An Organometallic Strategy for Assembling Atomically Precise Hybrid Nanomaterials

For decades, chemists have strived to mimic the intricate design and diverse functions of naturally occurring systems through the bioinspired synthesis of programmable inorganic nanomaterials. The development of thiol-capped gold nanoparticles (AuNPs) has driven advancement in this area; however, although versatile and readily accessible, hybrid AuNPs are rarely atomically precise, which limits control over their surface topology and therefore the study of complex structure-function relationships. Here, we present a bottom-up approach to the systematic assembly of atomically precise hybrid nanoclusters employing a strategy that mimics the synthetic ease with which thiol-capped AuNPs are normally constructed, while producing welldefined covalent nanoscale assemblies with diverse surface topologies. For the first time, using a structurally characterized cluster-based organometallic building block, we demonstrate the systematic synthesis of nanoclusters with multivalent binding capabilities to complex protein targets.

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Synthesis of a silymarin-gold nanoparticle conjugate and analysis of its liver-protecting activity

Current Pharmaceutical Biotechnology ◽

10.2174/1389201022666210101163734 ◽

2021 ◽

Vol 22 ◽

Author(s):

Sergey Staroverov ◽

Sergey Kozlov ◽

Alexander Fomin ◽

Konstantib Gabalov ◽

Alexey Volkov ◽

...

Keyword(s):

Gold Nanoparticles ◽

Liver Disease ◽

Carbon Tetrachloride ◽

Glutathione Depletion ◽

Laboratory Animals ◽

Experimental Hepatitis ◽

Acute Liver Disease ◽

The Mean ◽

Extent Of Damage ◽

First Time

Background: The liver disease problem prompts investigators to search for new methods of liver treatment. Introduction: Silymarin (Sil) protects the liver by reducing the concentration of free radicals and the extent of damage to the cell membranes. A particularly interesting method to increase the bioavailability of Sil is to use synthesized gold nanoparticles (AuNPs) as reagents. The study considered whether it was possible to use the silymarin-AuNP conjugate as a potential liver-protecting drug. Method: AuNPs were conjugated to Sil and examine the liver-protecting activity of the conjugate. Experimental hepatitis and hepatocyte cytolysis after carbon tetrachloride actionwere used as a model system, and the experiments were conducted on laboratory animals. Result: For the first time, silymarin was conjugated to colloidal gold nanoparticles (AuNPs). Electron microscopy showed that the resultant preparations were monodisperse and that the mean conjugate diameter was 18–30 nm ± 0.5 nm (mean diameter of the native nanoparticles, 15 ± 0.5 nm). In experimental hepatitis in mice, conjugate administration interfered with glutathione depletion in hepatocytes in response to carbon tetrachloride was conducive to an increase in energy metabolism, and stimulated the monocyte–macrophage function of the liver. The results were confirmed by the high respiratory activity of the hepatocytes in cell culture. Conclusion: We conclude that the silymarin-AuNP conjugate holds promise as a liver-protecting agent in acute liver disease caused by carbon tetrachloride poisoning.

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Phosphatidylserine-Gold Nanoparticles (PS-AuNP) Induce Prostate and Breast Cancer Cell Apoptosis

Pharmaceutics ◽

10.3390/pharmaceutics13071094 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1094

Author(s):

Allan Radaic ◽

Nam E. Joo ◽

Soo-Hwan Jeong ◽

Seong-II Yoo ◽

Nicholas Kotov ◽

...

