Impact of free curcumin and curcumin nanocapsules on viability and oxidative status of neural cell lines.

Curcumin is an active polyphenol substance found in the highest concentrations in the roots of Curcuma longa. Its health benefits have led to recent increases in the consumption of curcumin. It has anti-inflammatory and antioxidant activities and is a potent neuroprotective against diseases of the brain. Nevertheless, its low bioavailability and its relative difficulty crossing the blood-brain barrier limit curcumin's use for these purposes. Curcumin-loaded nanoparticles may be an effective treatment for several diseases although there is a paucity of studies reporting its safety in the central nervous system (CNS). Therefore, this study aimed to identify non-neurotoxic concentrations of free curcumin and two nanoformulations of curcumin. Cell lines BV-2 and SH-SY5Y, both originating from the CNS, were evaluated after 24, 48, and 72 h of treatment with free curcumin and nanocapsules We measured viability, proliferation, and dsDNA levels. We measured levels of reactive oxygen species and nitric oxide as proxies for oxidative stress in culture supernatants. We found that free curcumin was toxic at 10 and 20 µM, principally at 72 h. Nanoformulations were more neurotoxic than the free form. Safe concentrations of free curcumin are between 1-5 µM, and these concentrations were lower for nanoformulations. We determined the ideal concentrations of free curcumin and nanocapsules serving as a basis for studies of injuries that affect the CNS.

Azo modified hyaluronic acid based nanocapsules: CD44 targeted, UV-responsive decomposition and drug release in liver cancer cells.

Herein, we demonstrate a novel UV-induced decomposable nanocapsule of natural polysaccharide (HA-azo/PDADMAC). The nanocapsules are fabricated based on layer-by-layer co-assembly of anionic azobenzene functionalized hyaluronic acid (HA-azo) and cationic poly diallyl dimethylammonium chloride (PDADMAC). When the nanocapsules are exposed to 365 nm light, ultraviolet photons can trigger the photo-isomerization of azobenzene groups in the framework. The nanocapsules could decompose from large-sized nanocapsules to small fragments. Due to their optimized original size (~180 nm), the nanocapsules can effectively avoid biological barriers, provide a long blood circulation and achieve high tumor accumulation. It can fast eliminate nanocapsules from tumor and release the loaded drugs for chemotherapy after UV-induced dissociation. Besides, HA is an endogenous polysaccharide that shows intrinsic targetability to CD44 receptors on surface of cancer cells. The intracellular experiment shows that the HA-azo/PDADMAC nanocapsules with CD44 targeting ability and UV-controlled intracellular drug release are promising for cancer chemotherapy.

Sonochemical preparation of folate-decorated reductive-responsive carboxymethylcellulose-based nanocapsules for targeted drug delivery.

In this study, a biocompatible folate-decorated reductive-responsive carboxymethylcellulose-based nanocapsules (FA-RCNCs) were designed and prepared via sonochemical method for targeted delivery and controlled release of hydrophobic drugs. The shell of FA-RCNCs was cross-linked by disulfide bonds formed from hydrosulfuryl groups on the thiolated carboxymethylcellulose (TCMC) and encapsulated hydrophobic drug dispersed in the oil phase into nanocapsules. Moreover, the size and morphology of drug loaded FA-RCNCs were characterized by DLS, SEM and CLSM which indicated that the synthesized nanocapsules have suitable size range and excellent stability for circulating in the bloodstream. The drug release rate of FA-RCNCs could be controlled by adjusting their sizes and shell thickness, which could be dominated by the concentration of TCMC and sonochemical conditions. Furthermore, the obtained FA-RCNCs could be ingested into Hela cells via folate-receptor (FR)-mediated endocytosis and quickly release drugs under reductive environment, which demonstrated that FA-RCNCs could become potential hydrophobic drugs carries for cancer therapy.

Photosensitive nanocarriers for specific delivery of cargo into cells.

