Rajasokkappan.S

1959, Feynman’s talk “There is plenty of room at the bottom”

1965, Moore’s original paper 1981, Drexler began popularizing the "Molecular

Manufacturing,” 1984, invention of STM [Binning] 1985, discovery of fullerens [smalley] 1986, invention of AFM 1990, IBM written in Xenon

Relatively larger surface area

Chemically more reactive and affect their strength or electrical properties

Quantum effects of materials - that affect the optical, electrical and magnetic behaviour of materials

Transmission Electron Microscope (TEM)

Atomic Force Microscope (AFM)

Scanning Tunneling Microscope (STM)

Small silicon tip as probe - make images of sample material

Probe moves along surface

Electrons of atoms in sample repel those in probe

Creates 3-D images

High-energy electron beam to probe material with thickness < 100 nm

Some electrons are absorbed or bounced off object; some pass through the object and make magnified images

Digital camera records images

Nanosized probe to scan objects and materials

Uses tunneling to detect surface and creates a map of surface

Rate of electrons that tunnel from probe to surface related to distance between probe and surface

Antimicrobial agent

Nanoparticles that deliver chemotherapy drugs

Nanotubes used in broken bones to provide a structure for new bone material to grow

Nanoshells that concentrate the heat from infrared light to destroy cancer cells with minimal damage to surrounding healthy cells.

Q.dots that identify the location of cancer cells in the body

Nanoparticles that can attach to cells infected with various diseases in a blood sample, the particular disease

One dimension Less than 100nm Nanoscale layers

Eg. thin films or surface coatings like computer chips

Two dimensions Nanowires and nanotubes Three dimensions Precipitates Colloids and Quantum dots (tiny particles of

semiconductor materials)

Dispersion of preformed polymers

Polymerization of monomers

Ionic gelation or coacervation of hydrophilic polymers

Nanoparticles prepared from such as proteins, polysaccharides and synthetic polymers

The selection of matrix materials is dependent on (Kreuter )

a) Size of nanoparticles required

b) Inherent properties of the drug, e.g., aqueous solubility and stability

c) Surface characteristics such as charge and permeability

d) Degree of biodegradability, biocompatibility and toxicity

e) Drug release profile desired

f) Antigenicity of the final product

Liposomes, polymer nanoparticles (nanospheres and nanocapsules)

Solid lipid nanoparticles, nanocrystals, polymer therapeutics such as dendrimers, fullerenes (most common as C60 or buckyball, similar in size of hormones and peptide a-helices)

Inorganic nanoparticles (e.g. gold and magnetic nanoparticles)

Fullerenes, a carbon allotrope The buckminster fullerene is the most common

form of fullerene 7 Å in diameter with 60 carbon atoms arranged in

a shape known as truncated icosahedrons It resembles a soccer ball with 20 hexagons and

12 pentagons

Nanotubes -

opened on two sides with additional atom groups added in the characteristic hexagon shape to form a hollow carbon tube (cylinder)

Sheet of graphite (a hexagonal lattice of carbon) rolled into a cylinder

This nanotubes are used to tracking oestrus in animals - detect the estradiol antibody at the time of oestrus by near infrared fluorescence

Used in gene therapy

Dendrimers are nanomolecules with regular branching structures

The branches arise from the core in shape of a spherical structure by means of polymerisation

This results in formation of cavities within the dendrimer molecule which can be used for drug transport

The ends of the dendrimer molecule can be attached with other molecules for transport

Dendrimer - antimicrobial agents against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli

Synthetic nanomaterials will be the diagnoses, treatment and eradication of malignant tumors that commonly affect the small animal geriatric population

Alternative to direct irradiation of tumors

Dendrimers can act as carriers, called vectors, in gene therapy

A 2-10 nm nano-scale crystalline structure made from cadmium selenide

Re-emits the white light in a couple of nanoseconds - specific color

which can be made to fluorescence when stimulated by light

Their structure consists of an inorganic core, the size of which determines the colour emitted, an inorganic shell and an aqueous organic coating to which biomolecules are conjugated

These particles enable powerful new approaches to genetic analysis, drug discovery, and disease diagnostics

