The Application Of Nanocomposites In Biological Detection And Bioimaging

Malignant tumor is a major threat to human health and effective diagnosis and treatment of cancer has attracted increasing attention in the field of biomedicine. Tumor fluorescence imaging is an important means of early diagnosis and real-time monitoring of cancer. In recent years, the researchers utilize nanomaterials to mark tumor cells specifically due to their luminescent properties, for instance, fluorescent quantum dots, precious metal nanoclusters, upconverting luminescent nanoparticles and fluorescent nanocomposites have highly sensitive optical imaging which have been proved in cancer cells and animal level. Fluorescent nanomaterials with good biocompatibility and high signal to noise ratio have attracted more and more attention.Fluorescent gold nanoclusters have good water-solubility and high biocompatibility which can be used as fluorescent probe because of their good biomarking function. In this thesis work, we synthesized Ce3+doped gold nanoclusters and made use of the composite materials to incubate with tumor cells in vitro such as HepG2, HeLa and L02 cell lines and analysed laser scanning confocal results. In addition, we also characterized the targeting marker function of Au/Ce nanoclusters in in vivo tumor models. In this work, the results show that trivalent cerium ion doped into seed crystal growth process of gold through hydrothermal reaction successfully. The synthesized glutathione stabilized Au/Ce NCs possess stable and bright fluorescence that can be readily utilized for high sensitive fluorescence probe. Our results suggest that Au/Ce NCs have good fluorescent marking effect on HepG2 and HeLa but L02 cell lines. Meanwhile, We further established xenograft tumor model of Cervical carcinoma, subcutaneous injection of Au/Ce NCs around xenograft tumors allowed the clear observation of bright fluorescence around the tumor after 24 hours while the fluorescence in the mouse injected with intravenous injection Au/Ce NCs solution through the tail was also observed by in vivo fluorescence.At the same time, we explore the biomedical application of composite materials. One-step synthesis of glutathione-stabilized Ag NPs could be readily realized by photoreduction, and we introduced them into the research of inhibiting the growth of bacteria and preventing biofilm formation. Finally, we prepared excellent antimicrobial nanocomposites through the improvement and optimization, thus reversing multidrug resistance (MDR) of bacteria. As a consequence, it is vital that we need to develop effective antimicrobial agents and antibacterial materials. In this contribution we report the first green photochemical synthesis of carbon spheres through in-situ enwrapping around silver nanoparticles (CS-Ag NPs). TEM characterization of CS-Ag NPs nanocomposites illustrates that Ag NPs were superbly wrapped inside the carbon spheres and also adhered to the surfaces of the carbon spheres. These porous CS-Ag NPs show excellent fluorescence and effective antibacterial efficiency, exhibiting ideal lengthened activities against Escherichia coli and Staphylococcus aureus compared with bare Ag NPs. The relevant rationale behind it could be attributed to the fact that CS-Ag NPs nanocomposites can provide some excellent niches for the durable and slow release of silver ions. This raises the possibility of promising applications of CS-Ag NPs nanocomposites as excellent antibacterial agents for the efficient monitoring of some disease-related bacteria.