Influence of Eu3+ Doping on Physiochemical Properties and Neuroprotective Potential of Polyacrylic Acid Functionalized Cerium Oxide Nanoparticles.

Cerium oxide nanoparticles (CeONPs) exhibiting antioxidant properties are investigated as potential tools for neurodegenerative diseases. Here, we synthesized polyacrylic acid conjugated cerium oxide (CeO) nanoparticles, and further to enhance their neuroprotective effect, Eu3+ was substituted at different concentrations (5, 10, 15 and 20 mol%) to the CeO, which can also impart fluorescence to the system. CeONPs and Eu-CeONPs in the size range of 15-30 nm were stable at room temperature. The X-ray Photoelectron Spectroscopy (XPS) analysis revealed the chemical state of Eu and Ce components, and we could conclude that all Eu3+ detected on the surface is well integrated into the cerium oxide lattice. The emission spectrum of Eu-CeO arising from the 7F0 → 5D1 MD and 7F0 → 5D2 transitions indicated the Eu3+ ion acting as a luminescence center. The fluorescence of Eu-CeONPs was visualized by depositing them at the surface of positively charged latex particles. The developed nanoparticles were safe for human neuronal-like cells. Compared with CeONPs, Eu-CeONPs at all concentrations exhibited enhanced neuroprotection against 6-OHDA, while the protection trend of Eu-CeO was similar to that of CeO against H2O2 in SH-SY5Y cells. Hence, the developed Eu-CeONPs could be further investigated as a potential theranostic probe.

New SDS-Based Polyelectrolyte Multicore Nanocarriers for Paclitaxel Delivery-Synthesis, Characterization, and Activity against Breast Cancer Cells.

The low distribution of hydrophobic anticancer drugs in patients is one of the biggest limitations during conventional chemotherapy. SDS-based polyelectrolyte multicore nanocarriers (NCs) prepared according to the layer by layer (LbL) procedure can release paclitaxel (PTX), and selectively kill cancer cells. Our main objective was to verify the antitumor properties of PTX-loaded NCs and to examine whether the drug encapsulated in these NCs retained its cytotoxic properties. The cytotoxicity of the prepared nanosystems was tested on MCF-7 and MDA-MB-231 tumour cells and the non-cancerous HMEC-1 cell line in vitro. Confocal microscopy, spectrophotometry, spectrofluorimetry, flow cytometry, and RT PCR techniques were used to define the typical hallmarks of apoptosis. It was demonstrated that PTX encapsulated in the tested NCs exhibited similar cytotoxicity to the free drug, especially in the triple negative breast cancer model. Moreover, SDS/PLL/PTX and SDS/PLL/PGA/PTX significantly reduced DNA synthesis. In addition, PTX-loaded NCs triggered apoptosis and upregulated the transcription of Bax, AIF, cytochrome-c, and caspase-3 mRNA. Our data demonstrate that these novel polyelectrolyte multicore NCs coated with PLL or PLL/PGA are good candidates for delivering PTX. Our discoveries have prominent implications for the possible choice of newly synthesized, SDS-based polyelectrolyte multicore NCs in different anticancer therapeutic applications.

Fluorophore Localization Determines the Results of Biodistribution of Core-Shell Nanocarriers.

INTRODUCTION: Biodistribution of nanocarriers with a structure consisting of core and shell is most often analyzed using methods based on labeling subsequent compartments of nanocarriers. This approach may have serious limitations due to the instability of such complex systems under in vivo conditions. METHODS: The core-shell polyelectrolyte nanocarriers were intravenously administered to healthy BALB/c mice with breast cancer. Next, biodistribution profiles and elimination routes were determined post mortem based on fluorescence measurements performed for isolated blood, tissue homogenates, collected urine, and feces. RESULTS: Despite the surface PEGylation with PLL-g-PEG, multilayer polyelectrolyte nanocarriers undergo rapid degradation after intravenous administration. This process releases the shell components but not free Rhodamine B. Elements of polyelectrolyte shells are removed by hepatobiliary and renal clearance. CONCLUSION: Multilayer polyelectrolyte nanocarriers are prone to rapid degradation after intravenous administration. Fluorophore localization determines the obtained results of biodistribution and elimination routes of core-shell nanomaterials. Therefore, precise and reliable analysis of in vivo stability and biodistribution of nanomaterials composed of several compartments requires nanomaterials labeled within each compartment.

