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- 1. ASPECTS OF NANOTECHNOLOGY IN FOOD SCIENCE AND ANIMAL NUTRITION Dr Rai Dhirendra Prasad Bihar Veterinary College, Patna, India Dr Saurabh Raidhirendra Prasad 1
- 2. 2 PART I Science at Nanoscale
- 3. “The design, characterization, production, and application of structures, devices, and systems by controlling shape and size at the nanometer”
- 4. Nanotechnology in Ancient Period Ras-Ratnakar: • The first relationship between human life and nano-scale was developed in Ayurveda, which is about 5000 years old the Indian system of medicine. Ayurveda described the formation of metallic nanoparticles about 5000 years ago Alchemist- • History claims that nanoparticles have been around us for a long time. Presumably, the use of nanoparticles was reported in 1570 as aurum potable (potable gold) and Luna potable (potable silver) which alchemists used as elixirs. Dr Samuel Hahnemann- Organon of medicines Lycurgus Cup: 4th century AD 4
- 5. History The idea of nanotechnology was born in December 29, 1959 when physicist “Richard Feynman” gave a lecture exploring the idea of building things at the atomic and molecular scale. He is regarded as Father of Nanotechnology and given the Famous statement “There is plenty of Room at the bottom” He imagined the entire Encyclopedia Britannica written on the head of a pin.
- 6. Nanomaterilas: • The Greek word nano identifies a material whose size has been reduced to 10-9 m, which is 1000 times smaller than one micron. • Structures on a nano scale are considered at the borderline of the smallest of human-made devices and the largest molecule of a living system. Definition given by The Royal Society and The Royal Academy of Engineering is “nanotechnology is the design, characterization, production, and application of structures, devices, and systems by controlling shape and size at the nano-meter scale
- 7. Historical Evidences • History claims that nanoparticles have been around us for a long time. • one of the oldest application of nanoparticles that we come across in literature is the use of gold Nano particles for staining glasses, a famous example of which is Lycurgus cup that dates back to 4th century AD • The Lycurgus cup contains nanomaterials of gold and silver and looks jade green in natural light and on impressive red color when a bright light is shines through it. • This is made up of glass that changes color when light is shone through it.
- 8. Nanoparticles "A particle with the size of the order of 1-nm to 100nm in any dimension and at least any one property different from that of bulk". During the synthesis of nanoparticles, size of nanoparticles depends on the steochiometric ratio of metal ion to capping ligands concentration. 8
- 9. Classification of Nanomaterials (a) Classification based upon the origin of nanoparticles: The nanomaterials can be classified in different ways. One of the ways to classify nanomaterials is based on their origin.
- 10. (b) Based upon Dimension (1) Zero Dimensional Nanomaterials: In this type of nanomaterial all the three dimensions lie within the nano range i.e. 1nm to 100nm. Eg molecules, clusters, fullerenes, rings, metal carbides, powders, grains, etc (2) One Dimensional Nanomaterials: In this type of nanomaterial out of three dimensions two dimensions lie within the nano range i.e. 1nm to 100nm and one dimension is not within the nano range. Eg. Nanotubes, nanorods, nanowires, fibers, filaments, whiskers, spirals, belts, springs, columns, needles, etc (3) Two Dimensional Nanomaterials: In this type of nanomaterial out of three dimensions one dimension lies within the nano range i.e. 1nm to 100nm and two- dimension are not within the nano range. Eg. Layers, nano wells, nanofilms, nanocoatings (4) Three Dimensional Nanomaterials: In this type of nanomaterial all the three dimensions lie outside the nano range i.e. 1nm to 100nm. In a true sense, these are not nanomaterials. Eg bulk powders, bulk nanomaterials, dispersion of nanoparticles, bundles of nanowires and nanotubes as well as multinanolayers.
- 11. (1) Organic Nanomaterials and (2) Inorganic Nanomaterials Organic Nanomaterials: The organic nanoparticle includes dendrimers, chitosans, liposomes, micelles, etc. The organic nanoparticles can be used as drug delivery vehicles. Casein, the milk protein is safe can be used as drug carrier. It is an alternative for albuminbecause it is inexpensive and has better amphiphilicity, good dispersibility, and rapid reconstruction in an aqueous solution. Inorganic Nanomaterials: Inorganic nanomaterials have been widely used in various fields due to their excellent mechanical properties, optical properties, magnetic properties, electrical properties, catalytic properties, thermal properties, and sensitivity properties. According to different sources, inorganic nanomaterials can be classified into two main categories (1) Non- metallic nanomaterials eg silica-based nanomaterials, and (2) Metallic nanomaterials eg silver, gold nanomaterials, etc.
