Doxorubicin (DOX) Gadolinium-Gold-Complex: A New Way to Tune Hybrid Nanorods as Theranostic Agent

INTRODUCTION

In this paper, we have designed and formulated, a novel synthesis of doxorubicin (DOX) loaded bimetallic gold nanorods in which gold salt (HAuCl4) is chelated with anthracycline (DOX), diacid polyethylene-glycol (PEG-COOH) and gadolinium salt (GdCl3 * 6 H2O) to form DOX IN-Gd-AuNRs compared with DOX ON-Gd-AuNRs in which the drug was grafted onto the bimetallic pegylated nanoparticle surface by electrostatic adsorption.

MATERIAL AND METHOD

The physical and chemical evaluation was performed by spectroscopic analytical techniques (Raman spectroscopy, UV-Visible and transmission electron microscopy (TEM)). Magnetic features at 7T were also measured. Photothermal abilities were assessed. Cytotoxicity studies on MIA PaCa-2, human pancreatic carcinoma and TIB-75 hepatocytes cell lines were carried out to evaluate their biocompatibility and showed a 320 fold higher efficiency for DOX after encapsulation.

RESULTS

Exhaustive physicochemical characterization studies were conducted showing a mid size of 20 to 40 nm diameters obtained with low polydispersity, efficient synthesis using seed mediated synthesis with chelation reaction with high scale-up, long duration stability, specific doxorubicin release with acidic pH, strong photothermal abilities at 808 nm in the NIR transparency window, strong magnetic r1 relaxivities for positive MRI, well adapted for image guided therapy and therapeutical purpose in biological tissues.

CONCLUSION

In this paper, we have developed a novel theranostic nanoparticle composed of gadolinium complexes to gold ions, with a PEG biopolymer matrix conjugated with antitumoral doxorubicin, providing multifunctional therapeutic features. Particularly, these nano conjugates enhanced the cytotoxicity toward tumoral MIAPaCa-2 cells by a factor of 320 compared to doxorubicin alone. Moreover, MRI T1 features at 7T enables interesting positive contrast for bioimaging and their adapted size for potential passive targeting to tumors by Enhanced Permeability Retention. Given these encouraging antitumoral and imaging properties, this bimetallic theranostic nanomaterial system represents a veritable promise as a therapeutic entity in the field of medicinal applications.

Single-cell detection by gradient echo 9.4 T MRI: a parametric study

Recent studies have shown that cell migration can be monitored in vivo by magnetic resonance imaging after intracellular contrast agent incorporation. This is due to the dephasing effect on proton magnetization of the local magnetic field created by a labelled cell. Anionic iron oxide nanoparticles (AMNP) are among the most efficient and non-toxic contrast agents to be spontaneously taken up by a wide variety of cells. Here we measured the iron load and magnetization of HeLa tumour cells labelled with AMNP, as a function of the external magnetic field. High-resolution gradient echo 9.4 T MRI detected individual labelled cells, whereas spin echo sequences were poorly sensitive. We then conducted a systematic study in order to determine the gradient echo sequence parameters (echo time, cell magnetization and resolution) most suitable for in vivo identification of single cells.

In vivo 2D magnetic resonance spectroscopy of small animals

Localized in vivo NMR spectroscopy, chemical shift imaging or multi-voxel spectroscopy are potentially useful tools in small animals that are complementary to MRI, adding biochemical information to the mainly anatomical data provided by imaging of water protons. However the contribution of such methods remains hampered by the low spectral resolution of the in vivo 1D spectra. Two-dimensional methods widely developed for in vitro studies have been proposed as suitable approaches to overcome these limitations in resolution. The different homonuclear and heteronuclear sequences adapted to in vivo studies are reviewed. Their specific contributions to the spectral resolution of spectroscopic data and their limitations for in vivo investigations are discussed. The applications to experimental models of pathological processes or pharmacological treatment in mainly brain and muscle are presented. According to their combined sensitivity, acquisition duration and spatial resolution, the heteronuclear 2D experiments, which are mainly used for 1H detected-13C spectroscopy after administration of 13C-labeled compounds, appear to be less efficient than 1H detected-13C 1D methods at high field. However, the applications of 2D proton homonuclear methods show that they remain the best tools for in vivo studies when an improved resolution is required.

Two-year stability of borderline personality measures

Two-year stability coefficients were computed for several measures of borderline personality disorder within a nonclinical sample (n = 65) that included individuals with significant borderline features. Overall, the stability coefficients were modest (r ranging from .28 to .62; intraclass correlations ranging from .26 to .62). Stability values for each of the self-report measures under study were higher than those for the interview-based measure of BPD features, and, in some cases, these values varied as a function of the prototypicality of the subsamples examined. Analyses conducted to identify moderator effects provided no evidence that the stability of BPD scores was moderated by change in personal distress level; however, changes in BPD self-report scores were related to changes in level of negative affectivity.

