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Biomedical Materials (Bristol, England) Mar 2021With a rapid advancement of nanotechnology and the close integration of disciplines, research on nanozymes (nanomaterials with enzyme-like activities), is becoming an... (Review)
Review
With a rapid advancement of nanotechnology and the close integration of disciplines, research on nanozymes (nanomaterials with enzyme-like activities), is becoming an expeditiously developing field. In recent years, platinum group element (PGE)-based (Pt, Pd, Ru, Rh, Ir, and Os) nanozymes developed successively, have not only promoted the research of nanozymes but also expanded the biomedical applications of nanomaterials. Generally speaking, PGE-based nanozymes process high catalytic efficiency, specific surface area, stability, and other physical/chemical properties, which benefit for their applications in biosensing, biological medicine, biomedical imaging, and environmental protection. This paper will introduce the research progress of PGE-based nanozymes including their synthesis, characterization, enzyme-like activities, stability, biocompatibility, toxicity, and applications for biological detection and clinical relevance. Our emphasis is put on unfolding the roles of PGE-based nanozymes in biomedical applications and how they overcome the limitations. Last but not least, trends and future perspectives of PGE-based nanozymes in biomedical applications are also provided.
Topics: Catalysis; Nanostructures; Nanotechnology; Platinum
PubMed: 33171457
DOI: 10.1088/1748-605X/abc904 -
Inorganic Chemistry Dec 2021Half-sandwich Os-arene complexes exhibit promising anticancer activity, but their photochemistry has hardly been explored. To exploit the photocytotoxicity and...
Half-sandwich Os-arene complexes exhibit promising anticancer activity, but their photochemistry has hardly been explored. To exploit the photocytotoxicity and photochemistry of Os-arenes, -chelated complexes [Os(η--cymene)(Curc)Cl] (, Curc = curcumin) and [Os(η-biphenyl)(Curc)Cl] (), and -chelated complexes [Os(η-biphenyl)(dpq)I]PF (, dpq = pyrazino[2,3-][1,10]phenanthroline) and [Os(η-biphenyl)(bpy)I]PF (, bpy = 2,2'-bipyridine), have been investigated. The Os-arene curcumin complexes showed remarkable photocytotoxicity toward a range of cancer cell lines (blue light IC: 2.6-5.8 μM, photocytotoxicity index PI = 23-34), especially toward cisplatin-resistant cancer cells, but were nontoxic to normal cells. They localized mainly in mitochondria in the dark but translocated to the nucleus upon photoirradiation, generating DNA and mitochondrial damage, which might contribute toward overcoming cisplatin resistance. Mitochondrial damage, apoptosis, ROS generation, DNA damage, angiogenesis inhibition, and colony formation were observed when A549 lung cancer cells were treated with . The photochemistry of these Os-arene complexes was investigated by a combination of NMR, HPLC-MS, high energy resolution fluorescence detected (HERFD), X-ray adsorption near edge structure (XANES) spectroscopy, total fluorescence yield (TFY) XANES spectra, and theoretical computation. Selective photodissociation of the arene ligand and oxidation of Os(II) to Os(III) occurred under blue light or UVA excitation. This new approach to the design of novel Os-arene complexes as phototherapeutic agents suggests that the novel curcumin complex , in particular, is a potential candidate for further development as a photosensitizer for anticancer photoactivated chemotherapy (PACT).
Topics: A549 Cells; Antineoplastic Agents; Apoptosis; Calixarenes; Cell Proliferation; Cell Survival; Coordination Complexes; DNA Damage; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Osmium; Photochemical Processes
PubMed: 34503331
DOI: 10.1021/acs.inorgchem.1c00241 -
Chemical Communications (Cambridge,... Feb 2022We report a new osmium(VI) nitrido complex bearing a nonplanar tetradentate ligand with potent anticancer activity. This complex causes mitochondrial damage, which...
We report a new osmium(VI) nitrido complex bearing a nonplanar tetradentate ligand with potent anticancer activity. This complex causes mitochondrial damage, which induces liver cancer cell death oncosis and apoptosis. This is the first osmium-based anticancer candidate that induces oncosis.
Topics: Antineoplastic Agents; Apoptosis; Cell Proliferation; Coordination Complexes; Drug Screening Assays, Antitumor; Hep G2 Cells; Humans; Mitochondria; Molecular Structure; Nitriles; Osmium
PubMed: 35024704
DOI: 10.1039/d1cc05148b -
Journal of Inorganic Biochemistry Sep 2022Being identified with less toxic and generally showing selective effects for solid tumor metastases, ruthenium and osmium compounds are promising drug candidates for...
