Hypoxia-Activatable Nanovesicles as In Situ Bombers for Combined Hydrogen-Sulfide-Mediated Respiration Inhibition and Photothermal Therapy

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

Theranostic Fluorescent Probes

The ability to gain spatiotemporal information, and in some cases achieve spatiotemporal control, in the context of drug delivery makes theranostic fluorescent probes an attractive and intensely investigated research topic. This interest is reflected in the steep rise in publications on the topic that have appeared over the past decade. Theranostic fluorescent probes, in their various incarnations, generally comprise a fluorophore linked to a masked drug, in which the drug is released as the result of certain stimuli, with both intrinsic and extrinsic stimuli being reported. This release is then signaled by the emergence of a fluorescent signal. Importantly, the use of appropriate fluorophores has enabled not only this emerging fluorescence as a spatiotemporal marker for drug delivery but also has provided modalities useful in photodynamic, photothermal, and sonodynamic therapeutic applications. In this review we highlight recent work on theranostic fluorescent probes with a particular focus on probes that are activated in tumor microenvironments. We also summarize efforts to develop probes for other applications, such as neurodegenerative diseases and antibacterials. This review celebrates the diversity of designs reported to date, from discrete small-molecule systems to nanomaterials. Our aim is to provide insights into the potential clinical impact of this still-emerging research direction.

Monophenylboryl aza-BODIPY with free rotation of the B-phenyl group for enhanced photothermal conversion

Owing to the efficient non-radiative relaxation by the free rotation of the B-phenyl moiety, monophenyl substituted aza-BODIPY on the boron centre with near-infrared absorption has high photothermal conversion efficiency, which is highly desirable for a photothermal therapy agent.

A metal-organic framework-derived ruthenium-nitrogen-carbon nanozyme for versatile hydrogen sulfide and cystathionine γ-lyase activity assay

In this study, a novel approach exploiting the interactions between hydrogen sulfide (H2S) and ruthenium-nitrogen-carbon (Ru-N-C) nanozymes is presented, advancing H2S and cystathionine γ-lyase (CSE) biosensing techniques. Utilizing the intrinsic peroxidase-like activity of Ru-N-C nanozymes and the noticeable inhibition effect caused by H2S, an efficient, simple, and economical assay has been developed. This innovative method allows for the versatile real-time monitoring of H2S from various sources, including specialized donors and native bacterial production. Furthermore, the assay has been applied to reveal the interactions within tumor cells and tissues ex vivo, providing a clearer and simpler view of CSE expression levels through an improved colorimetric method. This contribution enhances our understanding of the complex roles of H2S metabolism and represents a significant advancement in the versatile application of nanozymes in biomedical research.

Aza-BODIPY with two efficacious fragments for NIR light-driven photothermal therapy by triggering cancer cell apoptosis

The reasonable structure of aza-BODIPY renders it as an efficient photothermal reagent for photothermal therapy. Herein, we describe the design and synthesis of aza-BODIPY NMeBu with the free rotating tert-butyl group and the dimethylamino-substituted segment to promote the photothermal conversion via the excited state non-radiative transition. NMeBu was found to be the π-π stacking form in the unit cell based on X-ray analysis. NMeBu-NPs by self-assembly possessed a near-infrared absorption (λabs = 772 nm), and once activated by near-infrared light, the photothermal efficiency in aqueous solution can reach 49.3%. NMeBu-NPs can penetrate the cell and trigger cell death via the apoptosis pathway under low concentration and low light power irradiation, thereby avoiding dark toxicity. Aza-BODIPY created using this procedure has excellent photothermal efficiency and could serve as a potential candidate for the treatment of cancer cells and tumors.