Biocompatible Hollow Polydopamine Nanoparticles Loaded Ionic Liquid Enhanced Tumor Microwave Thermal Ablation in Vivo

Exploring the in vivo toxicity of nanoparticles

Toxicological tests of a xenobiotic play a key role to determine the safety of the new compound before it reaches the market. In this review article, we describe the main types of toxicological studies that can be performed in vivo to detect a possible undesired effect of a xenobiotic with especial emphasis on the data available for the different types of nanoparticles. The different procedures described in this review allow to obtain valuable information about the possible toxic effects of a xenobiotic to minimize the possible risks for patients once the compound has been approved for therapeutic use.

Mesoporous polydopamine nanoparticles with co-delivery function for overcoming multidrug resistance via synergistic chemo-photothermal therapy

Theranostic agents for combined chemo-photothermal therapy have attracted intensive interest in the treatment of multi-drug resistance (MDR) in cancer therapy. However, the development of simple theranostic agents as dual hosts for both heat and a high payload of chemotherapeutic agents remains a big challenge. Herein, mesoporous polydopamine nanoparticles (MPDA) were successfully developed with properties of a high payload of DOX (up to 2000 μg mg^-1) and the drug efflux inhibitor TPGS (d-α-tocopheryl polyethylene glycol 1000 succinate), as well as strong near-infrared absorption. Particularly, DOX and TPGS were sequentially loaded in the pore space and on the external particle surface of MPDA via π-π stacking and hydrophobic interactions, resulting in a MPDA-DOX@TPGS complex. The DOX release observably relies on the pH value and glutathione (GSH). Furthermore, it is possible to accelerate the rate of drug release by NIR irradiation. Importantly, the MPDA-DOX@TPGS complex was found to escape from endosomes after cellular uptake and release the loaded drugs into the cytosol. By TPGS mediated MDR reversal, the delivered DOX induced significant cytotoxicity to MCF-7/ADR cells. Besides, MPDA can absorb the NIR light and convert it into fatal heat to kill the cancer cells. As a consequence, the combined therapy in our system yields a synergistic effect with high therapeutic efficacy.

Thermoacoustic Imaging and Therapy Guidance based on Ultra-short Pulsed Microwave Pumped Thermoelastic Effect Induced with Superparamagnetic Iron Oxide Nanoparticles

Multifunctional nanoparticle-mediated imaging and therapeutic techniques are promising modalities for accurate localization and targeted treatment of cancer in clinical settings. Thermoacoustic (TA) imaging is highly sensitive to detect the distribution of water, ions or specific nanoprobes and provides excellent resolution, good contrast and superior tissue penetrability. TA therapy is a potential non-invasive approach for the treatment of deep-seated tumors. In this study, human serum albumin (HSA)-functionalized superparamagnetic iron oxide nanoparticle (HSA-SPIO) is used as a multifunctional nanoprobe with clinical application potential for MRI, TA imaging and treatment of tumor. In addition to be a MRI contrast agent for tumor localization, HSA-SPIO can absorb pulsed microwave energy and transform it into shockwave via the thermoelastic effect. Thereby, the reconstructed TA image by detecting TA signal is expected to be a sensitive and accurate representation of the HSA-SPIO accumulation in tumor. More importantly, owing to the selective retention of HSA-SPIO in tumor tissues and strong TA shockwave at the cellular level, HSA-SPIO induced TA effect under microwave-pulse radiation can be used to highly-efficiently kill cancer cells and inhibit tumor growth. Furthermore, ultra-short pulsed microwave with high excitation efficiency and deep penetrability in biological tissues makes TA therapy a highly-efficient anti-tumor modality on the versatile platform. Overall, HSA-SPIO mediated MRI and TA imaging would offer more comprehensive diagnostic information and enable dynamic visualization of nanoagents in the tumorous tissue thereby tumor-targeted therapy.

