Whither magnetic hyperthermia? A tentative roadmap

The scientific community has made great efforts in advancing magnetic hyperthermia for the last two decades after going through a sizeable research lapse from its establishment. All the progress made in various topics ranging from nanoparticle synthesis to biocompatibilization and in vivo testing have been seeking to push the forefront towards some new clinical trials. As many, they did not go at the expected pace. Today, fruitful international cooperation and the wisdom gain after a careful analysis of the lessons learned from seminal clinical trials allow us to have a future with better guarantees for a more definitive takeoff of this genuine nanotherapy against cancer. Deliberately giving prominence to a number of critical aspects, this opinion review offers a blend of state-of-the-art hints and glimpses into the future of the therapy, considering the expected evolution of science and technology behind magnetic hyperthermia.status: publishe

Mononuclear metal complexes of the second-generation quinolone antibacterial agent enrofloxacin: Synthesis, structure, antibacterial activity and interaction with DNA

Seven novel metal complexes of the second-generation quinolone antibacterial agent enrofloxacin with Mn2+, Fe3+, Co2+, Ni2+, Zn2+, Cd2+ and UO22 + have been prepared and characterized with physicochemical methods and infrared, UV-Vis and nuclear magnetic resonance spectroscopies. In the resultant complexes, enrofloxacin acts as a bidentate deprotonated ligand bound to the metal through the pyridone oxygen and one carboxylate oxygen. The central metal atoms are six-coordinate with slightly distorted octahedral geometry. Molecular modeling calculations have been performed in order to propose a model for the structure of Mn2+, Fe3+ and UO22 + complexes. The investigation of the interaction of the complexes with calf-thymus DNA has been performed with UV and circular dichroism spectroscopies. The antimicrobial activity of the complexes has been tested on three different microorganisms. The complexes exhibit better or equal inhibition in comparison to free enrofloxacin. © 2008 Elsevier Ltd. All rights reserved

Multisensitive Polymeric Nanocontainers as Drug Delivery Systems: Biological Evaluation

This chapter focuses on the in vitro biological evaluation of multisensitive nanocontainers as drug delivery systems for cancer treatment. Cancer tissues possess some unique characteristics such as increased temperature due to inflammation, thermal vulnerability (40–45 °C), low cellular pH, and redox instabilities. The employment of polymers bearing pH, thermo, and/or redox sensitivities in the synthesis of hollow polymeric nanostructures has led to the formulation of a variety of drug delivery vehicles that are capable of targeted delivery and trigger specific drug release. The cavity in the structure allows for the encapsulation of anticancer drugs as well as other moieties with anticancer activity, like iron oxide magnetic nanoparticles. The drug loading and release capability of the nanocontainers is evaluated prior to biological studies in order to determine the concentration of the drug in the structure. The in vitro assessment includes cytotoxicity studies, quantitatively through the colorimetric MTT assay as well as qualitatively via the scratch-wound healing assay, on both cancer and healthy cell lines. The cellular localization of the studied drug-loaded and unloaded nanocontainers is determined through confocal fluorescence microscopy. © 2021, Springer Science+Business Media, LLC, part of Springer Nature

Mononuclear dioxomolybdenum(VI) complexes with the quinolones enrofloxacin and sparfloxacin: Synthesis, structure, antibacterial activity and interaction with DNA

The neutral mononuclear dioxomolybdenum(VI) complexes of the quinolone antibacterial agents enrofloxacin and sparfloxacin have been prepared and characterized with physicochemical and spectroscopic techniques. In these complexes, enrofloxacin and sparfloxacin act as bidentate deprotonated ligands bound to the metal through the pyridone oxygen and one carboxylate oxygen. The central molybdenum atoms are six-coordinate with slightly distorted octahedral geometry. The lowest energy model structure of each complex has been proposed with molecular modeling calculations. The antimicrobial activity of the complexes has been tested on three different microorganisms. The investigation of the interaction of the complexes with calf-thymus DNA has been performed with diverse spectroscopic techniques. © 2007 Elsevier Ltd. All rights reserved

Structure, antimicrobial activity and DNA-binding properties of the cobalt(II)-sparfloxacin complex

The neutral mononuclear cobalt(II) complex with sparfloxacin has been prepared and characterized with physicochemical, spectroscopic and electrochemical techniques, and molecular mechanics calculations. The interaction of the complex with calf-thymus DNA has been investigated with UV spectroscopy, cyclic voltammetry, and competitive studies with ethidium bromide. The antimicrobial activity of the complex has been tested against three microorganisms. © 2008 Elsevier Ltd. All rights reserved

Metal complexes of the third-generation quinolone antimicrobial drug sparfloxacin: Structure and biological evaluation

