Multifunctional Cellular Targeting, Molecular Delivery, and Imaging by Integrated Mesoporous-Silica with Optical Nanocrescent Antenna: MONA

Multifunctional nanoprobes have attracted significant attention in a wide range of disciplines such as nanomedicine, precision medicine, and cancer diagnosis and treatment. However, integrating multifunctional ability in a nanoscale structure to precisely target, image, and deliver with cellular spatial/temporal resolution is still challenging in cellulo applications. This is because the development of such high-precision resolution needs to be carried out without labeling, photobleaching, and structurally segregating live cells. In this study, we present an integrated nanostructure of a mesoporous-silica nanosphere with an optical nanocrescent antenna (MONA) for multifunctional cellular targeting, drug delivery, and molecular imaging with spatiotemporal resolution. MONA comprises a systematically constructed Au nanocrescent (AuNC) antenna as a nanosensor and optical switch on a mesoporous-silica nanosphere as a cargo to molecular delivery. MONA made of antiepithelial cell adhesion molecules (anti-EpCAM)-conjugated AuNC facilitates the specific targeting of breast cancer cells, resulting in a highly focused photothermal gradient that functions as a molecular emitter. This light-driven molecular, doxorubicin (DOX) delivery function allows rapid apoptosis of breast cancer cells. Since MONA permits the tracking of quantum biological electron-transfer processes, in addition to its role as an on-demand optical switch, it enables the monitoring of the dynamic behavior of cellular cytochrome c pivoting cell apoptosis in response to the DOX delivery. Owing to the integrated functions of molecular actuation and direct sensing at the precisely targeted spot afforded by MONA, we anticipate that this multifunctional optical nanoantenna structure will have an impact in the fields of nanomedicine, cancer theranostics, and basic life sciences.

Facile Preparation of Gold-Decorated Fe₃O₄ Nanoparticles for CT and MR Dual-Modal Imaging

The development of a multifunctional nanoprobe capable of non-invasive multimodal imaging is crucial for precise tumour diagnosis. Herein, we report a facile polymer-assisted method to produce Au-Fe₃O₄ nanocomposites (NCPs) for the dual-modal magnetic resonance (MR) and X-ray computed tomography (CT) imaging of tumours. In this approach, amino-functionalized Au nanospheres were first obtained by surface modification of the bifunctional polymer SH-PEG-NH₂. Hydrophilic and carboxyl-functionalized Fe₃O₄ nanoparticles were produced by phase transfer of reverse micelle oxidation in our previous work. The Au nanoparticles were conjugated with hydrophilic Fe₃O₄ nanoparticles through an amide reaction. The obtained Au-Fe₃O₄ nanocomposites display a high r₂ relativity (157.92 mM⁻¹ s⁻¹) and a Hounsfield units (HU) value (270 HU) at Au concentration of 8 mg/mL and could be applied as nanoprobes for the dual-modal MR/CT imaging of a xenografted tumour model. Our work provides a facile method to prepare Au-Fe₃O₄ nanocomposites for dual-modal MR/CT imaging, and this method can be extended to prepare other multifunctional nanoparticles for multimodal bioimaging.

Activatable Multifunctional Persistent Luminescence Nanoparticle/Copper Sulfide Nanoprobe for in Vivo Luminescence Imaging-Guided Photothermal Therapy

Multifunctional nanoprobes that provide diagnosis and treatment features have attracted great interest in precision medicine. Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) are optimal materials due to no in situ excitation needed, deep tissue penetration, and high signal-to-noise ratio, while activatable optical probes can further enhance signal-to-noise ratio for the signal turn-on nature. Here, we show the design of an activatable multifunctional PLNP/copper sulfide (CuS)-based nanoprobe for luminescence imaging-guided photothermal therapy in vivo. Matrix metalloproteinases (MMPs)-specific peptide substrate (H₂N-GPLGVRGC-SH) was used to connect PLNP and CuS to build a MMP activatable system. The nanoprobe not only possesses ultralow-background for in vivo luminescence imaging due to the absence of autofluorescence and optical activatable nature but also offers effective photothermal therapy from CuS nanoparticles. Further bioconjugation of c(RGDyK) enables the nanoprobe for cancer-targeted luminescence imaging-guided photothermal therapy. The good biocompatibility and the multiple functions of highly sensitive tumor-targeting luminescence imaging and effective photothermal therapy make the nanoprobe promising for theranostic application.