One-pot synthesis of multifunctional metal–organic frameworks for magnetic resonance/optical imaging

doi:10.1016/j.matlet.2020.129025

Materials Letters

Volume 284, Part 2, 1 February 2021, 129025

https://doi.org/10.1016/j.matlet.2020.129025 Get rights and content

Highlights

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For the first time, a one-step method was used to synthesize multifunctional MOFs for MRI/OI.
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The length of RhB@Gd-MOFs can be adjusted to 200 nm as well as the width of RhB@Gd-MOFs can decrease to 100 nm.
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The as-prepared RhB@Gd-MOFs display good biocompatibility and distribution in naked mouse.

Abstract

In this paper, a novel magnetic resonance imaging (MRI) and optical imaging (OI) bimodal probe has been developed via an efficient one pot synthetic strategy. Benefiting from the presence of RhB and Gd³⁺ ions, the as-prepared RhB@Gd-MOFs exhibit excellent OI and MRI. Simultaneously, RhB@Gd-MOFs have good biocompatibility proved by cytotoxicity test. RhB@Gd-MOFs also exhibit good stability and distribution in naked mouse.

Graphical abstract

A simple, one-pot process has been developed for the synthesis of multifunctional MOFs for magnetic resonance and optical imaging.

Introduction

As is well known, OI technology has the advantages of fast imaging speed, good selectivity and high sensitivity, playing an important role in microscopic imaging analysis of cells and tissues [1]. However, due to the limitation of the penetration depth of light in tissues and the interference of tissue autofluorescence, it is difficult for OI to obtain accurate information of deep tissues in the body. MRI technology has the advantages of non-invasive, strong penetrating power and high spatial resolution, while the imaging technology has low sensitivity, long imaging time, difficult quantitative analysis [2]. The MRI and OI dual-mode imaging technology can realize the complementary advantages of the two technologies, acquiring more realistic, accurate and comprehensive information at the disease site.

MOFs have been widely used in the various fields due to their excellent properties [3], [4]^. At present, multifunctional MOFs are certainly capable of dual-modal imaging [5], [6]. Tang’s group introduced UCNP@Fe-MIL-101-NH₂@PEG@FA for targeted cancer cell and MRI/OI imaging [7]. Our group also reported a MOF-based MRI/OI bimodal probe [8]. Such materials, however, have relatively complex synthesis process. Compared with multi-step synthesis method, the one-step synthesis method is free of special equipment and operations, thus, is an easy-to-use pathway. To the best of our knowledge, no previous study has been reported on fabricating of MOFs-based MRI and OI dual-mode probes via one-step synthesis.

Based on the above discussion, herein, a simple one-step method was used to encapsulate RhB in the framework of Gd-MOFs successfully (Fig. S1). Gd³⁺ ions exist as metal nodes in the framework of Gd-MOFs. Thus, Gd-MOFs can be used for nuclear magnetic resonance imaging [9]. Rhodamine B (RhB) emits red fluorescence and can be used for biological imaging [10]. The experimental results show that the obtained RhB@Gd-MOFs have ideal MRI/OI capabilities. Besides, RhB@Gd-MOFs exhibit good biocompatibility on HL-7702 normal cells and HepG2 cancer cells as well as good stability in naked mouse. In this section, a one-step method was used to synthesize multifunctional MOFs for MRI/OI. This method greatly simplifies the operation process

Section snippets

Results and discussion

Different amount of surfactant pvp is applied to regulate the size of RhB@Gd-MOFs (Fig. 1). Apparently, with the amount of pvp increases from 0 to 1.5 g, the length of RhB@Gd-MOFs decreases from 10 µm to 200 nm as well as the width of RhB@Gd-MOFs changes from 2 µm to 100 nm. Simultaneously, the shapes are tuned to rod-shaped. To check the crystallinity, the products were further investigated by XRD, which is depicted in Fig. S2. The diffraction peaks of all the achieved RhB@Gd-MOFs are

Conclusion

For the first time, multifunctional MOFs integrating MRI and OI are obtained through a one-step method. The relaxation efficiency of RhB@Gd-MOFs is as high as 16.5 mM⁻¹ s⁻¹, which is an ideal T₁ contrast agent. In vitro cell experiments show that RhB@Gd-MOFs can be taken up by cells for fluorescence imaging. We also confirm the good stability and distribution of RhB@Gd-MOFs in naked mouse. All in all, the obtained RhB@Gd-MOFs is an excellent MRI and OI bimodal probe.

CRediT authorship contribution statement

Gao Xuechuan: Conceptualization, Methodology, Investigation, Formal analysis, Data curation, Writing - original draft. Zhang Man: Investigation. Lv li: Writing - review & editing.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This work was supported by Natural Science Foundation of Inner Mongolia (2019BS02010, 2020MS02014), Higher Education Research Project of Inner Mongolia (NJZY19073), Research Funds of Inner Mongolia University of Technology (BS201909) and National Natural Science Foundation of China (21763021). The author extends special thank to the center for new drug safety evaluation and research in Inner Mongolia Medical University.

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View full text

One-pot synthesis of multifunctional metal–organic frameworks for magnetic resonance/optical imaging

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Results and discussion

Conclusion

CRediT authorship contribution statement

Declaration of Competing Interest

Acknowledgements

Biocompatible semiconductor quantum dots as cancer imaging agents

Adv. Mater.

What we can really do with bioresponsive MRI contrast agents

Angew. Chem. Int. Ed.

Advantages and limitations of microwave reactors: from chemical synthesis to the catalytic valorization of biobased chemicals

ACS Sustain. Chem. Eng.

Probing the water stability limits and degradation pathways of Metal–organic frameworks

Chem. Eur. J.

Metal–organic framework composites and their electrochemical applications

J. Mater. Chem. A