Biphasic synthesis of biodegradable urchin-like mesoporous organosilica nanoparticles for enhanced cellular internalization and precision cascaded therapy

Recent Advances in Functional Nanomaterials for Catalytic Generation of Nitric Oxide: A Mini Review

As a gaseous second messenger, nitric oxide (NO) plays an important role in a series of signal pathways. Research on the NO regulation for various disease treatments has aroused wide concern. However, the lack of accurate, controllable, and persistent release of NO has significantly limited the application of NO therapy. Profiting from the booming development of advanced nanotechnology, a mass of nanomaterials with the properties of controllable release have been developed to seek new and effective NO nano-delivery approaches. Nano-delivery systems that generate NO through catalytic reactions exhibit unique superiority in terms of precise and persistent release of NO. Although certain achievements have been made in the catalytically active NO delivery nanomaterials, some basic but critical issues, such as the concept of design, are of low attention. Herein, an overview of the generation of NO through catalytic reactions and the design principles of related nanomaterials are summarized. Then, the nanomaterials that generate NO through catalytic reactions are classified. Finally, the bottlenecks and perspectives are also discussed in depth for the future development of catalytical NO generation nanomaterials.

Ultrasmall Gold-Coated Mesoporous Polydopamine Nanoprobe to Enhance Chemodynamic Therapy by Self-Supplying H2O2 and Photothermal Stimulation

Tumor microenvironment (TME) responsive chemodynamic therapy (CDT) showed an important application in inhibiting tumor growth by producing the highly toxic hydroxyl radical (·OH), but insufficient hydrogen peroxide (H₂O₂) and overexpressed glutathione (GSH) limited its application. Herein, by integrating photothermal therapy (PTT) and CDT, a new kind of mesoporous polydopamine (MPDA)-based cascade-reaction nanoplatform (MPDA@AuNPs-Cu) was designed for enhanced antitumor therapy, in which ultrasmall gold nanoparticles (AuNPs) with glucose oxidase (GOx)-like activity were deposited on MPDA for providing H₂O₂, and Cu²⁺ was chelated for GSH-responsive Fenton-like reaction. It was demonstrated that the MPDA@AuNPs-Cu nanoprobe showed high photothermal conversion efficiency and excellent biocompatibility. Moreover, the MPDA@AuNPs-Cu nanoprobe exhibited strong ·OH generation because of H₂O₂ self-generation and photothermal stimulation. Importantly, compared with MPDA-Cu, MPDA@AuNPs-Cu exhibited enhanced in vitro and in vivo CDT/PTT performance, by which the tumor growth was completely inhibited, achieving TME-responsive antitumor efficacy.

Biodegradable Metal-Organic-Framework-Gated Organosilica for Tumor-Microenvironment-Unlocked Glutathione-Depletion-Enhanced Synergistic Therapy

The clinical employment of cisplatin (cis-diamminedichloroplatinum(II) (CDDP)) is largely constrained due to the non-specific delivery and resultant serious systemic toxicity. Small-sized biocompatible and biodegradable hollow mesoporous organosilica (HMOS) nanoparticles show superior advantages for targeted CDDP delivery but suffer from premature CDDP leakage. Herein, the smart use of a bimetallic Zn²⁺ /Cu²⁺ co-doped metal-organic framework (MOF) is made to block the pores of HMOS for preventing potential leakage of CDDP and remarkably increasing the loading capacity of HMOS. Once reaching the acidic tumor microenvironment (TME), the outer MOF can decompose quickly to release CDDP for chemotherapy against cancer. Besides, the concomitant release of dopant Cu²⁺ can deplete the intracellular glutathione (GSH) for increased toxicity of CDDP as well as catalyzing the decomposition of intratumoral H₂ O₂ into highly toxic •OH for chemodynamic therapy (CDT). Moreover, the substantially reduced GSH can also protect the yielded •OH from scavenging and thus greatly improve the •OH-based CDT effect. In addition to providing a hybrid HMOS@MOF nanocarrier, this study is also expected to establish a new form of TME-unlocked nanoformula for highly efficient tumor-specific GSH-depletion-enhanced synergistic chemotherapy/chemodynamic therapy.

Multifaceted Therapy of Nanocatalysts in Neurological Diseases

With the development of enzymes immobilization technology and the discover of nanozymes, catalytic therapy exhibited tremendous potential for neurological diseases therapy. In especial, since the discovery of Fe₃O₄ nanoparticles possessing intrinsic peroxidase-like activity, various nanozymes have been developed and recently started to explore for neurological diseases therapy, such as Alzheimer's disease, Parkinson's disease and stroke. By combining the catalytic activities with other properties (such as optical, thermal, electrical, and magnetic properties) of nanomaterials, the multifunctional nanozymes would not only alleviate oxidative and nitrosative stress on the basis of multienzymes-mimicking activity, but also exert positive effects on immunization, inflammation, autophagy, protein aggregation, which provides the foundation for multifaceted treatments. This review will summarize various types of nanocatalysts and further provides a valuable discussion on multifaceted treatment by nanozymes for neurological diseases, which is anticipated to provide an easily accessible guide to the key opportunities and current challenges of the nanozymes-mediated treatments for neurological diseases.