We report the fabrication of aqueous multimodal imaging nanocomposites based on superparamagnetic nanoparticles (MNPs) and two different sizes of photoluminescent upconverting nanoparticles (UCNPs). The controlled and simultaneous incorporation of both types of nanoparticles (NPs) was obtained by controlling the solvent composition and the addition rate of the destabilizing solvent. The magnetic properties of the MNPs remained unaltered after their encapsulation into the polymeric beads as shown by the T2 relaxivity measurements. The UCNPs maintain photoluminescent properties even when embedded with the MNPs into the polymer bead. Moreover, the light emitted by the magnetic and upconverting nanobeads (MUCNBs) under NIR excitation (λ_exc = 980 nm) was clearly observed through different thicknesses of agarose gel or through a mouse skin layer. The comparison with magnetic and luminescent nanobeads based on red-emitting quantum dots (QDs) demonstrated that while the QD-based beads show significant autofluorescence background from the skin, the signal obtained by the MUCNBs allows a decrease in this background. In summary, these results indicate that MUCNBs are good magnetic and optical probes for in vivo multimodal imaging sensors.

中文翻译：

---

多功能磁和上转换纳米珠作为双模态成像工具

我们报告基于超顺磁性纳米粒子（MNPs）和两种不同尺寸的光致发光上转换纳米粒子（UCNPs）的水性多峰成像纳米复合材料的制造。通过控制溶剂组成和去稳定溶剂的添加速率，可以控制并同时掺入两种类型的纳米颗粒（NPs）。如T2弛豫度测量所示，在将MNP包封到聚合物珠粒中之后，其磁性质保持不变。UCNP即使与MNP嵌入到聚合物珠中，也可以保持光致发光性能。此外，光通过下NIR激发磁场和上变频纳米珠粒（MUCNBs）发射（λ _EXC通过不同厚度的琼脂糖凝胶或通过小鼠皮肤层可以清楚地观察到= 980 nm）。与基于红色发光量子点（QD）的磁性和发光纳米珠的比较表明，尽管基于QD的珠在皮肤上显示出显着的自发荧光背景，但MUCNB所获得的信号允许降低该背景。总之，这些结果表明，MUNCB是用于体内多峰成像传感器的良好磁性和光学探针。