简介：Bunchingofelementarystepsbysolutionflowisstillnotyetclarifiedforproteincrystals.Hence,inthisstudy,weobservedelementarystepsoncrystalsurfacesofmodelproteinhenegg-whitelysozyme(HEWL)underforcedflowconditions,byouradvancedopticalmicroscopy.WefoundthatinthecaseofaHEWLsolutionof99.99%purity,forcedflowchangedbunchedstepsintoelementaryones(debunching)ontetragonalHEWLcrystals.Incontrast,inthecaseofaHEWLsolutionof98.5%purity,forcedflowsignificantlyinducedbunchingofelementarysteps.TheseresultsindicatethatinthecaseofHEWLcrystals,themasstransferofimpuritiesismoresignificantlyenhancedbyforcedsolutionflowthanthatofsoluteHEWLmolecules.Wealsoshowedthatforcedflowinducedtheincorporationofmicrocrystalsintoamothercrystalandthesubsequentformationofscrewdislocationsandspiralgrowthhillocks.