Abstract
This research purposes the development of phase contrast electron microscopy by a MEMS electrostatic phase plate, and the achievement to high resolution bio-sample imaging without staining. TEM provides high resolution images to in-organic materials due to high contrast of the in-organic materials to the supporting substrate materials when interacted with electron beams. In bio-image, most of the bio-specimen, containing mostly carbohydrate, needs staining to enhance the image contrast, due to the weak interactions between low Z atoms and incident electron beam. Zernike invented a phase plate to converse the phase information of transparent object to image intensity for getting high contrast images in optical microscopy. To obtain nm resolution for bio-molecule observation, Matsumoto proposed the employment of Boersch micro-lens (Electrostatic Zernike Phase Plate, EZPP) to shift the phase of a center electron beam to improve TEM phase images. The highest contrast occurs at the EZPP providing π/2 phase shift. We demonstrate an advanced version of the EZPP for protein visualization after the reduction of electron beam interaction. Lower the background absorption contrast by increasing the demension of the aperture and decreasing the width of the supporting cantilever. A special retraction design could avoid the electron charging to distort the diffraction pattern.