论著 · 基础研究

开发用于肿瘤微环境成像的pH敏感荧光探针

  • 王雨心 ,
  • 孙瑞琪 ,
  • 刘坚华 ,
  • 何伟娜
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  • 上海交通大学基础医学院药物化学与生物信息学中心,上海 200025
王雨心(1995—),女,硕士生;电子信箱yuxinwang@sjtu.edu.cn
何伟娜,电子信箱:hewn0319@sjtu.edu.cn
刘坚华,电子信箱:jhliu7912@sjtu.edu.cn

收稿日期: 2022-03-19

  录用日期: 2022-06-25

  网络出版日期: 2022-09-04

基金资助

上海交通大学基础医学院前沿研究中心原创探索类青年支持项目(YCTSQN2021001);上海交通大学“交大之星”计划医工交叉研究基金(YG2016MS22)

Development of pH-responsive fluorescent probe for tumor microenvironment imaging

  • Yuxin WANG ,
  • Ruiqi SUN ,
  • Jianhua LIU ,
  • Weina HE
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  • Medical Chemistry and Bioinformatics Center, Shanghai Jiao Tong University College of Basic Medical Sciences, Shanghai 200025, China
HE Weina, E-mail: hewn0319@sjtu.edu.cn.
LIU Jianhua, E-mail: jhliu7912@sjtu.edu.cn

Received date: 2022-03-19

  Accepted date: 2022-06-25

  Online published: 2022-09-04

Supported by

Original Exploration Youth Support Project of Frontier Research Center, Shanghai Jiao Tong University College of Basic Medical Sciences(YCTSQN2021001);“Star of SJTU” Program of Shanghai Jiao Tong University, Medical-Engineering Cross Research Fund(YG2016MS22)

摘要

目的·合成水溶性pH响应性花菁类近红外荧光探针,评估其光学性能,并将其应用于模拟肿瘤微环境的在体成像。方法·应用两步经典的化学反应,合成水溶性pH响应性近红外荧光探针R2S,同步合成脂溶性探针R2Z作为对照。应用磁共振氢谱、质谱及高效液相色谱验证探针的化学结构及纯度。利用紫外-可见、光致发光光谱学测试评价探针的pH响应性、响应可逆性、光稳定性及结构稳定性。利用细胞荧光共定位成像评价探针的细胞膜通透性,使用HCT-116细胞、HeLa细胞进行细胞毒性实验,使用BALB/c健康雌性小鼠进行小动物在体成像实验,评估探针的安全性。通过在小鼠背部左侧和右侧分别皮下注射pH 6.50和pH 7.40的PBS溶液模拟肿瘤微酸性环境和正常的细胞环境,随后注射探针R2S进行在体成像实验,比较R2S在pH 6.50侧和pH 7.40侧的荧光强度。结果·成功合成了水溶性pH响应性近红外荧光探针R2S及其脂溶性类似物R2Z。随着溶液酸性逐渐增强(从pH 11.10到pH 3.47),R2S的最大吸收波长由642 nm红移至774 nm,最大发射波长亦由794 nm红移至808 nm。探针R2S的酸解离常数(pKa)值约为6.88。与脂溶性探针R2Z相比,R2S在保留了较好细胞膜通透性的前提下,展现出更大的斯托克斯位移、更好的响应可逆性、更高的稳定性。R2Z在12.5 μmol/L浓度下,细胞相对存活率低于80%;而R2S在100 μmol/L浓度下,仍未表现出明显的细胞生长抑制现象,表明其具有更高的生物安全性。R2S在模拟肿瘤微酸性环境的低pH组织和正常pH组织中的成像具有明显的区分度。结论·水溶性pH响应性花菁类近红外荧光探针R2S对pH变化响应灵敏、稳定,最佳响应范围与肿瘤所处微环境的pH相符,在肿瘤成像领域展现出了较强的在体成像应用潜力。

本文引用格式

王雨心 , 孙瑞琪 , 刘坚华 , 何伟娜 . 开发用于肿瘤微环境成像的pH敏感荧光探针[J]. 上海交通大学学报(医学版), 2022 , 42(7) : 875 -884 . DOI: 10.3969/j.issn.1674-8115.2022.07.005

Abstract

Objective

·To synthesize a water-soluble pH-responsive near-infrared cyanine-based fluorescent probe, evaluate its optical properties, and conduct in vivo imaging analysis of the quasi-tumor microenvironment.

Methods

·The water-soluble pH-responsive near-infrared fluorescent probe R2S was synthesized via two classic chemical transformation steps and the liposoluble probe R2Z was synthesized in the similar way. 1H nuclear magnetic resonance spectroscopy, mass spectroscopy and high performance liquid chromatography were used to verify the structure and the purity of the probes synthesized. Ultraviolet-visible and photoluminescence spectroscopy were used to evaluate its pH responsiveness, response reversibility and stability. Then, cell permeability of the probe was measured by cell imaging. The cytotoxicity of the probe was evaluated with HCT-116 cells and HeLa cells, and in vivo imaging experiments were performed by using healthy BALB/c female mice. Finally, imaging experiments of quasi-tumor-acidic-microenvironment were carried out by separately injecting PBS solution with pH 6.50 and pH 7.40 into the back of the mice, and the fluorescence intensity of R2S at pH 6.50 and pH 7.40 was compared.

Results

·The water-soluble pH-responsive near-infrared fluorescent probe R2S and its liposoluble analog R2Z were synthesized successfully. As the acidity of the probe solution increased (from pH 11.10 to pH 3.47), the maximum absorption wavelength of R2S shifted from 642 nm to 774 nm, while the maximum emission wavelength shifted from 794 nm to 808 nm, with a pKa value of 6.88. Compared to the liposoluble probe R2Z, R2S showed a larger Stokes shift, higher stability without affecting the cell membrane permeability. At the high administration concentration of 100 μmol/L, R2S did not exhibit the inhibition of proliferation, while for R2Z at the concentration of 12.5 μmol/L, the relative cell viability already descended to below 80%, indicating R2S had higher biosecurity than R2Z. Imaging of R2S in low pH tissue (simulating tumor tissue) and normal pH tissue exhibited a high degree of discrimination.

Conclusion

·The water-soluble pH-responsive near-infrared cyanine fluorescent probe R2S exhibits sensitive and stable responses to pH changes, and the optimal response range is consistent with the pH of the tumor acidic microenvironment, illustrating a strong potential for its in vivo tumor imaging applications.

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