Keyword(s):

Breast Cancer ◽

Gold Nanoparticles ◽

Biomedical Applications ◽

Therapeutic Potential ◽

Control Treatment ◽

Track Record ◽

Males And Females ◽

Breast And Prostate Cancer ◽

First Time

Prostate and breast cancer are the current leading causes of new cancer cases in males and females, respectively. Phosphatidylserine (PS) is an essential lipid that mediates macrophage efferocytosis and is dysregulated in tumors. Therefore, developing therapies that selectively restore PS may be a potential therapeutic approach for carcinogenesis. Among the nanomedicine strategies for delivering PS, biocompatible gold nanoparticles (AuNPs) have an extensive track record in biomedical applications. In this study, we synthesized biomimetic phosphatidylserine-caped gold nanoparticles (PS-AuNPs) and tested their anticancer potential in breast and prostate cancer cells in vitro. We found that both cell lines exhibited changes in cell morphology indicative of apoptosis. After evaluating for histone-associated DNA fragments, a hallmark of apoptosis, we found significant increases in DNA fragmentation upon PS-AuNP treatment compared to the control treatment. These findings demonstrate the use of phosphatidylserine coupled with gold nanoparticles as a potential treatment for prostate and breast cancer. To the best of our knowledge, this is the first time that a phosphatidylserine-capped AuNP has been examined for its therapeutic potential in cancer therapy.

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Facile Green, Room-Temperature Synthesis of Gold Nanoparticles Using Combretum erythrophyllum Leaf Extract: Antibacterial and Cell Viability Studies against Normal and Cancerous Cells

Antibiotics ◽

10.3390/antibiotics10080893 ◽

2021 ◽

Vol 10 (8) ◽

pp. 893

Author(s):

Olufunto T. Fanoro ◽

Sundararajan Parani ◽

Rodney Maluleke ◽

Thabang C. Lebepe ◽

Jose R. Varghese ◽

...

Keyword(s):

Gold Nanoparticles ◽

Cell Viability ◽

Leaf Extract ◽

Room Temperature ◽

Klebsiella Oxytoca ◽

Cost Effective ◽

Average Diameter ◽

Antibacterial Activities ◽

Inhibition Concentration ◽

First Time

We herein report a facile, green, cost-effective, plant-mediated synthesis of gold nanoparticles (AuNPs) for the first time using Combretum erythrophyllum (CE) plant leaves. The synthesis was conducted at room temperature using CE leaf extract serving as a reducing and capping agent. The as-synthesized AuNPs were found to be crystalline, well dispersed, and spherical in shape with an average diameter of 13.20 nm and an excellent stability of over 60 days. The AuNPs showed broad-spectrum antibacterial activities against both pathogenic Gram-positive (Staphylococcus epidermidis (ATCC14990), Staphylococcus aureus (ATCC 25923), Mycobacterium smegmatis (MC 215)) and Gram-negative bacteria (Proteus mirabilis (ATCC 7002), Escherichia coli (ATCC 25922), Klebsiella pneumoniae (ATCC 13822), Klebsiella oxytoca (ATCC 8724)), with a minimum inhibition concentration of 62.5 µg/mL. In addition, the as-synthesized AuNPs were highly stable with exceptional cell viability towards normal cells (BHK- 21) and cancerous cancer cell lines (cervical and lung cancer).

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Gold Nanoparticles: Can They Be the Next Magic Bullet for Multidrug-Resistant Bacteria?

Nanomaterials ◽

10.3390/nano11020312 ◽

2021 ◽

Vol 11 (2) ◽

pp. 312

Author(s):

Mohammad Okkeh ◽

Nora Bloise ◽

Elisa Restivo ◽

Lorenzo De Vita ◽

Piersandro Pallavicini ◽

...

