Reseach On Biocompatibility Of Nanocarriers Material

Background:Biomedical materials must have good biocompatibility to ensure the safety of clinical applications. Not only biomedical materials could not cause significant clinical response and weren’t be exclusion/destruction,but also be able to keep the role of the host of system and remained relatively stable, which were evaluated biomaterials good compatibility.The bio-safety of biomaterials of evaluation methods include:genotoxicity, carcinogenicity and reproductive toxicity experiments choose interaction with blood, irritation and sensitization test, systemic toxicity experiments. Biomedical materials, as a foreign substance, which will inevitably contact with blood. Therefore, it will not be effect bloood cells and proteins of the blood system, but also will be recognized by the host immune system, and lead to a complex immune response. Hemocompatibility and immunocompatibility of the biomedical materials research has important theoretical and clinical value, which mainly including the biosafety evaluation of biological materials, and guided for optimizing design and practical application of the biological material, and be use of immune effector biomaterials for immune regulation, immune adjuvant and vaccine delivery, such as immunotherapy.Nowadays, nanotechnology is the most popular technology of research areas. Various different forms of carbon nanotubes have been widely for biomedical, electronic components etc. One of the most important prerequisite of single-walled carbon nanotubes (SWCNTs) which is able to stable in aqueous solution, dispersed in the biomedical applications field. Besides, single-walled carbon nanotubes (SWCNTs), as a drug carrier, which will be inevitably into the blood circulation. Therefore, it is vary important to understand the hemocompatibility of single-walled carbon nanotubes for Security applications in the biomedical area. Although there are a lot of literature has reported that carbon nanotubes would reduce the activity of vascular endothelial cells and promote the endogenous coagulation induced platelet activation and aggregation, etc. However, there is very limited reports about the effect of single-walled carbon nanotubes on red blood cells and coagulation process.Poly(amidoamine) dendrimers, as a novel biomedical polymer material,which is currently the most in-depth and extensive study of dendrimers. Recently, Poly(amidoamine) dendrimers is divided into PAMAM-NH2, PAMAM-OH, PAMAM-COOH, PAMAM-C12,PAMAM-NH2/OH (mixing surface) and PAMAMOS-TMOS (silicone surfactant), all of those depending on the terminal functional groups, and the previous three kinds of Poly(amidoamine) dendrimers were most widely studied. Poly(amidoamine) dendrimers are widely used biomedical polymers, which are extensively applied in drug delivery, gene delivery, contrast agent, etc. In the biomedical applications area, those will be how to impact the body, whether their biomedical functioning will be changed, etc. Therefore, it is essential to the safe use of the Poly(amidoamine) dendrimers in the medical field.Based on these, we intend to choose single-walled carbon nanotubes (SWCNTs) as a model, and investigate the effect of SWCNT-COOH which were been chemical oxidatived modification of SWCNTs on the morphology of red blood cells and coagulation functions in the blood. To clarify the bio-safety of PAMAM dendrimers, the effects of generation 5 PAMAM dendrimers with amine, hydroxyl or carboxyl groups on immune molecules immune cells, antigen-antibody reaction and complement activation effects were explored in this work. This project will provide scientific base to circumvent the safety risks of biomaterials, promote their optimization design and clinical application, and also screen and optimize immunomodulatory biomaterials for immunotherapy.This thesis mainly consists of two parts:Part one:Preparation and hemocompatibility study of carboxyl single-walled carbon nanotubesObjective:In this study, carboxyl single-walled carbon nanotubes (SWCNT-COOH) were prepared, and their hemocompatibility studied.Methods:SWCNTs was treated with H2SO4/HNO3 mixture. The introduction of carboxyl groups on SWCNTs was confirmed with Fourier transform infrared spectroscopy (FTIR) and zeta potential analyzer. The effect of SWCNTs and SWCNT-COOH on red blood cell morphology and blood coagulation was studied by scanning electron microscope (TEM) observation and thromboelastography (TEG) assay, respectively.Results:SWCNT-COOH was successfully synthesized as confirmed by FITC and zeta potential measurement. SWCNT-COOH at 10 mg/mL caused aggregation and morphological alteration of red blood cells. SWCNTs at 0.01 mg/mL and SWCNT-COOH at 0.001 mg/mL promoted the activity of clotting factors. Conclusion:SWCNT-COOH was successfully prepared by oxidation with H2SO4/HNO3 mixture. The information on the effect of SWCNTs and SWCNT-COOH on red blood cell aggregation and morphological change, and on blood coagulation is important for their design and biomedical applications.Part two:A preliminary study of the poly(amidoamine) dendrimers on the immunocompatibilityObjective:To clarify the effect of poly(amidoamine) dendrimers with amine, hydroxyl or carboxyl groups on immune molecules immune cells, antigen-antibody reaction and complement activation.Methods:Specifically, the effect of the PAMAM dendrimers on the secondary structure and conformation of immune molecule y-globulin was studied by using UV-vis, fluorescence, and circular dichroism spectroscopy. The effect of the PAMAM dendrimers on complement activation was determined by enzyme-linked immunosorbent assay. Further, the effect of the PAMAM dendrimers on antigen-antibody reaction was studied by using human red blood cell agglutination assay. The cytotoxicity of the PAMAM dendrimers was measured with CCK-8 detection. And the phagocytosis assay was used to analyze the effect of the PAMAM dendrimers on the bio-functions of mouse peritoneal macrophages.Results:The results showed that, the PAMAM dendrimers could affect the secondary structure and conformation of y-globulin, and inhibited complement activation. Generation 5 PAMAM dendrimer with carboxyl group at 10 mg/mL impaired RBC antigen-antibody reaction. Generation 5 PAMAM with amine group at 0.1-10 mg/mL and Generation 5 PAMAM with carboxyl group at 10 mg/mL denmonstrated cytotoxicity to the murine macrophage cells (RAW264.7), but Generation 5 PAMAM with hydroxyl group without it. The PAMAM dendrimers couldn’t affect the phagocytosis of the mouse peritoneal macrophages on the morphology.Conclusions:From these results, the effects of the PAMAM dendrimers on immune molecules and immune cells depend on their bulk structure and surface groups.