Hongyan Li

Bio: Hongyan Li is an academic researcher from University of Edinburgh. The author has contributed to research in topics: Transferrin & Metal ions in aqueous solution. The author has an hindex of 14, co-authored 17 publications receiving 1437 citations. Previous affiliations of Hongyan Li include Hong Kong Polytechnic University & Birkbeck, University of London.

The First Specific TiIV -Protein Complex: Potential Relevance to Anticancer Activity of Titanocenes.

Abstract: The transfer of titanium ions from titanium citrate and titanocene dichloride to the blood plasma protein transferrin was proven unequivocally by UV/Vis and NMR spectroscopy. The results may provide insight intoan important step in the mechanism of action of titanium anticancer drugs.

Elucidating the Mechanism of Cellular Uptake and Removal of Protein-Coated Gold Nanoparticles of Different Sizes and Shapes

Abstract: We investigated the mechanism by which transferrin-coated gold nanoparticles (Au NP) of different sizes and shapes entered mammalian cells. We determined that transferrin-coated Au NP entered the cells via clathrin-mediated endocytosis pathway. The NPs exocytosed out of the cells in a linear relationship to size. This was different than the relationship between uptake and size. Furthermore, we developed a mathematical equation to predict the relationship of size versus exocytosis for different cell lines. These studies will provide guidelines for developing NPs for imaging and drug delivery applications, which will require "controlling" NP accumulation rate. These studies will also have implications in determining nanotoxicity.

Toxic effects of metals

Abstract: Essentiality Toxicity Carcinogenicity Lead(Pb) Exposure Toxicokinetics Toxicity Neurologic, Neurobehavioral, and Developmental Effects in Children Mechanisms of Effects on the Developing Nervous System Peripheral Neuropathy Hematologic Effects Renal Toxicity Lead and Gout Effects on Cardiovascular System Immunotoxicity Bone Effects Reproductive Effects Birth Outcomes Carcinogenicity Other Effects Dose Response Treatment Organic Lead Compounds Mercury (Hg) Exposure Disposition and Toxicokinetics Metabolic Transformation Cellular Metabolism Toxicology Biological Indicators Treatment Nickel (Ni) Exposure Toxicokinetics Essentiality Toxicity Nickel Carbonyl Poisoning Dermatitis Indicators of Nickel Toxicity

Organometallic Anticancer Compounds

Abstract: The quest for alternative drugs to the well-known cisplatin and its derivatives, which are still used in more than 50% of the treatment regimes for patients suffering from cancer, is highly needed.1,2 Despite their tremendous success, these platinum compounds suffer from two main disadvantages: they are inefficient against platinum-resistant tumors, and they have severe side effects such as nephrotoxicity. The latter drawback is the consequence of the fact that the ultimate target of these drugs is ubiquitous: It is generally accepted that Pt anticancer drugs target DNA, which is present in all cells.3,4 Furthermore, as a consequence of its particular chemical structure, cisplatin in particular offers little possibility for rational improvements to increase its tumor specificity and thereby reduce undesired side effects. In this context, organometallic compounds, which are defined as metal complexes containing at least one direct, covalent metal−carbon bond, have recently been found to be promising anticancer drug candidates. Organometallics have a great structural variety (ranging from linear to octahedral and even beyond), have far more diverse stereochemistry than organic compounds (for an octahedral complex with six different ligands, 30 stereoisomers exist!), and by rational ligand design, provide control over key kinetic properties (such as hydrolysis rate of ligands). Furthermore, they are kinetically stable, usually uncharged, and relatively lipophilic and their metal atom is in a low oxidation state. Because of these fundamental differences compared to “classical coordination metal complexes”, organometallics offer ample opportunities in the design of novel classes of medicinal compounds, potentially with new metal-specific modes of action. Interestingly, all the typical classes of organometallics such as metallocenes, half-sandwich, carbene-, CO-, or π-ligands, which have been widely used for catalysis or biosensing purposes, have now also found application in medicinal chemistry (see Figure ​Figure11 for an overview of these typical classes of organometallics). Figure 1 Summary of the typical classes of organometallic compounds used in medicinal chemistry. In this Perspective, we report on the recent advances in the discovery of organometallics with proven antiproliferative activity. We are emphasizing those compounds where efforts have been made to identify their molecular target and mode of action by biochemical or cell biology studies. This Perspective covers more classes of compounds and in more detail than a recent tutorial review by Hartinger and Dyson.(5) Furthermore, whereas recent reviews and book contributions attest to the rapid development of bioorganometallic chemistry in general,6,7 this Perspective focuses on their potential application as anticancer chemotherapeutics. Another very recent review article categorizes inorganic anticancer drug candidates by their modes of action.(8) It should be mentioned that a full description of all currently investigated types of compounds is hardly possible anymore in a concise review. For example, a particularly promising class of organometallic anticancer compounds, namely, radiolabeled organometallics, has been omitted for space limitations. Recent developments of such compounds have been reviewed in detail by Alberto.(9)

Targeted Drug Delivery via the Transferrin Receptor-Mediated Endocytosis Pathway

Abstract: The membrane transferrin receptor-mediated endocytosis or internalization of the complex of transferrin bound iron and the transferrin receptor is the major route of cellular iron uptake. This efficient cellular uptake pathway has been exploited for the site-specific delivery not only of anticancer drugs and proteins, but also of therapeutic genes into proliferating malignant cells that overexpress the transferrin receptors. This is achieved either chemically by conjugation of transferrin with therapeutic drugs, proteins, or genetically by infusion of therapeutic peptides or proteins into the structure of transferrin. The resulting conjugates significantly improve the cytotoxicity and selectivity of the drugs. The coupling of DNA to transferrin via a polycation or liposome serves as a potential alternative to viral vector for gene therapy. Moreover, the OX26 monoclonal antibody against the rat transferrin receptor offers great promise in the delivery of therapeutic agents across the blood-brain barrier to the brain.

Bismuth-coated carbon electrodes for anodic stripping voltammetry

Abstract: Bismuth-coated carbon electrodes display an attractive stripping voltammetric performance which compares favorably with that of common mercury-film electrodes. These bismuth-film electrodes are prepared by adding 400 μg/L (ppb) bismuth(III) directly to the sample solution and simultanously depositing the bismuth and target metals on the glassy-carbon or carbon-fiber substrate. Stripping voltammetric measurements of microgram per liter levels of cadmium, lead, thallium, and zinc in nondeaerated solutions yielded well-defined peaks, along with a low background, following short deposition periods. Detection limit of 1.1 and 0.3 ppb lead are obtained following 2- and 10-min deposition, respectively. Changes in the peak potentials (compared to those observed at mercury electrodes) offer new selectivity dimensions. Scanning electron microscopy sheds useful insights into the different morphologies of the bismuth deposits on the carbon substrates. The in situ bismuth-plated electrodes exhibit a wide accessible po...