Feathery Tellurium-Selenium Heterostructural Nanoadjuvant for the Synergistic Treatment of Bacterial Infections.

Antibacterial nanoagents with well-controlled structures are greatly desired to address the challenges of bacterial infections. In this study, a featherlike tellurium-selenium heterostructural nanoadjuvant (TeSe HNDs) was created. TeSe HNDs produced 1O2 and had high photothermal conversion efficiency when stimulated with 808 nm near-infrared (NIR) light. To create a synergistic treatment system (TeSe-ICG) with better photothermal and photodynamic capabilities, the photosensitizer indocyanine green (ICG) was then added. With a bactericidal rate of more than 99%, the NIR-mediated TeSe-ICG demonstrated an efficient bactericidal action against both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). In addition, TeSe-ICG was also effective in treating wound infections and could effectively promote wound healing without obvious toxic side effects. In conclusion, TeSe-ICG is expected to be a good candidate for the treatment of bacterial infections.

Correction: Polydopamine-functionalized selenium nanoparticles as an efficient photoresponsive antibacterial platform.

[This corrects the article DOI: 10.1039/D2RA07737J.].

Polydopamine-functionalized selenium nanoparticles as an efficient photoresponsive antibacterial platform.

A photoresponsive therapeutic antibacterial platform was designed and constructed using polydopamine-functionalized selenium nanoparticles as a carrier loaded with indocyanine green (Se@PDA-ICG). The therapeutic platform was confirmed by characterization and the antibacterial activity of Se@PDA-ICG against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was investigated. Under 808 nm laser irradiation, the antibacterial rate of Se@PDA-ICG against E. coli and S. aureus was 100% at 125 µg mL-1. Furthermore, in a mouse wound infection model, the wound closure rate of the Se@PDA-ICG photoresponse group was 88.74% compared with 45.8% for the control group after 8 days of treatment, indicating that it could effectively kill bacteria and dramatically accelerate the wound healing process. These results suggested that Se@PDA-ICG could be a promising photo-activated antibacterial candidate material for biomedical applications.

Metal selenide nanomaterials for biomedical applications.

Metal selenide nanomaterials have received enormous attention as they possess diverse compositions, microstructures, and properties. The combination of selenium with various metallic elements gives the metal selenide nanomaterials distinctive optoelectronic and magnetic properties, such as strong near-infrared absorption, excellent imaging properties, good stability, and long in vivo circulation. This makes metal selenide nanomaterials advantageous and promising for biomedical applications. This paper summarizes the research progress in the last five years in the controlled synthesis of metal selenide nanomaterials in different dimensions and with different compositions and structures. Then we discuss how surface modification and functionalization strategies are well-suited for biomedical fields, including tumor therapy, biosensing, and antibacterial biological applications. The future trends and issues of metal selenide nanomaterials in the biomedical field are also discussed.

Antimicrobial properties of heterojunction BiSnSbO6-ZnO composites in wastewater treatment.

BiSnSbO6-ZnO composite photocatalytic material with type II heterojunction structure was synthesized by a simple solid-phase sintering method, it was characterized by XRD, UV-vis, and PT methods. The photocatalytic antibacterial experiments were carried out under LED light irradiation. The experimental results showed that the photocatalytic antibacterial properties of BiSnSbO6-ZnO composites against bacteria and fungi were significantly stronger than those of single BiSnSbO6 and ZnO. Under light conditions, the antibacterial efficiencies of 500 mg/L BiSnSbO6-ZnO composites against E. coli, S. aureus, and P. aeruginosa reached 99.63%, 100%, and 100% for 6 h, 4 h, and 4 h, respectively. The best antibacterial concentration of BiSnSbO6-ZnO composite against the eukaryotic microorganism Candida albicans was 250 mg/L, and the antibacterial efficiency reached the highest 63.8% at 6 h. Antibacterial experiments were carried out on domestic livestock and poultry wastewater, which showed that the BiSnSbO6-ZnO composite photocatalytic material has broad-spectrum antibacterial activity against bacteria, and the antibacterial effect has species differences. Through the MTT experiment, it is proved that the prepared BiSnSbO6-ZnO composite photocatalytic material has no toxicity at the experimental concentration. According to the free radical scavenging experiment and SEM observation of the morphological changes of the bacteria after light treatment, the prepared BiSnSbO6-ZnO composite photocatalytic material can generate active species OH, h+, and e- through light irradiation to achieve the purpose of sterilization, where e- play a major role, indicating that the BiSnSbO6-ZnO composite photocatalytic material has broad application prospects in the actual antibacterial field.