Nanoencapsulation is a rapidly expanding technology to enclose cargo into inert material at the nanoscale size, which protects cargo from degradation, improves bioavailability and allows for controlled release. Encapsulation of drugs into functional nanocarriers enhances their specificity, targeting ability, efficiency, and effectiveness. Functionality may come from cell targeting biomolecules that direct nanocarriers to a specific cell or tissue. Delivery is usually mediated by diffusion and erosion mechanisms, but in some cases, this is not sufficient to reach the expected therapeutic effects. This work reports on the development of a new photoresponsive polymeric nanocarrier (PNc)-based nanobioconjugate (NBc) for specific photo-delivery of cargo into target cells. We readily synthesized the PNcs by modification of chitosan with ultraviolet (UV)-photosensitive azobenzene molecules, with Nile red and dofetilide as cargo models to prove the encapsulation/release concept. The PNcs were further functionalized with the cardiac targeting transmembrane peptide and efficiently internalized into cardiomyocytes, as a cell line model. Intracellular cargo-release was dramatically accelerated upon a very short UV-light irradiation time. Delivering cargo in a time-space controlled fashion by means of NBcs is a promising strategy to increase the intracellular cargo concentration, to decrease dose and cargo side effects, thereby improving the effectiveness of a therapeutic regime.

Biological response and cytotoxicity induced by lipid nanocapsules.

BACKGROUND: Lipid nanocapsules (LNCs) are promising vehicles for drug delivery. However, since not much was known about cellular toxicity of these nanoparticles in themselves, we have here investigated the mechanisms involved in LNC-induced intoxication of the three breast cancer cell lines MCF-7, MDA-MD-231 and MDA-MB-468. The LNCs used were made of Labrafac™ Lipophile WL1349, Lipoid® S75 and Solutol® HS15. RESULTS: High resolution SIM microscopy showed that the DiD-labeled LNCs ended up in lysosomes close to the membrane. Empty LNCs, i.e. without encapsulated drug, induced not only increased lysosomal pH, but also acidification of the cytosol and a rapid inhibition of protein synthesis. The cytotoxicity of the LNCs were measured for up to 72 h of incubation using the MTT assay and ATP measurements in all three cell lines, and revealed that MDA-MB-468 was the most sensitive cell line and MCF-7 the least sensitive cell line to these LNCs. The LNCs induced generation of reactive free oxygen species and lipid peroxidation. Experiments with knock-down of kinases in the near-haploid cell line HAP1 indicated that the kinase HRI is essential for the observed phosphorylation of eIF2α. Nrf2 and ATF4 seem to play a protective role against the LNCs in MDA-MB-231 cells, as knock-down of these factors sensitizes the cells to the LNCs. This is in contrast to MCF-7 cells where the knock-down of these factors had a minor effect on the toxicity of the LNCs. Inhibitors of ferroptosis provided a large protection against LNC toxicity in MDA-MB-231 cells, but not in MCF-7 cells. CONCLUSIONS: High doses of LNCs showed a different degree of toxicity on the three cell lines studied, i.e. MCF-7, MDA-MD-231 and MDA-MB-468 and affected signaling factors and the cell fate differently in these cell lines.

Encapsulation of Doxorubicin in Furcellaran/Chitosan Nanocapsules by Layer-by-Layer Technique for Selectively Controlled Drug Delivery.

