High-affinity early gastric cancer combined near-infrared probe and preparation method thereof

Abstract

The invention discloses a high-affinity early gastric cancer combined near-infrared probe and a preparation method thereof. The preparation method of the high-affinity early gastric cancer combined near-infrared probe comprises the steps: S1, firstly, constructing a polypeptide SNF and a three-dimensional structure thereof, obtaining a binding receptor EpCAM extracellular three-dimensional structure of the polypeptide SNF, and carrying out SNF modification and screening on a three-dimensional simulated SNF and EpCAM binding site to obtain a candidate optimized oligopeptide; S2, carrying out fluorescent staining and affinity comparison on the optimized polypeptide and EpCAM high-expression gastric cancer cell line SGC7901 cells; and S3, preparing a probe: linking the optimal oligopeptide screened out in the step S2 with CY5.5 through GGGSK to synthesize the near-infrared probe. A fluorescent probe capable of specifically targeting the early gastric cancer can be formed.The near-infrared probe has good characteristics of good stability, low immunogenicity, low production cost, capable of implementing rapid imaging after administration and the like.

Description

technical field [0001] The invention relates to the technical field of biomedical molecular imaging, in particular to a near-infrared probe that binds to early gastric cancer with high affinity and a preparation method thereof. Background technique [0002] Among all malignant tumors in China, the incidence rate of gastric cancer and its resulting mortality rate ranks second; the 5-year survival rate of patients with early gastric cancer after surgical treatment by endoscopic submucosal dissection or endoscopic mucosal resection As high as more than 90%; therefore, if early detection and precise resection of gastric cancer can further prolong the patient's survival and improve their quality of life; ordinary white-light endoscopy is a routine method for detecting early gastric cancer, under white-light endoscopy, Features including color changes (such as redder or paler), disappearance of blood vessels, and local elevations or depressions are often used to describe early gas...

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Problems solved by technology

[0002] Among all malignant tumors in China, the incidence rate of gastric cancer and its resulting mortality rate ranks second; the 5-year survival rate of patients with early gastric cancer after surgical treatment by endoscopic submucosal dissection or endoscopic mucosal resection As high as more than 90%; therefore, if early detection and precise resection of gastric cancer can further prolong the patient's survival and improve their quality of life; ordinary white-light endoscopy is a routine method for detecting early gastric cancer, under white-light endoscopy, Features including color changes (such as redder or paler), disappearance of blood vessels, and local elevations or depressions are often used to describe early gastric cancer, but the detection rate of gastric cancer in suspicious lesion biopsy based on these features is not high, multiple prospective Parallel clinical trials found that the positive detection rate of early gastric cancer under white light endoscopy is only 40%-72%;

[0003] Near-infrared endoscopy (NIR endoscopy) is a new product of the combination of near-infrared imaging technology and endoscopy, which can provide tumor lesion information that cannot be obtained by ordinary white light endoscopy, and help endoscopists to locate more real-time, fast and accurate Tumors, especially help to find some small cancer lesions; NIR endoscope is composed of white light and near-infrared imaging systems, and the white light and NIR imaging modes can be switched by one-button switching during use; this imaging method has a large field of view, allowing for Large-scale screening of hollow viscera surfaces; now, NIR endoscopy combined with intravenous ICG has been successfully used for near-infrared imaging of laryngeal cancer, esophageal cancer, and gastric cancer; however, early gastric cancer lesions are not clearly displayed under normal white light endoscopy , the boundary is still uncertain, and when switching to near-infrared imaging, the tumor tissue containing ICG is displayed in blue; however, NIR endoscopy still only relies on untargeted ICG to determine the type of lesion, which limits the use of near-infrared endoscopy in digestion application in precise diagnosis of tract tumors;

[0004] Therefore, designing a tumor-specific ICG targeting probe is the key to solving the poor specificity of NIR endoscopic tumor diagnosis.

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