Inorganic nanomaterials for intelligent photothermal antibacterial applications.

Antibiotics are currently the main therapeutic agent for bacterial infections, but they have led to bacterial resistance, which has become a worldwide problem that needs to be addressed. The emergence of inorganic nanomaterials provides a new opportunity for the prevention and treatment of bacterial infection. With the continuous development of nanoscience, more and more inorganic nanomaterials have been used to treat bacterial infections. However, single inorganic nanoparticles (NPs) are often faced with problems such as large dosage, strong toxic and side effects, poor therapeutic effect and so on, so the combination of inorganic nano-materials and photothermal therapy (PTT) has become a promising treatment. PTT effectively avoids the problem of bacterial drug resistance, and can also reduce the dosage of inorganic nanomaterials to a certain extent, greatly improving the antibacterial effect. In this paper, we summarize several common synthesis methods of inorganic nanomaterials, and discuss the advantages and disadvantages of several typical inorganic nanomaterials which can be used in photothermal treatment of bacterial infection, such as precious metal-based nanomaterials, metal-based nanomaterials and carbon-based nanomaterials. In addition, we also analyze the future development trend of the remaining problems. We hope that these discussions will be helpful to the future research of near-infrared (NIR) photothermal conversion inorganic nanomaterials.

Ultrathin tellurium nanosheets for simultaneous cancer thermo-chemotherapy.

The emerging two-dimensional monoelemental materials (2D Xenes) have been commonly supposed as promising drug delivery carriers, photothermal and photodynamic therapeutic agents, biosensors, theranostics, and some other candidates for biomedical applications. Here, high-performance and bioactive ultrathin 2D Tellurium nanosheets (Te NSs) are prepared by a simple but efficient liquid-phase exfoliation approach. The as-obtained Te NSs possess a mean size of ∼90 nm and a mean thickness of ∼5.43 nm. The pegylation Te NSs (Te-PEG NSs) possess excellent biocompatibility and stability. The Te-PEG NSs could generate local hyperthermia with a remarkable photothermal conversion efficiency of about 55% under 808 nm laser irradiation. Additionally, Te-PEG NSs exhibit an extremely high loading capacity of chemo drug (∼162%) owing to their ultra-high surface area and tumor microenvironment-triggered drug release superiority. The results of in vivo experiments show that the Te-PEG NSs have higher tumor elimination efficiency via the combination of photothermal and chemotherapy, comparing to any other single therapeutic modalities. Therefore, our work not only highlights the promising potentials of tellurene as an ideal anti-cancer platform but also expands the application of 2D Te for cancer nanomedicine.

The Application of Inorganic Nanoparticles in Molecular Targeted Cancer Therapy: EGFR Targeting.

Epidermal growth factor receptor (EGFR) is an anticancer drug target for a number of cancers, such as non-small cell lung cancer. However, unsatisfying treatment effects, terrible side-effects, and development of drug resistance are current insurmountable challenges of EGFR targeting treatments for cancers. With the advancement of nanotechnology, an increasing number of inorganic nanomaterials are applied in EGFR-mediated therapy to improve those limitations and further potentiate the efficacy of molecular targeted cancer therapy. Given their facile preparation, easy modification, and biosecurity, inorganic nanoparticles (iNPs) have been extensively explored in cancer treatments to date. This review presents an overview of the application of some typical metal nanoparticles and nonmetallic nanoparticles in EGFR-targeted therapy, then discusses and summarizes the relevant advantages. Moreover, we also highlight future perspectives regarding their remaining issues. We hope these discussions inspire future research on EGFR-targeted iNPs.

Cryogenic Exfoliation of 2D Stanene Nanosheets for Cancer Theranostics.