Polyaminoacid Based Core@shell Nanocarriers of 5-Fluorouracil: Synthesis, Properties and Theranostics Application.

Cancer is one of the most important health problems of our population, and one of the common anticancer treatments is chemotherapy. The disadvantages of chemotherapy are related to the drug's toxic effects, which act on cancer cells and the healthy part of the body. The solution of the problem is drug encapsulation and drug targeting. The present study aimed to develop a novel method of preparing multifunctional 5-Fluorouracil (5-FU) nanocarriers and their in vitro characterization. 5-FU polyaminoacid-based core@shell nanocarriers were formed by encapsulation drug-loaded nanocores with polyaminoacids multilayer shell via layer-by-layer method. The size of prepared nanocarriers ranged between 80-200 nm. Biocompatibility of our nanocarriers as well as activity of the encapsulated drug were confirmed by MTT tests. Moreover, the ability to the real-time observation of developed nanocarriers and drug accumulation inside the target was confirmed by fluorine magnetic resonance imaging (19F-MRI).

Nafion-Based Nanocarriers for Fluorine Magnetic Resonance Imaging.

The aim of our study was to develop a novel method for nanocarriers' preparation as a fluorine magnetic resonance imaging (19F MRI)-detectable drug delivery system. The novelty of the proposed approach is based on the application of fluorinated polyelectrolyte Nafion as a contrast agent since typical MRI contrast agents are based on paramagnetic gadolinium or ferro/superparamagnetic iron oxide compounds. An advantage of using an 19F-based tracer comes from the fact that the 19F image is detected at a different resonance frequency than the 1H image. In addition, the close to zero natural concentration of 19F nuclei in the human body makes fluorine atoms a promising MRI marker without any natural background signal. That creates the opportunity to localize and identify only exogenous fluorinated compounds with 100% specificity. The nanocarriers were formed by the deposition of polyelectrolytes on nanoemulsion droplets via the layer-by-layer technique with the saturation approach. The polyelectrolyte multilayer shell was composed of Nafion, the fluorinated ionic polymer used for labeling by 19F nuclei, and poly-l-lysine (PLL). The surface of such prepared nanocarriers was further pegylated by adsorption of pegylated polyanion, poly-l-glutamic acid (PGA). The 19F MRI-detectable hydrophobic nanocarriers with an average size of 170 nm and a sufficient signal-to-noise ratio have been developed and optimized to be used for passive tumor targeting and drug delivery.

Polymeric Core-Shell Nanoparticles Prepared by Spontaneous Emulsification Solvent Evaporation and Functionalized by the Layer-by-Layer Method.

The aim of our study was to develop a novel method for the preparation of polymeric core-shell nanoparticles loaded with various actives for biomedical applications. Poly(caprolactone) (PCL), poly(lactic acid) (PLA) and poly(lactide-co-glycolide) (PLGA) nanoparticles were prepared using the spontaneous emulsification solvent evaporation (SESE) method. The model active substance, Coumarin-6, was encapsulated into formed polymeric nanoparticles, then they were modified/functionalized by multilayer shells' formation. Three types of multilayered shells were formed: two types of polyelectrolyte shell composed of biocompatible and biodegradable polyelectrolytes poly-L-lysine hydrobromide (PLL), fluorescently-labeled poly-L-lysine (PLL-ROD), poly-L-glutamic acid sodium salt (PGA) and pegylated-PGA (PGA-g-PEG), and hybrid shell composed of PLL, PGA, and SPIONs (superparamagnetic iron oxide nanoparticles) were used. Multilayer shells were constructed by the saturation technique of the layer-by-layer (LbL) method. Properties of our polymeric core-shell nanoparticle were optimized for bioimaging, passive and magnetic targeting.

Magnetically responsive polycaprolactone nanocarriers for application in the biomedical field: magnetic hyperthermia, magnetic resonance imaging, and magnetic drug delivery.

