tailieunhanh - Atomic Force Microscopy in Cell Biology Episode 1 Part 3

Tham khảo tài liệu 'atomic force microscopy in cell biology episode 1 part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 42 Hegner and Arntz Am k 4nn2 -1 f1-2 - f0-2 2 where the resonance frequency before and during the experiment are f0 and f1 k is the spring constant of cantilever and n is a factor dependent of the geometry of the cantilever. The uptake of mass as a result of specifically interacting molecules is doubled in this manner and the cantilever does not respond to temperature changes via a bimetallic effect. Additionally the preparation involves fewer steps as in the case of the static detection mode 5 . 4. Setups At the Institute of Physics at the University of Basel Basel Switzlerland in collaboration with the IBM Research Laboratory Zurich we developed cantilever array setups both for static and dynamic mode operation in liquids and in the gas phase. The principal part of the setup is an array of eight cantilevers produced by classic lithography technology with wet etching. A typical picture of such a cantilever array is shown in Fig. 3. The structure of an array is composed of eight cantilevers with a length of 500 pm a width of 100 pm and a pitch of 250 pm from lever to lever. The etching process provides cantilever thickness ranging from 250 nm to 7 pm adapted for the individual application . static or dynamic mode . The cantilever deflection or motion detection is provided by a classic laser beam deflection optical detection for both the static and dynamic mode set up as shown in Fig. 4. The laser source is an array of eight vertical-cavity surface-emitting lasers VCESLs 760 nm wavelength 250 pm pitch and position detection obtained through a linear position-sensitive detector . The array is mounted in a cell useable for gas or liquid phase measurement. A scheme showing the setup is displayed in Fig. 5. The operation of the instrument is fully automatic and during the time course of a few hours up to eight different samples can be probed using the automatic fluid delivery. The instrumental noise of the static setup lies in the subnanometer range and the dynamic