Preparation Of Naphthalimide Detection System And Its Application In Early Detection Of Atherosclerosis

In recent years,the mortality of cardiovascular diseases caused by atherosclerosis(AS)has continued to increase,which is gradually higher than that of tumors and other diseases.Because of its concealed incidence and being ignored easily,it is known as the "silent killer".Although there are various mature diagnostic methods for AS in clinic,they all have some shortcomings:the complicated operation process,taking a long time,and some certain requirements for the patient's physiological conditions.Morever,the coronary angiography and intravascular ultrasound examination with intuitive and high-precision results also have the disadvantage of poor repeatability.Most importantly,these diagnostic methods are only aimed at the later stage of AS,that is,the imaging of plaques,and can not achieve the purpose of "early detection" before plaque formation,so it is urgent to develop a detection and diagnosis method before plaque formation which can diagnose AS one to two decades in advance.In order to solve this problem,this study intends to use two self-synthesized two naphthimide-based fluorescent probes TBNG and GNTB with a hydroxyl group of o-triphenol and the biological homologous platelet membrane(Mp)extracted from the animal models to obtain the naphthalimide detection systems TBNG@Mp and GNTB@Mp with the co-extrusion method.When the nanosystem reaches the lesion site of early AS,under membrane fusion,the reactive naphthalimide fluorescent probe TBNG or GNTB with reactive oxygen species(ROS)response can enter the cell,and then with the help of the in-vivo live imager,the fluorescence signal can be observed in the thoracic aorta,so as to achieve the purpose of early AS detection.The research content of this article is mainly divided into the following three aspects:1)Preparation of naphthalimide detection system.This part used a step-by-step synthesis method to optimize the synthesis routes of TBNG and GNTB.And separate and purify each product,using Fourier transform infrared spectroscopy(FTIR),nuclear magnetic resonance hydrogen spectroscopy(1H NMR)were used for structural characterization.Ultraviolet-visible spectrophotometry(UV-Vis)and fluorescence analysis were used to test whether it had fluorescent properties.And the hydroxyl radical scavenging experiment was used to verify whether it had ROS scavenging ability.In addition,Mp-encapsulated probes with foam cell recognition were used to prepare the two naphthalimide detection systems TBNG@Mp and GNTB@Mp,and they were characterized by dynamic light scattering(DLS),UV-Vis and fluorescence analysis methods.The results show that the two naphthalimide fluorescent probes TBNG and GNTB have been successfully synthesized,and both have ultraviolet absorption and fluorescent absorption.The hydroxyl radical scavenging experiments indirectly show that they both have the ability of ROS recognition.In addition,DLS,UV-Vis and fluorescence analysis methods have shown that Mp has been successfully packaged,and TBNG@Mp and GNTB@Mp have a particle size of about 120 nm with no obvious difference.And the encapsulation rates of TBNG@Mp and GNTB@Mp are 70.4±2.13%and 69.1±1.9%,respectively.These indicate that TBNG@Mp and GNTB@Mp were successfully prepared,which laid the foundation for the subsequent in vivo and in vivo activity research.2)Cytotoxicity of naphthalimide detection system.In this section,the murine macrophage RAW 264.7 cell line and the human umbilical vein endothelial cell(HUVEC)line were used as models.And to screen out the naphthalimide detection system with better biological description,the effect of TBNG@Mp and GNTB@Mp on the proliferation of RW264.7 and HUVEC cells was investigated using the MTT method.The results suggest that the cytotoxicity of TBNG and GNTB encapsulated by biomaterial Mp was significantly reduced;however,compared with GNTB@Mp,TBNG@Mp was less toxic to RAW 264.7 and HUVEC cells,indicating that the nanometer detection system TBNG@Mp prepared in this study has a good biocompatibility and will not cause damage to the vascular endothelium,which will not aggravate the inflammatory reaction in the AS lesion.Therefore,TBNG@Mp can be used for in vivo imaging studies of early AS rat models.3)In vivo fluorescence imaging study of naphthalimide detection system.This part judged whether the early animal model of AS is successfully constructed by observing the changes of relevant indexes of animal models in different periods.After the early AS model was successfully constructed,the method of tail vein injection of naphthalimide detection system TBNG@Mp was used to evaluate its detection effect on early AS rats and its distribution in vivo with the aid of a small animal live imager.The results show that the naphthalimide detection system TBNG@Mp can accumulate and display a fluorescent signal in the thoracic aorta of AS rats 2 h after injection,and then can be metabolized by the liver.These results show that TBNG@Mp is a nano-detection system with a good biocompatibility and can be used for early AS detection.To sum up,this paper successfully prepared a novel naphthalimide fluorescent probe detection system TBNG@Mp with early AS detection.In addition,in vitro and in vivo experiments show that the nanometer detection system has a low toxicity and a good biocompatibility,which provides some theoretical bases for the early detection of ASCVD and other oxidative stress diseases.