Introduction to Nano science and Nanotechnology Part 3
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The document outlines the classification and applications of nanomaterials, particularly focusing on silver nanoparticles, polymers, and dendrimers. It discusses the antibacterial properties of silver ions, the structure and properties of polymers, and the synthesis and multifunctional uses of dendrimers in medical and non-medical fields. Additionally, it describes mechanisms of drug delivery using dendrimers, illustrating their potential in targeted treatments and biomedical applications.
Introduction to Nano science and Nanotechnology Part 3
- 2. Nanoscience& Nanotechnology Steps To the future Usama Abd Elhafeez 28/7/2018
- 3. Last Session Crystal structures Classification of nanomaterials
- 4. Sliver Nanoparticles Ranges from 30 – 50 nm High surface to volume ratios High electrical & thermal conductivity Chemical Stability – Catalytic activity
- 5. Antibacterial Applications It is well known that silver ions and silver based compounds are highly toxic to microorganisms. Used to control bacterial growth in a variety of applications, including dental work, surgery applications, wounds and burns treatment, and biomedical devices.
- 6. How silver ions kills bacteria:
- 7. How silver ions kills bacteria: Step 1 : Bacteria contaminates the surface Step 2 : Silver ions are available to act against contaminated bacteria Step 3 : They Combines with bacteria proteins in the cell and cell wall and promote formation of active oxygen species Step 4 : Bacteria dies
- 9. Applications Used in biosensors Biological tags for quantitative detection
- 10. Conductive applications Used in conductive inks and integrated into composites to enhance electrical and conductive properties Used in conductive inks and integrated into composites to enhance electrical and conductive properties
- 11. Introduction To polymers What is a polymer? •A long molecule made up from lots of small molecules called monomers. •“Poly” “meros” = many parts •Monomer = non-linked “mer” material
- 12. What is a polymer? •Polymers = long continuous chain molecules formed from repeated sequences of small organic units (mers). molecular weight in excess of 10,000.
- 13. Why Polymers Polymers Such as cotton, wool, rubber, Teflon and plastics are used in every industry Natural & Synthetic Polymers can be produced in wide range of stiffness , strength , heat resistance.
- 15. Some Definitions
- 21. According to Mechanical response Thermoplasts • Soften when heated &harden when cooled • Simultaneous application of heat and pressure is required to fabricate these materials. • very soft and ductile. • Polyvinyl Chloride (PVC) and Polystyrene • Polymethyl methacrylate • Polystyrene
- 22. According to Mechanical response Thermosets • Soft during their first heating and become permanently hard when cooled. • They do not soften during subsequent heating. • They cannot be remolded/reshaped by subsequent heating • Epoxies • •Phenolic • •Polyester resins
- 27. What Are Dendrimers !! The name comes from Greek word “Dendron” which means “tree”. Also called as ‘’arborols/ cascade molecules’’ They are family of Nano sized, highly branched three dimensional molecules.
- 28. STRUCTURE OF DENDRIMER 1) An interior core 2) Interior layers composed of repeating units radically attached to cores. 3) Exterior layer (terminal functionality) attached to interior generations.
- 30. STRUCTURE OF DENDRIMER Are built from a starting atom, such as nitrogen, to which carbon and other elements are added by a repeating series of chemical reactions that produce a spherical branching structure. As the process repeats, successive layers are added, and the sphere can be expanded to the size required by the investigator. The result is a spherical macromolecular structure whose size is similar to albumin and hemoglobin
- 31. 3D STRUCTURE OF DENDRIMER
- 32. PROPERTIES OF DENDRIMERS Biodegradable. Nanoscale size and shape Viscosity High aqueous solubility High solubility in non polar solutions
- 33. PROPERTIES OF DENDRIMERS Non crystalline Low compressibility Inert and non-toxic Able to cross barriers such as blood-tissue barriers, cell membranes etc Able to stay in circulation for the time needed to have a clinical effect. Able to target to specific structures
- 34. SYNTHESIS OF DENDRIMERS There are two methods of synthesizing dendrimers: 1) Divergent method 2) Convergent method
- 35. 1)Divergent methodDendrimer grows from core. The core molecule reacts with the monomer molecule having two dormant and one reactive group.
- 36. 2-CONVERGENT METHOD Small molecules come together and reaction proceeds inward. Eventually the molecules become attached to the core.
- 39. Medical Dendrimers in Biomedical field Dendrimers are analogous to protein, enzymes and viruses . PAMAM dendrimers can be used to target tumor cells. Targeting groups can be conjugated to the host dendrimers surface.
- 40. Medical Dendrimer as magnetic resonance imaging contrast agents Dendrimer based metal chelates act as a magnetic resonance imaging contrast agent. Larger hydrophilic agents were useful for blood and lymphatic imaging. Smaller sized used for kidney imaging
- 41. Medical In-vivo degradation of drug dendrimer
- 42. Medical Drug delivery Due to change in temperature
- 43. Medical Drug delivery Due to change in pH
- 44. NON MEDICAL APPLICATIONS Dendrimers as catalysts/enzymes The combination of high surface area and high solubility makes dendrimers useful as nanoscale catalysts. Dendrimers have a multifunctional surface and all catalytic sites are always exposed towards the reaction mixture.
- 45. NON MEDICAL APPLICATIONS Dendrimers for additives, printing inks and paints Dendritic polymers ensure uniform adhesion of ink to polar and non-polar foils. Dendritic polymers used in polyurethane paints impart surface hardness, scratch resistance, chemical resistance, light, fastness, weathering resistance as well as high gloss.
- 46. Mechanisms of Drug Delivery Simple encapsulation:-It directly encapsulates guest molecules into macromolecule interior.
- 47. Mechanisms of Drug Delivery Electrostatic interaction:- Surface functional groups enhances solubility of hydrophobic drugs by electrostatic interaction e.g. Ibuprofen, ketoprofen.
- 48. Mechanisms of Drug Delivery Covalent conjugation:- The drug is covalently bound to dendrimers via chemical or enzymatic cleavage of hydrolytically labile bonds. It allows tissue targeting & controlled delivery as drug-dendrimer conjugate diffuse slower than the free.