- 12. Nano-composites These are a class of nanomaterials wherein one or more phases at nano- sized dimensions (zero dimension, one dimension, two-dimension) are embedded in ceramic, metal, or polymer materials. These can be made by inorganic or organic components at the molecular level to obtain new properties.
- 13. Carbon based nanoparticles The carbon-based nanomaterials include fullerene, single-walled carbon nanotubes, and multiple-walled carbon nanotubes. These are a novel class of nanomaterials that are widely used in biomedical fields including the delivery of therapeutics, and biomedical applications. Owing to exceptional structural, mechanical, electronic, and optical properties carbon nanotubes are regarded as new-generation nanoprobes.
- 14. Ceramic Nanoparticles These are inorganic solids made up of oxides, carbides, carbonates, and phosphates. These nanoparticles have high heat resistance and chemical inertness. These nanomaterials can be successfully applied in various ways such as photo-catalyst, photo-degradation of dyes, drug delivery, and imaging.
- 15. Metal Nanoparticles Metal nanoparticles are generally synthesized through a bottom-up approach using precursors of metals. Normally salts of metals are used for the synthesis of metallic nanomaterials. The metallic nanoparticles are having high absorption capacity. Therefore, such nanoparticles are widely used as a catalyst in organic transformation reactions. Apart from catalytic applications, these nanoparticles have applications in research areas, detection and imaging of biomolecules, and in the environment and bioanalytical applications.
- 16. Semiconductor Nanoparticles Semiconductor nanoparticles have properties like those of metals and also like non-metals. Thus they have intermediate properties. These particles have a wide bandgap, which on tuning shows different types of properties. They are widely used as a photo-catalyst, in electronic industries, photo- optics, and water splitting applications.
- 17. Polymer Nanoparticles Polymeric nanoparticles are organic-based nanoparticles. Depending upon the method of preparations, these have structures like nano- capsules or nano-spheres. A nano-sphere particle has a matrix-like structure whereas nano-capsules particles have core-shell morphology. The polymeric nanomaterials can protect drugs and control their release of the drug. They have a wide range of applications in drug delivery and diagnostics.
- 18. Food Nanotechnology Nano-food‟ can be defined as food that has been produced or packaged by nanotechnology techniques. Nanotechnology for food-packaging aims at reducing ultraviolet Ultra Violet light exposure or microbial growth. Food safety can be improved by Nano-sensors able to detect pathogens or contaminants. Food materials are often considered not only a source of nutrients but also as having to contribute to the health of consumers.
- 19. Food Nanotechnology Most of the nanoparticles used traditionally belong to the group of colloids (i.e. emulsions, micelles, mono- and bi-layers). In the food industry, several novel applications of nanotechnologies have become apparent, which include the use of nanoparticles, such as micelles, liposomes, nano-emulsions, bio-polymeric nanoparticles, and cubosomes, as well as the development of nano-sensors, which are aimed at ensuring food safety.
- 20. Nanotechnology in Food Modulation Food in nano form can be better uptaken, and absorbed, and also bioavailability is higher. Nanotechnologists are attracted to develop and commercialize nano-sized ingredients, supplements, and nutraceuticals. Nanotechnology is having an impact on the entire food sector starting from production, processing, transportation, safety, storage, and delivery. • Nutrients and other additives preparation, structure control, and encapsulation are applications of nanotechnology in the food industry.
- 21. Nanotechnology in Food Modulation Nano-food is developed to improve food safety, enhance nutrition, and flavor, and cut costs. Bioactive compounds that can be found naturally in certain foods have physiological benefits and might help to reduce the risk of certain diseases, including cancer. By reducing particle size, nanotechnology can contribute to improving the properties of bioactive compounds, such as delivery properties, solubility, prolonged residence time in the gastrointestinal tract, and efficient absorption through cells.