Being identified with less toxic and generally showing selective effects for solid tumor metastases, ruthenium and osmium compounds are promising drug candidates for clinical uses. Human serum proteins, such as albumin and transferrin, play vital roles in the transportation and accumulation of ruthenium and osmium agents into target tissues. However, the molecular mechanism of how transferrin transport ruthenium and their osmium analogues at atomic level remains obscure. In this study, we uncovered that the cellular uptake of Os or Ru are not competed by Fe. To unveil the molecular mechanism behind the phenomena, we report the first crystal structures of human serum transferrin (hTF) in complex with ruthenium and osmium compounds bound to the non-conserved residues on the surface of hTF without altering its overall conformation. As for Ru and Os, these binding sites by descending affinity are: His14/His289, His349-350 ~ His578/Arg581. Ruthenium drugs and their osmium analogues preferentially bind to His14/His289 with bipyridine or imidazole ligands leaving. These binding sites on hTF surface are also available in human lactoferrin and some transferrin family member of other species. The presence of these binding sites makes the cellular uptake of Ru and Os less affected by Fe, compare to Zr or Hf. Collectively, these findings are critical for our understanding of the role of serum transferrin in cellular delivery of ruthenium and osmium anticancer agents.
Topics: Binding Sites; Humans; Models, Molecular; Osmium; Osmium Compounds; Ruthenium; Transferrin
PubMed: 35690040
DOI: 10.1016/j.jinorgbio.2022.111885 -
Basic & Clinical Pharmacology &... Nov 2020Osmium tetroxide is a strong oxidizing agent used in electron microscopy. Eye exposure may cause severe burns, and after inhalation or ingestion damage to the...
Osmium tetroxide is a strong oxidizing agent used in electron microscopy. Eye exposure may cause severe burns, and after inhalation or ingestion damage to the respiratory or gastrointestinal tract occurs. Exposure to osmium and its compounds is extremely rare. We present a case of a 32-year-old female stained by 9 mL of 2% osmium tetroxide in acetone during an accident in the laboratory, with rare dermal and ocular findings. Due to lack of data in toxicological databases and the absence of antidote, the therapy was symptomatic. Osmium was detected in serum 19 hours later (0.22 μg/L) and in urine during the 15-hour collection (three samples-7.05, 1.65 and 8.45 μg/L). In blood serum on admission, after 1 and 2 days after exposure, the levels of iron (28.2, 39.8 and 50.5 μmol/L; reference range 5.8-34.5 μmol/L) and transferrin receptor/ferritine were elevated. To our knowledge, this is the first paper documenting a significant absorption from the skin and potentially from the eye conjunctiva, based on serum and urine analysis. The relationship between increased iron in blood and exposure has not been described yet, and the mechanism remains unknown. The patient is being followed up for the unknown long-term effects.
Topics: Adult; Eye; Female; Humans; Osmium Tetroxide; Skin
PubMed: 32524772
DOI: 10.1111/bcpt.13450 -
Frontiers in Cell and Developmental... 2022Volume electron microscopy, a powerful approach to generate large three-dimensional cell and tissue volumes at electron microscopy resolutions, is rapidly becoming a...
Volume electron microscopy, a powerful approach to generate large three-dimensional cell and tissue volumes at electron microscopy resolutions, is rapidly becoming a routine tool for understanding fundamental and applied biological questions. One of the enabling factors for its adoption has been the development of conventional fixation protocols with improved heavy metal staining. However, freeze-substitution with organic solvent-based fixation and staining has not realized the same level of benefit. Here, we report a straightforward approach including osmium tetroxide, acetone and up to 3% water substitution fluid (compatible with traditional or fast freeze-substitution protocols), warm-up and transition from organic solvent to aqueous 2% osmium tetroxide. Once fully hydrated, samples were processed in aqueous based potassium ferrocyanide, thiocarbohydrazide, osmium tetroxide, uranyl acetate and lead acetate before resin infiltration and polymerization. We observed a consistent and substantial increase in heavy metal staining across diverse and difficult-to-fix test organisms and tissue types, including plant tissues (), nematode () and yeast (). Our approach opens new possibilities to combine the benefits of cryo-preservation with enhanced contrast for volume electron microscopy in diverse organisms.
PubMed: 36003147
DOI: 10.3389/fcell.2022.933376 -
Nature Chemistry Jul 2022The σ-alkane complexes of transition metals, which contain an essentially intact alkane molecule weakly bound to the metal, have been well established as crucial...
