Antibacterial nanocomposite supporting cell growth and spheroid formation by chemical surface treatment of polymer foil

Octenidine dihydrochloride (OCT) has a wide spectrum of antibacterial, antifungal and virucidal activity. OCT is also newly used in tissue engineering. The aim of this work was to create a new nanocomposite consisting of OCT-grafted polymer with (i) antibacterial effect and/or (ii) surface for better cell adhesion and proliferation. The polymer foils were chemically activated with Piranha solution and subsequently grafted with OCT. Changes in surface properties before and after modifications were detected by electrokinetic analysis, goniometry, atomic force microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The final nanocomposite polymer/OCT exhibits antibacterial activity against Staphylococcus epidermidis (S. epidermidis). The new nanocomposite material has also been shown to support the growth of B14 cell culture on the substrate and to form cell multilayers, which could lead to the formation of spheroids. This behaviour strongly depends on the concentration of OCT grafted onto the polymer surfaces. This new nanocomposite could be used in medicine, for bioapplications, environmental protection.     

The Use of Voltammetry for Sorption Studies of Arsenic (III) Ions by Magnetic Beads Functionalized with Nucleobase Hydrazide Derivatives

In this work the interaction characteristics of nucleobases with As(III) are studied. Novel materials consisting of magnetic nanoparticles (MNPs) functionalized with adenine hydrazide (AH), guanine hydrazide (GH) and uracil hydrazide (UH) were elaborated. The adsorption isotherms were investigated electrochemically and it was shown that the adsorption capacity of the nanoparticles towards arsenic (III) increased in the following order: AH<UH<GH. The electrochemical detection of As(III) using the GH functionalized MNPs offered better results compared with the other functionalizations, with a sensitivity of 1.92 μA μg⁻¹ L and a limit of detection of 1.6 μg/L (21 nM).     

Atypical Film-Forming Behavior of Soluble Tetra-3-Nitro-Substituted Copper Phthalocyanine

Thin films of metal phthalocyanines (MPc) are known to exhibit excellent physical properties but poorly controlled morphologies. Therefore, the present work seeks to understand the film growth mechanism of a model compound for potentially usable MPc, specifically, copper tetra(3-nitro-5-tert-butyl)phthalocyanine (CuPc*). The Langmuir-Schaefer (LS) technique was applied to prepare a series of CuPc* films under different processing conditions. The film growth was examined by Brewster angle microscopy (BAM) on the water surface and small-angle X-ray scattering (SAXS) from the solid films. Neutron reflectometry (NR) measurements of the water uptake into the films and computer simulation of hydrated CuPc* were performed to substantiate an idea of colloidal MPc-water aggregates as nanoscale precursors of smooth solid films. This idea appears fruitful in terms of materials chemistry.     

Relaxometric investigations addressing the determination of intracellular water lifetime: a novel tumour biomarker of general applicability

ABSTRACT

¹H Fast-Field Cycling NMR relaxometry is proposed as a powerful method to investigate tumour cell metabolism by measuring changes in cell water content and mobility across the cellular membrane. Measurements of intracellular water residence time in cultured cells were carried out by measuring T₁ at fixed field (0.2?T) after the addition of a paramagnetic Gd complex (Prohance) at different concentrations in the external medium. Investigations on tumour cells (mammary adenocarcinoma TS/A) grown in normo- or hypoxic conditions or suspended in ‘hypo-osmotic’ solutions allowed us to demonstrate that both hypoxic and hypo-osmotic conditions cause a marked increase in water mobility as assessed by the elongation of T₁. Conversely, the metabolic change caused by glutamine (an aminoacid essential for tumour growth) deprivation caused a water mobility decrease (shorter T₁). These findings suggest that T₁ measurements at low and variable magnetic field strengths, giving access to the assessment of intracellular water lifetime, can provide important information about tumour cell metabolism in real time and non-invasively.     

