Tetraphenylethylene-conjugated polycation covered iron oxide nanoparticles for magnetic resonance/optical dual-mode imaging

Abstract Magnetic resonance (MR)/optical dual-mode imaging with high sensitivity and high tissue resolution have attracted many attentions in biomedical applications. To avert aggregation-caused quenching of conventional fluorescence chromophores, an aggregation-induced emission molecule tetraphenylethylene (TPE)-conjugated amphiphilic polyethylenimine (PEI) covered superparamagnetic iron oxide (Alkyl-PEI-LAC-TPE/SPIO nanocomposites) was prepared as an MR/optical dual-mode probe. Alkyl-PEI-LAC-TPE/SPIO nanocomposites exhibited good fluorescence property and presented higher T2 relaxivity (352 Fe mM−1s−1) than a commercial contrast agent Feridex (120 Fe mM−1s−1) at 1.5 T. The alkylation degree of Alkyl-PEI-LAC-TPE effects the restriction of intramolecular rotation process of TPE. Reducing alkane chain grafting ratio aggravated the stack of TPE, increasing the fluorescence lifetime of Alkyl-PEI-LAC-TPE/SPIO nanocomposites. Alkyl-PEI-LAC-TPE/SPIO nanocomposites can effectively labelled HeLa cells and resulted in high fluorescence intensity and excellent MR imaging sensitivity. As an MR/optical imaging probe, Alkyl-PEI-LAC-TPE/SPIO nanocomposites may be used in biomedical imaging for certain applications.

Download Full-text

Integration of PEG-conjugated gadolinium complex and superparamagnetic iron oxide nanoparticles as T1-T2 dual-mode magnetic resonance imaging probes

Regenerative Biomaterials ◽

10.1093/rb/rbab064 ◽

2021 ◽

Author(s):

Li Yang ◽

Shengxiang Fu ◽

Zhongyuan Cai ◽

Li Liu ◽

Chunchao Xia ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Iron Oxide ◽

Magnetic Resonance ◽

Liver Tissue ◽

Imaging Modality ◽

Superparamagnetic Iron Oxide ◽

Molar Ratio ◽

Raw 264.7 Cells ◽

Resonance Imaging ◽

Dual Mode

Abstract The T1−T2 dual-mode probes for magnetic resonance imaging (MRI) can noninvasively acquire comprehensive information of different tissues or generate self-complementary information of the same tissue at the same time, making MRI a more flexible imaging modality for complicated applications. In this work, three Gd-DTPA complex conjugated superparamagnetic iron oxide (SPIO) nanoparticles with different Gd/Fe molar ratio (0.94, 1.28 and 1.67) were prepared as T1-T 2 dual-mode MRI probes, named as [email protected], [email protected] and [email protected], respectively. All SPIO@PEG-GdDTPA nanocomposites with 8 nm spherical SPIO nanocrystals showed good Gd3+ chelate stability. [email protected] nanocomposites with lowest Gd/Fe molar ratio shows no cytotoxicity to Raw 264.7 cells as compared to [email protected] and [email protected]. [email protected] nanocomposites with r1 (8.4 mM−1s−1), r2 (83.2 mM−1s−1) and relatively ideal r2/r1 ratio (9.9) were selected for T 1-T2 dual-mode MRI of blood vessels and liver tissue in vivo. Good contrast images were obtained for both cardiovascular system and liver in animal studies under a clinical 3 T scanner. Importantly, one can get high quality contrast-enhanced blood vessel images within the first 2 hours after contrast agent administration and acquire liver tissue anatomy information up to 24 hours. Overall, the strategy of one shot of the dual mode MRI agent could bring numerous benefits not only for patients but also to the radiologists and clinicians, e.g., saving time, lowering side effects, and collecting data of different organs sequentially.