ReviewOpticalImagingPavestheWayforAutophagyResearchYiminWang,1YuLi,1FujingWei,1andYixiangDuan1,*Autophagyisadegradationprocessineukaryoticcellsthatrecyclescellularcomponentsfornutritionsupplyunderenvironmentalstressandplaysadou-ble-edgedroleindevelopmentofmajorhumandiseases.Noninvasiveopticalimagingenablesustoclearlyvisualizevariousclassesofstructuresinvolvedinautophagyatmacroscopicandmicroscopicdynamiclevels.Inthisreview,wediscussimportanttrendsofemergingopticalimagingtechnologiesusedtoexploreautophagyandprovideinsightsintothemechanisticinvestigationandstructuralstudyofautophagyinmammaliancells.Someexcitingnewpros-pectsandfutureresearchdirectionsregardingopticalimagingtechniquesinthisfieldarealsohighlighted.TheRiseofOpticalImagingInthelastfewdecades,opticalimaginghasgreatlyenhancedourabilitytoviewtheworldmicroscopically[1].Opticalbioimagingandbiophotonics,whichprovidevisibledetailedinfor-mationaboutthetargetsample,havebeenusedwidelyinadvancingbiomedicineatscalesrangingfromasinglemoleculetotissues[2].Thehugedemandsofbiologicalspecimendetectionhavestronglypromotedthedevelopmentofbioimaginginstrumentation.Accordingtothedesiredspatialresolution(seemoredetailsinTable1),opticalbioimagingcanbeachievedmainlythroughwide-fieldmicroscopy,confocalmicrocopy,multiphotonmicrocopy,andsuper-resolutionmicrocopy.Forexample,organicandinorganicnanoparticles,small-moleculefluorophores,andcolorfulfluorescentproteinscanbeusedaloneorconjugatedwithotherbioactivecompoundstoimagethecellorlivingtissues[2].Inaddition,inbiomaterialandbiomedicinesciences,near-infraredfluorophoresareemergingforimagingandcanpenetratetumortissueorotherhumanorgans[3].Autophagy,adegradationprocessofcellularcontentsandpathogens,occursunderstarvationorintracellularstressineukaryotestorecyclenutrientsandmaintaincellhomeostasis.Thisbalancedconditionreferstothecytoplasmorotherunwantedcellularcomponentssuchasendoplasmicreticulum(ER),mitochondria,nucleus,peroxisomes,ribosomes,orinvadingpathogensbeingconvertedintoaminoacid...
