Combined two photon excited fluorescence and second harmonic generation imaging microscopy of collagen structures

Psilodimitrakopoulos, S; Filippidis, G; Kouloumentas, C; Alexandratou, E; Yova, D

dc.contributor.author	Psilodimitrakopoulos, S	en
dc.contributor.author	Filippidis, G	en
dc.contributor.author	Kouloumentas, C	en
dc.contributor.author	Alexandratou, E	en
dc.contributor.author	Yova, D	en
dc.date.accessioned	2014-03-01T02:50:19Z
dc.date.available	2014-03-01T02:50:19Z
dc.date.issued	2006	en
dc.identifier.issn	0277786X	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/35059
dc.subject	Collagen	en
dc.subject	Harmonophore	en
dc.subject	Second harmonic generation	en
dc.subject	Two-photon excited fluorescence	en
dc.subject.other	Diagnosis	en
dc.subject.other	Fluorescence	en
dc.subject.other	Gels	en
dc.subject.other	Medical imaging	en
dc.subject.other	Molecular structure	en
dc.subject.other	Scanning electron microscopy	en
dc.subject.other	Second harmonic generation	en
dc.subject.other	Diagnostic tools	en
dc.subject.other	Harmonophore	en
dc.subject.other	Molecular organization	en
dc.subject.other	Two-photon excited fluorescence	en
dc.subject.other	Collagen	en
dc.title	Combined two photon excited fluorescence and second harmonic generation imaging microscopy of collagen structures	en
heal.type	conferenceItem	en
heal.identifier.primary	10.1117/12.644478	en
heal.identifier.secondary	http://dx.doi.org/10.1117/12.644478	en
heal.identifier.secondary	60891P	en
heal.publicationDate	2006	en
heal.abstract	Collagen is known to be a very efficient producer of both second harmonic generation (SHG) and two-photon excited fluorescence and the combined use of those nonlinear signals is emerging as a new imaging probe to be used as a diagnostic tool. By recording structural information of collagen between different samples, the technique shows promising for the study of the distribution of collagen in tissue and for identifying pathologic conditions. Unique information about the molecular organization of collagen can be extracted from SHG and TPEF imaging data in several ways and we have initiated a systematic study of these issues. The main objectives of this work are to combine TPEF and SHG methodologies, in order to elucidate and quantify cross-linking and to describe a model of fibrils orientation within different samples. In this early approach we discuss fundamental principles governing SHG and TPEF and present the first results of applying these rules to collagen type I images analysis. By comparing signals between lyophilized and soluble collagen we validate that the SHG signal arises from dipolar interactions that are enhanced by the quaternary structure of collagen fibrils, while TPEF arises from fluorophores which are suggested to be products of cross-linking. Using a homogenization protocol of acid treated collagen gels we manage to produce SHG and TPEF active thin films, which characterized by means of their contrast capability. A home-built scanning microscope employing SHG and TPEF was used for the high-resolution imaging of endogenous SHG and TPEF signals, without exogenous dyes.	en
heal.journalName	Proceedings of SPIE - The International Society for Optical Engineering	en
dc.identifier.doi	10.1117/12.644478	en
dc.identifier.volume	6089	en