Imaging study cell contrast

Visual imaging of cell population in vitro) using low signal-to-noise ratio phase contrast microscopy can enable systematic monitoring measurements of cell quality, development and apoptosis. In the present study, microscopic evaluations as seen in Fig. 11 did not reveal any significant alteration in cellular morphology upto 1000 ng/ml. 

Patches are normally obtained under an inverted microscope. The magnification will depend on the size of the cells that are going to be studied. Illumination is phase contrast or differential interference contrast (Nomarski) in order to have a clear image of cells, taking into account that they are living cells without any dye. The illumination power supply of the microscope has to be localized far from the set-up, especially when it is an a.c. power supply. 

In contrast to many other surface analytical techniques, like e. g. scanning electron microscopy, AFM does not require vacuum. Therefore, it can be operated under ambient conditions which enables direct observation of processes at solid-gas and solid-liquid interfaces. The latter can be accomplished by means of a liquid cell which is schematically shown in Fig. 5.6. The cell is formed by the sample at the bottom, a glass cover - holding the cantilever - at the top, and a silicone o-ring seal between. Studies with such a liquid cell can also be performed under potential control which opens up valuable opportunities for electrochemistry [5.11, 5.12]. Moreover, imaging under liquids opens up the possibility to protect sensitive surfaces by in-situ preparation and imaging under an inert fluid [5.13]. 

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