Quantum dots - emit light at any wavelength

Inserted almost anywhere, including liquid solution, dyes etc

Quantum dots can be attached to a variety of surface ligands, and inserted into a variety of organisms for in-vivo research

quantum dots respond to light it may be possible to illuminate the body with light and stimulate the quantum dot to heat up sufficient to kill the cancerous cell

Name Size Composition Details

Quantum Dots 2-10 nm

Colloidal fluorescent semiconductor nanocrystals. Central core consists of elements from groups II - VI of the periodic table

Dendrimers <15 nm

Highly branched synthetic polymers with a layered architecture - consisting of a central core, an internal region, and several terminal groups

Magnetic nanoparticles

10-20 nmSpherical nanocrystals with Fe2+ and Fe3+ core surrounded by dextran or PEG (polyethelene glycol) molecules

Gold nanoparticles

<50 nmCan be prepared into different geometries - nanospheres, nanoshells, nanorods, or nanocages

Carbon Nanotubes (CNT)

<100 nm Coaxial graphite sheets

Nano pharmaceuticals – Drug delivery system

Early diagnosis of disease

Nano therapy

The development of ‘smart’ treatment delivery systems on the nanoscale uses similar concepts applied at the molecular level.

For example, ‘smart’ drug delivery systems in animals would most likely contain small, sealed packages of the drug to be delivered.

The packages would not be opened until they reach the desired location in the animal, e.g. the site of infection.

Time-controlled

Spatially Targeted

Self-regulated

Remotely Regulated

Pre-programmed

The silver nanoparticles show efficient antimicrobial property compared to other salts

Most effective on E.Coli, S.aureus, Klebsiella, Pseudomonas

The nanoparticles preferably attack the respiratory chain, cell division finally leading to cell death

The STEM (Scanning Transmission Electron Microscopy) confirms the presence of silver in the cell membrane and inside the bacteria

Silver nanoparticles in most studies are suggested to be non-toxic. But it suggested to be hazardous to the environment (Braydich-Stolle et al., 2005)

The current systems are limited by their selectivity and efficiency to concentrate rare cells for molecular assays

Nanoscience can detect - circulating cancer cells, which present often at 1–2 cells per milliliter of blood.

Combinatorial use of magnetic nanoparticles and semiconductor QDs - increase the ability to capture and evaluate these rare circulating cancer cells

Bionanobarcodes, nanocantilevers, and nanowires are promising technologies

Cancer cells detection Protein and nucleic acid detection based on

biobarcode-amplification Gold nanoparticles are modified with both target

capture strands and bar code strands that are subsequently hybridized to bar code DNA, and magnetic microparticles modified with target capture strands (BCA)

Gold nanoparticles and the magnetic microbeads form sandwich structures that are magnetically separated from solution.

Unhybridized bar code DNA are removed The bar codes (hundreds to thousands per target)

are detected by using a colorimetric method

QD staining provides spatial localization information (both inter- and intracellular),

QD probes are delivered to tumors by both a passive targeting mechanism and an active targeting mechanism

In the passive mode, macromolecules and nanometer-sized particles are accumulated preferentially at tumor sites through the Enhanced permeability and retention (EPR)effect.

For active tumor targeting, Gao et al. used antibody conjugated QDs to target a specific membrane antigen.

Multifunctional nanoparticles for integrated cancer imaging and therapy

Vaccines require immunostimulating compounds, adjuvants, which act nonspecifically to increase the immune response to a defined antigen

Nanometer adjuvants are

1. Liposome

2. ISCOM based adjuvant

3. Biobullets

4. Virus like particles

Nano-particles - 40–50 nm - potential to induce potent cell mediated (CD4 and CD8 T cells) as well as humoral immune responses

VLP vaccine against BT & AHS – strong protection

ISCOM based vaccines effective on H5N1 in chickens and EHV - 2 in horses

Liposomes added vaccines protect the cattle against BVDV

Liposomes have also been used to deliver allergen extracts as immunotherapy for refractory canine atopic dermatitis

“Biobullets” made of photopolymerized PEG hydrogels can serve as biodegradable bullets used to wild animals for vaccination. Eg. Bruella abortus