- 22. Nanotechnology and Food Science Preservatives Coloring Flavoring and Nutrients
- 23. Nanotechnology and Food Science Food additives are substances added to food to improve its Storage properties Appearance Flavor and Nutritional values
- 24. Nanotechnology and Food Science Nanoceuticals: Carotenoids nanoparticles can be dispersed in water and can be added to fruit drinks for improved bioavailability; Canola oil-based nano-sized micellar system is claimed to provide delivery of materials such as vitamins, minerals, or phytochemicals; A wide range of nanomedical products containing nanocages or nanoclusters that act as delivery vehicles, e.g., a chocolate drink claimed to be sufficiently sweet without added sugar or sweeteners; . Nanosilver or nanogold is available as mineral supplements; To prevent the accumulation of cholesterol some of the nutraceuticals incorporated in the carriers include lycopene, beta-carotenes, and phytosterols
- 25. Animal Nutrition: Welcome Nanotechnology The application of nanoscience and technology in animal nutrition includes the use of different nanoparticles in the administration of medications, nutrients, probiotics, supplements, and other substances. In recent years feed additives such as trace minerals in nano forms can be used. Application of nanomaterials is currently used for meat and food generally including the use of NPs and nanomaterials as food ingredients which are placed directly into food or as a part of packaging materials. Nano minerals are having great potential as mineral feed supplements in animals even at very lower doses than the conventional organic and inorganic sources. Silver, Copper, Iron, and Manganese di-oxide are metal nano-composites added to poultry feed. Various researchers have described the disease-prevention properties of dietary supplements such as polyphenols. The biological activity of the nanomaterials may be anti-microbial, anti-oxidants, and prevention and management of some chronic diseases.
- 26. Nature of Nanomaterials Area of application in animal nutrition Selenium It significantly decreases ruminant Ph and ammonia concentration. Increases total VFA concentration linearly and quadratically. The urinary excretion of purine derivatives was also significantly changed by improving nano-Se supplementation. Selenium has a positive effect against peroxide damage in blood components. The selenium content increases the final weight of an individual. Selenium nanoparticles blood, serum and tissue selenium concentration, serum antioxidant enzyme activity. Nano selenium shows favorable effects on fertility in male goats and shows positive effects on testicular microstructure, testicular spermatozoa, testicular glutathione peroxides activity, and semen quality.
- 27. Nanotechnology in Animal Nutrition Nanomaterials Area of Application in Animal Nutrition Copper Nano-copper supplements improved growth performances in piglets. Significant improvement was observed in IgG, γ- globulin, total globulin protein level, and SOD activity. Silver Supplements enriched with nano-silver show anti-microbial activity. Nano-silver is a growth promoter too. The concentration of Clostridium perfringens and Clostridium histolyticum group was reduced in the ilium. Zinc The nano zinc feed supplements showed improved immune status and bio-availability in animals. The ZnO nanoparticles showed to inhibit mycotoxin fungus growth.
- 28. Properties at nanoscale Properties of nanoparticles: depend upon size, shape, electrostatic force of attraction or repulsion, reaction condition, pH of the medium, time of contact, stabilizing agent, method of preparation etc. The materials at nanoscale often acquires some exotic properties which are different from that of bulk materials. It is observed that the materials sustain their regular physical and chemical properties up to micrometer level Changes in optical, thermal, electrical, electronic, magnetic and mechanical properties 28
- 29. Thermal properties: Melting Point • The thermal properties of the materials are the properties that are exhibited when the material is heated. Graph of melting point (Tm) vs size of particle (D) Melting point of nanoparticles is below the melting point of bulk material Tm= TmBulk (1-1/D) 29
- 30. Optical Property • Light is the form of energy detected by the eyes and at an ordinary scale can be treated as waves. Light waves are part of electromagnetic waves. Size dependent optical properties of gold nanoparticles This effect appears due to the interaction of electro-magnetic radiation with the electron cloud present on the surface of metal nanoparticles 30
- 31. Surface Plasmon Resonance Surface Plasmon oscillations. Large number of atoms present on the surface of nanoparticles contributes electron cloud which interacts with E-field of light and thus oscillates 31
- 32. Electronic Property When the size enters nano level, electron motion is restricted to a smaller space, they don’t follow classical theory & restricts themselves from diffusion of valence and conduction band. The energy gap between valence band and conduction bond (Kubo gap) becomes larger than thermal energy (KBT) and hence metallic nanoparticles become semiconductor further becomes an insulator 32