Five metal complexes of the third-generation quinolone antimicrobial agent sparfloxacin with Fe3+, VO2+, Mn2+, Ni2+ and UO22+ have been prepared and characterized with physicochemical and spectroscopic techniques. In these complexes, sparfloxacin acts as a bidentate deprotonated ligand bound to the metal through the ketone oxygen and a carboxylate oxygen. The complexes are six-coordinate with distorted octahedral geometry. For VO(sparfloxacinato)2(H2O) the axial position, trans to the vanadyl oxygen, is occupied by a ketone oxygen atom. Molecular mechanics calculations have been performed in order to propose a model for the structure of each complex. The antimicrobial activity of the complexes has been tested against three microorganisms showing that they exhibit lower activity than free sparfloxacin. UV spectroscopic titration with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA and the binding constants to CT DNA have been calculated. The cyclic voltammograms of the complexes in the presence of CT DNA have shown that they bind to CT DNA probably by the intercalative binding mode. Fluorescence competitive studies with ethidium bromide (EB) have revealed the ability of the complexes to displace the DNA-bound EB. The complexes exhibit good binding propensity to human and bovine serum albumin proteins having relatively high binding constant values. © 2009 Elsevier Inc

Mononuclear copper(II) complexes with quinolones and nitrogen-donor heterocyclic ligands: Synthesis, characterization, biological activity and interaction with DNA

The neutral mononuclear copper(II) complexes with the quinolone antibacterial drugs, pipemidic acid and N-propyl-norfloxacin, in the presence or absence of nitrogen-donor heterocyclic ligands, 2,2′-bipyridine, 1,10-phenanthroline or 2,2′-dipyridylamine, have been prepared and characterized spectroscopically. The interaction of copper(II) with the deprotonated quinolone ligand leads to the formation of the neutral mononuclear complexes of the type [Cu(quinolone)2(H2O)] (1)-(2) while the presence of the N-donor ligand leads to the formation of the neutral mononuclear complexes of the type [Cu(quinolone)(N-donor)Cl] (3)-(8). In all the complexes, copper(II) is pentacoordinate having a distorted square pyramidal geometry. The electron paramagnetic resonance spectra of 1 and 2 are typical of mononuclear Cu(II) complexes, while for the mixed-ligands complexes 3-8 a mixture of dimeric and monomeric species is indicated. The interaction of the complexes with calf-thymus DNA has been investigated with diverse spectroscopic techniques and has shown that the complexes can be bound to calf-thymus DNA by the intercalative mode. The antimicrobial activity of the complexes has been tested on three different microorganisms. All the complexes show an increased biological activity in comparison to the corresponding free quinolone ligand. © 2007 Elsevier B.V. All rights reserved

Synthesis of biocompatible silver nanoparticles by a modified polyol method for theranostic applications: Studies on red blood cells, internalization ability and antibacterial activity

Recently, there has been ongoing research in the field of nanotechnology and nanomedicine aiming at developing multifunctional biomaterials using noble metals. The unique properties of silver (Ag) are known from ancient times and thus are being explored for their behavior on the nano scale. Silver shows high antimicrobial activity against different microorganisms, while modification of the surface of its nanostructures can be useful in active targeting regarding cancer treatment. During the synthetic procedure, in order to obtain a more uniform sample of silver nanoparticles (Ag NPs) with spherical morphology, a stabilizer is essential. The stabilizers used not only control the progression of the reaction, but also increases the biocompatibility of the NPs. Thus, we managed to synthesize spherical and rod-like Ag NPs via a polyol method and stabilize them with polyvinylpyrrolidone (PVP). The resulted Ag NPs were characterized morphologically with Transmission Electron Microscopy (TEM) and further confirmed by their structural characterization (FT-IR, UV-Vis, Dynamic Light Scattering (DLS) and Zeta Potential). For their biocompatibility profile, we studied their interaction with red blood cells (RBCs) through hemolysis assay and we monitored their structural alterations through SEM. The antimicrobial activity was tested with the agar diffusion disc assay for Gram negative and Gram positive microorganisms E. coli and S. aureus respectively. Nanoparticles' (NPs) internalization and localization studies in cancer cells were monitored with fluorescence microscopy in MCF-7 and U87-MG. According to our results it is worth it to investigate the potential of these nanomaterials since they can have a significant role in applications of theranostics in nanomedicine. Copyright © 2020 Elsevier Inc. All rights reserved

Bulk nanobubbles, generation methods and potential applications

The existence of nanobubbles, especially bulk nanobubbles, remains a mystery mainly due to their stability and longevity, properties that are investigated by many research groups worldwide. At the same time, high efforts are given to develop new generation methods, and so far, their potential uses have spread to high-value applications. Some of them are relevant to drinking water and wastewater treatment, surface cleaning, biomedical, engineering, medical imaging but also in ‘nutritional’” applications such as fishery and agriculture. Although the bulk of nanobubbles generation methods are thorough and known well enough, a remarkable lag is still recorded concerning the detailed explanation of their formation, their special physicochemical properties, and the stability mechanisms. In this short review, a condensed description of the nanobubbles production methods, their major properties, and potential important applications are presented. Emphasis has been given to the results and findings during the research effort of the last four years. © 2021 Elsevier Lt

Synthesis, characterization, antibacterial activity, and interaction with DNA of the vanadyl-enrofloxacin complex

The neutral mononuclear vanadyl complex with the quinolone antibacterial drug enrofloxacin has been prepared and characterized with physicochemical and spectroscopic techniques and molecular mechanics calculations. The interaction of the complex with calf-thymus DNA has also been investigated and the antimicrobial activity has been evaluated against three different microorganisms. © 2006 Elsevier Ltd. All rights reserved