BODIPY-conjugated chitosan nanoparticles as a fluorescent probe

Recently, development of fluorescent nanoparticle-based probes for various bioimaging applications has attracted great attention. This work aims to develop a new type fluorescent nanoparticle conjugate and evaluate its cytotoxic effects on A549 and BEAS 2B cell lines. Throughout the study, ionically crosslinked chitosan nanoparticles (CNs) were conjugated with carboxylated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY-COOH). The results of conjugates (BODIPY-CNs) were investigated with regard to their physic-chemical, optical, cytotoxic properties and cellular internalization. The morphology of BODIPY-CNs was found to be spherical in shape and quite uniform having average diameter of 70.25 ± 11.99 nm. Cytotoxicty studies indicated that although BODIPY-COOH itself was quite toxic on both A549- and BEAS 2B-treated cells, CNs increased the cell viability of both cell lines via conjugation to BODIPY-COOH fluorescent molecule up to 67% for A549 and 74% for BEAS 2B cells. These results may suggest a possible utilization of the new fluorescent nanoparticle-based probe for bioimaging in biology and medicine

Internal lamellar and inverse hexagonal liquid crystalline phases during the digestion of krill and astaxanthin oil-in-water emulsions

Krill oil represents an important alternative natural source of omega-3 (ω-3) polyunsaturated fatty acids (PUFAs). Considering the beneficial health effects of these essential fatty acids, particularly in various disorders including cancer, cardiovascular, and inflammation diseases, it is of paramount importance to gain insight into the digestibility of krill oil. In this work, we study the fate of krill oil-in-water emulsion, stabilized by sodium caseinate, during lipolysis by coupling time-resolved synchrotron small-angle X-ray scattering (SAXS) to flow-through lipolysis model. For gaining further insight into the effect of ω-3 PUFA-containing oil type on the dynamic structural features occurring during lipolysis, two additional astaxanthin oil-in-water emulsions, stabilized using either sodium caseinate or citrem, were subjected to lipolysis under identical experimental conditions. In addition to the difference in lipid composition in both oils, ω-3 PUFAs in astaxanthin oil, similar to fish oil, exist in the form of triacylglycerols; whereas most of those in krill oil are bound to phospholipids. SAXS showed the formation of highly ordered nanostructures on exposure of these food emulsions to the lipolysis medium: the detection of a biphasic feature of coexisting inverse hexagonal (H2) and lamellar (Lα) liquid crystalline phases in the digested krill oil droplets' interiors, as compared to a neat Lα phase in the digested astaxanthin oil droplets. We discuss the dynamic phase behavior and describe the suggested important role of these phases in facilitating the delivery of nutrients throughout the body. In addition, the potential implication in the development of food and drug nanocarriers is briefly described

Next Generation of Brain Cancer Nanomedicines to Overcome the Blood–Brain Barrier (BBB):Insights on Transcytosis, Perivascular Tumor Growth, and BBB Models

Brain cancers, particularly malignant gliomas such as glioblastoma, are highly invasive and characterized by elevated complexity, heterogeneity, and high infiltration ability. Therefore, they pose a significant challenge to conventional treatments due to the limited drug permeability of the blood–brain barrier (BBB), the involvement of numerous acquired and intrinsic drug resistance mechanisms in metastatic brain tumors, and the high sensitivity of surrounding healthy tissues. Despite recent advances in diagnosis and treatment, their prognosis remains poor, with their median overall survival rarely exceeding 12 months. To overcome these limitations, different nanomedicine-based therapeutic approaches have recently been proposed, aiming to provide more effective and safer drug delivery for targeting brain cancers. However, most reported nanomedicines to date have failed to meet the high expectations in the clinic. This fact can be attributed to limited understanding of brain tumor biology and lack of knowledge about bio-nanoparticle interactions, among other factors. This review discusses recent progress in brain cancer nanomedicines, with a particular focus in understanding intracellular sorting mechanisms, perivascular tumor growth, and the design of advanced BBB models. It also highlights how an improved understanding of brain tumor biology can pave the way for designing safer and more effective nanomedicines for brain cancer treatment.</p

Zinc induced activation of GABA-shunt in tobacco (Nicotiana tabaccum L.)