- 33. Other Properties Magnetic Property: Bulk materials forms multiple magnetic domains, but nanoparticles form only a single magnetic domain thus could be used for super magnetism. Bio-compatibility: Electrical Properties: The metals that are good conductance behave as semiconductor at nano-level. 33
- 34. Property changes… opaque substances become transparent (copper) stable materials turn combustible (aluminum) insoluble materials become soluble (gold) Chemically inert becomes active (Gold) Insulators can show electrical conductivity Thermal properties eg melting point changes Magnetic properties changes 34
- 35. Why different property at Nanoscale ? • High Surface to Volume ratio (Aspect ratio) : Surface is in stretched condition resulting in increase in surface energy.Because of this the nanoparticle become less stable . Gravitational force: Due to extremely small size and low mass gravitational force is ineffective Electrostatic force: The electrostatic force of attraction or repulsion predominates. Size comparable to wavelength of light: thus entire different optical properties like Surface Plasmon Resonance is exhibited. Dangling bonds: These are unsatisfied valences tends to quickly form bonds 35
- 36. Surface to Volume Ratio spherical particle, surface area = 4πr2 and volume = 4/3 π r3 Sp= 4πr2σ/ (4/3)πr3ρ Where, σ is surface area factor and ρ is volume factor r→o , Sp→∞ 36
- 37. Quantum mechanics Nanoparticles do not obey the laws of classical mechanics or Newtonian mechanics; instead they follow the principles of quantum mechanics. Exhibits interesting shape dependence due to electronic motion in different dimensions. 37
- 38. Example of shape dependent property Electronic tunneling phenomenon is observed for 0-D nanostructures which is the key concept used for building artificial atoms and devices like single electron transistors. Electron can oscillate in two distinct ways in 1-D nanostructures under electromagnetic field, namely in longitudinal and transverse modes. The way electrons executes its motion alters their various properties and thus nano-rods and nano-tubes give rise to Surface Plasmon absorption peaks due to the two different types of electronic motion. 38
- 39. Nanoparticles as Smart Material: Smart materials are the materials that respond favorably to change in temperature, pH, conductivity, moisture or electromagnetic fields thus are extensively used as sensors and actuators. Today smart materials are widely used as biosensors, chemical sensors etc Nanoparticles can also be used as advanced engineering materials which can withstand high temp, high impact. Such nanomaterials can be used in smart textiles, technical textiles etc 39
- 40. Nano-composites Light weight Nano composites can replace heavy metals in automobile industry to achieve high speed in vehicles Nano-composites can be used as a catalyst in organic transformation reactions. Nano-composites can be used in construction materials. Nano-composites are actively used to enhance the efficiency of solar cells, semi-conducting materials, and also in superconductor and super capacitors 40
- 42. Norio Taniguchi The term "nanotechnology" was defined by Tokyo Science University Professor Norio Taniguchi in a 1974 paper as follows: "'Nanotechnology' mainly consists of the processing, separation, consolidation, and deformation of materials by one atom or by one molecule." 42
- 43. Stabilization of Nanoparticles Tendency to form agglomeration: Due to stretched surface, the nanomaterials have high surface energy and becomes thermodynamically unstable. Thus, they show tendency to aggloromate so as to acquire stability. Stabilizing agent: usually accomplished by suitable passivating agents also called as capping agent eg CTAB, polyvinyl alcohols, amino acids, templates etc. 43
- 44. Gibb’s Free Energy & Stability As size of the nanoparticles decreases their surface energy increases. Increase in the surface energy results in increase in the Gibb’s free energy. According to the law of thermodynamics, every system always tries to attain minimum Gibb’s free energy Therefore it loses its nanoness and exotic properties related to it. Hence it is very important to stabilize the nanoparticles against the aggregation. 44
- 46. Potential energy vs distance between the nanoparticles Particles formed are surrounded by the electronic double layer of reactant ions on the surface of nanoparticles Two forces: Van der Waals forces of attraction , and electrostatic force of repulsion due to the charged ions on the surface. Stability of nanoparticles is dependent on the combined effect of these two forces. Greater the thickness of the double layer, higher is the potential energy barrier & higher is stability 46
- 47. 47 Different Capping agents used for Surface Modification & Stabilization
- 48. Surface Modification using Capping Agent Electron rich ligands such as amines, thiols, phosphates, carboxylates used for capping of nanoparticles. The capping agents provides stability to the materials at nanoscale. Surface modifications like reactivity, Charge on the surface, specific gravity, nature of surface i.e. hydrophobicity induced in the nanoparticles with the help of different capping agents. 48