Minimization of drug side effects is a hallmark of advanced targeted therapy. Herein we describe the synthesis of polysaccharide-based nanocapsules prepared from furcellaran and chitosan via layer-by-layer deposition using electrostatic interaction. Using doxorubicin as a model drug, prepared nanocapsules showed excellent drug loading properties and release influence by pH and stability. Targeted delivery of doxorubicin was achieved by nanocapsule surface modification using homing peptide (seq SMSIARLC). The synthesized nanocapsules possess excellent compatibility to eukaryotic organisms. In the case of nonmalignant cells (PNT1A and HEK-293), toxicity tests revealed the absences of DNA fragmentation, apoptosis, necrosis, and also disruption of erythrocyte membranes. In contrast, results from treatment of malignant cell lines (MDA-MB-231 and PC3) indicate good anticancer effects of synthesized bionanomaterial. Internalization studies revealed the nanocapsule's ability to enter the malignant cell lines by endocytosis and triggering the apoptosis. The occurrence of apoptosis is mostly connected to the presence of ROS and inability of DNA damage reparation. Additionally, the obtained results strongly indicate that peptide modification increases the speed of nanocapsule internalization into malignant cell lines while simultaneously nonmalignant cell lines are untouched by nanocapsules highlighting the strong selectivity of the peptide.

Anthelmintic activity of nanoencapsulated carvacryl acetate against gastrointestinal nematodes of sheep and its toxicity in rodents / Atividade anti-helmíntica do acetato de carvacrila nanoencapsulado sobre nematoides gastrintestinais de ovinos e toxicidade em roedores

Abstract The objective of this study was to evaluate the efficacy of carvacryl acetate (CVA) and nanoencapsulated CVA (nCVA) on gastrointestinal nematodes of sheep. The CVA was nanoencapsulated with chitosan/gum arabic and the efficacy of nanoencapsulation (EE), yield, zeta potential, nanoparticle morphology and release kinetics at pH 3 and 8 were analyzed. Acute and subchronic toxicity were evaluated in rodents and reduction of egg counts in the faeces (FECRT) of sheep. The sheep were divided into four groups (n = 10): G1, 250 mg/kg CVA; G2, 250 mg/kg nCVA; G3, polymer matrix and G4: 2.5 mg/kg monepantel. EE and nCVA yield were 65% and 57%, respectively. The morphology of the nanoparticles was spherical, size (810.6±286.7 nm), zeta potential in pH 3.2 (+18.3 mV) and the 50% release of CVA at pHs 3 and 8 occurred at 200 and 10 h, respectively. nCVA showed LD50 of 2,609 mg/kg. CVA, nCVA and monepantel reduced the number of eggs per gram of faeces (epg) by 57.7%, 51.1% and 97.7%, respectively. The epg of sheep treated with CVA and nCVA did not differ from the negative control (P>0.05). Nanoencapsulation reduced the toxicity of CVA; however, nCVA and CVA presented similar results in the FECRT.

Resumo O objetivo deste trabalho foi avaliar a eficácia do acetato de carvacrila (ACV) e do ACV nanoencapsulado (nACV) sobre nematóides gastrintestinais de ovinos. O ACV foi nanoencapsulado com quitosana/goma arábica e foi analisada a eficácia de nanoencapsulamento (EE), o rendimento, potencial zeta, morfologia das nanopartículas e cinética de liberação em pH 3 e 8. Foram avaliadas as toxicidades aguda e subcrônica em roedores e a redução da contagem de ovos nas fezes (RCOF) de ovinos. Os ovinos foram divididos em quatro grupos (n = 10): G1, 250 mg/kg ACV; G2, 250 mg/kg de nACV; G3, matriz polimérica e G4: 2,5 mg/kg de monepantel. A EE e o rendimento de nACV foram de 65% e 57%, respectivamente. A morfologia das nanopartículas foi esférica, tamanho (810,6±286,7 nm), potencial zeta no pH 3,2 (+18,3 mV) e a liberação de 50% de CVA nos pHs 3 e 8 ocorreu às 200 e 10 h, respectivamente. nACV apresentou DL50 de 2.609 mg/kg. ACV, nACV e o monepantel reduziram a contagem de ovos por grama de fezes (opg) em 57,7%, 51,1% e 97,7%, respectivamente. A contagem de opg de ovelhas tratadas com ACV e nCVA não diferiu do controle negativo (P>0,05). O nanoencapsulamento reduziu a toxicidade do AVC; no entanto, nACV e ACV apresentaram resultados semelhantes na RCOF.

