Preparation Of Dual Fluorescent Nanoparticles And Their Rotation On Lipid Membrane

The interaction between cell membrane and nanoparticles has a regulatory effect on cell endocytosis.Studies have found that parameters such as shape and surface charge can regulate the interaction between cell membranes and nanoparticles.At present,most studies on the interaction between cell membranes and nanoparticles focus on tracking the two-dimensional or three-dimensional translational motion of nanoparticles,but many chemical or biological processes also involve rotational dynamics.With the development of imaging technology and nano-synthesis technology,single particle rotation tracking becomes possible.In this work,we mainly study the effect of the interaction between nanoparticles and cell membranes on the rotation of nanoparticles on the supporting membrane.In this paper,we have synthesized a novel rod-shaped fluorescent nanoparticles with red and green fluorescence at both ends.Compared with the traditional nanoparticles,we can obtain higher temporal and spatial resolution and track the rotation in a larger range.The motion of rod-shaped particles on films with different electrical properties was studied by means of dual channel total internal reflection fluorescence microscopy（TIRF）.We use electrical interaction to simulate the interaction between nanoparticle and cell membrane in cell environment,and further explore the influence of the shape of rod-shaped nanoparticles on their movement on the supporting membrane.We found that the SiO₂nanoparticles are more prone to lie down on the positively charged supporting film,and the change of their azimuth angle is smaller because the SiO₂nanoparticles are negatively charged.However,due to the influence of charge rearrangement,the change of polar angle is relatively larger.For the non charged supporting membrane,because there is no electrostatic binding,the degree of freedom of its movement is greater,which is close to standing on the cell membrane,and its azimuth distribution range is wider.However,due to the influence of their own shape,their azimuth changes are relatively small,showing the trend of axial movement along the rod.Through this work,we have deepened our understanding of the interaction between geometrically symmetric broken particles and membranes,and provided guidance for their application in biomedicine.