- 49. 49 Stabilization by Steric interaction where Electrostatic Force of repulsion are weak
- 50. Steric Interaction for Stabilization Nanoparticles dispersion in organic medium experiences less significant electrostatic effects and stability comes from steric interactions by adsorption of amphiphilic molecules. The lead group of these molecules binds with metal nanoparticles surface while hydrocarbon chain prevents aggregation sterically as shown in figure. Due to these steric interactions, the nanoparticles are found to be stable in the form of powder even after complete evaporation of solvent. 50
- 51. Choice of Capping Agent It determines: Stability Reactivity Size and shape e.g. Poly vinyl alcohol Stability can be determined as: Visualization Zeta Potential Electron microscopic study 51
- 52. Synthesis Techniques 1) Bottom-up technique 2) Top- down technique
- 53. 53
- 54. Methodology Adopted method is Chemical route of synthesis and Biosynthesis using cow urine We require reducing and capping agent for synthesis Reducing agents are electron donars such as NaBH4, LiAlH4 etc Natural reducing agents are anti-oxidants Several plants contain anti-oxidant which can act as reducing agents Proteins present in plant may act as capping agent. 54
- 55. Methodology Prasad et al developed biosynthesis using Indian cow urine. Ayurveda describes the significance of cow urine in medicine. The chemical composition of cow urine includes urea, albumin, minerals, water etc Upon the action of enzyme urease or just by heating for particular time, ammonia can be generated. Ammonia can act as reducing agent.
- 56. Methodology
- 57. PART II Biosynthesis Of Nanoparticles
- 60. Why green synthesis? To avoid production of unwanted/harmful by-products For reliable and cost-effective build-ups For production of nanoparticles at large-scale 3 R’s (Reduce, Recycle, Reuse) Controlled morphologies Bio-compatible products
- 61. Biosynthesis: • Production of chemical compounds from precursors in living organism. • Involves enzymes and energy sources. • some examples; photosynthesis, chemosynthesis, amino acid synthesis, nucleic acid synthesis, and ATP synthesis. • The biosynthesis method for production of nanoparticles have more effective applications than physical and chemical synthesis method, because this method is reliable, nontoxic, and eco-friendly. Nanoparticles are biosynthesized when the microorganisms grab target ions from their environment and then turn the metal ions into the element metal through enzymes generated by the cell activities. It can be classified into intracellular and extracellular synthesis according to the location where nanoparticles are formed. The organisms used for synthesis of nanoparticles are bacteria, fungi, yeast.
- 63. 1. Bacteria: Bacterial species have been widely utilized for commercial biotechnological applications such as bioremediation, genetic engineering, and bioleaching. Bacteria possess the ability to reduce metal ions and are momentous candidates in nanoparticles preparation . For the preparation of metallic and other novel nanoparticles, a variety of bacterial species are utilized. Prokaryotic bacteria and actinomycetes have been broadly employed for synthesizing metal/metal oxide nanoparticles. 2. Fungi: Fungi-mediated biosynthesis of metal/metal oxide nanoparticles is also a very efficient process for the generation of monodispersed nanoparticles with well-defined morphologies. They act as better biological agents for the preparation of metal and metal oxide nanoparticles, due to the presence of a variety of intracellular enzyme . Competent fungi can synthesize larger amounts of nanoparticles compared to bacteria. Moreover, fungi have many merits over other organisms due to the presence of enzymes/proteins/reducing components on their cell surfaces. The probable mechanism for the formation of the metallic nanoparticles is enzymatic reduction (reductase) in the cell wall or inside the fungal cell.
- 64. 3. Yeasts: Yeasts are single-celled microorganisms present in eukaryotic cells. A total of 1500 yeast species have been identified. Successful synthesis of nanoparticles/nanomaterials via yeast has been reported by numerous research groups. The biosynthesis of silver and gold nanoparticles by a silver-tolerant yeast strain and Saccharomyces cerevisiae broth has been reported. 4. Plants: • Plants have the potential to accumulate certain amounts of heavy metals in their diverse parts. Consequently, biosynthesis techniques employing plant extracts have gained increased consideration as a simple, efficient, cost effective and feasible methods as well as an excellent alternative means to conventional preparation methods for nanoparticle production. • There are various plants that can be utilized to reduce and stabilize the metallic nanoparticles in “one-pot” synthesis process. • Many researchers have employed green synthesis process for preparation of metal/metal oxide nanoparticles via plant leaf extracts to further explore their various applications.
