PEGylated (NH4)xWO3 nanorods as efficient and stable multifunctional nanoagents for simultaneous CT imaging and photothermal therapy of tumor

Tungsten-based Nanomaterials in the Biomedical Field: A Bibliometric Analysis of Research Progress and Prospects

Tungsten-based nanomaterials (TNMs) with diverse nanostructures and unique physicochemical properties have been widely applied in the biomedical field. Although various reviews have described the application of TNMs in specific biomedical fields, there are still no comprehensive studies that summarize and analyze research trends of the field as a whole. To identify and further promote the development of biomedical TNMs, a bibliometric analysis method is used to analyze all relevant literature on this topic. First, general bibliometric distributions of the dataset by year, country, institute, referenced source, and research hotspots are recognized. Next, a comprehensive review of the subjectively recognized research hotspots in various biomedical fields, including biological sensing, anticancer treatments, antibacterials, and toxicity evaluation, is provided. Finally, the prospects and challenges of TNMs are discussed to provide a new perspective for further promoting their development in biomedical research.

Laser-induced breakdown spectroscopy-guided synergistic phototherapy: A theranostic platform mediated by a single laser wavelength

Currently, cancer theranostic studies have only focused on integrating existing medical imaging techniques with therapeutic modalities. Obviously, this strategy is not a real theranostic method, as diagnosis and therapy are based on different principles and require independent operation. Here, a cancer theranostic method was established by laser-induced breakdown spectroscopy (LIBS)-mediated synergistic photothermal/photodynamic therapy, which was activated by a single 1064-nm light for simultaneous tumor localization and treatment. PEGylated cobalt phosphate (CoP@PEG) nanoparticles (NPs) with strong near-infrared (NIR)-II absorbance, high photothermal conversion efficiency and a reactive oxygen species generation effect were fabricated, and they produced excellent antitumor outcomes under 1064-nm excitation, as evidenced by the substantial increase in HepG2 cell death in vitro and complete tumor elimination in vivo. Meanwhile, the diagnostic method of the LIBS imaging system used in the present study also uses 1064-nm light. The LIBS imaging system can provide fast, real-time analysis and imaging of elements and facilitate the localization of the tumor site by monitoring the distribution of CoP@PEG NPs for precise tumor treatment. We postulate that this theranostic platform will promote the development of further theranostic research.

Biodegradation Mn-CoS@carbon di-shell nanoheterostructure with enhanced nanozyme-mediated phototherapy

The efficacy of phototherapy is dependent on intracellular O₂ concentration and NIR harvest. Here, a simple nanoplatform with nanoenzyme mediated phototherapy enhances anticancer capacity. Mn-CoS@carbon (CMS/C) di-shell hollow nanospheres (50 nm) are synthesized successfully through two-step consecutive Kirkendall process. The nanoheterostructure reveals the higher near-infrared (NIR) light absorption and photothermal conversion rate of 66.3% than pure CoS (45.5%), owing to the decreased band gap and multi-reflection of incident light in the hollow structure. And CMS/C reveals the reactive oxygen species (ROS) production and nanoenzyme activities (mimic peroxidase and catalase) that are 6 and 2 times than those of pure CoS. Furthermore, the nanoenzyme exhibits NIR-enhanced abilities to produce more OH and O₂ facilitating anticancer. In addition, it also depletes glutathione (mimicking glutathione oxidase), to disturb intracellular redox-homeostasis, boosting the increase of oxidative stress. With grafting bovine serum albumin (BSA) and drug loading, CMS/C@BSA-Dox integrated multi-therapy make the great anticancer effect in vitro and vivo. After that, the nanocomposite could be biodegraded and eliminated via urinary and feces within 14 days. Based on this work, the efficient charge-separation can be designed to reveal high performance nanoenzymes as well as photosensitizers for anticancer.

2D LDH-MoS2 clay nanosheets: synthesis, catalase-mimic capacity, and imaging-guided tumor photo-therapy

Owing to the hypoxia status of the tumor, the reactive oxygen species (ROS) production during photodynamic therapy (PDT) of the tumor is less efficient. Herein, a facile method which involves the synthesis of Mg-Mn-Al layered double hydroxides (LDH) clay with MoS2 doping in the surface and anionic layer space of LDH was presented, to integrate the photo-thermal effect of MoS2 and imaging and catalytic functions of Mg-Mn-Al LDH. The designed LDH-MoS2 (LMM) clay composite was further surface-coated with bovine serum albumin (BSA) to maintain the colloidal stability of LMM in physiological environment. A photosensitizer, chlorin e6 (Ce6), was absorbed at the surface and anionic layer space of LMM@BSA. In the LMM formulation, the magnetic resonance imaging of Mg-Mn-Al LDH was enhanced thanks to the reduced and acid microenvironment of the tumor. Notably, the ROS production and PDT efficiency of Ce6 were significantly improved, because LMM@BSA could catalyze the decomposing of the overexpressed H2O2 in tumors to produce oxygen. The biocompatible LMM@BSA that played the synergism with tumor microenvironment is a promising candidate for the effective treatment of cancer.

