Nanotechnology

Nanotechnology is the practical application of Nanoscience in various fields.

Depiction of Nanotechnology as the practical application of Nanoscience in various fields

Nanoscience studies the properties of materials at nanoscale and Nanotechnology uses these properties to manufacture products.

Nanotechnology is defined as the design, characterization, production, and application of structures, devices, and systems by controlled manipulation of size and shape at the nanometer scale that produces structures, devices, and systems with at least one novel/superior characteristic or property

Nanodevices

Just to get an idea of what nanotechnology can do, we examine two nanodevices in this section.

The Medical Nanorobot

Imagine going to the doctor to get treatment for a persistent fever. Instead of giving you a pill or a shot, the doctor refers you to a special medical team which implants a tiny robot into your bloodstream. The robot detects the cause of your fever, travels to the appropriate system and provides a dose of medication directly to infected area.

Nano robot with camera, micro-processed with claws and radio sign to aid to combat diseases. Clipping path included.

In Figure The robot in the illustration swims through the arteries and veins using a pair of tails.

We may see a future where surgeons would be replaced by nanorobots. Doctors could treat everything from heart disease to cancer using tiny robots the size of bacteria. Robots might work alone or in teams to eradicate disease and treat other conditions.

Nanorobotics is the technology of creating machines or robots at the nanometer scale. One of the objectives of Nanorobotics would be the rapid elimination of diseases and quick, painless recovery from physical trauma. Medical nanorobots might also make possible the correction of genetic defects, and help us to live much longer, healthier lives

The Quantum Dot

Quantum dots are tiny nanocrystalline structures of semiconductor material with optical properties. As explained earlier, these are small dots of a few hundred to a thousand atoms, which emit different wavelengths of light depending on the size of the dot. These properties may soon be used in detecting the tumor type and stages of cancer.

These quantum dots can generate a kind of optical barcode reflecting the levels of various tumor markers. This barcode could indicate tumor type and stage. Using this application as an example to once more clarify the difference between Nanoscience and Nanotechnology, Nanoscience explains the optical properties of quantum dots, and the laws behind these properties, and Nanotechnology uses these properties to make nanodevice

Characteriation

Characterization is the study and classification of nanomaterials, and falls into the realm of Nanoscience. However, characterization is accomplished by instrumentation. For example Nanoparticles can only be seen using high resolution electron microscopy such as the Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). There are a number of characterization tools which are used to see nano materials. These tools form a part of Nanotechnology. We discuss some tools below.

Scanning Electron Microscope

(Raster scanning means to cover an area line-by-line by bombarding it with a stream of electrons. This technique is used in forming images on television screens.)

The electrons interact with the atoms that make up the sample producing signals that contain information about the sample's surface topography (description of sample's surface shapes and features), composition and other properties such as electrical conductivity (a measure of a material's ability to conduct an electric current).

A Scanning Electron Microscope

An image of a Gold nanoparticle as seen by an SEM is shown in the figure. This gold nanoparticle has the size in 5nm. The image has been taken at the at 100nm resolution.

SEM image of Gold Nanoparticle

The scanning electron microscope (SEM) is a type of electron microscope that images the sample surface by scanning it with a high-energy beam of electrons in a raster scan pattern .A SEM, which is shown in the adjoining figure, can produce very detailed 3 dimensional high-resolution images of a sample surface, revealing details about 1 to 5 nm in size.

Transmission Electron Microscope

In transmission electron microscopy (TEM) a beam of electrons is transmitted through an ultra thin specimen. If the electron gets through, it shows that the sample is not very dense in that area. If a beam is blocked, it shows that the sample is dense at that point. By collecting the electron beams onto a screen positioned at the other side of the sample, an image is formed, giving the exact composition of the sample. The image is magnified and focused onto an imaging device, such as a fluorescent screen, on a layer of photographic film, to be detected by a sensor such as a CCD camera.

Transmission Electron Microscope

TEMs enables us to examine fine details of a specimen even as small as a single column of atoms, which is tens of thousands times smaller than the smallest resolvable object in a light microscope. TEMs find applications in cancer research, virology, material sciences as well as pollution and semiconductor research.

TEM image of brain cancer cells

Atomic Force Microscope

The Atomic Force Microscope (AFM ) is being used to solve problems in a wide range of

technologies affecting the electronics, telecommunications, biological, chemical, automotive, aerospace, and energy industries. The materials being investigating include thin and thick film coatings, ceramics, composites, glasses, synthetic and biological membranes, metals, polymers, and semiconductors.

A mentioned in previous chapters, in an AFM the information is gathered by "feeling" the surface with a mechanical probe. A nano-sized tip feels the bumps and troughs on the surface material. The movement of the tip is transmitted to a cantilever which is then used to graphically map the surface of the material.

Atomic Force Microscope

The AFM is being applied to studies of phenomena such as abrasion, adhesion, cleaning, corrosion, etching, friction, lubrication, plating, and polishing. By using an AFM one can not only map the surface of a material at the atomic scale but also measure the inter-atomic forces using a nano-Newton scale.

In the figures below, images of carbon Nanotubes and Chromosome can be seen under AFM.

AFM image of Carbon Nano Tube

Nanotechnology- Definitions & Components