Preparation Of Fluorescent Silk Fibroin Micro/Nano Particles And Their Interaction With Cells

Different cells responde to different-sized silk fibroin particles with different adherence or endocytosis. When silk fibroin particles were used as controlled drug delivery, whether the particles were attached to cells or taken up by cells would directly influence the efficiency of drug release and target site. In order to discuss the different cell behavior, four different diameter particles were prepared with electrostatic differentiation, and the interaction law of particles and cells were investigated by culturing EA.hy 926 cells and HeLa cells with different-sized silk fibroin particles. These studies provide primary bases for choosing corresponding sized silk fibroin particles to delivery drug to different cells.First, silk fibroin particles were fabricated by electrostatic differentiation method, then we prepared fluorescent silk fibroin micro/nano particles with covalent binding of FITC and quantum dots to particles. The particles were observed by SEM, and the fluorescent particles were analysed by laser confocal microscopy, TEM, FT-IR spectra, EDS and fluorescent spectrometer. The results indicated that the average diameters of particles were 232.1 μm, 105.1 μm, 1.9 μm and 51.1 nm respectively, and the spheroidal particles had rough surface with numerous small particles. The two fluorescent labels could be coupled on the surface of particles, and quantum dots labeled particles showed unique fluorescent stability.The interactions of SFMP3 and SFNP with cells were studied by fluorescent tracer technique and CCK-8. The adhesion and cellular uptake were tracked with fluorescent tracer technique in real-time, and the cell proliferation were investiged by CCK-8. The results revealed that SFMP3 promoted proliferation of cells, and the ability of proliferation of HeLa was higher than that of EA.hy 926 when the concentration of particles was 0.5 mg/ml. Compared with microspheres, the nanoparticles inhibited the proliferation of cells, and the effect of inhibition of EA.hy 926 was greater than that of HeLa. The results of tracking the particles showed SFMP3 could attach on cells but not be taken up by cells. However, SFNP could be internalized by cells. As the prolongation of time, the particle intake increased. Moreover, compared with the EA.hy 926 cells, He La cells had a stronger capability of endocytosis.Finally, adhesion and growth of cells on silk fibroin microsphere surface were investigated. The SEM observation showed that cells start to migrate from the culture plate to microsphere surface after co-culturing with microspheres for 8-12 hours. As the prolongation of time, the cells on microspheres begain to spread and proliferate, and the ability of proliferation of HeLa was higher than that of EA.hy 926. In addition, SFMP2 were more helpful to adhere in comparation to SFMP1.The preparation of silk fibroin micro/nano particles and the experimental phenomena that cells showed relevant behaviors to different-sized particles obtained in this paper provide primary experimental basis for choosing corresponding carries to delivery drug to cells.