Bionanomaterials

Dr. P.Gopinath Ph.D.Assistant Professor

Centre for NanotechnologyIndian Institute of Technology Roorkee

Email: nanobiogopi@gmail.com

Nanoparticle is any material having atleast one of itsdimensions in the range of 1-100nm.

“Nano” – derived from a Greek word “Nanos” meaningDWARF or small.

'Norio Taniguchi, 1974‘ -- coined the term nanotechnology

NPs are mainly of two types1) Monodispersed-such NPs are uniformly sized Difficult to synthesize

2) Polydispersed-these NPs have non uniform dimensions.

What is a Nanoparticle? Nanoparticle is any material having atleast one of its

dimensions in the range of 1-100nm.

“Nano” – derived from a Greek word “Nanos” meaningDWARF or small.

'Norio Taniguchi, 1974‘ -- coined the term nanotechnology

NPs are mainly of two types1) Monodispersed-such NPs are uniformly sized Difficult to synthesize

2) Polydispersed-these NPs have non uniform dimensions.

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TEM Image of Nanoparticles

Monodispersed nanoparticles Polydispersed nanoparticles

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These highly monodisperse nanoparticles consistsof an Au core and a shell of Pd. They are designedwith a highly faceted morphology which makesthem ideal for catalytic applications.

http://www.boutiq.co.nz/products/au-pd-core-shell/

Oliveira et al., 2009.Brazilian Journal of Physics. ISSN 0103-9733Synthesis and characterization of thermo-responsiveparticles of poly(hydroxybutirate-co-hydroxyvalerate)-b-poly(N-isopropylacrylamide)

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Nano-objects are:

- Faster

- Lighter

- Can get into small spaces

- Cheaper

- More energy efficient

- Different properties at

very small scale

Why small is Good?

Nano-objects are:

- Faster

- Lighter

- Can get into small spaces

- Cheaper

- More energy efficient

- Different properties at

very small scale

Surface area increases as size decreases 5

Surface area-to-volume ratio

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Nanoscale Size Effect

• Manifestation of novel phenomena and properties, includingchanges in:

- Physical Properties (e.g. melting point)

- Chemical Properties (e.g. reactivity)

- Electrical Properties (e.g. conductivity)

- Mechanical Properties (e.g. strength)

- Optical Properties (e.g. light emission)

• Manifestation of novel phenomena and properties, includingchanges in:

- Physical Properties (e.g. melting point)

- Chemical Properties (e.g. reactivity)

- Electrical Properties (e.g. conductivity)

- Mechanical Properties (e.g. strength)

- Optical Properties (e.g. light emission)

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Top-down Approach

Building something by starting with a larger component andcarving away material (like a sculpture)

In nanotechnology: patterning (using photolithography) andetching away material, as in building integrated circuits

How to make Nanostructures?

Rock Statue8

Bottom-up

Building something by assembling smaller components(like building a car engine), atom by atom assembly.

In nanotechnology: self-assembly of atoms and molecules,as in chemical and biological systems

How to make Nanostructures?

Brick

Building

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Nanoscale Processes andFabrication

Top-down Approaches Bottom-up ApproachesOptical and x-ray lithography Layer-by-layer self assembly

E-beam and ion-beam lithography Molecular self assembly

Scanning probe lithography Direct assembly

Atomic force microscopiclithography Coating and growth

Material removal and deposition(Chemical, mechanical, or

ultrasonic)Colloidal aggregation

Printing and imprinting

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Physical Methods

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Mechanical Milling

• Nanoparticles from mechanical attrition are produced by a “top-down” process

• Nanoparticles formed in a mechanical device, generically referred to as a “mill,” inwhich energy is imparted to a course-grained material to effect a reduction in particlesize.

• The resulting particulate powders can exhibit nanostructural characteristics on atleast two levels.

• First, the particles themselves, which normally possess a distribution of sizes, can be“nanoparticles” if their average characteristic dimension (diameter for sphericalparticles) is less than 100 nm .

• Second, many of the materials milled in mechanical attrition devices are highlycrystalline, such that the crystallite (grain) size after milling is often between 1 and 10nm in diameter. Such materials are termed “nanocrystalline”.

• During the milling process, large amount of strain imparted to particles, it is virtuallyimpossible to obtain defect-free crystals via mechanical attrition. As a result, we willadhere to the more general definitions; that is, nanocrystals are 1–10 nm in diameter,and nanoparticles are less than 100 nm in diameter.

• Nanoparticles from mechanical attrition are produced by a “top-down” process

• Nanoparticles formed in a mechanical device, generically referred to as a “mill,” inwhich energy is imparted to a course-grained material to effect a reduction in particlesize.

• The resulting particulate powders can exhibit nanostructural characteristics on atleast two levels.

• First, the particles themselves, which normally possess a distribution of sizes, can be“nanoparticles” if their average characteristic dimension (diameter for sphericalparticles) is less than 100 nm .

• Second, many of the materials milled in mechanical attrition devices are highlycrystalline, such that the crystallite (grain) size after milling is often between 1 and 10nm in diameter. Such materials are termed “nanocrystalline”.

• During the milling process, large amount of strain imparted to particles, it is virtuallyimpossible to obtain defect-free crystals via mechanical attrition. As a result, we willadhere to the more general definitions; that is, nanocrystals are 1–10 nm in diameter,and nanoparticles are less than 100 nm in diameter.

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Principles of Milling• The fundamental principle of size reduction in mechanical attrition devices lies in the

energy imparted to the sample during impacts between the milling media.

• This model represents the moment of collision, during which particles are trappedbetween two colliding balls within a space occupied by mass of powder particles.

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Figure 1: Model of impact event at a time ofmaximum impacting force, showing the formationof a microcompact.