- 65. Green synthesis of silver nanoparticles using Gongura leaf extract
- 66. PART III Uses of Nanoparticles
- 67. Ayurveda and Unani uses of nanoparticles : In Sanskrit, Ayurveda means ‘ the science of life ’. Ayurveda is supposed to be originated from Atharvaveda. Ayurveda is the oldest form of Indian traditional system of medicine. The other traditional system of Indian medicine includes Unani and Siddha. Ayurveda aims at strengthening the capacity of the body and improving immunity by using herbs, animal products and minerals in its medicines. whereas Unani, which is the holistic system of medicine, is quite common throughout the India. A section of Ayurveda deals with herbo-mineral preparations called Bhasma (ash) is known as Rasa Shastra (Vedic chemistry).
- 68. The major therapeutic actions of Bhasma are their ability for Immunomodulation and anti-aging property (Rasayana) and ability to target drugs to the site. Ayurvedic preparations are claimed to be nontoxic, absorbed readily, and biocompatible. Bhasma is an important Ayurvedic formulation comprising mixture of herbs and metals. Bhasma are nearer to nanocrystallite materials which are solid composed of crystallite with sizes less than 100 nm, at least in one dimension. Ayurvedic metallic nanocrystallite or Bhasma have unique physicochemical properties such as biocompatibility and ease of surface fictionalization.
- 69. The nanotechnology in Ayurvedic drugs have application in: 1. molecular detection 2. targeted delivery 3. biological imaging. application of Nano-carriers for the delivery of Ayurvedic drugs can be a great initiative because such carriers are capable to cross the plasma membrane and deliver the drug in the desired concentration at the specific site of action. Integration of Ayurveda and nanotechnology may provide the best medicines to treat various life-threatening diseases. Nanoparticles are used in various sensors such as Gas sensors, Chemical sensors, artificial tongue, humidity sensors etc
- 70. Attributes of Nanotechnology Nanoparticles are used in solar cell devices Nanoparticles are used in memory storage devices such as memristers Nanoparticles are in super-capacitors to store electrical energy Nanoparticles are in electrochromic materials Nanoparticles are used in the area of veterinary and human medicine. Today we observe that efficiency of antibiotics against a pathogenic bacterium gets decrease after frequent uses. It is difficult to have new antibiotics. It has been observed that many nanoparticles especially silver nanoparticles show high antimicrobial activities.
- 71. PART IV Environmental Aspects Of Nanoparticles
- 72. POSITIVE IMPACT OF NMs Nanotechnology promises significant social, environmental, and financial benefits. Nanotechnology may ultimately be developed to help decrease the human footprint on the environment by providing more efficient and energy saving innovations.
- 73. NEGATIVE IMPACT OF NMs As the environmental impacts of NMs cannot be clearly diagnosed and there are too many variables to account for (e.g., NMs identification, low detection limits, and unknown environmental concentrations), it is very difficult to reach any conclusion about the ecological effects and environmental stability of NMs. Even a minor change in the chemical structure of NMs could radically change their properties, turning them into toxic compounds. According to the United States Environmental Protection Agency, “the toxicity of NMs is difficult to identify because they have unique chemical properties, high reactivity, and do not dissolve in liquid”
- 74. Analysis of Materials at Nanoscale The nanomaterials are so small that they cannot be visualized by naked eyes. The properties of materials at nanoscale depends upon size, shape, morphology, interatomic distance, electrostatic forece of attraction or repulsion, secondary bonds like van der waal’s interaction etc. It is possible to determine the properties of the materials at nanoscale using advanced characterization techniques such as XRD, Scanning Electron Microscopy, Transmission Electron Microscopy, Zeta Potential etc.
