Biogenic synthesis and applications of metal nanoparticles

BIOGENIC SYNTHESIS AND BIOGENIC SYNTHESIS AND APPLICATIONS OF METAL APPLICATIONS OF METAL

NANOPARTICLESNANOPARTICLES

Why Nano Particles ?

Nanoparticles are of interest because of the new properties (such as chemical reactivity and optical behaviour) that they exhibit compared with larger particles of the same materials.

For example, titanium dioxide and zinc oxide become transparent at the nanoscale and have found application in sunscreens.

Nanoparticles have a range of potential applications: in cosmetics, textiles and paints. in drug delivery. as catalysts.

Nanoparticles and Nanoparticles and Bulk MaterialsBulk Materials

o Metallic nanoparticles have different physical and chemical properties from bulk metals

o Nanoparticles have unique optical, electronic and chemical properties.

o As the dimensions of the material is reduced the electronic properties change drastically.

o Magnetic properties are also different between bulk and nanomaterials

Nano-scale effects on properties

Synthesis- Bottom Up - Liquid Phase Methods

The chemical reduction (liquid/liquid) method carried out by the reduction of metal ions to their zero oxidation states (i.e., Mn+ → M0)

Principal advantage of this method is the facile fabrication of particles of various shapes viz., nanorods, nanowires, nanoprisms, nanoplates, and hollow nanoparticles

It is possible to fine-tune the shape and size of the nanoparticles by changing the reducing agent, dispersing agent, reaction time and the temperature

Plant Extracts as Reducing Plant Extracts as Reducing AgentsAgents

Plant sources containing the phyto constituents viz., Plant sources containing the phyto constituents viz., Tannins, Alkaloids, Polyphenols, Flavonoids, Citric acid Tannins, Alkaloids, Polyphenols, Flavonoids, Citric acid are are Good reducing agentsGood reducing agentsEasily availableEasily availableCost effectiveCost effectiveEco-friendlyEco-friendlyDifferent size and shapes of nanoparticles are also Different size and shapes of nanoparticles are also prepared using plant extractsprepared using plant extracts

Silver Silver NanoparticlesNanoparticles

Among various noble metal nanoparticles, silver Among various noble metal nanoparticles, silver

nanoparticles (AgNPs) are of great interest to the nanoparticles (AgNPs) are of great interest to the

researchers because of easy availability, very low researchers because of easy availability, very low

cost and emerging applications in the areas viz., cost and emerging applications in the areas viz.,

catalysis, medicine, energy, sensors and optics. catalysis, medicine, energy, sensors and optics.

Factors affecting the formation of Factors affecting the formation of AgNpsAgNps

Concentration of AgNOConcentration of AgNO33

pH of the reactionpH of the reaction Concentration of the ExtractConcentration of the Extract Temperature and EnvironmentTemperature and Environment Reaction time and LightReaction time and Light

Characterization of Characterization of NanoparticlesNanoparticles

Visual observation and UV-Vis spectroscopyVisual observation and UV-Vis spectroscopy FT-IR Spectroscopy (To analyze capping mechanism)FT-IR Spectroscopy (To analyze capping mechanism) X-Ray Diffraction (To analyze geometry)X-Ray Diffraction (To analyze geometry) DLS (To analyze size distribution)with Zeta potential DLS (To analyze size distribution)with Zeta potential

(To analyze the stability)(To analyze the stability) HR-TEM (To investigate the size and distribution)HR-TEM (To investigate the size and distribution) EDS (To analyze elements presents in colloidal nano)EDS (To analyze elements presents in colloidal nano)

Shape dependent SPR of AgNPsShape dependent SPR of AgNPs

Various colors of AgNPs with different shapes

Size dependent SPR of AgNPsSize dependent SPR of AgNPs

Blue Shift – Decrease in particle sizeBlue Shift – Decrease in particle sizeRed Shift – Increase in particle sizeRed Shift – Increase in particle size

High Resolution –High Resolution –Transmission Electron Transmission Electron

MicroscopyMicroscopy

TEM images of Different TEM images of Different size of AgNPssize of AgNPs

TEM images of silver nanoparticles with diameters of 20 nm, 60 nm and 100 nm.

Scale bars are 50 nm.

Triangular gold nanoparticles – using Triangular gold nanoparticles – using Lemongrass extractLemongrass extract

Dynamic Light ScatteringDynamic Light Scattering

Dynamic Light Scattering (DLS) is an important tool for characterizing the size of nanoparticles in solution.

