简介：Nano-sizedzincoxide(nZnO)particlesareonekindofthemostcommonlyusedmetaloxidenanoparticles(NPs).ThisstudycomparedthecytotoxicandembryotoxiceffectsofthreeincreasingsizedZnOparticles(30nm,80?150nmand2μm)inthefloundergill(FG)cellsandzebrafishembryos,andanalyzedthecontributionofsize,agglomerationandreleasedZn2+tothetoxiceffects.AllthetestedZnOparticleswerefoundtobehighlytoxictobothFGcellsandzebrafishembryos.Theyinducedgrowthinhibition,LDHrelease,morphologicalchangesandapoptosisinFGcellsinaconcentration-,size-andtime-dependentmanner.Moreover,thereleaseofLDHfromtheexposedFGcellsintothemediumoccurredbeforetheobservablemorphologicalchangeshappened.TheultrasonicationtreatmentandadditionofserumfavoredthedispersionofZnOparticlesandalleviatedtheagglomeration,thussignificantlyincreasedthecorrespondingcytotoxicity.ThereleasedZn2+ionsfromZnOparticlesintotheextracellularmediumonlypartiallycontributedtothecytotoxicity.AllthethreesizesofZnOparticlestestedinduceddevelopmentalmalformations,decreaseofhatchingratesandlethalityinzebrafishembryos,butsize-andconcentration-dependenttoxiceffectswerenotsoobviousasinFGcellspossiblyduetotheeasyaggregationofZnOparticlesinfreshwater.Inconclusion,bothFGcellsandzebrafishembryosaresensitivebioassaysystemsforsafetyassessmentofZnOparticlesandtheenvironmentalreleaseofZnOparticlesshouldbecloselymonitoredasfarasthesafetyofaquaticorganismsisconcerned.