Self-assembly of stimuli-responsive imine-linked calix[4]arene nanocapsules for targeted camptothecin delivery.

Here we report template-free synthesis of imine-linked calix[4]arene hollow nanocapsules and their utility in the effective delivery of a poorly soluble cancer drug into tumor cells. These stimuli-responsive nanocapsules show high drug loading and release which resulted in a 40-fold higher cytotoxicity for breast cancer cell line over normal cells.

Nanoencapsulation of the flavonoid dihydromyricetin protects against the genotoxicity and cytotoxicity induced by cationic nanocapsules.

We evaluated the influence of nanoencapsulation of the flavonoid Dihydromyricetin (DMY) in reducing the genotoxicity and cytotoxicity induced by cationic nanocapsules. Assays were conducted in order to evaluate the potential of protein corona formation, cytotoxicity, genotoxicity and the antioxidant capacity. Nanocapsules containing DMY (NC-DMY) and free DMY (DMY-F) did not demonstrate cytotoxicity and genotoxicity. However, Eudragit RS100® nanocapsules (NC-E) increased cytotoxicity and DNA damage formation. NC-DMY and NC-E presented high interaction with the DNA in vitro, suggesting DNA sequestration. These results indicate that nanoencapsulated DMY does not induce cytotoxicity or genotoxicity, and demonstrates high antioxidant capacity. This antioxidant capacity is probably associated with DMY, and occurs due to its ability to avoid the formation of free radicals, thus preventing the toxicity caused by the nanostructure with the cationic polymer Eudragit RS100®. Therefore, NC-DMY can be considered an important formulation with significant antioxidant potential to be exploited by nanomedicine.

Zwitterionic Cross-Linked Biodegradable Nanocapsules for Cancer Imaging.

Zwitterionic cross-linked biodegradable nanocapsules (NCs) were synthesized for cancer imaging. A polylactide (PLA)-based diblock copolymer with two blocks carrying acetylenyl and allyl groups respectively was synthesized by ring-opening polymerization (ROP). Azide-alkyne "click" reaction was conducted to conjugate sulfobetaine (SB) zwitterions and fluorescent dye Cy5.5 onto the acetylenyl-functionalized first block of the diblock copolymer. The resulting copolymer with a hydrophilic SB/Cy5.5-functionalized PLA block and a hydrophobic allyl-functionalized PLA block could stabilize miniemulsions because of its amphiphilic diblock structure. UV-induced thiol-ene "click" reaction between a dithiol cross-linker and the hydrophobic allyl-functionalized block of the copolymer at the peripheral region of nanoscopic oil nanodroplets in the miniemulsion generated cross-linked polymer NCs with zwitterionic outer shells. These NCs showed an average hydrodynamic diameter ( Dh) of 136 nm. They exhibited biodegradability, biocompatibility and high colloidal stability. In vitro study indicated that these NCs could be taken up by MIA PaCa-2 cancer cells. In vivo imaging study showed that, comparing to a small molecule dye, NCs had a longer circulation time, facilitating their accumulation at tumors for cancer imaging. Overall, this work demonstrates the applicability of zwitterionic biodegradable polymer-based materials in cancer diagnosis.

In vitro toxicity studies of biodegradable, polyelectrolyte nanocapsules.

