Cm20 transmission electron microscope

Transmission electron microscopy was employed to observe the structure of nanliposomes and chitosan-coated liposome with a negative staining method according to the protocol of Colas et al. (2007) [57 (link)]. Briefly, the samples were diluted 25-folds with distilled water to reduce the concentration of the particles. Same volume of the diluted solution was mixed with an aqueous solution of ammonium molybdate (2%) as a negative staining agent. Staining was followed by a 3 min wait at room temperature, and 5 min on a copper mesh coated with carbon, then samples were examined using a Philips CM20 Transmission Electron Microscope associated with an Olympus TEM CCD camera.

The morphology and microstructure of nanoliposomes were studied via the negative staining method and by transmission electron microscopy (TEM). First, to decline the effect of concentration, the samples were diluted with distilled water about 30 times. Then, the diluted sample was mixed with ammonium molybdate solution 2% (as the negative staining agent) in a ratio of 1:1 and left exposed to room temperature. The resulting mixture was placed on copper grids coated with formvar-carbon for 5 min (mesh 200, diameter 300 mm). The additional samples were removed by filter paper and the grids were dried at room temperature. Eventually, the images of the stained samples were recorded by a Phillips CM20 transmission electron microscope with a voltage of 200 kV and using an Olympus TEM CCD camera [34 (link)].