Publikation

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

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 (Online: http://www.sciencedirect.com/science/article/pii/S0304399109000886?via%3Dihub), 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.