The σ-alkane complexes of transition metals, which contain an essentially intact alkane molecule weakly bound to the metal, have been well established as crucial intermediates in the activation of the strong C-H σ-bonds found in alkanes. Methane, the simplest alkane, binds even more weakly than larger alkanes. Here we report an example of a long-lived methane complex formed by directly binding methane as an incoming ligand to a reactive organometallic complex. Photo-ejection of carbon monoxide from a cationic osmium-carbonyl complex dissolved in an inert hydrofluorocarbon solvent saturated with methane at -90 °C affords an osmium(II) complex, [η-CpOs(CO)(CH)], containing methane bound to the metal centre. Nuclear magnetic resonance (NMR) spectroscopy confirms the identity of the σ-methane complex and shows that the four protons of the metal-bound methane are in rapid exchange with each other. The methane ligand has a characteristically shielded H NMR resonance (δ -2.16), and the highly shielded carbon resonance (δ -56.3) shows coupling to the four attached protons (J = 127 Hz). The methane complex has an effective half-life of about 13 hours at -90 °C.
Topics: Alkanes; Ligands; Metals; Methane; Osmium; Protons
PubMed: 35469008
DOI: 10.1038/s41557-022-00929-w -
BioRxiv : the Preprint Server For... Sep 2023Mapping the complete synaptic connectivity of a mammalian brain would be transformative, revealing the pathways underlying perception, behavior, and memory. Serial...
Mapping the complete synaptic connectivity of a mammalian brain would be transformative, revealing the pathways underlying perception, behavior, and memory. Serial section electron microscopy, via membrane staining using osmium tetroxide, is ideal for visualizing cells and synaptic connections but, in whole brain samples, faces significant challenges related to chemical treatment and volume changes. These issues can adversely affect both the ultrastructural quality and macroscopic tissue integrity. By leveraging time-lapse X-ray imaging and brain proxies, we have developed a 12-step protocol, ODeCO, that effectively infiltrates osmium throughout an entire mouse brain while preserving ultrastructure without any cracks or fragmentation, a necessary prerequisite for constructing the first comprehensive mouse brain connectome.
PubMed: 37808722
DOI: 10.1101/2023.09.26.558265 -
Clinical Toxicology (Philadelphia, Pa.) Nov 2023Osmium tetroxide is a strong oxidizing agent. After dermal exposure to osmium tetroxide, skin discoloration and red papules can occur. We describe a patient with skin...
INTRODUCTION
Osmium tetroxide is a strong oxidizing agent. After dermal exposure to osmium tetroxide, skin discoloration and red papules can occur. We describe a patient with skin discoloration due to osmium tetroxide.
CASE SUMMARY
A 25-year-old postgraduate student unintentionally exposed his hand to osmium tetroxide while working in a laboratory setting. After immediate washing, he sought medical care due to left middle finger discoloration. He reported no discomfort in the affected area. Thorough water rinsing was continued, and corticosteroid ointment was applied.
IMAGES
Our patient developed dark brown pigmentation on the ventral side of the left middle finger. The pigmentation disappeared one week later.
CONCLUSION
Osmium tetroxide may induce dark brown skin discoloration.
Topics: Adult; Humans; Male; Osmium Tetroxide; Skin Diseases
PubMed: 37987740
DOI: 10.1080/15563650.2023.2281253 -
Methods in Cell Biology 2023Volume electron microscopy techniques play an important role in plant research from understanding organelles and unicellular forms to developmental studies,...
Volume electron microscopy techniques play an important role in plant research from understanding organelles and unicellular forms to developmental studies, environmental effects and microbial interactions with large plant structures, to name a few. Due to large air voids central vacuole, cell wall and waxy cuticle, many plant tissues pose challenges when trying to achieve high quality morphology, metal staining and adequate conductivity for high-resolution volume EM studies. Here, we applied a robust conventional chemical fixation strategy to address the special challenges of plant samples and suitable for, but not limited to, serial block-face and focused ion beam scanning electron microscopy. The chemistry of this protocol was modified from an approach developed for improved and uniform staining of large brain volumes. Briefly, primary fixation was in paraformaldehyde and glutaraldehyde with malachite green followed by secondary fixation with osmium tetroxide, potassium ferrocyanide, thiocarbohydrazide, osmium tetroxide and finally uranyl acetate and lead aspartate staining. Samples were then dehydrated in acetone with a propylene oxide transition and embedded in a hard formulation Quetol 651 resin. The samples were trimmed and mounted with silver epoxy, metal coated and imaged via serial block-face scanning electron microscopy and focal charge compensation for charge suppression. High-contrast plant tobacco and duckweed leaf cellular structures were readily visible including mitochondria, Golgi, endoplasmic reticulum and nuclear envelope membranes, as well as prominent chloroplast thylakoid membranes and individual lamella in grana stacks. This sample preparation protocol serves as a reliable starting point for routine plant volume electron microscopy.
Topics: Volume Electron Microscopy; Osmium Tetroxide; Staining and Labeling; Glutaral; Microscopy, Electron, Scanning
PubMed: 37451777
DOI: 10.1016/bs.mcb.2023.04.008