Imaging agent, preparation method and application

Abstract

The invention relates to an imaging agent. The imaging agent is characterized by comprising IR820-CSQ-Fe nanoparticles, wherein the IR820-CSQ-Fe nanoparticles comprises Fe3O4 coated with an A-X-B structure, wherein A is chitosan quaternary ammonium salt CSQadopting a structure shown as a formula (I), and n is an integer ranging from 17 to 290; B is new indocyanine green IR820 adopting a structure shown as a formula (II); X is a compound adopting a structure shown as a formula (III), and R is an alkylene group. The imaging agent has the advantages of superparamagnetism, outstanding T1 and T2 relaxation enhancement effect, photoacoustic imaging capacity, obvious fluorescence spectra, small and uniform particle size, good penetrability, avoidance of obvious cytotoxicity, good biocompatibility and better long circulation effect; a preparation method is simple, mild in condition and lower in cost; the imaging agent can be freeze-dried and stored for a long time in a solid form.

Description

technical field [0001] The invention belongs to the field of nano-imaging agents, in particular to a multi-mode imaging agent and its preparation method and application, especially to an imaging agent capable of T1 and T2 relaxation enhancement, fluorescence imaging or photoacoustic imaging for MRI imaging. In particular, it relates to an imaging agent that can be used as a tumor-targeted T1-T2 dual-nuclear magnetic resonance imaging contrast agent. Background technique [0002] At present, for major diseases, it is very limited to use only one imaging method to determine the lesion location or lesion degree, and it has become a development trend to be able to image jointly by multiple methods. [0003] The sensitivity of fluorescence imaging is particularly high, but the tissue penetration ability is relatively poor; the sensitivity of photoacoustic imaging is also high, and the penetration ability is strong, but due to the limited penetration ability of laser light, there ...

AI Technical Summary

Problems solved by technology

The commonly used negative contrast agent is iron, but many of them are unstable due to their large particle size, or can only be stable in the organic phase due to the limitation of the preparation method, which limits their application.

In addition, most contrast agents only have one contrast-enhancing effect, and cannot achieve two contrast effects at the same time, which limits the accuracy of disease diagnosis

[0006] For example, although the MRI contrast agent gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) has been approved for clinical use, it causes toxicity due to the easy release of its chelated gadolinium ions, and it does not have long circulation and target directional effect, so that its application is limited; in addition, although this contrast agent has T 1 and T 2 Contrast effect at the same time, but T 1 Contrast effect is better than T 2 Contrast effect; contrast effect of negative contrast agent SPIO is opposite

[0007] CN104174037A discloses a 1 , T 2 A method for preparing a blended contrast agent with imaging function. The method uses a double-headed amphiphilic organic molecule as a template agent, and in the presence of an aromatic acid, mixes rare earth ions and VIB-VIIIB group ions in a self-autoclaved system. A blended contrast agent prepared with nanoscale particle size and better T 1 , T 2 Contrast effect; but it cannot exist in aqueous solution stably for a long time, the operation is complicated, and the cost is also high

But its poor solubility in water limits its application in many aspects

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