Microenvironment-responsive electrocution of tumor and bacteria by implants modified with degenerate semiconductor film

Selective Tumor Inhibition Effect of Drug-Free Layered Double Hydroxide-Based Films via Responding to Acidic Microenvironment

Nickel-titanium alloy stents are widely used in the interventional treatment of various malignant tumors, and it is important to develop nickel-titanium alloy stents with selective cancer-inhibiting and antibacterial functions to avoid malignant obstruction caused by tumor invasion and bacterial colonization. In this work, an acid-responsive layered double hydroxide (LDH) film was constructed on the surface of a nickel-titanium alloy by hydrothermal treatment. The release of nickel ions from the film in the acidic tumor microenvironment induces an intracellular oxidative stress response that leads to cell death. In addition, the specific surface area of LDH nanosheets could be further regulated by heat treatment to modulate the release of nickel ions in the acidic microenvironment, allowing the antitumor effect to be further enhanced. This acid-responsive LDH film also shows a good antibacterial effect against S. aureus and E. coli. Besides, the LDH film prepared without the introduction of additional elements maintains low toxicity to normal cells in a normal physiological environment. This work offers some guidance for the design of a practical nickel-titanium alloy stent for the interventional treatment of tumors.

Piezoelectric Ba0.85 Sr0.15 TiO3 Nanosonosensitizer with Nitric Oxide Delivery for Boosting Cancer Therapy

The efficacy of sonodynamic therapy (SDT) mainly relies on the sonosensitizers, which generate reactive oxygen species (ROS) upon ultrasound (US) stimulation. However, the limited availability of high-efficiency sonosensitizers hampers the therapeutic effectiveness of SDT as a standalone modality. In this work, a robust sonodynamic and gas cancer therapeutic platform is constructed based on strontium (Sr) doped barium titanate (BST) piezoelectric nanoparticles functionalized with L-arginine (BST@LA). The doping of Sr into A site of the ABO3 piezoelectric nanocrystals not only introduces oxygen vacancies into the nanoparticles and enhance the intrinsic piezoelectricity, but also narrows the semiconductor band gap and enhances charge carrier migration, all of which facilitate the sonodynamic production of superoxide anion (•O2 - ) and hydroxyl radical (•OH). In addition, the generated ROS promotes the decomposition of the surface-tethered LA, enabling the controlled release of nitric oxide (NO) gas at the tumor site, thereby achieving a combination therapeutic effect. In vivo experiments exhibit remarkable tumor suppression rate (89.5%) in 4T1 tumor mice model, demonstrating the effectiveness of this strategy. The ion doping and oxygen vacancy engineering to improve sonosensitizers, along with the synergistic combination of sonodynamic and gas therapy, provides promising avenues for improving cancer therapy.

Design and fabrication of intracellular therapeutic cargo delivery systems based on nanomaterials: current status and future perspectives

Intracellular cargo delivery, the introduction of small molecules, proteins, and nucleic acids into a specific targeted site in a biological system, is an important strategy for deciphering cell function, directing cell fate, and reprogramming cell behavior. With the advancement of nanotechnology, many researchers use nanoparticles (NPs) to break through biological barriers to achieving efficient targeted delivery in biological systems, bringing a new way to realize efficient targeted drug delivery in biological systems. With a similar size to many biomolecules, NPs possess excellent physical and chemical properties and a certain targeting ability after functional modification on the surface of NPs. Currently, intracellular cargo delivery based on NPs has emerged as an important strategy for genome editing regimens and cell therapy. Although researchers can successfully deliver NPs into biological systems, many of them are delivered very inefficiently and are not specifically targeted. Hence, the development of efficient, target-capable, and safe nanoscale drug delivery systems to deliver therapeutic substances to cells or organs is a major challenge today. In this review, on the basis of describing the research overview and classification of NPs, we focused on the current research status of intracellular cargo delivery based on NPs in biological systems, and discuss the current problems and challenges in the delivery process of NPs in biological systems.

Enhanced Bactericidal Effect of Calcinated Mg-Fe Layered Double Hydroxide Films Driven by the Fenton Reaction

Osteogenic and antibacterial abilities are the permanent pursuit of titanium (Ti)-based orthopedic implants. However, it is difficult to strike the right balance between these two properties. It has been proved that an appropriate alkaline microenvironment formed by Ti modified by magnesium-aluminum layered double hydroxides (Mg-Al LDHs) could achieve the selective killing of bacteria and promote osteogenesis. However, the existence of Al induces biosafety concerns. In this study, iron (Fe), an essential trace element in the human body, was used to substitute Al, and a calcinated Mg-Fe LDH film was constructed on Ti. The results showed that a proper local alkaline environment created by the constructed film could enhance the antibacterial and osteogenic properties of the material. In addition, the introduction of Fe promoted the Fenton reaction and could produce reactive oxygen species in the infection environment, which might further strengthen the in vivo bactericidal effect.