E. Kuhn, “Powder Metallurgy,” ASM Handbook, Vol. 7, ASM International: Materials Park, OH. pp. 56–70. 1984.

Planetary Ball Mills

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SEM of Bi4Ti3O12 milled fordifferent times: (a) 3, (b) 9, (c)15,and (d) 20 h.

L. B. Kong et al., Mater. Lett. 51, 108 (2001).

Laser Ablation

Light Amplification by Stimulated Emission of Radiation (LASER)

• Using a laser to vaporize material.16

• NPs by laser ablation, which involves the generation of NPs by laser ablating asolid target that lies in a gaseous or a liquid environment and collection of theNPs in the form of nanopowder or a colloidal solution.

• It is an easy, fast and straightforward method for NPs synthesis/generation ascompared to other methods. It does not require long reaction times or multi-stepchemical synthetic procedures.

• It does not require the use of toxic/hazardous chemical precursors fornanomaterial synthesis and thus is an environmentally friendly (“green”) andlaboratory safe method.

• In the event that generation occurs in water, the resulting NPs, colloidal solutionsare ultrapure, (i.e., they do not contain any counter ions or reaction by- products),and this facilitates the use of the these NPs in biological or biochemical in vivoapplications.

• The produced NPs can easily be functionalized with a ligand of choice, throughthe subsequent addition of the ligand into the NPs’ colloidal solution after itssynthesis or by performing the ablation in a suitable solvent.

Laser Ablation• NPs by laser ablation, which involves the generation of NPs by laser ablating a

solid target that lies in a gaseous or a liquid environment and collection of theNPs in the form of nanopowder or a colloidal solution.

• It is an easy, fast and straightforward method for NPs synthesis/generation ascompared to other methods. It does not require long reaction times or multi-stepchemical synthetic procedures.

• It does not require the use of toxic/hazardous chemical precursors fornanomaterial synthesis and thus is an environmentally friendly (“green”) andlaboratory safe method.

• In the event that generation occurs in water, the resulting NPs, colloidal solutionsare ultrapure, (i.e., they do not contain any counter ions or reaction by- products),and this facilitates the use of the these NPs in biological or biochemical in vivoapplications.

• The produced NPs can easily be functionalized with a ligand of choice, throughthe subsequent addition of the ligand into the NPs’ colloidal solution after itssynthesis or by performing the ablation in a suitable solvent.

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Synthesis of Nanoparticles by LA

To synthesize Ag (Cu2O @ Cu) NPsby LA, a high purity silver (copper)slice is placed on the bottom of glassvessel containing 20 ml of distilledwater.

It is irradiated with focused output of1064 nm of pulsed Nd:YAG laser(Spectra Physics Inc. USA) operatingat fixed energy for 30 minutes.

This results a yellow color in Ag (lightgreen in Copper) colloidal solution.

To synthesize Ag (Cu2O @ Cu) NPsby LA, a high purity silver (copper)slice is placed on the bottom of glassvessel containing 20 ml of distilledwater.

It is irradiated with focused output of1064 nm of pulsed Nd:YAG laser(Spectra Physics Inc. USA) operatingat fixed energy for 30 minutes.

This results a yellow color in Ag (lightgreen in Copper) colloidal solution.

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Experimental configurations and equipment

Generation in Liquids• Synthesis of NPs by laser ablation in liquids the simplest experimental configuration

commonly used by many groups around the world is shown in figure .

• The target is placed at the bottom of a beaker or a petri dish, which is filled with theliquid and fixed onto an XYZ translational stage. The laser beam irradiates thetarget vertically.

XYZ translational stage

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Experimental configurations for the generation on NPs by laser ablation in liquids, with the beamirradiating the target material vertically in an open beaker/Petri dish (a).

Critical Reviews in Solid State and Materials Sciences, 35:105–124, 2010

Chemical MethodsChemical Methods

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Synthesis of metal nanoparticles

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The distinctive colors of colloidal gold and silver are due to a phenomenon known as plasmonabsorbance. Incident light creates oscillations in conduction electrons on the surface of thenanoparticles and electromagnetic radiation is absorbed.

Surface plasmon resonance

When a nanoparticle is much smaller than thewave length of light, coherent oscillation of theconduction band electrons induced by interactionwith an electromagnetic field. This resonance iscalled Surface Plasmon Resonance (SPR).

Figure: Schematic of plasmonoscillation for a sphere, showingthe displacement of theconduction electron chargecloud relative to the nuclei.

When a nanoparticle is much smaller than thewave length of light, coherent oscillation of theconduction band electrons induced by interactionwith an electromagnetic field. This resonance iscalled Surface Plasmon Resonance (SPR).

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Bionanomaterials

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The size of Things

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The greatest discovery: Chemistry inBiology

J.D.Watson & F.Crick D.N.A Double Helix

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DNA

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Lessons fromnature--

DNA bound by base pairs

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Lipids and Protiens

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(Bio) Nanomachines• Biological nanomachines

– Dynein• Molecular motors that walk along microtubule in a cell

– F1ATPase• Synthesizes ATP (energy) by using an influx of protons to rotate

– Bacterium• Swims toward the chemicals (e.g, food) using flagellum

• Biological nanomachines– Dynein

• Molecular motors that walk along microtubule in a cell– F1ATPase

• Synthesizes ATP (energy) by using an influx of protons to rotate– Bacterium

• Swims toward the chemicals (e.g, food) using flagellum

Figures: Alberts, Molecular Biology of the CellDynein F1ATPase

Bacterium30

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Salmonella

10 nm dia. x 10,000 nm long helix

20,000 rpm; reverses within 1 msec

10-16 watts proton motive force

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“Programmed” Self-Assembly

How do we getto these levelsof complexity?

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How do we getto these levelsof complexity?

Hierarchical assembly-molecules to mammals

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