DLS measures the light scattered from a laser that passes through a colloidal solution and by analyzing the modulation of the scattered light intensity as a function of time, the hydrodynamic size of particles and particle agglomerates can be determined.

Larger particles will diffuse slower than smaller particles.

Zeta Zeta potentialpotential• Zeta Potential analysis is a technique for determining

the surface charge of nanoparticles which attracts a thin layer of ions of opposite charge to the nanoparticle surface from solution (colloids).

• The magnitude of the zeta potential is predictive of the colloidal stability.

• Nanoparticles with Zeta Potential values greater than +25 mV or less than -25 mV typically have high

degrees of stability. Dispersions with a low zeta potential value will eventually aggregate due to van der Waal inter-particle attractions.

Works done in our Works done in our lab lab

Visual observation and UV-Vis spectrum of AgNPs synthesized using T. chebula

Effect of pH on formation of AgNPs synthesized using T. chebula

Blue shift was observed (acidic to basic pH)– Particle size decreases

Synthesis of AgNPs by T. chebula

Characterization of AgNPs synthesized Characterization of AgNPs synthesized using using T. chebulaT. chebula

FT-IR spectra of aq. Extract of T. chebula (A) and synthesized AgNPs (B) XRD pattern of synthesized AgNPs using T. chebula

HR-TEM and SAED images of AgNPs (25 nm)

DLS (30 nm) and Zetapotential (-30.2 mV)

Characterization of AgNPs synthesized Characterization of AgNPs synthesized using using T. chebulaT. chebula

UV–Vis spectra of methylene blue reduction by Terminalia chebula capped AgNPs

Reduction of methylene blue using Reduction of methylene blue using biogenic AgNPs synthesizedbiogenic AgNPs synthesized

Ag Ag + e

Ag + e Ag

Reduced

Methylene blue(Blue color)

Leucomethylene blue(Colorless)e

e

Terminalia chebula Fruit extract Oxidized product+e

e

Start Here

S

N

NNH3C

CH3

CH3

CH3Cl-S

HN

NNH3C

CH3

CH3

CH3

Catalytic action of AgNPs in the presence of Terminalia chebula on the degradation of methylene blue (electron relay effect)

Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using P. P. granatumgranatum

UV-Vis spectra of Aq. Extract of P. granatum (A) UV-Vis spectra of Aq. Extract of P. granatum (A) synthesized AgNPs (initial) (B) After 10 min (C)synthesized AgNPs (initial) (B) After 10 min (C)

FT-IR spectra of Aq. Peel extract of P. granatum (A) FT-IR spectra of Aq. Peel extract of P. granatum (A) synthesized AgNPs (B)synthesized AgNPs (B)

A B

C

(111)

Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using P. P. granatumgranatum

HR-TEM and DLS images of AgNPs synthesized using P. granatum (40 nm – distorted spherical)

Reduction of 4-NP by NaBHReduction of 4-NP by NaBH44 in the presence of in the presence of AgNPs synthesized using AgNPs synthesized using P. granatumP. granatum

Polyphenols

Extract BiogenicAgNPs

BH4

BiogenicAgNPs

HH H

BiogenicAgNPs

H HH Biogenic

AgNPs

H

4-AP

4-NP 4-NP

0.01 MAgNO3

Catalytic action of AgNPs on the reduction of 4-NP (Langmuir-Hinshelwood model)

UV-Vis spectra of 4-nitrophenol reduction by NaBH4

using AgNPs as catalyst

A- 4-nitrophenolB- 4-nitrophenolateC- 4-aminophenol

Capping Capping MechanismMechanism

OH

OH

HO

O-

O-

HO

+ 2 H+ + 2 e-2 Ag

O-Ag+

O-Ag+

HO

OO

HO

O

O

OH

O

O

OH

O O

OH

Ag

Capping of AgNPs

Phytoconstituent

Stabilized through electrostaticallyStabilized through electrostatically

Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using A. A. niloticanilotica

Phytoconstituents of Acacia nilotica Effect of concentration of Acacia nilotica extract

Visual observation at various pH

Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using A. A. niloticanilotica

FT-IR spectra of Acacia nilotica and synthesized AgNPs HR-TEM images of AgNPs synthesized using

A. nilotica

Ag+

H2O

GC/AgNPsCl

CH3

TolueneBenzyl chloride

Acacia nilotica pods

AgNPs

AgNPsAgNPs

AgNPs

AgNPs

Electrocatalytic activity of AgNPs

Role of AgNPs synthesized using Role of AgNPs synthesized using A. nilotica A. nilotica on reduction of on reduction of benzyl chloridebenzyl chloride