Stanene (Sn)-based materials have been extensively applied in industrial production and daily life, but their potential biomedical application remains largely unexplored, which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials. Herein, we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional (2D) Sn nanosheets (SnNSs). The obtained SnNSs exhibited a typical sheet-like structure with an average size of ~ 100 nm and a thickness of ~ 5.1 nm. After PEGylation, the resulting PEGylated SnNSs (SnNSs@PEG) exhibited good stability, superior biocompatibility, and excellent photothermal performance, which could serve as robust photothermal agents for multi-modal imaging (fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer. Furthermore, we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs, revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal. This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics. This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.

Biomedical applications of 2D monoelemental materials formed by group VA and VIA: a concise review.

The development of two-dimensional (2D) monoelemental nanomaterials (Xenes) for biomedical applications has generated intensive interest over these years. In this paper, the biomedical applications using Xene-based 2D nanomaterials formed by group VA (e.g., BP, As, Sb, Bi) and VIA (e.g., Se, Te) are elaborated. These 2D Xene-based theranostic nanoplatforms confer some advantages over conventional nanoparticle-based systems, including better photothermal conversion, excellent electrical conductivity, and large surface area. Their versatile and remarkable features allow their implementation for bioimaging and theranostic purposes. This concise review is focused on the current developments in 2D Xenes formed by Group VA and VIA, covering the synthetic methods and various biomedical applications. Lastly, the challenges and future perspectives of 2D Xenes are provided to help us better exploit their excellent performance and use them in practice.

Light-induced degradation of rhodamine B by tellurium quantum dots.

Tellurium quantum dots (Te QDs) were prepared using bulk tellurium as the precursor. Te QDs can be a highly active photocatalyst for boosting the photocatalytic degradation of rhodamine B (RhB) under visible light irradiation. The morphology and composition of Te QDs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that in the presence of H2O2, the photocatalytic efficiency of Te QDs on RhB could achieve a good degradation effect within a very short time (30 min). The effects of initial dye concentration, pH value, light intensity, catalyst dosage and H2O2 concentration on dye degradation were successively studied. The effects of inorganic ions (NO3-, Cl-, SO42-, Ca2+, Mg2+ and Fe3+) on photocatalytic degradation were also discussed. Experimental results of free radical capture showed that OH• and O2•- played important roles in photocatalytic degradation. More importantly, Te QDs efficiency still remained above 85% after four cycles of use, indicating good stability, recyclability and utility. This work may inspire further design of other semiconductor QDs for highly efficient dye degradation.

Accurate assembly of ferrocene-functionalized {Ti22Fc4} clusters with photocatalytic amine oxidation activity.

We report here the synthesis of a ferrocene-functionalized {Ti22Fc4} cluster with a 'dimer-of-clusters' topology, which represents the largest Ti-oxo cluster (TOC) modified with organometallic groups ever reported. The exact assembly path of {Ti22Fc4} can be inferred from its two substructures, {Ti11Fc2} and {Ti5Fc}, which can also be synthesized independently through subtle changes in reaction conditions. Furthermore, we used these clusters as photocatalysts, and have studied, for the first time, the photocatalytic activity of TOCs in the oxidative coupling of amines.

Monocarboxylate-driven structural growth in Calix[n]arene-polyoxotitanate hybrid systems: utility in hydrogen production from water.

A carboxylate-driven assembly strategy has been developed for the first time to build calix[n]arene-based polyoxotitanate clusters with tuneable nuclearity and structures. Photocatalytic studies revealed that these clusters exhibit structural-dependent H2 evolution ability with a maximum rate up to 415.11 µmol h-1 g-1, which is almost the highest recorded in polyoxotitanate clusters.

Ultrathin two-dimensional polydopamine nanosheets for multiple free radical scavenging and wound healing.

Novel 2D polydopamine nanosheets were successfully prepared by using a simple but effective "bottom-up" synthesis method. The ultrathin polydopamine nanosheets exhibit excellent multiple free radical scavenging activities including DPPH˙ and ABTS˙+ free radicals, especially O2˙-. Full-thickness skin defect regeneration was accelerated by treatment with the nanosheets.

