PEGylation and preliminary biocompatibility evaluation of magnetite–silica nanocomposites obtained by high energy ball milling

Combining high energy ball milling and liquid crystal templating method to prepare magnetic ordered mesoporous silica. A physico-chemical investigation

The physico-chemical investigation of superparamagnetic MCM41 like materials prepared by the novel combination of high energy ball milling and a liquid crystal templating method is presented. Structural, morphological, textural, thermal, and preliminary magnetic characterization demonstrated the successful combination of the two synthesis techniques, avoiding the problems associated with the current methods used for the preparation of magnetic ordered mesoporous silica. MCM41 like materials with high specific surface area values (625-720 m2 g-1) and high mesopore volumes in the range 1-0.7 cm3 g-1 were obtained. The ordered mesoporous structure and accessible pores were maintained after the inclusion of increasing amounts of the magnetic component in the silica structure. All the samples showed superparamagnetic behaviour.

High Energy Ball Milling and Liquid Crystal Template Method: A Successful Combination for the Preparation of Magnetic Nano-Platforms

In this study, we present the preparation of superparamagnetic ordered mesoporous silica (SOMS) for biomedical applications by the combination of high energy ball milling (HEBM) and the liquid crystal template method (LCT) to produce a material comprised of room temperature superparamagnetic Fe₃O₄ nanoparticles in a MCM-41 like mesostructured silica. In a typical synthesis, a mixture of Fe₂O₃ and silica was sealed in a stainless-steel vial with steel balls. Ball milling experiments were performed in a vibratory mill apparatus. The milling process produced nanocomposites with an average size ranging from ∼100-200 nm, where the Fe₃O₄ nanoparticles (4.8 nm size) are homogeneously dispersed into the amorphous SiO₂ matrix. The obtained nanocomposite has been used for the preparation of the SOMS through the LCT method. Structural, morphological and textural characterization were performed using X-ray powder diffraction, transmission electron microscopy and nitrogen sorption analysis. Field dependence of magnetization was investigated and showed superparamagnetic behaviour at 300 K with a value of saturation magnetization (M_s) that is of interest for biomedical applications.

Morpholine- and Thiomorpholine-Based Amidodithiophosphonato Nickel Complexes: Synthesis, Characterization, P-N Cleavage, Antibacterial Activity and Silica Nano-Dispersion

The reactivity of thiomorpholinium P-(4-methoxyphenyl)-N-thiomorpholin-amidodithiophosphonate (S-MorH⁺₂)(S-Mor-adtp^-) and morpholinium P-(4-methoxyphenyl)-N-morpholin-amidodithiophosphonate (O-MorH⁺₂)(O-Mor-adtp^-) towards nickel (II) dichloride hexahydrated is presented and the hydrolysis of the relevant metal complexes investigated. The hydrolytic products (S-MorH⁺₂)₂ [Ni(dtp)₂]²- and (O-MorH⁺₂)₂[Ni(dtp)₂]²- were characterized by means of FT-IR, ¹H, and ³¹P NMR and XRD and the experimented P-N cleavage investigated and elucidated by means of DFT calculations. The antimicrobial activity of the neutral nickel complex [Ni(S-Mor-adtp)₂] was tested against a set of Gram-positive and Gram-negative bacteria alongside with its nanodispersion in a silica matrix. The complex [Ni(S-Mor-adtp)₂] did not show antibacterial activity, whilst the nano-dispersed sample [Ni(S-Mor-adtp)₂]_SiO₂ demonstrated inhibition to growth of Staphylococcus aureus. The nanocomposites were fully characterized by means of XRPD, TGA, SEM and dinitrogen sorption techniques.

Isothermal titration calorimetry as a complementary method for investigating nanoparticle-protein interactions

Isothermal titration calorimetry (ITC) is a complementary technique that can be used for investigations of protein adsorption on nanomaterials, as it quantifies the thermodynamic parameters of intermolecular interactions in situ. As soon as nanomaterials enter biological media, a corona of proteins forms around the nanomaterials, which influences the surface properties and therefore the behavior of nanomaterials tremendously. ITC enhances our understanding of nanoparticle-protein interactions, as it provides information on binding affinity (in form of association constant K_a), interaction mechanism (in form of binding enthalpy ΔH, binding entropy ΔS and Gibbs free energy ΔG) and binding stoichiometry n. Therefore, as a complementary method, ITC enhances our mechanistic understanding of the protein corona. In this minireview, the information obtained from a multitude of ITC studies regarding different nanomaterials and proteins are gathered and relations between nanomaterials' properties and their resulting interactions undergone with proteins are deduced. Nanomaterials formed of a hydrophilic material without strongly charged surface and steric stabilization experience the weakest interactions with proteins. As a result, such nanomaterials undergo the least unspecific protein-interactions and are most promising for allowing an engineering of the protein corona.

Fe3O4@zirconium phosphate core–shell nanoparticles for pH-sensitive and magnetically guided drug delivery applications

Fe₃O₄@zirconium phosphate core–shell nanoparticles with good biocompatibility have been synthesized for pH-sensitive and magnetically guided drug delivery applications.

Modified wound dressing with phyto-nanostructured coating to prevent staphylococcal and pseudomonal biofilm development

This paper reports a newly fabricated nanophyto-modified wound dressing with microbicidal and anti-adherence properties. Nanofluid-based magnetite doped with eugenol or limonene was used to fabricate modified wound dressings. Nanostructure coated materials were characterized by TEM, XRD, and FT-IR. For the quantitative measurement of biofilm-embedded microbial cells, a culture-based method for viable cell count was used. The optimized textile dressing samples proved to be more resistant to staphylococcal and pseudomonal colonization and biofilm formation compared to the uncoated controls. The functionalized surfaces for wound dressing seems to be a very useful tool for the prevention of wound microbial contamination on viable tissues.

Odyssey of a cancer nanoparticle: from injection site to site of action

No chemotherapeutic drug can be effective until it is delivered to its target site. Nano-sized drug carriers are designed to transport therapeutic or diagnostic materials from the point of administration to the drug's site of action. This task requires the nanoparticle carrying the drug to complete a journey from the injection site to the site of action. The journey begins with the injection of the drug carrier into the bloodstream and continues through stages of circulation, extravasation, accumulation, distribution, endocytosis, endosomal escape, intracellular localization and-finally-action. Effective nanoparticle design should consider all of these stages to maximize drug delivery to the entire tumor and effectiveness of the treatment.

Applications of isothermal titration calorimetry in pure and applied research--survey of the literature from 2010

Isothermal titration calorimetry (ITC) is a biophysical technique for measuring the formation and dissociation of molecular complexes and has become an invaluable tool in many branches of science from cell biology to food chemistry. By measuring the heat absorbed or released during bond formation, ITC provides accurate, rapid, and label-free measurement of the thermodynamics of molecular interactions. In this review, we survey the recent literature reporting the use of ITC and have highlighted a number of interesting studies that provide a flavour of the diverse systems to which ITC can be applied. These include measurements of protein-protein and protein-membrane interactions required for macromolecular assembly, analysis of enzyme kinetics, experimental validation of molecular dynamics simulations, and even in manufacturing applications such as food science. Some highlights include studies of the biological complex formed by Staphylococcus aureus enterotoxin C3 and the murine T-cell receptor, the mechanism of membrane association of the Parkinson's disease-associated protein α-synuclein, and the role of non-specific tannin-protein interactions in the quality of different beverages. Recent developments in automation are overcoming limitations on throughput imposed by previous manual procedures and promise to greatly extend usefulness of ITC in the future. We also attempt to impart some practical advice for getting the most out of ITC data for those researchers less familiar with the method.