Publikation

Second Harmonic Atomic Force Microscopy Imaging of Live and Fixed Mammalian Cells

Publikation, 2009

Outline

A. Dulebo, J. Preiner, F. Kienberger, G. Kada, C. Rankl, L. Chtcheglova, C. Lamprecht, D. Kaftan, P. Hinterdorfer - Second Harmonic Atomic Force Microscopy Imaging of Live and Fixed Mammalian Cells - Ultramicroscopy, 2009

Abstract

Higherharmoniccontributionsinthemovementofanoscillatingatomicforcemicroscopy(AFM) cantileveraregeneratedbynonlineartip–sampleinteractions,yieldingadditionalinformationonstructure andphysicalpropertiessuchassamplestiffness.Higherharmonicamplitudesarestronglyenhancedin liquidcomparedtotheoperationinair,andwerepreviouslyreportedtoresultinbetterstructural resolutioninhighlyorganizedlatticesofproteinsinbacterialS-layersandviralcapsids[J.Preiner,J.Tang, V. Pastushenko,P.Hinterdorfer,Phys.Rev.Lett.99(2007)046102].Wecomparedfirstandsecond harmonicsAFMimagingofliveandfixedhumanlungepithelialcells,andmicrovascularendothelialcells frommousemyocardium(MyEnd).Phase–distancecyclesrevealedthatthesecondharmonicphaseis8 timesmoresensitivethanthefirstharmonicphasewithrespecttovariationsinthedistancebetween cantileverandsamplesurface.Frequencyspectrawereacquiredatdifferentpositionsonlivingandfixed cellswithsecondharmonicamplitudevaluescorrelatingwiththesamplestiffness.Weconcludethat variationsinsamplestiffnessandcorrespondingchangesinthecantilever–sampledistance,lattereffect causedbythefinitefeedbackresponse,resultinsecondharmonicimageswithimprovedcontrastand informationthatisnotattainableinthefundamentalfrequencyofanoscillatingcantilever.