Fabrication of Gd/Eu-codoped SmPO₄ nanorods for dual-modal magnetic resonance and bio-optical imaging

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• 作者：Zhi Wu^a ; Zhongbing Huang^a ; ^{zbhuang@scu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Guangfu Yin^a ; Lei Wang^b ; Fabao Gao^b ; ^{gaofabao@yahoo.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Gd/Eu-codoped ; Silk fibroin ; Magnetic resonance imaging ; Luminescence imaging
• 刊名：Journal of Colloid and Interface Science
• 出版年：2016
• 出版时间：15 March 2016
• 年：2016
• 卷：466
• 期：Complete
• 页码：1-11
• 全文大小：3306 K

文摘

Ln-based complexes can be used as T₁-enhanced contrast agents of magnetic resonance (MR) imaging in clinical field. Herein, we present a facile and feasible biomineralization process to fabricate Gd/Eu-codoped SmPO₄ nanorods (NRs) with silk fibroin (SF) peptides (codoped SF-NRs) as T₁-enhanced contrast agents, which possess paramagnetic property, photoluminescence (PL), better cyto-/tissue-compatibility and longer half-life in blood due to SF coating on their surface. Their bio-distributions in TB-N mice via tail-vein injection indicated that, although SF-NRs could be safely cleared away through renal and fecal excretion, SF-NRs easily permeated and aggregated in tumors. The results of in vitro MR imaging demonstrate that the longitudinal relaxivity r₁ value of codoped SF-NRs (0.31 Sm–Gd mM⁻¹ s⁻¹) is not only significantly higher than those of Gd-doped and Eu-doped SmPO₄ SF-NRs, but also higher than those of codoped pure NRs. The tests of in vivo T₁ weighted MR imaging via intro-tumor injection and tail-vein injection confirm that, compared to the pure NRs, the codoped SF-NRs exhibited higher positive signal-enhancement ability. Furthermore, the better luminescence imaging of living cells under the fluorescence microscope (94% stronger than that of the NRs without SF). A formation mechanism of codoped SF-NRs is proposed, to explain the synergistic effect of Gd/Eu codoping and SF coating on their enhanced bio-compatibility, half-life in blood, T₁-weighted MR imaging and PL imaging.