-HPO’s
and damage the ―quorum sensing of bacteria, without being toxic to the other
marine biota.
H2O2 + X- + H+ = HOX + H2O
H2O2 + Br- + H+ = HOBr + H2O
(oxidant) (hypobromous acid)
Singlet molecular oxygen (1O2) formed. Exerts strong antibacterial activity.
Adv. Funct. Mater. 21, 501–509 (2011)
INTRODUCTION Contd.
Wolfgang et al
(hypohalous acid)(oxidant)

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Vanadium Pentoxide Nano
Wires(V2O5 NW)
50 nm
Synthesis of V2O5 NW & Bromination activity
Fig. 1 | TEM image of V2O5 nanowires
Synthesis of V2O5 NW-
VOSO4 + KBrO3 stirring for 30 min(@ RT)
180 C/24 h. Reaction cooled @ RT dark-
yellow precipitate(ppt.) dried @ 80 C overnight.
Observation: Linear dependence of the rate of
2-monochlorodimedone (MCD) bromination
with V2O5 NW concentration (Fig. 2 b).
Fourfold difference in activity of the nanoscale
and bulk V2O5, indicates that the higher surface
area of the nanostructured material is required
to achieve higher catalytic efficiency.
Chem. Rev. 104, (2004) & J. Am. Chem. Soc. 105, (1983)
Fig. 2. Concentration dependence of their bromination activity

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V2O5 NW activity at different parameters
Fig. 3 | Steady-state kinetics of the V2O5 nanowires at pH 8.3.
3.(a) At higher concentrations of Br-, non-competitive inhibitory effect observed as in
Vanadium chloroperoxidase (V-CPO) [13-15]. Such inhibition is unexpected for inorg. NP’s.
3.(b) Variation of H2O2 concentration, V2O5 nanowires, Br- and MCD Conc. constant.
Michaelis– Menten behaviour observed. Steady-state kinetics determined in phosphate
buffer (pH 8.0), inhibition effect did not occur, suggests that buffer plays an important role
in catalysis. Values observed are similar to [ref. 16,17]
V2O5 NW tolerate higher H2O2 conc., without reduction in their catalytic activity

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Wolfgang et al
3(c) Determine pH dependence
bromination reaction rate catalyzed by
V2O5 NW using diff. buffer, constant
reactant conc.
Buffer influences the stability of Peroxo
complex formed in initial stage of
reaction.
V2O5 NW activity at different parameters
3(d), Stability of catalytic activity of
V2O5 NW over a long period.
No change in surface morphology was
observed.

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Wolfgang et al
Fig. 3(e) Proposed catalytic bromination mechanism
for the V2O5 nanowires
A mechanistic proposal for the
bromination activity of V2O5 in the
presence of Br- and H2O2 based on the
crystal structure of V2O5 and the
kinetic parameters.
Figure S2 | 1O2 formation by V2O5 nanowires
catalyzing the oxidation of bromide by H2O2.
The chemiluminescence derived from
the singlet oxygen (1O2,1Δg) transition to
stable triplet (1O2, 3Σg) was measured.
A clear increase during the first 30 s is
observed reaching its maximum at 75s
and dropping afterwards due to H2O2
consumption.
Bromination Mechanism

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Wolfgang et al
a) Pure medium.
b) Medium to which H2O2 (10 μM) and
Br- (1mM) were added. No significant
color changes occur.
c) Medium to which V2O5 nanowires
(0.02m/mL), H2O2 (10 μM) and Br-
(1mM) were added.
Observation:
A significant color change from red to
purple observed due to the V2O5
mediated formation of HOBr that
diffuses and reacts strongly with phenol
red converting it to bromophenol.
This data confirms that the V2O5
nanowires, in the presence of H2O2 and
Br-, display an intrinsic brominating
activity.
Figure S5 | Bromination of phenol red
contained in the Mannitol Salt Phenol Red
Agar (S. aureus growth medium) by V2O5
nanowires after 8h incubation at 37 C.
Bromination of the MR Agar

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Wolfgang et al
V2O5 nanowires display bromination activity in seawater
Acute toxicity (24 h LD50, dose lethal to 50% of animals tested) assessed by different
concentrations of V2O5 nanowires on a marine biota model.
In parallel, acute toxicity of different concentrations of International Maritime Organization
(IMO)- approved compounds (Zn and Cu pyrithiones—Zn/CuPT) were also determined .
Result : From dose–response curves, in terms of marine biota toxicity, V2O5 nanowires are 14
and 1,000-fold less toxic than ZnPT and CuPT, respectively.
Toxicity against Marine biota
Figure S7 | Bioassays/acute toxicity (24h LD50). The dose response curve was build for: a) CuPT, b) ZnPT and
c) V2O5 nanowires.