Keyword(s):

Gold Nanoparticles ◽

Bacterial Resistance ◽

Multidrug Resistant ◽

World Health ◽

Resistant Bacteria ◽

Magic Bullet ◽

Global Challenge ◽

Gold Silver ◽

Inorganic Nanomaterials ◽

Health Organization

In 2017 the World Health Organization (WHO) announced a list of the 12 multidrug-resistant (MDR) families of bacteria that pose the greatest threat to human health, and recommended that new measures should be taken to promote the development of new therapies against these superbugs. Few antibiotics have been developed in the last two decades. Part of this slow progression can be attributed to the surge in the resistance acquired by bacteria, which is holding back pharma companies from taking the risk to invest in new antibiotic entities. With limited antibiotic options and an escalating bacterial resistance there is an urgent need to explore alternative ways of meeting this global challenge. The field of medical nanotechnology has emerged as an innovative and a powerful tool for treating some of the most complicated health conditions. Different inorganic nanomaterials including gold, silver, and others have showed potential antibacterial efficacies. Interestingly, gold nanoparticles (AuNPs) have gained specific attention, due to their biocompatibility, ease of surface functionalization, and their optical properties. In this review, we will focus on the latest research, done in the field of antibacterial gold nanoparticles; by discussing the mechanisms of action, antibacterial efficacies, and future implementations of these innovative antibacterial systems.

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Enhancement of efficiency in graphene/porous silicon solar cells by co-doping graphene with gold nanoparticles and bis(trifluoromethanesulfonyl)-amide

Journal of Materials Chemistry C ◽

10.1039/c7tc02686b ◽

2017 ◽

Vol 5 (35) ◽

pp. 9005-9011 ◽

Cited By ~ 18

Author(s):

Ju Hwan Kim ◽

Dong Hee Shin ◽

Ha Seung Lee ◽

Chan Wook Jang ◽

Jong Min Kim ◽

...

Keyword(s):

Gold Nanoparticles ◽

Solar Cells ◽

Porous Silicon ◽

Au Nanoparticles ◽

Silicon Solar Cells ◽

Porous Si ◽

Co Doping ◽

Si Solar Cells ◽

First Time

The co-doping of graphene with Au nanoparticles and bis(trifluoromethanesulfonyl)-amide is employed for the first time to enhance the performance of graphene/porous Si solar cells.

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The Langmuir–Hinshelwood approach for kinetic evaluation of cucurbit[7]uril-capped gold nanoparticles in the reduction of the antimicrobial nitrofurantoin

Physical Chemistry Chemical Physics ◽

10.1039/c7cp03534a ◽

2017 ◽

Vol 19 (29) ◽

pp. 18913-18923 ◽

Cited By ~ 7

Author(s):

E. Blanco ◽

P. Atienzar ◽

P. Hernández ◽

C. Quintana

Keyword(s):

Gold Nanoparticles ◽

Nitro Compound ◽

Kinetic Constants ◽

Kinetic Evaluation ◽

P Adsorption ◽

First Time

Adsorption and surface kinetic constants of nitrofurantoin are calculated and compared with those of another nitro compound for the first time.

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The kinetoplastid-specific phosphatase KPP1 attenuates PLK activity to facilitate flagellum inheritance in Trypanosoma brucei

Science Signaling ◽

10.1126/scisignal.abc6435 ◽

2021 ◽

Vol 14 (669) ◽

pp. eabc6435

Author(s):

Tai An ◽

Huiqing Hu ◽

Ziyin Li

Keyword(s):

Cell Cycle ◽

Trypanosoma Brucei ◽

Protein Phosphatase ◽

Catalytic Domain ◽

Complex Structure ◽

Cell Communication ◽

Specific Protein ◽

Activation Loop ◽

Human Parasite ◽

Complex Protein

Trypanosoma brucei, an important human parasite, has a flagellum that controls cell motility, morphogenesis, proliferation, and cell-cell communication. Inheritance of the newly assembled flagellum during the cell cycle requires the Polo-like kinase homolog TbPLK and the kinetoplastid-specific protein phosphatase KPP1, although whether TbPLK acts on KPP1 or vice versa has been unclear. Here, we showed that dephosphorylation of TbPLK on Thr125 by KPP1 maintained low TbPLK activity in the flagellum-associated hook complex structure, thereby ensuring proper flagellum positioning and attachment. This dephosphorylation event required the recognition of phosphorylated Thr198 in the activation loop of TbPLK by the N-terminal Plus3 domain of KPP1 and the dephosphorylation of phosphorylated Thr125 in TbPLK by the C-terminal catalytic domain of KPP1. Dephosphorylation of TbPLK by KPP1 prevented hyperphosphorylation of the hook complex protein TbCentrin2, thereby allowing timely dephosphorylation of phosphorylated TbCentrin2 for hook complex duplication and flagellum positioning and attachment. Thus, KPP1 attenuates TbPLK activity by dephosphorylating TbPLK to facilitate flagellum inheritance.

