Ultra-Small and Metabolizable Near-Infrared Au/Gd Nanoclusters for Targeted FL/MRI Imaging and Cancer Theranostics

Abstract

Tumor accurate imaging can effectively guide tumor resection and accurate follow-up targeted therapy. The development of imaging-stable, safe, and metabolizable contrast agents is key to accurate tumor imaging. Herein, ultra-small and metabolizable dual-mode imaging probe Au/Gd@FA NCs is rationally engineered by a simple hydrothermal method to achieve accurate FL/MRI imaging of tumors. The probes exhibit ultra-small size (2.5–3.0 nm), near-infrared fluorescence (690 nm), high quantum yield (4.4%), and a better T1 nuclear magnetic signal compared to commercial MRI contrast agents. By modifying the folic acid (FA) molecules, the uptake and targeting of the probes are effectively improved, enabling specific fluorescence imaging of breast cancer. Au/Gd@FA NCs with good biosafety were found to be excreted in the feces after imaging without affecting the normal physiological metabolism of mice. Intracellular reactive oxygen species (ROS) increased significantly after incubation of Au/Gd@FA NCs with tumor cells under 660 nm laser irradiation, indicating that Au/Gd@FA NCs can promote intracellular ROS production and effectively induce cell apoptosis. Thus, metabolizable Au/Gd@FA NCs provide a potential candidate probe for multimodal imaging and tumor diagnosis in clinical basic research. Meanwhile, Au/Gd@FA NCs mediated excessive intracellular production of ROS that could help promote tumor cell death.

Multifunctional Nanoprobe Au@Gd-SiO2-HA-Lyp-1/DOX with Dual-Targeting Functions Derived from HA and LyP-1: Diagnostic and Therapeutic Potential for Tumor Lymphatic Metastasis

“…At room temperature, a mixture of ethanol (18 mL), TEO (6 mL), and GdCl 3 ·6H 2 O aqueous solution (5 wt %, 20 mL) (with a Au-to-Gd mass ratio of 1:1) and an NH 4 OH solution containing 25% NH 3 (9 mL) were continuously stirred at 1500 rpm. TEOS and GdCl 3 were added to prepare the Gd-SiO 2 nanoshell, with a dropwise rate controlled at 20 drops/s and stirred for 1 h. The obtained silica colloid was aged for 1 day. − Au@Gd-SiO 2 nanoparticles underwent multiple centrifugation and washing steps to remove unreacted CTAB, GdCl 3 , and TEOS. Au@Gd-SiO 2 (200 mg) was dispersed in a solution containing concentrated hydrochloric acid (60 μL, 37%) and ethanol (30 mL).…”

Self-Assembled Au/CuS Nanoparticles for Targeted Imaging and Multimodal Therapy of Breast Cancer

“…Gold nanoclusters (Au NCs) have the advantages of easy preparation and modification, high biocompatibility, stable fluorescence (FL) performance, and easy assembly with other functional nanomaterials. − They have been extensively implemented in biological imaging, drug delivery, targeted therapy, and the construction of multifunctional therapeutic nanoplatforms. − Several studies have demonstrated the potential of Au NCs to achieve synergistic therapeutic effects with other materials. For example, Yang et al reported a novel bionanosystem by combining glutathione capped Au NCs with two-level mesoporous canal silica, which not only enhanced the FL intensity but also achieved the synergistic therapeutic effects of PTT and PDT .…”

A Novel pH-Responsive Iron Oxide Core-Shell Magnetic Mesoporous Silica Nanoparticle (M-MSN) System Encapsulating Doxorubicin (DOX) and Glucose Oxidase (Gox) for Pancreatic Cancer Treatment

“…[26][27][28][29] In addition, folate receptors (FRs) are considered a potential target for cancer therapeutics because they are overexpressed in many cancer cells. [30][31][32][33] For example, SW1990 pancreatic cancer cells highly express FRs and could be the subject of research targeting pancreatic cancer.…”