Hybrid Au-star@Prussian blue for high-performance towards bimodal imaging and photothermal treatment.

In recent years, branched or star-shaped Au nanostructures composed of core and protruding arms have attracted much attention due to their unique optical properties and morphology. As the clinically adapted nanoagent, prussian blue (PB) has recently gained widespread attention in cancer theranostics with potential applications in magnetic resonance (MR) imaging. In this article, we propose a hybrid star gold nanostructure（Au-star@PB）as a novel theranostic agent for T1-weighted magnetic resonance imaging (MRI)/ photoacoustic imaging（PAI） and photothermal therapy (PTT) of tumors. Importantly, the Au-star@PB nanoparticles function as effective MRI/PA contrast agents in vivo by increasing T1-weighted MR/PAI signal intensity and as effective PTT agents in vivo by decreasing the tumor volume in MCF-7 tumor bearing BALB / c mouse model as well as in vitro by lessening tumor cells growth rate. Interestingly, we found the main photothermal effect of Au-star@PB is derived from Au-star, but not PB. In summary, the hybrid structure of Au-star@PB NPs with good biological safety, significant photostability, dual imaging capability, and high therapeutic efficiency, might offer a novel avenue for the future diagnosis and treatment of cancer.

Oxygen-Evolving Mesoporous Organosilica Coated Prussian Blue Nanoplatform for Highly Efficient Photodynamic Therapy of Tumors.

Oxygen (O2) plays a critical role during photodynamic therapy (PDT), however, hypoxia is quite common in most solid tumors, which limits the PDT efficacy and promotes the tumor aggression. Here, a safe and multifunctional oxygen-evolving nanoplatform is costructured to overcome this problem. It is composed of a prussian blue (PB) core and chlorin e6 (Ce6) anchored periodic mesoporous organosilica (PMO) shell (denoted as PB@PMO-Ce6). In the highly integrated nanoplatform, the PB with catalase-like activity can catalyze hydrogen peroxide to generate O2, and the Ce6 transform the O2 to generate more reactive oxygen species (ROS) upon laser irradiation for PDT. This PB@PMO-Ce6 nanoplatform presents well-defined core-shell structure, uniform diameter (105 ± 12 nm), and high biocompatibility. This study confirms that the PB@PMO-Ce6 nanoplatform can generate more ROS to enhance PDT than free Ce6 in cellular level (p < 0.001). In vivo, the singlet oxygen sensor green staining, tumor volume of tumor-bearing mice, and histopathological analysis demonstrate that this oxygen-evolving nanoplatform can elevate singlet oxygen to effectively inhibit tumor growth without obvious damage to major organs. The preliminary results from this study indicate the potential of biocompatible PB@PMO-Ce6 nanoplatform to elevate O2 and ROS for improving PDT efficacy.

Ag-HPBs by a coating-etching strategy and their derived injectable implants for enhanced tumor photothermal treatment.

Herein, we demonstrate a coating-etching strategy to directly synthesize hollow Prussian blue (PB) nanocubes with well-dispersed Ag nanoparticles (denoted as Ag-HPB). The method is accomplished by introduction of PB precursors, K3Fe(CN)6 and Fe3+ into a reaction system containing AgNO3 and ascorbic acid, in which a series reactions contain formation of Ag nanoparticles, coating of PB on the nanoparticles, and diffusion of Ag into the PB frameworks occur. The strategy for preparation of the hollow structured Ag-HPB is intrinsically simple and does not require pre-preparation of any sacrificial templates or toxic etching agents. The obtained Ag-HPB nanocubes possess uniform size (69 nm), well-defined hollow structure, strong near-infrared photothermal conversion capacity, and excellent photoacoustic and magnetic resonance imaging abilities. Furthermore, an injectable photothermal implants are prepared for the first time by mixing the Ag-HPB nanocubes with clinically used biological glue, which significantly enhance photothermal anti-tumor efficacy, showing great potential for clinical tumor treatment.

Targeted fluorescent magnetic nanoparticles for imaging of human breast cancer.

Magnetic nanoclusters coated with ruthenium (II) complexes doped with silica (fluorescent magnetic nanoparticles or FMNPs) could be used for magnetic resonance imaging (MRI) and optical imaging (OI) of human breast cancer. To achieve the targeting imaging of tumors, the peptide cyclic-arginine-glycine-aspartic acid (RGD) was chosen as the probe for specific targeting integrin αvß3 over expressed in human breast cancer MDA-MB-231 cells. The cytotoxicity tests in vitro showed little toxicity of the synthesized RGD-FMNPs with the size of 150 nm. The in vivo study also showed no obvious acute toxicity after the injection of RGD-FMNPs in mice bearing MDA-MB-231 tumors. After 24 hours of co-culture with MDA-MB-231 cells, the cellular uptake of RGD-FMNPs significantly increased compared to that of FMNPs. T2-weighted (T2W) MRI demonstrated a negative enhancement in mice injected with RGD-FMNPs approximately three times of that injected with FMNPs (12.867 ± 0.451 ms vs. 4.833 ± 0.513 ms, P < 0.05). The Prussian blue staining results confirmed more RGD-FMNPs accumulated around the tumors than FMNPs. These results demonstrated the potential application of RGD-FMNPs as a targeting molecular probe for detection of breast cancer using MRI and OI. The synthesized RGD-FMNPs could be potentially used for biomedical imaging in the future.

[Mesoporous silica nanoparticles for cancer theranostic drug delivery].

Mesoporous silica nanoparticles as drug carrier have become the new hot point in the field of biomedical application in recent years. This review focuses on the more recent developments and achievements on experimental design aspect of mesoporous silica nanoparticles with cancer diagnosis and therapy. The key advances of functionalization strategies of mesoporous silica nanoparticles with controlled release, tumor targeting and overcoming multidrug resistance are discussed in particular. Mesoporous silica nanoparticles as unique delivery systems have the potential to provide significantly a sound platform for cancer theranostic application.