There are huge demands on multifunctional nanocarriers to be used in nanomedicine. Herein, we present a simple and efficient method for the preparation of multifunctional magnetically responsive polymeric-based nanocarriers optimized for biomedical applications. The hybrid delivery system is composed of drug-loaded polymer nanoparticles (poly(caprolactone), PCL) coated with a multilayer shell of polyglutamic acid (PGA) and superparamagnetic iron oxide nanoparticles (SPIONs), which are known as bio-acceptable components. The PCL nanocarriers with a model anticancer drug (Paclitaxel, PTX) were formed by the spontaneous emulsification solvent evaporation (SESE) method, while the magnetically responsive multilayer shell was formed via the layer-by-layer (LbL) method. As a result, we obtained magnetically responsive polycaprolactone nanocarriers (MN-PCL NCs) with an average size of about 120 nm. Using the 9.4 T preclinical magnetic resonance imaging (MRI) scanner we confirmed, that obtained MN-PCL NCs can be successfully used as a MRI-detectable drug delivery system. The magnetic hyperthermia effect of the MN-PCL NCs was demonstrated by applying a 25 mT radio-frequency (f = 429 kHz) alternating magnetic field. We found a Specific Absorption Rate (SAR) of 55 W g-1. The conducted research fulfills the first step of investigation for biomedical application, which is mandatory for the planning of any in vitro and in vivo studies.

In vivo Studies on Pharmacokinetics, Toxicity and Immunogenicity of Polyelectrolyte Nanocapsules Functionalized with Two Different Polymers: Poly-L-Glutamic Acid or PEG.

BACKGROUND: The functionalization of a nanoparticle surface with PEG (polyethylene glycol) is an approach most often used for extending nanomaterial circulation time, enhancing its delivery and retention in the target tissues, and decreasing systemic toxicity of nanocarriers and their cargos. However, because PEGylated nanomedicines were reported to induce immune response including production of anti-PEG antibodies, activation of the complement system as well as hypersensitivity reactions, hydrophilic polymers other than PEG are gaining interest as its replacement in nanomaterial functionalization. Here, we present the results of in vivo evaluation of polyelectrolyte nanocapsules with biodegradable, polyelectrolyte multilayer shells consisting of poly-l-lysine (PLL) and poly-l-glutamic (PGA) acid as a potential drug delivery system. We compared the effects of nanocapsules functionalized with two different "stealth" polymers as the external layer of tested nanocapsules was composed of PGA (PGA-terminated nanocapsules, NC-PGA) or the copolymer of poly-l-lysine and polyethylene glycol (PEG-terminated nanocapsules, NC-PEG). METHODS: Nanocapsules pharmacokinetics, biodistribution and routes of eliminations were analysed postmortem by fluorescence intensity measurement. Toxicity of intravenously injected nanocapsules was evaluated with analyses of blood morphology and biochemistry and by histological tissue analysis. DNA integrity was determined by comet assay, cytokine profiling was performed using flow cytometer and detection of antibodies specific to PEG was performed by ELISA assay. RESULTS: We found that NC-PGA and NC-PEG had similar pharmacokinetic and biodistribution profiles and both were eliminated by hepatobiliary and renal clearance. Biochemical and histopathological evaluation of long-term toxicity performed after a single as well as repeated intravenous injections of nanomaterials demonstrated that neither NC-PGA nor NC-PEG had any acute or chronic hemato-, hepato- or nephrotoxic effects. In contrast to NC-PGA, repeated administration of NC-PEG resulted in prolonged increased serum levels of a number of cytokines. CONCLUSION: Our results indicate that NC-PEG may cause undesirable activation of the immune system. Therefore, PGA compares favorably with PEG in equipping nanomaterials with stealth properties. Our research points to the importance of a thorough assessment of the potential influence of nanomaterials on the immune system.

Gadolinium labeled polyelectrolyte nanocarriers for theranostic application.

Here, we designed a novel Gadolinium (Gd) labeled drug-loaded polyelectrolyte nanocarriers for theranostics. The nanocarriers were formed via layer-by-layer technique with biodegradable polyelectrolytes: PLL (Poly-L-lysine), PLL-Gd (Gadolinium-labeled Poly-L-lysine) and PGA (Poly-L-glutamic acid). Anticancer drug (Paclitaxel) was encapsulated in the formed nanocarriers. The average size of synthesized nanocarriers was around 150 nm. The empty gadolinium labeled nanocarriers did not show any deleterious effects on tested cells (CT26-CEA, B16F10, 4T1 and PBMC), whereas encapsulated paclitaxel retained its cytotoxic/cytostatic activity. Using T2 and T1 NMR relaxation measurements with 9.4 T preclinical MRI scanner, we demonstrated that gadolinium labeled nanocarriers can be detected due to a locally altered contrast in the MR image. Thus, they may become a promising platform for future theranostic applications.