WOS: 000368219500010Zinc is among the important heavy metals which play a key role in plant growth and development for this reason, maintenance of its homeostasis is a critical prbcess within the plant cell. Not only deficiency but also excess Zn leads to reduced growth and development, chlorosis, senescence and increased generation of reactive oxygen species. gamma-amino butyric acid (GABA) is a neurotransmission inhibitor non-protein amino acid, which accumulates to high levels when plants are subjected to different stresses including heavy metal stress. In the brain cells of animals a direct interaction between GABA, glutamate and Zn was reported which might be valid for a different necessity in plant cells. In the presented study, we tried to understand if there is an interaction between GABA, glutamate and Zn that leads to the activation of GABA-shunt. We treated Nicotiana tabaccurn plants with medium (10 mu M) and high (100 mu M) Zn concentrations and, we analyzed GABA, glutamate levels in relation to GDH and GAD encoding genes' expression profiles and specific enzyme activities. Medium and high Zn concentrations affected GABA and glutamate levels differentially in accordance the gene expression profiles and activity levels in the short and long term of the experimental period. In conclusion we can speculate that, medium Zn concentration might be responsible for triggering GABA-shunt for activating the protective mechanisms against heavy metal stress however, high Zn concentrations might be related to the activation of programmed cell death due to toxicity. (C) 2015 Elsevier B.V. All rights reserved.Ege University Research FoundationEge University [2012-FEN-065]This research was supported by Ege University Research Foundation with the grant number 2012-FEN-065

Cytotoxic and cytostatic side effects of chitosan nanoparticles as a non-viral gene carrier

Although chitosan nanoparticles (CNs) became a promising tool for several biological and medical applications owing to their inherent biocompatibility and biodegradability features, studies regarding their effects on cytotoxic and cytostatic properties still remain insufficient. Therefore, in the present study, we decided to perform comprehensive analysis of the interactions between CNs–pKindling-Red-Mito (pDNA) and different cell line models derived from blood system and human solid tissues cancers. The resulting CNs-pDNA was investigated in terms of their cellular uptake, transfection efficiency, and physico-chemical, cytotoxic and cytostatic properties. The nanoparticles showed high encapsulation efficiency and physical stability for various formulations even after two days time period. Moreover, high gene expression levels were observed after 96 h of transfection. CNs-pDNA treatment, despite the absence of oxidative stress induction, caused cell cycle arrest in G0/G1 phase and as a consequence led to premature senescence which turned out to be both p21-dependent and p21-independent. Also, observed DNMT2 upregulation may suggest the activation of different pathways protecting from the results of CNs-mediated stress. In conclusion, treatment of different cell lines with CNs-pDNA showed that their biocompatibility was limited and the effects were cell type-dependent

Advances in microfluidic synthesis and coupling with synchrotron SAXS for continuous production and real-time structural characterization of nano-self-assemblies

Microfluidic platforms have become highly attractive tools for synthesis of nanoparticles, including lipid nano-self-assemblies, owing to unique features and at least three important aspects inherent to miniaturized micro-devices. Firstly, the fluids flow under controlled conditions in the microchannels, providing well-defined flow profiles and shorter diffusion lengths that play important roles in enhancing the continuous production of lipid and polymer nanoparticles with relatively narrow size distributions. Secondly, various geometries adapted to microfluidic device designs can be utilized for enhancing the colloidal stability of nanoparticles and improving their drug loading. Thirdly, microfluidic devices are usually compatible with in situ characterization methods for real-time monitoring of processes occurring inside the microchannels. This is unlike conventional nanoparticle synthesis methods, where a final solution or withdrawn aliquots are separately analysed. These features inherent to microfluidic devices provide a tool-set allowing not only precise nanoparticle size control, but also real-time analyses for process optimization. In this review, we focus on recent advances and developments in the use of microfluidic devices for synthesis of lipid nanoparticles. We present different designs based on hydrodynamic flow focusing, droplet-based methods and controlled microvortices, and discuss integration of microfluidic platforms with synchrotron small-angle X ray scattering (SAXS) for in situ structural characterization of lipid nano-self-assemblies under continuous flow conditions, along with major challenges and future directions in this research area.INP grant from the Danish Agency for Science and Higher Education [8073-00022B]AY and OYC acknowledge the INP grant (Ref. no.: 8073-00022B) from the Danish Agency for Science and Higher Education for initiating and exploring new networking and collaboration opportunities between Danish and Turkish research institutions

