Self-triggered thermoelectric nanoheterojunction for cancer catalytic and immunotherapy.

The exogenous excitation requirement and electron-hole recombination are the key elements limiting the application of catalytic therapies. Here a tumor microenvironment (TME)-specific self-triggered thermoelectric nanoheterojunction (Bi0.5Sb1.5Te3/CaO2 nanosheets, BST/CaO2 NSs) with self-built-in electric field facilitated charge separation is fabricated. Upon exposure to TME, the CaO2 coating undergoes rapid hydrolysis, releasing Ca2+, H2O2, and heat. The resulting temperature difference on the BST NSs initiates a thermoelectric effect, driving reactive oxygen species production. H2O2 not only serves as a substrate supplement for ROS generation but also dysregulates Ca2+ channels, preventing Ca2+ efflux. This further exacerbates calcium overload-mediated therapy. Additionally, Ca2+ promotes DC maturation and tumor antigen presentation, facilitating immunotherapy. It is worth noting that the CaO2 NP coating hydrolyzes very slowly in normal cells, releasing Ca2+ and O2 without causing any adverse effects. Tumor-specific self-triggered thermoelectric nanoheterojunction combined catalytic therapy, ion interference therapy, and immunotherapy exhibit excellent antitumor performance in female mice.

Nanoheterojunction-Mediated Thermoelectric Strategy for Cancer Surgical Adjuvant Treatment and ß-Elemene Combination Therapy.

As an indispensable strategy for tumor treatment, surgery may cause two major challenges: tumor recurrence and wound infection. Here, a thermoelectric therapeutic strategy is provided as either an independent cancer therapy or surgical adjuvant treatment. Bi0.5 Sb1.5 Te3 (BST) and Bi2 Te2.8 Se0.2 (BTS) nanoplates composed of Z-scheme thermoelectric heterojunction (BST/BTS) are fabricated via a two-step hydrothermal processes. The contact between BST and BTS constructs an interfacial electric field due to Fermi energy level rearrangement, guiding electrons in the conductive band (CB) of BTS combine with the holes in the valance band (VB) of BST, leaving stronger reduction/oxidation potentials of electrons and holes in the CB of BST and the VB of BTS. Moreover, under a mild temperature gradient, another self-built-in electric field is formed facilitating the migration of electrons and holes to their surfaces. Based on the PEGylated BST/BTS heterojunction, a novel thermoelectric therapy platform is developed through intravenous injection of BST/BTS and external cooling of the tumors. This thermoelectric strategy is also proved effective for combination cancer therapy with ß-elemene. Moreover, the combination of heterojunction and hydrogel is administrated on the wound after surgery, achieving efficient residual tumor treatment and antibacterial effects.

Novel biodegradable two-dimensional vanadene augmented photoelectro-fenton process for cancer catalytic therapy.

Fenton reaction-based chemodynamic therapy is hardly a self-sufficient cancer treatment, due to its stringent reaction conditions, limited substrate concentration, and negative feedback from the tumor microenvironment. Herein, we synthesized a novel two-dimensional (2D) vanadium-based nanosheets (Vanadene, V NSs) with polyvalent surfaces (VIV/VV), a very narrow band gap of 0.8 eV, and high biodegradability by a liquid-phase exfoliation strategy. The polyvalent surface endowed its multiple capabilities to modulate TME through GSH consumption and O2 production via VV and to catalyze a Fenton-like reaction to produce ·OH under a mild condition via VIV. In addition, efficient energy conversions including near-infrared (NIR)-thermal conversion (photothermal therapy, PTT) and NIR-electron conversion (photodynamic therapy, PDT) were ensured by the narrow band gap, in which NIR-thermal conversion enhanced the Fenton-like reaction activity through accelerating ionization while NIR-electron conversion catalyzed the conversion of O2 to ·O2- for further breaking redox homeostasis. Moreover, V NSs-based nanocatalyst can be slowly degraded into non-toxic species, enabling it to be innocuously eliminated from the body after completing tumor eradication by single drug injection and single NIR irradiation. Therefore, this study provides new insights into a universal nanoplatform for NIR-enhanced combination cancer therapy, highlighting the utility of 2D V NSs in the field of biomedicine.

Andrographolide simultaneously augments Nrf2 antioxidant defense and facilitates autophagic flux blockade in cigarette smoke-exposed human bronchial epithelial cells.

Cigarette smoking is the leading cause of chronic obstructive pulmonary disease (COPD). Cigarette smoke heightens oxidative stress and impairs autophagy, advancing COPD progression. Andrographolide is a bioactive diterpenoid lactone isolated from the plant Andrographis paniculata which has been a traditional medicinal herb for respiratory diseases. As airway epithelial cells form the first interface to be exposed to cigarette smoke, this study aimed to explore the modulatory effects of andrographolide on oxidative stress and autophagy in human bronchial epithelial BEAS-2B cells exposed to cigarette smoke extract (CSE). CSE (2%) exposure increased autophagic markers p62 and LC3B-II levels in BEAS-2B cells. Andrographolide alone increased p62 and p-p62 (S349) but not LC3B-II in BEAS-2B cells. However, in the presence of CSE, andrographolide was able to simultaneously increase LC3B-II level and enhance antioxidant defense by decreasing oxidative stress and increasing total antioxidant capacity, through upregulation of nuclear Nrf2 via the p62-Nrf2 positive feedback loop. Using RFP-GFP-LC3B transfected BEAS-2B cells exposed to CSE, andrographolide was found to impair autophagosome fusion with lysosome, which may account for the moderate increase in activated caspase 3/7 and annexin V levels. Our findings revealed for the first time that andrographolide simultaneously upregulated antioxidant defense through the p62-Nrf2 loop and moderately induced apoptosis through impairment of autophagic flux in CSE-exposed bronchial epithelium. Andrographolide facilitated cigarette smoke-induced apoptosis may be a potential toxicological outcome or may protect against chronic inflammation and aberrant DNA repair. Validation of these in-vitro findings in an experimental COPD model by andrographolide is warranted.