PEGylated (NH4)xWO3 nanorod mediated rapid photonecrosis of breast cancer cells

Photothermal therapy has emerged as a potential minimally invasive technique to destroy malignant cells with high selectivity. It utilizes low band gap nanoscale materials as photothermal agents dispersed at the affected area to increase the temperature locally by absorbing radiation in the near infrared (NIR) region and destroys the cells. In an effort to develop a photothermal agent with high efficacy for photothermal therapy, we found that (NH4)xWO3 nanorods of length 0.5-1.0 μm and diameter ∼100 nm could destroy breast cancer cells rapidly when irradiated with a wavelength in the therapeutic window. The material was prepared using a solvothermal route followed by PEGylation for improving the biocompatibility. X-ray diffraction and transmission electron microscopy studies revealed the hexagonal crystal lattice of the material. The uniform wrapping of polyethylene glycol (PEG) around the nanorods was confirmed using energy dispersive spectroscopy elemental mapping. An 808 nm laser was used to investigate the photothermal responses of the material on SUM-159 and MCF-7 breast cancer cells in vitro. The PEGylated-(NH4)xWO3 nanorods exhibited rapid temperature elevation from 20 °C to 60 °C within 3 min upon irradiation. A significant growth inhibition of SUM-159 and MCF-7 breast cancer cells with photonecrosis was observed. PEGylated (NH4)xWO3 nanorods could potentially be used in cancer therapy due to their strong photonecrotic properties at specific NIR wavelengths that suffer from minimal attenuation while passing through biological tissues.

Atomic-Scale Mechanism of Unidirectional Oxide Growth

A fundamental knowledge of the unidirectional growth mechanisms is required for precise control on size, shape, and thereby functionalities of nanostructures. The oxidation of many metals results in oxide nanowire growth with a bicrystal grain boundary along the axial direction. Using transmission electron microscopy that spatially and temporally resolves CuO nanowire growth during the oxidation of copper, here we provide direct evidence of the correlation between unidirectional crystal growth and bicrystal grain boundary diffusion. Based on atomic scale observations of the upward growth at the nanowire tip, oscillatory downward growth of atomic layers on the nanowire sidewall and the parabolic kinetics of lengthening, bicrystal grain boundary diffusion is the mechanism by which Cu ions are delivered from the nanowire root to the tip. Together with density-functional theory calculations, we further show that the asymmetry in the corner-crossing barriers promotes the unidirectional oxide growth by hindering the transport of Cu ions from the nanowire tip to the sidewall facets. We expect the broader applicability of these results in manipulating the growth of nanostructured oxides by controlling the bicrystal grain boundary structure that favors anisotropic diffusion for unidirectional, one-dimensional crystal growth for nanowires or isotropic diffusion for two-dimensional platelet growth.

Anti-CD24 bio Modified PEGylated Gold Nanoparticles as Targeted Computed Tomography Contrast Agent

Purpose: Molecular imaging is one of the import methods for recognition of cancer at the early stage in order to enhance the capacity of remedy. This study was aimed to introduce a new contrast agent that was targeted with CD24 so as to improve the CT scan detection of cancer cells with higher CD24 expression. Methods: The surface modifications of gold nanoparticles (Au-NPs) were done with long PEG (HS-PEG-CH3O) and short PEG (HS-PEG-COOH) chains to enhance their stability and capacity for immobilization of different antibodies. MTT assay was carried out to assess the biocompatibility of the NPs. The obtained contrast agent was implemented in the targeted CT imaging based on in vitro and in vivo studies of breast cancer. Results: The results revealed that the attached CD24 to the cell surface of PEGylated Au-NPs could enhance significantly the cells CT number (40.45 HU in 4T1, while it was 16.61 HU in CT26) It was shown that the attenuation coefficient of the molecularly targeted cells was more than 2 times excessive than the control groups. Further, the tumor region in model of xenograft tumor has higher density compare to the omnipaque groups, 60 min after injection (45 Hu vs.81 Hu). These results showed that the nanoparticles stayed in tumor region for longer time. Conclusion: It is predicted that the synthesized nanoparticle can be used as computed tomography contrast agent. Also, it can be used to identify the tumor cells with higher expression of CD24 at the early stages more efficiently compare to the other routine methods.

A tumor treatment strategy based on biodegradable BSA@ZIF-8 for simultaneously ablating tumors and inhibiting infection

Studies have shown a clear correlation between cancer incidence and infection, and cancer treatment can also trigger infection so as to lead to an inflammatory response. In this case, we have designed a new tumor treatment strategy based on biodegradable BSA@ZIF-8 for simultaneously ablating tumors and inhibiting infection. This biodegradable ZIF contains abundant porous structures, showing increased absorption of ions and inelastic collisions. A large amount of frictional heat produced by the collisions results in increased tumor cell death under microwave irradiation. This can effectively inhibit tumor growth in mice by microwave ablation with a good anti-tumor effect (95.4%). Intriguingly, the Zn²⁺ released from the degradation of BSA@ZIF-8 causes damage to bacterial cell walls, and destruction of the metabolism and structure of the membrane, leading to bacterial cell death, and ultimately achieving good antibacterial properties. Moreover, BSA@ZIF-8 is biodegradable without long-term toxicity in vivo. The in vivo experimental results show that BSA@ZIF-8 can protect 80% of the mice from lethal challenge with tumors and the accompanying infection. Overall, we present a novel strategy using biodegradable ZIFs for microwave ablation therapy with simultaneous antibacterial and anti-infection effects for the first time, which has achieved good tumor treatment outcomes.