A Highly Luminescent Tetrahydrocurcumin IrIII Complex with Remarkable Photoactivated Anticancer Activity

Curcumin has chemopreventative properties against a variety of tumours, but has poor bioavailability. Here, two new bis-cyclometallated iridium(III) complexes have been prepared, featuring the natural product curcumin (CUR) or its reduced form, tetrahydrocurcumin (THC), as bidentate, anionic O O-binding ligands. The iridium THC complex is highly luminescent in deoxygenated solution and efficiently generates singlet oxygen under aerated conditions, whereas in the CUR analogue, other non-radiative decay pathways are competitive. The complexes are rapidly taken up by a variety of human tumour cell lines from solutions of micromolar concentration. They show negligible cytotoxicity in the absence of irradiation. When briefly irradiated with visible light, Ir-THC becomes highly phototoxic, inducing rapid apoptosis within 2 h. The results show the high potential of such complexes as sensitizers in photodynamic therapy (PDT).     

Development of easy‐to‐use reverse‐phase liquid chromatographic methods for determining PRE‐084, RC‐33 and RC‐34 in biological matrices. The first step for in vivo analysis of sigma1 receptor agonists

Over the years there has been a growing interest in the therapeutic potential for central nervous system pathologies of sigma receptor modulators. The widely studied PRE‐084 and our compounds RC‐33 and RC‐34 are very potent and selective sigma 1 receptor agonists that could represent promising drug candidates for Amyotrophic Lateral Sclerosis (ALS). Herein, we develop and validate robust and easy‐to‐use reverse‐phase chromatographic methods suitable for detecting and quantifying PRE‐084, RC‐33 and RC‐34 in mouse blood, brain and spinal cord. An HPLC/UV/ESI‐MS system was employed for analyzing PRE‐084 and an HPLC/UV‐PDA system for determining RC‐33 and RC‐34. Chromatographic separations were achieved on Waters Symmetry RP₁₈ column (150 × 3.9 mm, 5 µm), eluting with water and acetonitrile (both containing 0.1% formic acid) in gradient conditions. The recovery of PRE‐084, RC‐33 and RC‐34 was >95% in all the considered matrices. Their limits of quantitation and detection were also determined. Validation proved the methods be suitable for separating tested compounds from endogenous interferences, being characterized by good sensitivity, linearity, precision and accuracy. A preliminary central nervous system distribution study showed a high distribution of RC‐33 in brain and spinal cord, with concentration values well above the determined limit of quantitation. The proposed methods will be used in future preclinical investigations. Copyright © 2015 John Wiley & Sons, Ltd.     

Structural discrimination of isomeric tetrahydrofuran lignan glucosides by tandem mass spectrometry

Due to the possible role in human health, the number of analytical studies on lignans aimed at their quali‐ and quantitative analysis in plant extracts, biological fluids and foods is continuously increasing. However, helpful systematic mass spectrometric investigations on these compounds are few and rather limited to specific lignan sub‐classes. To increase the comprehension of the previously outlined picture of the gas‐phase properties of furofuran lignans, we extended the study to tetrahydrofuran lignans and here we reported the collision‐activated dissociation (CAD) fragmentation patterns of the alkali metal cation adducts, [M+Alk]⁺, and [M–H]^? ions of three isomeric tetrahydrofuran lignans, (+)‐8′‐hydroxylariciresinol 4′‐O‐β‐D ‐glucopyranoside (1), (+)‐7′‐hydroxylariciresinol 7′‐O‐β‐D ‐glucopyranoside (2) and 4‐O‐β‐D ‐glucopyranosyloxy‐3,3′‐dimethoxy‐7,9′‐epoxylignan‐5′,8′,9‐triol (3) investigated by electrospray ionization triple quadrupole mass spectrometry (ESI‐TQMS). Hydrogen/deuterium (H/D) solution exchange experiments, allowing the selective H/D exchange of all the acidic hydrogen atoms, proved to be a very effective tool to obtain information on the nature of fragments generated during TQ/CAD processes. The [M+Na]⁺ CAD mass spectra of the three isomeric tetrahydrofurans revealed four different pathways involving the loss of the glucose moiety, which allowed the assignment of the glycosylation site. In the negative ion mode, the main fragmentation channel of the [M–H]^? ions of O‐glucosylated lignans at the phenolic oxygen atoms is represented by the loss of 162 Da. When the sugar is bound to a benzylic OH group the loss of the sugar as a 180 Da unit occurs eventually following the loss of a water molecule involving both the C(9)H₂OH chain and the sugar. Copyright © 2010 John Wiley & Sons, Ltd.