Recording The Endocytosis Of Nanoparticles By Spectrum And AFM

Compared with the conventional optical probe, gold nanoparticles as optical probe possess of many advantages comparing with other traditional optical probes, such as high photostability, large optical cross-section, easy to prepare and modify, well biocompatibility. So that the gold nanoparticles has been widely used in biosensors and imaging, and respect in the biomedical field and analytical chemistry fields. Based on the optical properties of metal nanoparticles, single-particle imaging and single-particle spectroscopy with nanometer-scale spatial resolution and millisecond time resolution have become important means for studying the behaviors and functions of biomolecules at single-cell level. In this paper, we studied the dynamic process of interaction between the nanoparticles and cells. We got the following results:1. In this paper, we verified gold nanoparticles entry into the living cell by the UV-visible absorption spectrum. Through the experiment we found that there was still an obvious absorption peak when gold nanoparticles entered into cells, which would be a tiny red shift compared with that of gold nanoparticles without interaction with cells. In order to determine the absorption peak of the two peaks was characteristic of nanoparticles, we used the discrete dipole approximation(discrete dipole approximation-DDA) theory to simulate the above two absorption peaks. Through modeling, we determined the absorption peak of 519 nm and 524 nm. With the concentration of gold nanoparticle decreasing, the absorption peak of gold nanoparticles will appear a red shift, and the intensity of the plasma resonance absorption peak will gradually reduce.2. Recording the dynamic endocytosis of single gold nanoparticles by AFM-based Force Tracing. In the experiment, the forces of Au NPs endocytosis into the living cells vary from 20 p N to 140 p N. With the increase of particle size, interaction force and time between nanoparticles and cells will increase, while the average rate decreases. In addition, we performed control and blocking experiments, which confirmed the dependence of Au NP endocytosis on membrane cholesterol, indicating a clathrin- or caveolae-mediated endocytosis pathway for Au NPs.There is a subtle interaction between gold nanoparticles and cells. After the experiment we used UV Vis absorption absorption spectra find the absorption spectra of nanoparticles in a small red shift. At the same time, we recording the dynamic endocytosis of single gold nanoparticles by AFM-based Force Tracing. The work were of great significance for the drug transport.