简介：Thispaperpresentedaninterestingnanoparticle-baseddrugdeliverysystemwithmorphologytransitionbehaviordependingonthecontentofexposedPEGchainontheparticlesurface,whichisadjustablebyadditionofdifferentamountofcyclodextrin(a-CD).Theeffectofa-CDinclusiontotheself-assemblybehaviorofmethoxypolyethyleneglycol(mPEG)graftedchitosan(CS)wasstudied.TheresultsshowedthatthemPEGgraftedchitosan(mPEG-[9_TD$IF]g-CS)formsself-assemblednanoparticleswitheithermicelleorhollowspheremorphologydependingontheratioofa-CDtomPEG,ascharacterizedbyatomicforcemicroscopy(AFM),transmissionelectronmicroscopy(TEM),andX-raydiffraction(XRD).Theirsizesandzetapotentialincreasedfrom257.6nmto768.2nmandfrom+4.5mVto+11.6mV,respectively,withtheincreasingamountofa-CD.Thecorrelationbetweenzetapotentialandparticlesizeofa-CD/mPEG-[9_TD$IF]g-CSnanoparticlesindicatedvariedPEGdensityonsurfaceofnanoparticles.Basedontheaboveexperimentalobservations,alikelymechanismforthemorphologicaltransitionoftherod-coilgraftcopolymermPEG-[9_TD$IF]g-CSwasproposed.