A structurally diverse library of glycerol monooleate/oleic acid non-lamellar liquid crystalline nanodispersions stabilized with nonionic methoxypoly(ethylene glycol) (mPEG)-lipids showing variable complement activation properties

Pluronic F127-stabilized non-lamellar liquid crystalline aqueous nanodispersions are promising injectable platforms for drug and contrast agent delivery. These nanodispersions, however, trigger complement activation in the human blood, where the extent of complement activation and opsonization processes may compromise their biological performance and safety. Here, we introduce a broad family of nanodispersions from glycerol monooleate (GMO) and oleic acid (OA) in different weight ratios, and stabilized with a plethora of nonionic methoxypoly(ethylene glycol) (mPEG)-lipids of different PEG chain length and variable lipid moiety (monounsaturated or saturated diglycerides or D-α-tocopheryl succinate). Through an integrated biophysical approach involving dynamic light scattering, synchrotron small-angle scattering, and cryo-transmission electron microscopy, we examine the impact of nonionic mPEG-lipid stabilization on size, internal self-assembled architecture, and gross morphological characteristics of nanodispersions. The results show how the nonionic mPEG-lipid type and concentration, and dependent on GMO/OA weight ratio, can variably modulate the internal architectures of nanoparticles. Assessment of complement profiling from selected nanodispersions with diverse structural heterogeneity further suggests a variable modulatory role for the lipid type of the nonionic mPEG-lipid in the extent of complement activation, which span from no activation to moderate to high levels. We comment on plausible mechanisms driving the observed complement activation variability and discuss the potential utility of these nanodispersions for future development of injectable nanopharmaceuticals

Synthesis of bioactive hemoglobin-based oxygen carrier nanoparticles via metal-phenolic complexation

The transfusion of donor red blood cells (RBCs) is seriously hampered by important drawbacks that include limited availability and portability, the requirement of being stored in refrigerated conditions, a short shelf life or the need for RBC group typing and crossmatching. Thus, hemoglobin (Hb)-based oxygen (O2) carriers (HBOCs) which make use of the main component of RBCs and the responsible protein for O2 transport, hold a lot of promise in modern transfusion and emergency medicine. Despite the great progress achieved, it is still difficult to create HBOCs with a high Hb content to attain the high O2 demands of our body. Herein a metal–phenolic self-assembly approach that can be conducted in water and in one step to prepare nanoparticles (NPs) fully made of Hb (Hb-NPs) is presented. In particular, by combining Hb with polyethylene glycol, tannic acid (TA) and manganese ions, spherical Hb-NPs with a uniform size around 350–525 nm are obtained. The functionality of the Hb-NPs is preserved as shown by their ability to bind and release O2 over multiple rounds. The binding mechanism of TA and Hb is thoroughly investigated by UV–vis absorption and fluorescence spectroscopy. The binding site number, apparent binding constant at two different temperatures and the corresponding thermodynamic parameters are identified. The results demonstrate that the TA-Hb interaction takes place through a static mechanism in a spontaneous process as shown by the decrease in Gibbs free energy. The associated increase in entropy suggests that the TA-Hb binding is dominated by hydrophobic interactions.</p