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Microbialite-like structures in Cladophora sp. (Ulvophyceae) mats from a subtropical Andean basin: ecological implications

Revista de Biología Tropical ◽

10.15517/rbt.v67i1.31542 ◽

2019 ◽

Vol 67 (1) ◽

Author(s):

Hugo R. Fernández ◽

Ana Lucia Gonzalez Achem ◽

Marcela Correa ◽

Virginia H. Albarracín

Keyword(s):

Organic Pollution ◽

Biological Factors ◽

X Ray Diffraction ◽

Calcite Precipitation ◽

Annual Cycles ◽

X Ray ◽

Naturally Occurring ◽

Ecological Implications ◽

First Time ◽

Solubility Equilibrium

The solubility equilibrium of calcite is influenced by physicochemical, climatic and biological factors. Annual cycles of exceptionally prolonged drought, in conjunction with naturally occurring diffuse organic pollution, generate the unique conditions for the precipitation of lithified carbonate structures (microbialites). The aim of this article is to analyze the possible implications of calcite precipitation produced in mats of Cladophora sp. in an Andean subtropical basin, considering it is the first time this phenomenon is described for the region. We collected samples from selected sites at the Lules River Basin, in four sampling dates between the years 2003 and 2004, within a monitoring work of 15 years. Samples were analyzed using an electron microscope and X-ray diffraction analysis. We found that Gomphonema sp. attached to Cladophora sp. contributes to precipitation of calcite and formation of microbialite like structures, in the studied area. This work presents an initial discussion of the discovery of microbialites-like structures attached to Cladophora sp. mats in a subtropical Andean stream and the environmental conditions that lead to their production, as well as the possible ecological implications of these microbialites.

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COMPLEXITY-BASED ANALYSIS OF THE ALTERATIONS IN THE STRUCTURE OF CORONAVIRUSES

Fractals ◽

10.1142/s0218348x21501231 ◽

2021 ◽

Vol 29 (02) ◽

pp. 2150123

Author(s):

HAMIDREZA NAMAZI ◽

ALI SELAMAT ◽

ONDREJ KREJCAR

Keyword(s):

Hurst Exponent ◽

Complex Structure ◽

Approximate Entropy ◽

Sample Entropy ◽

Long Term Memory ◽

Complex Structures ◽

Term Memory ◽

The World ◽

First Time

The coronavirus has influenced the lives of many people since its identification in 1960. In general, there are seven types of coronavirus. Although some types of this virus, including 229E, NL63, OC43, and HKU1, cause mild to moderate illness, SARS-CoV, MERS-CoV, and SARS-CoV-2 have shown to have severer effects on the human body. Specifically, the recent known type of coronavirus, SARS-CoV-2, has affected the lives of many people around the world since late 2019 with the disease named COVID-19. In this paper, for the first time, we investigated the variations among the complex structures of coronaviruses. We employed the fractal dimension, approximate entropy, and sample entropy as the measures of complexity. Based on the obtained results, SARS-CoV-2 has a significantly different complex structure than SARS-CoV and MERS-CoV. To study the high mutation rate of SARS-CoV-2, we also analyzed the long-term memory of genome walks for different coronaviruses using the Hurst exponent. The results demonstrated that the SARS-CoV-2 shows the lowest memory in its genome walk, explaining the errors in copying the sequences along the genome that results in the virus mutation.

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