Electrode Potential (V) Current density × 10-

5 (A)GC -0.81 -6.14

Bulk silver -0.78 -7.19GC/AgNPs -0.74 -8.22

Negative shift of reduction potential of GC/AgNPs

Indicates the catalytic activity of biogenic AgNPs

HO

HO

H3C CH3

O

OHHO

H

HH3C CH3

Arjunic acid

HO

CH3 CH3 HHO

H H CH3

HO

CH3

H3C CH3

OH

O

CH3

CH3

Arjunolic acid

HO

OH

HO

CH3

CH3

CH3

CH3

H3C CH3

HO

O

OH

Arjungenin

Terminalia cuneata

Major Phytoconstituents -Terminalia cuneata

Synthesis of AgNPs using Synthesis of AgNPs using Terminalia cuneataTerminalia cuneata(Revision submitted to Colloids and Surfaces: B)

200 300 400 500 600 700 8000.00

0.05

0.10

0.15

0.20

Abs

orba

nce

Wavelength ( (nm))

0.50 ml (413 nm) 1.00 ml (415 nm) 1.75 ml (415 nm) 2.00 ml (415 nm) 2.50 ml (415 nm)

200 300 400 500 600 700 8000.0

0.5

Abs

orba

nce

Wavelength ( (nm))


200 300 400 500 600 700 8000.0

0.5

pH - 9

pH - 8

pH - 7

pH - 5

Abs

orba

nce

Wavelength ( (nm))

417 nm 417 nm 416 nm 416 nm 413 nm

pH - 6

200 300 400 500 600 700 8000.0

0.5

1.0

Abs

orba

nce

Wavelength ( (nm))

420 nm 418 nm 417 nm 412 nm 399 & 545 nm

pH - 9

pH - 8

pH - 7

pH - 6

pH - 5

Synthesis of AgNPs at 10 min usingTerminalia cuneataSynthesis of AgNPs at 24 h usingTerminalia cuneata

Efeect of pH on AgNPs synthesis – at 10 min Efeect of pH on AgNPs synthesis – at 24 h

Absorbance increasesRed shift – Size increases

Λmax- 413 – Mostly spherical

Red shift – Size increases

Blue shift – Size decreases Blue shift – Size decreases & anisotropic

Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using Terminalia Terminalia cuneatacuneata

4000 3500 3000 2500 2000 1500 1000 5000

20

40

60

80

% T

Wavenumber (cm-1)

A B

3385

1625

1440

1383

1050

30 40 50 60 70 80

0

1000

2000

3000

4000

5000

6000

7000

Cou

nts

2

38.2 (1 1 1)

44.5 (2 0 0)

64.5 (2 2 0)

77.6 (3 1 1)

FT-IR spectra of AgNPs synthesized by T. cuneata extract

XRD pattern of AgNPs synthesized by T. cuneata extract


HR-TEM images of synthesized AgNPS using T. cuneata (Average size 40 nm)


Na+

Na+

SO

O

-O

SO

OO-

N

NO

N

N O

Disodium 4,4'-bis[(4-ethoxyphenyl)azo]stilbene-2,2'-disulphonate

H2

H2

H2

H2

NaBH4

AgNPs

NH2O

2

Na+

Na+

SO

O

-O

SO

OO-

NH2

NH2

Disodium (E )-6,6'-(ethene-1,2-diyl)bis(3-aminobenzenesulfonate)4-ethoxyaniline

Catalytic action of AgNPs synthesized using Terminalia cuneata on the reduction of Direct Yellow 12

300 400 500

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

Abs

orba

nce

Wavelength () (nm)

Initial

5 mins

10 mins

40 mins

.

.

.

Degradation of Dirct Yellow-12 by AgNPS synthesized by T. cuneata follow Langmuir-Hinshelwood model

OH

OH

HO O

OH

OH

Catechin

OH

OH

HO O

OH

OH

Epicatechin

OOH

HO O

OH

Apigenin

O

O

HO

HO

Methyl 3,4-dihydroxybenzoate

O

O

HO

HO

3,4-dihydroxyphenyl acetate

O

OH

O

OH

HO

OH

OH

OH

OH

OH

HOOH

Procyanindin B2

OHO

OH

OH

OOH

OH

Taxifolin

Tamarindus indica

Phytoconstituents of T. indica seed coat

Synthesis of AgNPs using Synthesis of AgNPs using Tamarindus indicaTamarindus indica(Submitted to Spectroscopy Letters)

