Multimedia : Listen to "Structured Water" Podcast corresponding to journal article : Higgens, et al. Biophys. J. 2006 91, 2532.ATOMIC FORCE MICROSCOPY : GENERAL COMPONENTS AND FUNCTIONSATOMIC FORCE MICROSCOPY IMAGING : FACTORS AFFECTING RESOLUTIONATOMIC FORCE MICROSCOPY IMAGING : TIP DECONVOLUTIONAFM IMAGING OF BIOLOGICAL MACROMOLECULES: DNA3.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSEILECTURE 6: AFM IMAGING II : ARTIFACTS AND APPLICATIONSOutline :LAST TIME : BASIC PRINCIPLES OF ATOMIC FORCE MICROSCOPY.................................................2FACTORS AFFECTING RESOLUTION.....................................................................................................3 Tip Deconvolution.....................................................................................................................4IMAGING OF CELLS..................................................................................................................................5IMAGING OF DNA .....................................................................................................................................6HRFS COMBINED WITH AFM : SPATIALLY SPECIFIC SURFACE INTERACTIONS..............................7Objectives: To review artifacts present in atomic force microscopy imaging and current state of theart uses.Readings: Course Reader Document 12-15.Multimedia : Listen to "Structured Water" Podcast corresponding to journal article : Higgens, et al.Biophys. J. 2006 91, 2532.13.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSEATOMIC FORCE MICROSCOPY : GENERAL COMPONENTS AND FUNCTIONSAdvantages : 1) Unlike electron microscopes, samples do not need to be coatedor stained, minimal damage, 2) Unlike electron microscopes, samples can beimaged in fluid environments (near-physiological conditions), 3) Unlike STMsamples do not need to be conductive, 4) Sub-nm resolutions have beenachieved on biological samples (detailed information on the molecularconformation, spatial arrangement, structural dimensions, rate dependentprocesses, etc.)-Basic principles-Deflection vs. Height images-2D Section Profiles-3D Images-Normal modes of operation (Contact AC/DC, Tapping AC, Noncontact AC)-Other modes of operation (LFM, CFM, Force/Volume)-DEMOs23.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSEATOMIC FORCE MICROSCOPY IMAGING : FACTORS AFFECTING RESOLUTION33.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSEATOMIC FORCE MICROSCOPY IMAGING : TIP DECONVOLUTION-Imaging very sharp vertical surfaces is influenced by the sharpness of the tip. Only a tip with sufficient sharpness can properly imagea given z-gradient. Some gradients will be steeper or sharper than any tip can be expected to image without artifact. False images are generated that reflect the self-image of the tip surface, rather than the object surface. Mathematical methods of tip deconvolution can be employed for image restoration. The effectiveness of these methods will depend on the specific characteristics of the sample and the probe tip. (q) = � (q)+ (q)= + (q)xtan x =wtanwwr*= wtan2r * 1tanw 2-Deep feature-Depth underestimated-Need high aspect ratio probe tip.43.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSE-tip broadening-width is overestimated → mention pset53.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSEAFM IMAGING OF BIOLOGICAL MACROMOLECULES: DNA63.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSEHRFS COMBINED WITH AFM : SPATIALLY SPECIFIC SURFACES INTERACTION INFORMATION (Vandiver, et al. Biomaterials 26 (2005) 271–283).73.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSESUPPORTED LIPID BILAYERShttp://en.wikipedia.org/wiki/Image:Cell_membrane_detailed_diagram.svghttp://faculty.virginia.edu/tamm/pages/project_support.html DPPC DOPCHiggens, et al. Biophys. J. 2006 91, 2532.83.052 Nanomechanics of Materials and Biomaterials Tuesday 02/27/07 Prof. C. Ortiz, MIT-DMSENANOMECHANICS OF SUPPORTED LIPID BILAYERS Higgens, et al. Biophys. J. 2006 91, 2532.
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