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Wolfgang et al
Bacterial cell density/adhesion evaluated by fluorescence microscopy on
the different halves of painted stainless steel plates.
No significant decrease of bacterial cells adhesion is observed indicating
that the V2O5 nanowires are not toxic per se and is active only the
presence of the correspondent substrates (Br- and H2O2). Scale bar: 100
μm.
Fig. 5 | Potential biotechnological application of V2O5 nanowires as additive for marine paints with
antibacterial/antifouling properties.
−V2O5 NW
+V2O5 NW +V2O5 NW−V2O5 NW −V2O5 NW +V2O5 NW
Paintedstainlesssteel
E. coli S. aureusa b c
RESULT & DISCUSSION

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Wolfgang et al
S. aureus
S. aureus+V2O5
NW +Br−+H2O2
E. coli+V2O5
NW +Br−+H2O2E. coli
Fig. 4 | Representative digital images showing the influence of the catalytic activity of V2O5 nanowires
on the growth of Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria.
a b c d
RESULT & DISCUSSION
4(b) Gram-negative: E. coli co-incubated with V2O5 nanowires, Br- and H2O2.
Decrease in bacterial population observed.
4(d) Gram-positive: S. aureus co-incubated with V2O5 nanowires, Br- and H2O2.
Color change from red to yellow indicates presence and growth of S. aureus.
Comparatively, decrease in the bacterial population (90%) observed in 4(d).

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+V2O5 NW +V2O5 NW
t = 0 t = 60 days
Fig. 6 | Effect of nanoparticles on biofouling in situ.
6(a-b) | Immediately after fixation, both stainless-steel plates (with and without
V2O5 nanowires) had clean surfaces. The boat was kept in seawater (lagoon with
tidal water directly connected to the Atlantic Ocean). After 60 days, the boat was
taken from the water. The painted stainless-steel plates with no V2O5 nanowires
suffered from severe natural biofouling and covered with Algae. Plates with V2O5
nanowires showed a complete absence of biofouling.
Result For Real Time Experiments

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CONCLUSION
Vanadium pentoxide nanowires have the potential to be an
alternative approach to conventional anti-biofouling agents.

 Nanotechnology- One of the most explored fields of Chemistry-
Physics in the recent past (Thanks to Faraday’s colloidal Gold
suspension), must be taken into consideration for it’s possible uses in
Green chemistry and Technology.
 Many scientists and researchers are using Nanomaterials over bulk
materials for Catalysis and other metal-catalyzed reactions.
 Nanomaterials have opened a new dimension of green chemistry
by bringing down the consumption of chemicals to nano metrics.
 This paper displays one of the most important principle of Green
Chemistry “Atom Economy”.
 Hence, I conclude, “SIZE DOES MATTERS”!
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[3] DOI: 10.1038/NNANO.2012.91
[4] Adv. Mater. 23, 690–718 (2011).
[5] J. Biol. Chem. 281, 9738–9744 (2006).
[6] Phytochemistry 57, 633–642 (2001).
[7] Biochemistry 34, 12689–12696 (1995).
[8] Chem. Rev. 104, 849–902 (2004).
[9] J. Am. Chem. Soc. 105, 3101–3110 (1983).
[10] J. Am. Chem. Soc. 114, 760–767 (1992).
[11] Adv. Funct. Mater. 21, 501–509 (2011).
[12] J. Biol. Chem. 263, 12326–12332 (1988).
[13] Ch. 5, 55–79 (Marcel Dekker, 1991).
[14] Proc. Natl Acad. Sci. USA 94, 2145–2149 (1997).
[15] IUBMB Life 39, 665–670 (1996).
[16] Chem. Rev. 94, 625–638 (1994).
[17] J. Am. Chem. Soc. 114, 760–761 (1992).
[18] Chem. Rev. 237, 89–101 (2003).
[19] Adv. Synth. Catal. 345, 849–858 (2003).
[20] Biochim. Biophys. Acta. 1079, 1–7 (1991).
[21] Mar. Chem. 112, 72–80 (2008).
REFERENCES

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Vanadium pentoxide nanoparticles mimic vanadium haloperoxidases and thwart biofilm formation

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