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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Sri Sivakumar
- Dept. of Chemical Engineering
Indian Institute of Technology Kanpur DST Unit on Nanosciences
Nanobiotechnology Sri Sivakumar Dept. of Chemical Engineering - - PowerPoint PPT Presentation
Nanobiotechnology Sri Sivakumar Dept. of Chemical Engineering - - PowerPoint PPT Presentation
Nanobiotechnology Sri Sivakumar Dept. of Chemical Engineering Indian Institute of Technology Kanpur Email: srisiva@iitk.ac.in Indian Institute of Technology Kanpur DST Unit on Nanosciences How old is it? (Lycurgus Cup) Transmission
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20–40 nm in diameter gold nanoparticles Faraday’s gold sol
Indian Institute of Technology Kanpur DST Unit on Nanosciences
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
CdSe nanoparticles Same material but emits different colours!!!
“Nano” A Magic Word!!
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
How many number of 1 nm cubes can be carved
- ut of 1 m cubes and calculate the surface area?
Number of nanocubes = 1 m3/ 1x 10-27 m3 = 1x 1027 Surface area = (1 x 1027) x (6 x 10-18 m2) = 6 x 109 m2 = 6000 Km2 The total area of the nanocubes is a billion times that of the 1 m cube. Approximately Equal to the area of 1/7th of Haryana state (44000 Km2). Why surface area is important? It decides many physical properties of material The power of nano Lesson: Surface area is inversely proportional to size of the particle
- f the same volume
Nanomaterials vs Bulk materials
SA = 6 m2 m
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
How to minimize surface energy?
Citrate ligand
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Electr trical, ical, o
- ptica
ical, l, t thermal, rmal, magnetic, netic, c chemical, emical, mechan anical, ical, a and biological
- logical p
properties
- perties ?
??
- Quantum s
siz ize c confinement
- Wave-like
like t transpo nsport rt
- Domin
inant ant i interfac erfacial ial phenomena
“Nano” A Magic Word!!
Nature of electron in nanostructure (Wave like) is different from microstructure (particle like)
Indian Institute of Technology Kanpur DST Unit on Nanosciences
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
How to make nanomaterials as smart materials?
Why do we need smart materials?
- Materials senses a stimulus (eyes).
- pH, temperature, enzyme, antigen, light, etc.
- Takes an intelligent decision (brain).
- Should remain silent in the absence of stimuli
What are smart materials?
After chemo Befor chem
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Stimuli
- pH
- Temperature (healthy cells – 37oC
cancerous cell - 40oC)
- Glucose concentration (Diabetic patients)
- Enzyme (Glutathione in lysosome)
Internal Stimuli (inside our body) External Stimuli
- Light
- Ultrasonics
- Magnetic
Smart materials – Biomedical Applications
How to make them act smart?
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Smart materials
Drug delivery Bioimaging Biosensors NIR sensors
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Broad classification of materials
- Polymers (capsules, Micells, nanoparticles)
- Inorganic materials (Gold, Iron, Semiconductor Nps)
- Biomaterials (Proteins, DNAs)
- Carbon-based materials (CNTs, C60, graphene,)
Smart materials
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Quantum Dots vs Organic Dyes
Organic dye Quantum dot Organic dye Quantum dot
Lesser photobleaching – Better Imaging
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Targeted Nanoparticles
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Indian Institute of Technology Kanpur DST Unit on Nanosciences
Multifunctional nanomaterials
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Top-down approach
Synthesis of nanomaterials
e.g. Ball milling, Extrusion, Lithography, Etching
Bottom-up approach
e.g. Colloidal synthesis, Chemical vapour deposition, Combustion and etc.
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Turkevich Method (Reduction of Gold ion by citrate ions)
+
~ 15-20 nm (Color My Nanoworld by Adam D. McFarland, Christy L. Haynes, Chad A. Mirkin, Richard P. Van Duyne, and Hilary A. Godwin*, J. Chem. Educ. 2004, 81, 544 A.
Au nanoparticles: How to prepare? Undergraduate Lab experiments
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Silica particles
Stober’s synthesis Tetraethyl orthosilicate NH4OH, Ethanol, H2O Silica particles
Undergraduate Lab experiments Characterization techniques – UV vis absorption, scanning electron microscope (table top), Fluorescence spectroscopy, FTIR, XRD, etc
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Aqueous medium synthesis
Cd(ClO4)2 + H2S/Se/Te Thiol ligands R-SH CdX (X = S, Se, Te) Control of growth:
- Concentration of ligand, reactants
- pH
- Temperature and duration of heating
- 15-20% broad distribution
Bottom-up approach
95 0C
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