200 300 400 500 600 700 8000.00

0.05

0.10

0.15

0.20

0.25

Abs

orba

nce

Wavelength ( (nm))


200 300 400 500 600 700 8000.0

0.1

0.2

0.3

0.4

0.5

Abs

orba

nce

Wavelength ( (nm))

0.10 ml (441 nm) 0.25 ml (432 nm) 0.50 ml (434 nm) 1.00 ml (438 nm) 2.00 ml (aggregated)

200 300 400 500 600 700 8000.00

0.05

0.10

0.15

0.20

0.25

0.30

Abs

orba

nce

Wavelength () (nm)

433 nm 432 nm 428 nm 423 nm 414 nm

pH - 5

pH - 6

pH - 7

pH - 8

pH - 9

200 300 400 500 600 700 8000.0

0.5

Abs

orba

nce

Wavelength ( (nm))

448 nm 430 nm 428 nm 419 nm 398 nm & 555 nm

pH - 7

pH - 6

pH - 5

pH - 8

pH - 9

Synthesis of AgNPs at 10 min using T. indica Synthesis of AgNPs at 24 h using T. indicaEffect of pH on AgNPs synthesis – at 10 min Effect of pH on AgNPs synthesis – at 24 h


Blue shift – Size decreases



Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using Tamarindus Tamarindus indicaindica

4000 3500 3000 2500 2000 1500 1000 500

60

80

100

120

% T

Wavenumber (cm-1)

3417

3409

29192850

29212863

1619

1635

1384

1112

1112A

B

FT-IR spectra of AgNPs synthesized by T. indica extract

HR-TEM images of synthesized AgNPS using T. indica (30 nm) Spherical


10 20 30 40 50 60 700

500

1000

1500

2000

2500

3000

Cou

nts

2

38.23 (111)

44.62 (200)

64.51 (220)

XRD patterns of AgNPs synthesized by T. indica extract DLS (30 nm) Zeta potential (-35 mV) of AgNPs synthesized by T. indica

200 300 400 500 600-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Abs

orba

nce

Wavelength () (nm)

412 nm282 nm

224 nm

300 400 500 6000.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

Initial 2 min 5 min10 min15 min30 min35 min40 min45 min

Abs

orba

nce

Wavelength () (nm)

394 nm

380 nm282 nm

UV-Vis spectra of 2–nitro aniline Reduction of 2–nitro aniline by AgNPs synthesized by T. indica


O

OH

O

O

HO

Syringic acid

OHO

HO

p-coumaric acid

O

OH

OH

HOOH

OH

OH

Epigallocatechin

Anacardium occidentale Anacardium occidentale –seed coat

Phytoconstituents of Anacardium occidentale

Synthesis of AgNPs using Synthesis of AgNPs using Anacardium occidentaleAnacardium occidentale(Revision submitted to Process Biochemistry)

•Red shift was observed at different times

•Particle size increased with increase of concentration of extract

Effect of Concentration of Extract


Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using Anacardium Anacardium occidentaleoccidentale

UV-Vis spectroscopy

Effect of pH•Blue shift was observed at different times

•Particle size decreased with change of pH from acidic to basic

4000 3500 3000 2500 2000 1500 1000 5000

20

40

60

80

100

% T

rans

mitt

ance

Wave Number (cm-1)

A. occidentale extract AgNPs synthesized using A. occidentale

3395

2925

1614

1519

1450

1384

1143

835

A

B

10 20 30 40 50 60 70 800

200

400

600

800

1000

1200

1400

Cou

nts

2

Ag (111)

Ag (200)

Ag (220)

HR-TEM images of synthesized AgNPS using A. occidentale (40 nm)

FT-IR spectra of AgNPs synthesized by A. occidentale extract XRD pattern of AgNPs synthesized by A. occidentale extract

Characterization of AgNPs synthesized using Characterization of AgNPs synthesized using Anacardium Anacardium occidentaleoccidentale

Electrode Potential (V) Current density × 10-5 (A)

GC 0.73 2.12

Bulk silver 0.69 2.98

GC/AgNPs 0.60 5.03

Cyclic voltammogram of electrocatalytic oxidation of hydrazine hydrate in K2SO4 at GC, bulk silver and GC

modified AgNPsVoltammeteric data for the oxidation of hydrazine at GC,

bulk silver and GC/AgNPs in K2SO4

Negative shift of oxidation potential indicates the catalytic activity of biogenic AgNPs