Chemical modifications of the vasoconstrictor peptide angiotensin II by nitrogen oxides (NO, HNO2, HOONO)--evaluation by mass spectrometry

Nitric oxide (NO) and angiotensin II are natural regulators of blood pressure. Under aerobic conditions, NO is transformed into its higher oxides (N2O4, NO2, NO/NO2 or N2O3) and oxoperoxonitrate (currently named peroxynitrite) by coupling with superoxide. Previous studies have shown that these reactive nitrogen species should be involved in vivo in the transformation of cysteine and tyrosine into the corresponding nitrosothiol and 3-nitrotyrosine. In the present study, attention has been focused on the relative reactivities of HNO2, peroxynitrite, and NO in the presence of dioxygen, towards the arginine and tyrosine residues of the peptide angiotensin II. Nitration of the tyrosine residue is clearly the main reaction with peroxynitrite. By contrast, besides 20% of nitration of the tyrosine residue, NO in the presence of dioxygen leads to nitrosation reactions with the arginine residue similar to those observed with HNO2 at pH 5, possibly through the intermediate N2O3 reactive species. Angiotensin II is converted for the most part to peptides having lost either a terminal amine function or the whole guanido group, leading respectively to citrulline-containing angiotensin II or to a diene derivative. Identification established mainly by tandem mass spectrometry of peptidic by-products allows us to propose a cascade of nitrosations of all the amine functions of the arginine residue. Further in vivo studies show that transformations of the arginine residue in angiotensin II do not alter its vasoconstrictive properties, whereas nitration of the tyrosine residue totally inhibits them.

Mapping the active site of factor Xa by selective inhibitors: an NMR and MD study

The structure of two selective inhibitors, Ac-Tyr-Ile-Arg-Ile-Pro-NH2 and Ac-(4-Amino-Phe)-(Cyclohexyl-Gly)-Arg-NH2, in the active site of the blood clotting enzyme factor Xa was determined by using transferred nuclear Overhauser effect nuclear magnetic resonance (NMR) spectroscopy. They represent a family of peptidic inhibitors obtained by the screening of a vast combinatorial library. Each structure was first calculated by using standard computational procedures (distance geometry, simulated annealing, energy minimization) and then further refined by systematic search of the conformation of the inhibitor docked in the active site and repeating the simulated annealing and energy minimization. The final structure was optimized by molecular dynamics simulations of the inhibitor-complex in water. The NMR restraints were kept throughout the refinement. The inhibitors assume a compact, very well defined conformation, embedded into the substrate binding site not in the same way as a substrate, blocking thus the catalysis. The model allows to explain the mode of action, affinity, and specificity of the peptides and to map the active site.

Borderline personality disorder features in nonclinical young adults: 2. Two-year outcome

Borderline personality disorder (BPD) is thought to develop by early adulthood, and it is characterized by lack of control of anger, intense and frequent mood changes, impulsive acts, disturbed interpersonal relationships, and life-threatening behaviors. We describe data from a 2-year follow-up study of nonclinical young adults who, at study entry, exhibited a significant number of BPD features. Individuals with borderline features were more likely to have academic difficulties over the succeeding 2 years, and these participants were more likely to meet lifetime criteria for a mood disorder and to experience interpersonal dysfunction than their peers at the 2-year follow-up assessment. These findings indicate that BPD features are associated with poorer outcome even within a nonclinical population.

Borderline personality disorder features in nonclinical young adults: 2. Two-year outcome

Borderline personality disorder (BPD) is thought to develop by early adulthood, and it is characterized by lack of control of anger, intense and frequent mood changes, impulsive acts, disturbed interpersonal relationships, and life-threatening behaviors. We describe data from a 2-year follow-up study of nonclinical young adults who, at study entry, exhibited a significant number of BPD features. Individuals with borderline features were more likely to have academic difficulties over the succeeding 2 years, and these participants were more likely to meet lifetime criteria for a mood disorder and to experience interpersonal dysfunction than their peers at the 2-year follow-up assessment. These findings indicate that BPD features are associated with poorer outcome even within a nonclinical population.

Phase-sensitive two-dimensional experiment on living animals

This report describes the first 1H-1H phased spectrum obtained in vivo from the hind-leg muscles of an intact mouse. TOCSY correlations can follow the complete spin system and give a more detailed graph of each molecule than can COSY. TOCSY is also better suited than COSY for studying long fatty-acid chains. All the peaks are in phase in a TOCSY experiment and the intensities of the cross-correlation peaks are less sensitive to low digitalization in the t1 domain than are those of COSY. The improvement in sensitivity was estimated by measuring the volumes of the cross-correlation peaks in COSY and TOCSY spectra.

In vivo 2D 1H NMR of mdx mouse muscle and myoblast cells during fusion: evidence for a characteristic signal of long chain fatty acids

We have previously demonstrated that 2D 1H NMR is suitable for studying cerebral metabolism. The same technique was used to study the hind leg muscle of normal (C57BL10) and dystrophic (mdx) mice. The results were compared to preliminary results for cultured muscle cells to determine the origin of fatty acid signals.