Imaging-guided synergetic therapy of orthotopic transplantation tumor by superselectively arterial administration of microwave-induced microcapsules

It is an ambitious target to improve overall Hepatocellular Carcinoma therapeutic effects. Recently, MW ablation has emerged as a powerful thermal ablation technique, affording favorable survival with excellent local tumor control. To achieve better therapeutic effects of MW ablation, MW sensitizers are prepared for enhanced MW ablation to preferentially heat tumor territory. However, it is still not practicable for treatment of the orthotopic transplantation tumor. Herein, biocompatible and degradable methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid) (mPEG-PLGA) microcapsules with hierarchical structure have been designed for microwave-induced tumor therapy. Chemical drug doxorubicin hydrochloride (DOX·HCl), microwave (MW) sensitizers and CT imaging contrast MoS₂ nanosheets and MR imaging contrast Fe₃O₄ nanoparticles are co-incorporated into the microcapsules. In vitro/vivo MR/CT dual-modal imaging results prove the potential application for guiding synergetic therapy and predicting post-therapy tumor progression in the orthotopic transplantation tumor model. After blocking the tumor-feeding arteries, these microcapsules not only exclude the cooling effect by cutting off the blood flow but also enhance MW heating conversion at tumor site. The focused MW heating makes microcapsules mollescent or ruptured and releases DOX·HCl from the microcapsules, achieving the controlled release of drugs for chemical therapy. Compared with MW ablation, 29.4% increase of necrosis diameter of normal liver in rabbit is obtained under MW ablation combined with transcatheter arterial blocking, and the average size of necrosis and inhibition rate of VX-2 liver orthotopic transplantation tumor in rabbit has increased by 129.33% and 73.46%. Moreover, it is proved that the superselectively arterial administration of the as-prepared microcapsules has no recognizable toxicity on the animals. Therefore, this research provides a novel strategy for the construction of MW-induced microcapsules for orthotopic transplantation tumor ablation with the properties of MW sensitizing, superselective arterial blocking, control release and enhanced accumulation of DOX·HCl, and MR/CT dual-modal imaging, which exhibits great potential applications in the field of HCC therapy.

Functional hollow nanostructures for imaging and phototherapy of tumors

Various types of inorganic and organic phototherapeutic hollow nanostructures for the imaging and treatment of tumors are reviewed.

An injectable ionic hydrogel inducing high temperature hyperthermia for microwave tumor ablation

Microwave tumor ablation is of clinical significance and has been considered as a promising cancer minimally invasive therapy.

In Vivo Magnetic Resonance Imaging and Microwave Thermotherapy of Cancer Using Novel Chitosan Microcapsules

Herein, we develop a novel integrated strategy for the preparation of theranostic chitosan microcapsules by encapsulating ion liquids (ILs) and Fe3O4 nanoparticles. The as-prepared chitosan/Fe3O4@IL microcapsules exhibit not only significant heating efficacy in vitro under microwave (MW) irradiation but also obvious enhancement of T2-weighted magnetic resonance (MR) imaging, besides the excellent biocompatibility in physiological environments. The chitosan/Fe3O4@IL microcapsules show ideal temperature rise and therapeutic efficiency when applied to microwave thermal therapy in vivo. Complete tumor elimination is realizing after MW irradiation at an ultralow power density (1.8 W/cm(2)), while neither the MW group nor the chitosan microcapsule group has significant influence on the tumor development. The applicability of the chitosan/Fe3O4@IL microcapsules as an efficient contrast agent for MR imaging is proved in vivo. Moreover, the result of in vivo systematic toxicity shows that chitosan/Fe3O4@IL microcapsules have no acute fatal toxicity. Our study presents an interesting type of multifunctional platform developed by chitosan microcapsule promising for imaging-guided MW thermotherapy.

A pH-responsive poly(ether amine) micelle with hollow structure for controllable drug release

A pH-responsive poly(ether amine) micelle with hollow structure was developed for controllable drug release.