The strategy. using Atomic Force Microscope; Biomolecules and Neutraceuticals examples

Transcription

1 The strategy for Bionanomolecules Characterizations using Atomic Force Microscope; Biomolecules and Neutraceuticals examples Dr. NagibAli Elmarzugi, PhD Head of Nanotechnology Research gp., Biotechnology Research Centre. Faculty of Pharmacy, Alfateh Universityy

2 Nanotechnology Ability to work at the atomic, molecular and even sub-molecular levels in order to create and use material structures, t devices and systems with new properties and functions Source: National Science Foundation (NSF), USA

3 Two strategies: to go down to the nanometer scale Top-Down 3

4 Two strategies: Bottom Up 4

5 Characteristics at Nano level are different!!!! Surface area increases as size decreases

6 Why nano will change the properties of materials? Example: Smaller size means larger surface area diameter 10 µm 50 nm diameter Area 0.22 m 2 /g 44 m 2 /g 6

7 Melting Point of Nanoparticles The melting point decreases dramatically as the particle size gets below 5 nm

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9 Metal Nanoparticles As a material becomes more and more finely divided it reaches a point whereby the physical properties that the bulk material possess begin to differ significantly. This, of course, happens on the nanoscale. Gold for example changes colour from gold to blue to red and is soluble in organic solvents. As well as going from being a conductor to a semiconductor. Bulk Metal Continuum of Electronic states Electrons roam about through all of these electronic states Metal Nanoparticles Band Gap Conduction Band Valence Band

10 What are some unique nanomaterials properties? p Nanomaterials in the life-sciences area are most likely Nanomaterials in the life sciences area are most likely to represent supramolecular aggregates of active and non-active atoms/molecules where the overall particulate size may be between nm (but in some cases more than 100 nm). Due to the increased surface area of nanoparticles, even well-characterized nanomaterials may have unique physical and chemical properties compared with larger particulate aggregates of the same materials. Nanoparticles may differ substantially from larger aggregates in their biodistribution.

11 Examples of nanomaterials with pharmaceutical applications Dendrimers Gold nanoparticles, silver nanoparticles Metal oxides (FeO, TiO2, ZnO) Liposomes

12 Which products expected to be impacted by nanotechnology? Drugs (novels or delivery systems) Medical devices Biotechnology products Tissue engineering products Vaccines Cosmetics Neutraceutical Combination products

13 So Why small is good? Nano-objects are: - Faster - Lighter - Can get into small spaces - Cheaper - More energy efficient - Different properties at very small scale

14 Scanning Microscopes? Represents the signal which the probe is sensing to allow it to accurately trace the surface profile. It may be Current STM AFM Heat SThM, etc..

15 Atomic Force Microscopy AFM Invented in 1985 Measures the force between the tip and the surface Can easily image non-conducting objects i.e., DNA and proteins etc. 3-D image of nano-objects AFM tip

16 Bio-AFM through the ages Library

17 Atomic Force Microscopy (AFM) Genes Quadrant (deflection detector) Storage Fe eedback loop Z Mirror Laser Beam Sample SEM image of an AFM Cantilever probe Y X Piezoscanner Probe Path of tip Feedback signal, plus x, y movement processed Image 3μm SEM image of AFM probe

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58 Sample for AFM imaging... Genes Successful strategies involve the careful balance of Storage tip-specimen, tip-substrate and specimen-substrate interactions AFM imaging requires Biomolecular immobilization strategy and a substrate

59 Immobilization strategies can be non-covalent or covalent biomolecule substrate physisorption p electrostatic Affinity immobilization covalent

60 Which substrates? Ideally atomically flat, but at worst must have a roughness less than the size of the biomolecules of interest Hydrophobic surfaces not usually recommended e.g. Mica and gold most commonly used, but also graphite, silicon, glass.

61 Muscovite mica Mica most commonly used Hydrophilic aluminosilicate material which is highly negatively charged Crystals exhibit a large degree of basal cleavage, allowing them to be split into v.thin atomically flat sheets cleavage plane cleavage plane Red O Silver Si Purple K Brown - Al

62 Examples of Bio molecules Visualisation by TM AFM 200nm 110nm 25nm () (c) 250nm 180nm 25 nm

63 Nanoscale Visualisation 200 nm AFM topography image of DMAEMA (Polymer) in air on mica Z range 9nm AFM image of plain mica by AFM, Z = 5 nm 500 nm Measurements of mean width & height (nm) of different polymer systems by AFM Width 22.4 ± 4.4 nm (N=31) Height 1.8 ± 0.9 nm ( N=28)

64 2 (b) nm 350 nm AFM Storage image of Single a) AFM image of supercoiled plasmid DNA on mica DNA plasmid, b) Section analysis (in Liquid), Z=5nm of height measurement. Measurements of single plasmid DNA Width 17.8 ± 7.3nm (N=16) Height 6.3 ± 1.3 nm ( N=22) Contour lengths 1078 ± 86 nm (N=7) NA Elmarzugi, (2004)Charactrisation for Gene therapy, UK SPM

65 Nanoscale Visualisation AFM topography image of Lactuca Sativa granules extracts in air on mica Z range 70nm, scale bar 300nm 200 nm

66 Summary The Imaging of Biomolecular compounds influenced by the strategy of immobilization of these Biomolecules on the substrate by AFM Although imaging of DNA Polymer complexes at Nano level is routinely investigated by AFM these days However, characterization of natural products at nano level by AFM for their Pharmaceutical & neutraceutical purposes is newly method To get a high resultion images for Lactuca Sativa granules further optimization is required..(which is on going research..) 66

67 God Bless Us All, Ameen! Thanks! All of you!