Enhanced Immunostimulation Of CpG Hollow Gold Nanospheres And Chiral Optical Study Of Peptides-Gold Nanoparticles

Gold nanomaterials are hot materials in various research fields for many years,due to high biocompatibility and low toxicity and unique optical properties of gold nanomaterials.Hollow gold nanospheres(HGNs)are capable of modulating the surface plasmon resonance effect in the near-infrared region,and HGNs are therefore often used in photothermal ablation therapy.However,photothermal therapy can only eliminate local tumors in the primary site,and cannot effectively control metastatic tumors.Currently,the most promising strategy is to combine photothermal therapy with immunotherapy.The cytosine-phosphate-guanine(CpG)oligodeoxynucleotides(ODNs)motif are potent stimulators of the innate immune system,but free CpG ODNs are difficult to penetrate the cell membrane,which results in negligible immunostimulatory effects.In order to effectively achieve the uptake of CpG ODNs by cells,and enhance immune stimulation of CpG ODNs,the thiolated CpG ODNs was self-assembled on hollow gold nanospheres to form CpG-HGNs in Chapter 2.Cellular uptake of CpG-HGNs in immune cells was studied in RAW 264.7 cells.Due to the increased delivery efficiency,CpG-HGNs exhibited higher immunostimulatory activity than CpG alone,resulting in a significant increase in the secretion of tumor necrosis factor.Furthermore,CpG-HGNs showed low cytotoxicity in RAW 264.7 cells.CpG-HGNs could potentially synergistic photothermal therapy and immunotherapy in vivo.In addition,due to the unique optical properties of gold nanomaterials,the preparation of large chiral gold nanomaterials has received extensive attention in the scientific community.At present,great progress has been made in constructing nanostructures with chiral geometry.But there are few manufacturing methods that can be used for three-dimensional chiral structures.And when constructing three-dimensional chiral structures,little research on chiral transfer to size is nanomaterials of hundreds of nanometers.In order to develop a simple manufacturing method for a three-dimensional chiral structure and construct a chiral nanomaterial having a size of several hundred nanometers.In Chapter 3,the chirality in the peptides is transferred to the gold nanomaterials,which controllable synthesis asymmetric nanoparticles.The peptidesdirected gold nanoparticles can exhibit strong circular dichroism(~50 mdge)in the visible range(500-600 nm).And the synthesized chiral gold octahedral-peptides looks like "flower",showing asymmetric structure.In order to prove that the size and spatial structure of chiral gold nanoparticles have an influence on their chiral optical properties,chiral gold nanododecahedrons-peptides are prepared by using gold nanotrioctahedrons with complex morphology,and there are also double circular dichromatic response in the visible region.