Coordination-induced exfoliation to monolayer Bi-anchored MnB2 nanosheets for multimodal imaging-guided photothermal therapy of cancer.

Background: Rapid advance in biomedicine has recently vitalized the development of multifunctional two-dimensional (2D) nanomaterials for cancer theranostics. However, it is still challenging to develop new strategy to produce new types of 2D nanomaterials with flexible structure and function for enhanced disease theranostics. Method: We explore the monolayer Bi-anchored manganese boride nanosheets (MBBN) as a new type of MBene (metal boride), and discover their unique near infrared (NIR)-photothermal and photoacoustic effects, X-ray absorption and MRI imaging properties, and develop them as a new nanotheranostic agent for multimodal imaging-guided photothermal therapy of cancer. A microwave-assisted chemical etching route was utilized to exfoliate the manganese boride bulk into the nanosheets-constructed flower-like manganese boride nanoparticle (MBN), and a coordination-induced exfoliation strategy was further developed to separate the MBN into the dispersive monolayer MBBN by the coordination between Bi and B on the surface, and the B-OH group on the surface of MBBN enabled facile surface modification with hyaluronic acid (HA) by the borate esterification reaction in favor of enhanced monodispersion and active tumor targeting. Result: The constructed MBBN displays superior NIR-photothermal conversion efficiency (η=59.4%) as well as high photothermal stability, and possesses versatile imaging functionality including photoacoustic, photothermal, CT and T1 -wighted MRI imagings. In vitro and in vivo evaluations indicate that MBBN had high photothermal ablation and multimodal imaging performances, realizing high efficacy of imaging-guided cancer therapy. Conclusion: We have proposed new MBene concept and exfloliation strategy to impart the integration of structural modification and functional enhancement for cancer theranostics, which would open an avenue to facile fabrication and extended application of multifunctional 2D nanomaterials.

Acid-Responsive H2 -Releasing 2D MgB2 Nanosheet for Therapeutic Synergy and Side Effect Attenuation of Gastric Cancer Chemotherapy.

The hydrogen molecule is recognized as a high potential to attenuate toxic side effects of chemotherapy and also enhance chemotherapeutic efficacy, and the development of a novel hydrogen-generating prodrug for facile, safe, and efficient hydrogen delivery is vitally important for combined hydrogenochemotherapy but is still challenging. Here, targeting gastric cancer, a 2D magnesium boride nanosheet (MBN) is synthesized as a new type of acid-responsive hydrogen-releasing prodrug by an ultrasound-assisted chemical etching route, which is used to realize hydrogenochemotherapy by combination of facile oral administration of polyvinylpyrrolidone (PVP)-encapsulating MBN (MBN@PVP) pills with routine intravenous injection of doxorubicin (DOX). The MBN@PVP pill has high stability in normal tissues/blood environments as well as high gastric acid-responsiveness with sustained release behavior, which matches well with its metabolism rate in the stomach in great favor of continuous and long-term hydrogen administration. Hydrogenochemotherapy with DOX+MBN@PVP has remarkably prolonged the survival time of gastric tumor-bearing mice by reducing the toxic side effects of chemotherapy. The mechanism for therapeutic synergy and side effect attenuation of hydrogenochemotherapy is discovered to be derived from the selectivity of hydrogen molecules in inhibiting aerobic respiration of gastric cells but activating aerobic respiration of normal cells including marrow mesenchymal stem cells and cardiac, hepatic, and splenic cells.

MRI-guided and ultrasound-triggered release of NO by advanced nanomedicine.

Nitric oxide (NO) has been well identified as a specific free radical molecule possessing wide-ranging therapeutic effects. Targeted delivery and controlled release of NO are highly desired to realize precision gas therapy, but are still challenging owing to the non-targetability and uncontrollability of NO itself. Herein, we propose a new concept of MRI-guided and ultrasound-triggered gas release for precision gas therapy. Based on this concept, we develop a novel ultrasound-responsive BNN-type NO-releasing molecule (NORM) and an advanced rattle-type nano-carrier of superparamagnetic iron oxide-encapsulated mesoporous silica nanoparticles (SPION@hMSN), and use them to construct a new intelligent nanomedicine (BNN6-SPION@hMSN) for the first time. The BNN6-SPION@hMSN nanomedicine exhibits excellent passive tumor-targeting capability, high MRI-guided tumor localization performance and a unique ultrasound-triggered NO release profile. The tumor-targeted, MRI-guided and ultrasound-triggered release profiles of the developed nanomedicine enable the tumor site-specific controlled release of NO in favor of high-efficacy and safe NO gas therapy of tumor.

Intratumoral H2O2-triggered release of CO from a metal carbonyl-based nanomedicine for efficient CO therapy.

A new H2O2-responsive nanomedicine for CO therapy is constructed by effectively encapsulating the hydrophobic manganese carbonyl prodrug into an advanced hollow mesoporous silica nanoparticle carrier to realize the intratumoral H2O2-triggered release of CO and selective killing of tumour cells rather than normal cells, exhibiting high in vitro and in vivo efficacies of CO therapy.

Preparation and visible light photocatalytic activity of Ag/TiO2/graphene nanocomposite.

Great efforts have been made to develop efficient visible light-activated photocatalysts in recent years. In this work, a new nanocomposite consisting of anatase TiO(2), Ag, and graphene was prepared for use as a visible light-activated photocatalyst, which exhibited significantly increased visible light absorption and improved photocatalytic activity, compared with Ag/TiO(2) and TiO(2)/graphene nanocomposites. The increased absorption in visible light region is originated from the strong interaction between TiO(2) nanoparticles and graphene, as well as the surface plasmon resonance effect of Ag nanoparticles that are mainly adsorbed on the surface of TiO(2) nanoparticles. The highly efficient photocatalytic activity is associated with the strong adsorption ability of graphene for aromatic dye molecules, fast photogenerated charge separation due to the formation of Schottky junction between TiO(2) and Ag nanoparticles and the high electron mobility of graphene sheets, as well as the broad absorption in the visible light region. This work suggests that the combination of the excellent electrical properties of graphene and the surface plasmon resonance effect of noble metallic nanoparticles provides a versatile strategy for the synthesis of novel and efficient visible light-activated photocatalysts.