Ultra-stable tellurium-doped carbon quantum dots for cell protection and near-infrared photodynamic application

White light-driven enhanced cerium-doped carbon dots activity to combat multidrug-resistant bacterial infection

Infections caused by multidrug-resistant (MDR) bacteria are increasing and becoming an urgent global health crisis. The discovery and development of novel antibacterial agents to combat MDR are highly desirable. Here, we report the fabrication of cerium-doped carbon dots (CeCDs) with a simple hydrothermal method, which exhibit intrinsic broad efficacy against MDR bacteria including clinical isolates while maintaining low cytotoxicity and hemolytic effects. Importantly, the antibacterial activity of CeCDs is dramatically improved owing to the generation of reactive oxygen species (ROS) upon white light irradiation. Comprehensive analyses revealed that the CeCDs can penetrate the bacterial wall, disrupt the cell membrane, and prevent the biofilm formation, possibly hindering the bacterial resistance development. And the interaction of CeCDs with lipopolysaccharide (LPS) may contribute to the higher activity against Gram-negative bacteria strains. The treatment of CeCDs in a murine skin infection model can significantly reduce the number of bacteria on infected sites and accelerate wound healing by irradiation with light. Overall, CeCDs show great promise as low-cost and efficient antibacterial agents for chronic wounds and may be served as a powerful weapon to fight against the growing threat of MDR bacterial infection.

Recent theranostic applications of hydrogen peroxide-responsive nanomaterials for multiple diseases

It is well established that hydrogen peroxide (H2O2) is associated with the initiation and progression of many diseases. With the rapid development of nanotechnology, the diagnosis and treatment of those diseases could be realized through a variety of H2O2-responsive nanomaterials. In order to broaden the application prospects of H2O2-responsive nanomaterials and promote their development, understanding and summarizing the design and application fields of such materials has attracted much attention. This review provides a comprehensive summary of the types of H2O2-responsive nanomaterials including organic, inorganic and organic-inorganic hybrids in recent years, and focused on their specific design and applications. Based on the type of disease, such as tumors, bacteria, dental diseases, inflammation, cardiovascular diseases, bone injury and so on, key examples for above disease imaging diagnosis and therapy strategies are introduced. In addition, current challenges and the outlook of H2O2-responsive nanomaterials are also discussed. This review aims to stimulate the potential of H2O2-responsive nanomaterials and provide new application ideas for various functional nanomaterials related to H2O2.

Recent Developments in Heteroatom/Metal-Doped Carbon Dot-Based Image-Guided Photodynamic Therapy for Cancer

Carbon nanodots (CNDs) are advanced nanomaterials with a size of 2–10 nm and are considered zero-dimensional carbonaceous materials. CNDs have received great attention in the area of cancer theranostics. The majority of review articles have shown the improvement of CNDs for use in cancer therapy and bioimaging applications. However, there is a minimal number of consolidated studies on the currently developed doped CNDs that are used in various ways in cancer therapies. Hence, in this review, we discuss the current developments in different types of heteroatom elements/metal ion-doped CNDs along with their preparations, physicochemical and biological properties, multimodal-imaging, and emerging applications in image-guided photodynamic therapies for cancer.

Carbon dots nanozyme for anti-inflammatory therapy via scavenging intracellular reactive oxygen species

Developing an efficient antioxidant for anti-inflammatory therapy via scavenging reactive oxygen species (ROS) remains a great challenge owing to the insufficient activity and stability of traditional antioxidants. Herein, we explored and simply synthesized a biocompatible carbon dots (CDs) nanozyme with excellent scavenging activity of ROS for anti-inflammatory therapy. As expected, CDs nanozyme effectively eliminate many kinds of free radicals including •OH, O2•−, and ABTS+•. Benefiting from multienzyme activities against ROS, CDs nanozyme can decrease the levels of pro-inflammatory cytokines, resulting in good anti-inflammatory effect. Taken together, this study not only sheds light on design of bioactive antioxidants but also broadens the biomedical application of CDs in the treatment of inflammation.

Ahmed S. Controlled compositions of tellurium/vanadium co-doped into hydroxyapatite/-polycaprolactone for wound healing applications

Hydroxyapatite (HAP) was co-doped with tellurium and vanadium ions via the co-precipitation method. Pure HAP nanoparticles were embedded through polymeric materials, such as polycaprolactone (PCL) to improve and upgrade its...

Synergistic bioreduction of Te(Ⅳ) using S(0) as electron donor

This study for the first time bioreduced Te(IV) using elemental sulfur (S⁰) as electron donor, achieving 91.17%±0.8% conversion with reaction rate of 0.77 ± 0.01 mg/L/h in a 60-day cultivation. Characterization using X-ray photoelectron spectroscopy and X-ray power diffraction analyses confirmed that most removed Te(IV) was reduced to elemental Te(0) deposits, while ion chromatogram analysis showed that most S(0) was oxidized to sulfite and sulfate. High-throughput 16S rRNA gene sequencing indicated that the Te(IV) reduction coupled to S(0) oxidation was mediated synergistically by a microbial consortia with S(0)-oxidizing bacteria (Thiobacillus) to generate volatile fatty acids as metabolites and Te(IV)-reducing bacteria (Rhodobacter) to consume formed volatile fatty acids to yield Te(0). The synergy between these two strains presents a novel bioremediation consortium to efficiently treat Te(IV) wastewaters.

Quantum dots in cell imaging and their safety issues

When quantum dots are used as fluorescent probes or drug tracers for in vivo imaging, the quantum dots in the blood will come into direct contact with vascular endothelial cells. Thus, it is necessary to study whether quantum dots can affect endothelial function after being injected into blood vessels as imaging agents. In recent years, there have been numerous studies on the toxicity of quantum dots. Herein, we focused on five types of quantum dots (Cd-containing quantum dots, CuInS2 quantum dots, black phosphorus quantum dots, MXene quantum dots, and carbon-based quantum dots) for cell imaging and their toxicity in vivo and in vitro. Although current research on the toxicity of quantum dots has not reached a consistent conclusion, it can guide the next step in evaluating their cytotoxicity.