Wet/Sono-Chemical Synthesis of Enzymatic Two-Dimensional MnO2 Nanosheets for Synergistic Catalysis-Enhanced Phototheranostics

Magnetic Manganese Oxide Sweetgum-Ball Nanospheres with Large Mesopores Regulate Tumor Microenvironments for Enhanced Tumor Nanotheranostics

An important objective of cancer nanomedicine is to improve the delivery efficacy of functional agents to solid tumors for effective cancer imaging and therapy. Stimulus-responsive nanoplatforms can target and regulate the tumor microenvironment (TME) for the optimization of cancer theranostics. Here, we developed magnetic manganese oxide sweetgum-ball nanospheres (MMOSs) with large mesopores as tools for improved cancer theranostics. MMOSs contain magnetic iron oxide nanoparticles and mesoporous manganese oxide (MnO2) nanosheets, which are assembled into gumball-like structures on magnetic iron oxides. The large mesopores of MMOSs are suited for cargo loading with chlorin e6 (Ce6) and doxorubicin (DOX), thus producing so-called CD@MMOSs. The core of magnetic iron oxides could achieve magnetic targeting of tumors under a magnetic field (0.25 mT), and the targeted CD@MMOSs may decompose under TME conditions, thereby releasing loaded cargo molecules and reacting with endogenous hydrogen peroxide (H2O2) to generate oxygen (O2) and manganese (II) ions (Mn2+). Investigation in vivo in tumor-bearing mice models showed that the CD@MMOS nanoplatforms achieved TME-responsive cargo release, which might be applied in chemotherapy and photodynamic therapy. A remarkable in vivo synergy of diagnostic and therapeutic functionalities was achieved by the decomposition of CD@MMOSs and coadministration with chemo-photodynamic therapy of tumors using the magnetic targeting mechanism. Thus, the result of this study demonstrates the feasibility of smart nanotheranostics to achieve tumor-specific enhanced combination therapy.

A GSH-Gated DNA Nanodevice for Tumor-Specific Signal Amplification of microRNA and MR Imaging-Guided Theranostics

Developing tumor-responsive diagnosis and therapy strategies for tumor theranostics is still a challenge owing to their high accuracy and specificity. Herein, an AND logic gated-DNA nanodevice, based on the fluorescence nucleic acid probe and polymer-modified MnO₂ nanosheets, for glutathione (GSH)-gated miRNA-21 signal amplification and GSH-activated magnetic resonance (MR) imaging-guided chemodynamic therapy (CDT) is reported. In the presence of overexpressed miRNA and GSH (tumor cells), the nanodevice can be in situ activated and release significantly amplified fluorescence signals and MR signals. Conversely, the fluorescence signal is quenched and MR signal remains at the background level with low miRNA and GSH (normal cells), efficiently reducing the false-positive signals by more than 50%. Under the guide of miRNA profiling and MR imaging, the tumor-responsive hydroxyl radical (·OH) can effectively kill tumor cells. Furthermore, the nanodevice shows catalase-like activity and glucose oxidase-like activity with the performance of O₂ production and glucose consumption. This is the first time to fabricate a tumor-responsive theranostic DNA nanodevice with tumor-specific signal amplification of microRNA and GSH-activated MR imaging for CDT, potential hypoxia relief and starvation therapy, which provides a new insight for designing smart theranostic strategies.

Emerging blood–brain-barrier-crossing nanotechnology for brain cancer theranostics

The advancements, perspectives, and challenges in blood–brain-barrier (BBB)-crossing nanotechnology for effective brain tumor delivery and highly efficient brain cancer theranostics.