Electrocatalytic oxidation of hydrazine hydrate by AgNPs

N2H4 + H2O N2H3 (ads) + H3O+ + e-

N2H3 (ads) 3H2O+ N2 3H3O++ 3e-+

OHO

OH O

OH

OCH3

OH

Isorhamnetin

OH

OOH

HO O

OH

OH

Quercetin

OH

OH

HO O

OH

OH

(+)-Catechin

OH

HO

OH

Resveratrol

O

HO

O

OH

Ferulic acid

O

OH

O

OH

Vanillic acid

Areca catecheu

Chemical constituents present in the Areca catechu nut

Synthesis of AgNPs using Areca catechu nut

(Submitted to Spectrochimica Acta A)

Characterization of AgNPs synthesized using Areca catechu nut

Average particle size 40 nm

Electrode Potential (V) Current density × 10-4 (A)

GC 1.29 1.77

Bulk silver 0.71 2.39

GC/AgNPs 0.52 4.14

CV of electrocatalytic oxidation of glucose in NaOH at GC, bulk silver and GC modified AgNPs CV data of oxidation of glucose at GC, bulk silver and

GC/AgNPs in NaOH

Electrocatalytic oxidation of glucose in NaOH

CO H

OHR

OH-

CO

ROH + H+ + e-

CO

ROH

OH-

CO

RO + H+ + e-

H2OR'COOH

Negative shift of oxidation potential indicates the catalytic activity of biogenic AgNPs

Synthesis of silver Synthesis of silver nanoparticles using nanoparticles using

microorganismsmicroorganisms Synthesis of silver nanoparticles using Penicillium fungi, Bacillus strain, Synthesis of silver nanoparticles using Penicillium fungi, Bacillus strain,

marine bacterium (Idiomarina sp. PR58-8) Pseudomonas fluorescens has marine bacterium (Idiomarina sp. PR58-8) Pseudomonas fluorescens has also been reported. also been reported.

The extracellular mechanism of silver nanoparticle creation was The extracellular mechanism of silver nanoparticle creation was investigated by regular methods viz., UV-Vis spectroscopy, FT-IR, TEM, DLS, investigated by regular methods viz., UV-Vis spectroscopy, FT-IR, TEM, DLS, zeta potential and XRDzeta potential and XRD

Irradiation methodsIrradiation methods

Laser ablation methodLaser ablation method Microwave irradiationMicrowave irradiation Sun light exposureSun light exposure

– Highly stable nanoparticlesHighly stable nanoparticles– High purityHigh purity

Other Applications of biogenic Other Applications of biogenic nanoparticlesnanoparticles

Antibacterial agentsAntibacterial agents Antiviral agentsAntiviral agents Anti-oxidantsAnti-oxidants Anti biofilm Anti biofilm Larvicidal agentsLarvicidal agents Disinfection of waterDisinfection of water Decrease of biofoulingDecrease of biofouling Wettability of hairWettability of hair

•All the plant extracts chosen for the present study act as good reducing agents and protecting

agents for the formation and stabilization of AgNPs.

•Upon increasing the concentration of the chosen plant extracts, the size of AgNps increased,

as evident from the results of UV-Vis spectroscopic studies.

•In the AgNPs synthesis, pH played a crucial role to control the size and shape of AgNPs.

•In neutral pH, the synthesized AgNPs are highly stable when compared with other pH ranges.

Moreover, the sizes of the AgNPs were decreased on changing the pH from acidic to basic in

the case of studied extracts.

•The synthesized AgNPs using all the chosen plant extracts were found to have the absorbance

in the wavelength of 400-450 nm which suggested the spherical shape of biogenic AgNPs.

ConclusionsConclusions

•The phytoconstituents (mainly tannins and polyphenols) present in all the studied

plant extracts were responsible

for reduction of Ag+ and protection of AgNPs which was analyzed by FT-IR studies.

•The average size distribution of AgNPs (synthesized using all the extracts) was

found to be 20-50 nm in size as studied using DLS measurement.

•The high negative zeta potential (~30-40 mV) of synthesized AgNPs suggested the

high stability.

•HR-TEM and EDS profile corroborated the results of DLS studies

ConclusionsConclusions

To ConcludeTo Conclude

It is true that there is plenty of room It is true that there is plenty of room at the bottom at the bottom

Future will see Biogenic Future will see Biogenic nanotechnology in Medicine, nanotechnology in Medicine, Environment and other domainsEnvironment and other domains

Thank UThank UOlny post by Maruthupandi M Indian-TN-MDU

Biogenic synthesis and applications of metal nanoparticles

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