Characterization of bionanomaterials

1. Characterization of bionanomaterials

4. Small angle X-ray scattering (SAXS)

5. Scanning electron microscopy (SEM)

6. Transmission electron microscopy (TEM)

7. Scanning probe microscopy (SPM)

9. Optical spectroscopy

10. Absorption and transmission spectroscopy

11. Photoluminescence (PL)

12. Electron spectroscopy

13. Ionic spectrometry

14. Colorimetry

15. Fluorescence

17. In XRD, a collimated beam of X-rays, with a wavelength typically ranging from 0.7 to 2 A, is incident on a specimen and is diffracted by the crystalline phases in the specimen according to Bragg's law:A = 2d sin θ where d is the spacing between atomic planes in the crystalline phase and A is the X-ray wavelength. The intensity of the diffracted X-rays is measured as a function of the diffraction angle8 and the specimen's orientation.

20. Resolution of the SEMapproaches a few nanometers, and the instruments can operate at magnificationsthat are easily adjusted from - 10 to over 300,000.

21. Not only doesthe SEM produce topographical information as optical microscopes do, italso provides the chemical composition information near the surface.

22. In a typical SEM,a source of electrons is focused into a beam, with avery fine spot size of 5 nm and having energy ranging from a few hundredeV to 50 Key that is rastered over the surface of the specimen bydeflection coils.

25. Optical techniques can be generally categorized into two groups:

26. Absorption and emission spectroscopy

27. Vibrational spectroscopy

28. The absorption and emission spectroscopy determines the electronic structures of atoms, ions, molecules or crystals through exciting electrons from the ground to excited states(absorption) and relaxing from the excited to ground states (emission).

30. As a result, their wavelengths or photon energies can be determined with great accuracy.

33. Most common NPs used in mass spectrometry are Au NPs, TiO2 NPs, and Fe3O4 NPs.