Study on the efficient removal of azo dyes by heterogeneous photo-Fenton process with 3D flower-like layered double hydroxide.

As organic dyes are the main pollutants in water pollution, seeking effective removal solutions is urgent for humans and the environment. A novel environmentally friendly three-dimensional CoFe-LDHs (3D CoFe-LDHs) catalyst was synthesized by one-step hydrothermal method. Scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectra, X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller technique as well as UV-Vis diffuse reflectance spectra were used to characterize the prepared samples. The experimental results revealed that 3D CoFe-LDHs exhibited a rapid decolorization of methyl orange and Rhodamine B by heterogeneous photo-Fenton process after reaching the adsorption equilibrium, and the final decolorization efficiency reached 91.18% and 93.56%, respectively. On the contrary, the decolorizing effect of 3D CoFe-LDHs on neutral blue was relatively weak. The initial concentrations of azo dyes, pH and H2O2 concentration affected the decolorization of dyes and the catalyst maintained excellent reusability and stability after reuse over five cycles. The quenching experiments found that •OH, •O2 - and h+ were the main active substances and reaction mechanisms were further proposed. The study suggests that the synergistic effect of photocatalysis and Fenton oxidation process significantly improved the removal of azo dyes and the synthesized catalyst had potentially promising applications for difficult-to-biodegrade organic pollutants in wastewater.

Synthesis and structure of a family of rhodium polystannide clusters [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and the first triply-fused stannide, [Rh3@Sn24]5.

Through relatively subtle changes in reaction conditions, we have been able to isolate four distinct Rh/Sn cluster compounds, [Rh@Sn10]3-, [Rh@Sn12]3-, [Rh2@Sn17]6- and [Rh3@Sn24]5-, from the reaction of K4Sn9 with [(COE)2Rh(µ-Cl)]2(COE = cyclooctene). The last of these has a hitherto unknown molecular topology, an edge-fused polyhedron containing three Rh@Sn10 subunits, and represents the largest endohedral Group 14 Zintl cluster yet to have been isolated from solution. DFT has been used to place these new species in the context of known cluster chemistry. ESI-MS experiments on the reaction mixtures reveal the ubiquitous presence of {RhSn8} fragments that may play a role in cluster growth.

Synthesis, Crystal Structures, and Photochemical Properties of a Family of Heterometallic Titanium Oxo Clusters.

The incorporation of heterometallic atoms into the structure of titanium-oxygen nanomaterials is one of the known and effective strategies to develop new high-performance photovoltaic active materials. In this study, we have synthesized three benzoic acid-stabilized heterometallic titanium oxo clusters with the different transition metals Co, Cu, and Cd, formulated as [Ti4Co2(µ2-O)2(µ3-O)2(C6H5COO)12(CH3CN)2]·2CH3CN (1), [Ti5Cu4(µ3-O)6(C6H5COO)16] (2), and [Ti12Cd5(µ2-O)(µ3-O)15(µ4-O)2(C6H5COO)22(C6H5COOH)(CH3CN)]·CH3CN·C6H5COOH (3), and then we characterized their structures. UV-vis spectroscopy analysis revealed an enhanced UV-vis-light absorption of those heterometallic clusters. The density functional theory calculations indicated that charge transfer occurs from the p orbital of O atoms to the d orbital of Ti atoms in the TiO core (O → Ti) as well as from the metal to the core in 1 and 2. We also measured the photocurrent response and photocatalytic H2 evolution, which shows enhancement in the photocurrent intensity and good H2 evolution ability because of the cooperative effect of heterometal doping in titanium oxo clusters.

Co-delivery of Cisplatin(IV) and Capecitabine as an Effective and Non-toxic Cancer Treatment.

A strategy for preparing composite micelles (CM) containing both cisplatin(IV) [CisPt(IV)] prodrug and capecitabine using a co-assembly method is described in this study. The CM are capable of an effective release of the anticancer drug cisplatin(II) [CisPt(II)] and capecitabine via acid hydrolysis once they are internalized by cancer cells. Moreover, the CM display a synergistic effect in vitro and the combination therapy in the micellar dosage form leads to reduced systemic toxicity and enhanced antitumor efficacy in vivo.