nanoetechnology :method of synthesizing nanoparticles .1.precipitative method 2.reactive method
- 1. SYNTHESIS OF NANOSTRUCTURES : PRECIPITATIVE AND REACTIVE METHODS 1
- 2. Nanoparticle (NPs) Synthesis 1. Top – down approach – Bulk materials into nanoscale particles 2. Bottom – up :- Building nanoparticles from atoms or molecules through chemical or physical reactions. Bottom –up :- Solution-based chemical synthesis is widely used Reasons: Simplicity, scalability and cost effectiveness. Example: Precipitation and reactive methods 2
- 3. Precipitation Method Schematic illustration of spinet nano ferrites by coprecipitation method from N2-purged aqueous solution of metal chlorides. Requires aqueous medium for precipitation Simultaneous precipitation of two or more metal ions as hydroxides/oxides in alkaline aqueous. Used preparation of magnetite (Fe₃O₄). 3
- 4. Precipitation Method - Application 4 ZnO TiO2 Fe3O4, Fe2O3 Calcium phosphate Sunscreens and cosmetics – Uv absorption and protection Self-cleaning – windows and tiles due to photocatalysis MRI contrast agents – biomedical imaging Bone repair materials – orthopedic and dentistry Antibacterial coatings – medical devices and textiles Paints and coatings – UV protective and whitening agent Magnetic data storage – Electronics Drug carriers – for sustained release in bone tissue Photo catalyst – wastewater treatment and air purification Solar cells – dye-sensitized solar cells Magnetic drug delivery – Targeted delivery of cancer drugs
- 5. Reactive Method 5 • Chemical reaction :- 2 or more reactive precursors in solution to directly form nanoparticles. • Reactions used:- Reduction reactions – metal nanoparticles e.g Ag, Au, Cu Thermal decomposition for oxides Sol-gel reaction for silica and metal oxides. Reactive crystallization
- 6. Reactive Method - Application 6 Au NPs Ag NPs Quantum Dots (CdSe, ZnS) Cu NPs Cancer therapy (photo- thermal ablation) Antimicrobial agents – in bandages, clothes and water filters Bio-imaging – fluorescent markers in medical diagnostics Conductive inks – For printed electronics and RFID tags Drug delivery systems – targeting specific cells Food packaging – prevent bacterial growth LEDs – displays and lighting Antibacterial surfaces – in hospitals and public spaces Biosensors – Detecting DNA, glucose or toxins via color changes Wound dressing – promote healing and reduce infection Solar cells – Improve efficiency through tunable light absorption Catalysts – In chemical and environmental applications
- 7. Selected References 7 • Chokkareddy R, Thondavada N, Kabane B, Redhi GG. Current advances in biosynthesis of silver nanoparticles and their applications. In: Green metal nanoparticles: synthesis, characterization and their applications. WileyScrivener Publishing LLC, U.S.; 2018. p. 165e98 • Dhand C, Dwivedi N, Loh XJ, Ying AN, Verma NK, Beuerman RW, et al. Methods and strategies for the synthesis of diverse nanoparticles and their applications: a comprehensive overview. RSC Adv 2015;5(127):105003e37. • Abid N, Khan AM, Shujait S, Chaudhary K, Ikram M, Imran M, et al. Synthesis of nanomaterials using various top-down and bottom-up approaches, influencing factors, advantages, and disadvantages: a review. Adv Colloid Interface Sci 2021 Dec 29:102597. • Some S, Sarkar B, Biswas K, Jana TK, Bhattacharjya D, Dam P, et al. Bio-molecule functionalized rapid one-pot green synthesis of silver nanoparticles and their efficacy toward the multidrug resistant (MDR) gut bacteria of silkworms (Bombyx mori). RSC Adv 2020;10(38):22742e57. • D.N. Heo, W.K. Ko, M.S. Bae, J.B. Lee, D.W. Lee, W. Byun, C.H. Lee, E.C. Kim, B.Y. Jung, I.K. Kwon, Enhanced bone regeneration with a gold nanoparticle-hydrogel complex, J Mater Chem B. 2 (2014) 1584–1593. https://doi.org/10.1039/c3tb21246g • Huang, X., Zhu, Y., & Kianfar, E. (2021). Nano biosensors: Properties, applications and Electrochemical Techniques. Journal of Materials Research and Technology., 12, 1649–1672. https://doi.org/10.1016/j.jmrt.2021.03.048 Kianfar, E. (2016). The effect of nano-composites on the mechanic and morphological characteristics of NBR/PA6 blends. American Journal of Oil and Chemical Technologies, 4(1), 27–42. • Kianfar, E., Salimi, M., Pirouzfar, V., & Koohestani, B. (2018). Synthesis and modifcation of zeolite ZSM-5 catalyst with solutions of calcium carbonate (CaCO3) and sodium carbonate (Na2CO3) for methanol to gasoline conversion. International Journal of Chemical Reactor Engineering, 16(7), 20170229. https://doi.org/10.1515/ijcre-2017-0229
- 8. 8