A near-infrared light-controlled, oxygen-independent radical generating nano-system toward cancer therapy

AIBI Modified Mesoporous Copper Sulfide Nanocomposites for Efficient Non-Oxygen Dependent Free Radicals-Assisted Photothermal Therapy in Uveal Melanoma

Uveal melanoma (UM) is an ocular cancer predominantly affecting adults, characterized by challenging diagnostic outcomes. This research endeavors to develop an innovative multifunctional nanocomposite system sensitive to near-infrared (NIR) radiation, serving as both a non-oxygen free-radical generator and a photothermal agent. The designed system combines azobis isobutyl imidazoline hydrochloride (AIBI) with mesoporous copper sulfide (MCuS) nanoparticles. MCuS harnesses NIR laser energy to induce photothermal therapy, converting light energy into heat to destroy cancer cells. Simultaneously, AIBI is activated by the NIR laser to produce alkyl radicals, which induce DNA damage in remaining cancer cells. This distinctive feature equips the designed system to selectively eliminate cancers in the hypoxic tumor microenvironment. MCuS is also beneficial to scavenge the overexpressed glutathione (GSH) in the tumor microenvironment. GSH generally consumes free radicals and hiders the PDT effect. To enhance control over AIBI release in cancer cells, 1-tetradecyl alcohol (TD), a phase-changing material, is introduced onto the surface of MCuS nanoparticles to create the final AMPT nanoparticle system. In vitro and in vivo experiments confirm the remarkable anti-tumor efficacy of AMPT. Notably, the study introduces an orthotopic tumor model for UM, demonstrating the feasibility of precise and effective targeted treatment within the ocular system.

A mitochondria-targeting heptamethine cyanine-chlorambucil formulated polymeric nanoparticle to potentiate native tumor chemotherapeutic efficacy

Chlorambucil (Cbl) is a DNA alkylating drug in the nitrogen mustard family, but the clinical applications of nitrogen mustard antitumor drugs are frequently limited by their poor aqueous solubility, poor cellular uptake, lack of targeting, and severe side effects. Additionally, mitochondria are the energy factories for cells, and tumor cells are more susceptible to mitochondrial dysfunction than some healthy cells, thus making mitochondria an important target for tumor therapy. As a proof-of-concept, direct delivery of Cbl to tumor cells' mitochondria will probably bring about new opportunities for the nitrogen mustard family. Furthermore, IR775 chloride is a small-molecule lipophilic cationic heptamethine cyanine dye with potential advantages of mitochondria targeting, near-infrared (NIR) fluorescence imaging, and preferential internalization towards tumor cells. Here, an amphiphilic drug conjugate was facilely prepared by covalently coupling chlorambucil with IR775 chloride and further self-assembly to form a carrier-free self-delivery theranostic system, in which the two components are both functional units aimed at theranostic improvement. The theranostic IR775-Cbl potentiated typical "1 + 1 > 2" tumor inhibition through specific accumulation in mitochondria, which triggered a remarkable decrease in mitochondrial membrane potential and ATP generation. In vivo biodistribution and kinetic monitoring were achieved by real-time NIR fluorescence imaging to observe its transport inside a living body. Current facile mitochondria-targeting modification with clinically applied drugs was promising for endowing traditional drugs with targeting, imaging, and improved potency in disease theranostics.

Nanozyme hydrogel for enhanced alkyl radical generation and potent antitumor therapy

Alkyl radicals (R˙), which do not rely on oxygen generation for causing cellular stress, have been applied in tumor treatment, but a large amount of glutathione (GSH) in the tumor cells reacts with alkyl radicals, thereby reducing their antitumor effect. In this study, an enhanced alkyl radical generation system responsive to near-infrared light was designed. The alkyl radical trigger 2,2'-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) and nanozyme pyrite (FeS₂) were encapsulated in agarose hydrogel to prepare the AIPH-FeS₂-hydrogel (AFH) system. FeS₂ can be used as a photothermal agent to convert near-infrared light energy into heat energy, leading to the dissolution of the hydrogel. AIPH is simultaneously induced to produce alkyl radicals. FeS₂ can also be used as an oxidative stress amplifier to reduce intracellular GSH content, thereby boosting the therapeutic effect of alkyl radicals. Eventually, the oxygen-independent free radicals generated by the AFH system under near-infrared laser irradiation and photothermal treatment can kill cancer cells through the synergistic oxidation/photothermal effect. The AFH system developed herein provides new insights into enhancing the therapeutic effect of alkyl radicals.

Low-temperature photothermal irradiation triggers alkyl radicals burst for potentiating cancer immunotherapy

Although low-temperature photothermal therapy (PTT) can sensitize tumors to immune checkpoint inhibition, its efficacy is still restricted in the deep and internal tumors without enough oxygen and lymphocytic infiltration. Non-oxygen-dependent alkyl radicals have been demonstrated to synergistically enhance PTT through up-regulating lipid peroxidation and reactive oxygen species (ROS). Herein, an innovative strategy based on alkyl radicals to augment immunogenetic cell death (ICD) caused by mild PTT was proposed to improve poor efficacy of immunotherapy, which composed of a photothermal material of Chinse ink, an azo-initiator of 2,2-azobis[2-(2-imidazoline-2-acyl)propane]dihydrochloride (AIPH) and a PD-L1 inhibitor of HY19991 (HY). Upon near-infrared-II laser irradiation, low-temperature (<45℃) stimulation induced a high expression of immune checkpoint receptor (PD-L1) in tumors and triggered a large amount alkyl radicals generated by AIPH. Significantly, the alkyl radicals augmented the ICD and increased the recruitment of tumor-infiltrating lymphocytes against tumors after transformation of the immunologically cold tumor microenvironment into hot by mild PTT. The released HY further enhanced the immunotherapy effect by blocking the binding of activated T lymphocytes and PD-L1. In vivo studies exhibited that the all-in-one hydrogel with synergistic mechanisms had an extraordinary ability to reverse the immunosuppressive microenvironment, stimulate innate and adaptive immune responses to eliminate tumors and prevent metastasis.

Nanomaterials based on phase change materials for antibacterial application

This review presented the applications of PCM-based nanomaterials in bacterial infections. Firstly, the composition and biotoxicity were outlined. Secondly, various antibacterial tactics were highlighted. Lastly, the perspectives were discussed.