- 75. Characterization Techniques . The instruments used for analysis are of two types i.e. 1) spectroscopes and 2) microscopes. A. Spectroscopy: It is a branch of science that deals with the interaction of electromagnetic radiations with the matter. Spectroscopy is the most powerful tool available for the study of atomic and molecular structure and is used in the analysis of a wide range of samples. B. Microscopic Techniques Microscopy is the technical field of using a microscope to view samples and objects that cannot be seen with the unaided eye. There are three well-known branches of microscopy; optical, electron, and scanning probe microscopy.
- 76. Characterization Techniques Optical and electron microscopy involve the diffraction, reflection, and refraction of electromagnetic radiation/ electron beam interacting with the specimen and the subsequent collection of this scattered radiation or another signal to create an image. This process may be carried out by wide-field irradiation of the sample (e.g. Transmission Electron Microscope) or by scanning a fine beam over the sample (e.g. Scanning Electron Microscope).
- 78. UV-Visible Spectroscopy UV-visible spectroscopy is used for the measurement of the intensity of absorption in near-ultraviolet and visible radiation by a sample. Ultraviolet and visible radiation ranges in wavelength from 200 nm to 800 nm and is energetic enough to promote outer electrons in an atom to higher energy levels. UV-visible spectroscopy is useful for qualitative and quantitative analysis of the sample. Moreover, UV-visible spectroscopy can also be used to determine the band gap of semiconductors.
- 79. XRD
- 80. XRD X-rays are invisible, highly penetrating electromagnetic radiations of much shorter wavelengths than visible light. X-rays are electromagnetic radiations with a wavelength of the order of 10-10 m. Van Lave demonstrated in 1912 that X-rays could be diffracted by crystal. Later, in 1935 Le Galley first constructed an X-ray powder diffractometer. They are typically generated by bombarding a metal with high-energy electrons. The high-energy electrons must penetrate through the outer electron shells and interacts with the inner shell. If more than a critical amount of energy is transferred to an inner-shell electron, that electron is ejected i.e. it escapes the attractive field of the nucleus, leaving the hole in the inner shell and generating an ionized atom.
- 82. FT-IR Spectroscopy Infrared spectroscopy is a common spectroscopy technique used to identify the chemical functional groups present in the sample. It is an excellent tool to study the interactions and mechanisms of the reduction of metal ions. Spectroscopy in the middle IR region is extremely useful for the study of organic compounds. IR spectroscopy has been widely used for the identification of organic compounds because their spectra are generally complex and provide numerous maxima and minima that can be used for comparison purposes.
- 84. Scanning Electron Microscopy This is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with the atoms in the sample, producing various signals that can be detected and that contain information about the sample’s surface topography and composition. The electron beam scans in a raster scan pattern, and the beam’s position is combined with the detected signal to produce an image. Scanning electron microscopy is extremely useful for direct observations of the surface because they offer better resolution and depth of field than optical microscopes. The SEM shows very detailed 3-D images at a much higher magnification than is possible with a light microscope.
- 86. Transmission Electron Microscope Working Principle: TEM is a microscopic technique in which a beam of the electron is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through. An image is formed from the interaction of the electrons transmitted through the specimen; the image is magnified and focused onto the imaging device such as a fluorescent screen. In TEM analysis, a thin specimen is illuminated with electrons in which the electron intensity is uniform over the illuminated area. As the electrons travel through the specimen, they are either scattered by a variety of processes or they may remain unaffected by the specimen.
- 87. Brief Bio-data Dr. Rai Dhirendra Prasad: He has completed degree in Veterinary science and Animal Husbandry from Bihar Veterinary College, Patna, India which is one of the oldest veterinary college of India. This is the 5th college established in undivided India. After completion of the educational program Dr. Prasad joined department of Animal Husbandry government of Maharashtra where he served on various posts at different places. He rendered his services for several years in tribal area of Maharashtra, India. He is having high expertise in technical subjects like animal anatomy, animal nutrition and animal biochemistry. He is having vast direct clinical exposure where he treated various animal diseases. He is having expertise in treating trypanosoasis. Then, he tried to study effect of Homeopathic medicines for critical animal diseases.
Editor's Notes
- #4: by definiton as you can see ”it’s the art of manipulating matter at the nanoscale level”
- #42: Now this is a bit informative 3d chart, providing the size comparisons between different objects raised to the power of 10 meters. Here you can see, a 6 foot man is 1.62 meters or roughly around 2 billion nms tall. While on the other hand, a sample of a DNA molecule, as we have already seen in the previous slide, is approx. 2 nms long.