BACKGROUND: Toxicity of nanomaterials is one of the most important factors limiting their medical application. Evaluation of in vitro nanotoxicity allows for the identification and elimination of most of the toxic materials prior to animal testing. The current knowledge of the possible side effects of biodegradable nanomaterials, such as liposomes and polymeric organic nanoparticles, is limited. Previously, we developed a potential drug delivery system in the form of nanocapsules with polyelectrolyte, biodegradable shells consisting of poly-l-lysine and poly-l-glutamic acid (PGA), formed by the layer-by-layer adsorption technique. METHODS: Hemolysis assay, viability tests, flow cytometry analysis of vascular cell adhesion molecule-1 expression on endothelium, analysis of nitric oxide production, measurement of intracellular reactive oxygen species levels, detection of antioxidant enzyme activity, and analysis of DNA damage with comet assay were performed to study the in vitro toxicity of nanocapsules. RESULTS: In this work, we present the results of an in vitro analysis of toxicity of five-layer positively charged poly-l-lysine-terminated nanocapsules (NC5), six-layer negatively charged PGA-terminated nanocapsules (NC6) and five-layer PEGylated nanocapsules (NC5-PEG). PGA and polyethylene glycol (PEG) were used as two different "stealth" polymers. Of all the polyelectrolyte nanocapsules tested for blood compatibility, only cationic NC5 showed acute toxicity toward blood cells, expressed as hemolysis and aggregation. Neither NC6 nor NC5-PEG had proinflammatory activity evaluated through changes in the expression of NF-κB-dependent genes, iNOS and vascular cell adhesion molecule-1, induced oxidative stress, or promoted DNA damage in various cells. CONCLUSION: Our studies clearly indicate that PGA-coated (negatively charged) and PEGylated polyelectrolyte nanocapsules do not show in vitro toxicity, and their potential as a drug delivery system may be safely studied in vivo.

Nanoencapsulation of benznidazole in calcium carbonate increases its selectivity to Trypanosoma cruzi.

Chagas disease is a public health problem, affecting about 7 million people worldwide. Benznidazole (BZN) is the main treatment option, but it has limited effectiveness and can cause severe adverse effects. Drug delivery through nanoparticles has attracted the interest of the scientific community aiming to improve therapeutic options. The aim of this study was to evaluate the cytotoxicity of benznidazole-loaded calcium carbonate nanoparticles (BZN@CaCO3) on Trypanosoma cruzi strain Y. It was observed that BZN@CaCO3 was able to reduce the viability of epimastigote, trypomastigote and amastigote forms of T. cruzi with greater potency when compared with BZN. The amount of BZN necessary to obtain the same effect was up to 25 times smaller when loaded with CaCO3 nanoparticles. Also, it was observed that BZN@CaCO3 enhanced the selectivity index. Furthermore, the cell-death mechanism induced by both BZN and BZN@CaCO3 was evaluated, indicating that both substances caused necrosis and changed mitochondrial membrane potential.

Engineering pectin-based hollow nanocapsules for delivery of anticancer drug.

Multifunctional capsules have great applications in biomedical fields. In this study, novel polysaccharide-based nanocapsules were prepared via a layer-by-layer technique using silica as the templates. The shell was constructed based on the electrostatic interactions between pectin and chitosan. The pectin-chitosan nanocapsules ((Pec/Cs)3Pec) could keep good colloidal stability within 96h in PBS solution and 48h in BSA solution. Meanwhile, the nanocapsules exhibited a high drug loading and pH-sensitive release property for doxorubicin hydrochloride. Moreover, (Pec/Cs)3Pec nanocapsules had no cytotoxicity to both human hepatocellular carcinoma cells (HepG2 cells) and mouse fibroblast cells (L929 cells). More importantly, (Pec/Cs)3Pec nanocapsules could be more easily uptaken by HepG2 cells when compared with L929 cells. In vitro anticancer activity tests indicated the carriers could effectively kill HepG2 cells. Overall, (Pec/Cs)3Pec nanocapsules have great potential as a novel anticancer drug carrier as a result of their pH-sensitivity, good colloidal stability and anticancer activity.

Nanoencapsulation Improves Scavenging Capacity and Decreases Cytotoxicity of Silibinin and Pomegranate Oil Association.

Silibinin (SB) and pomegranate oil (PO) present therapeutic potential due to antioxidant activity, but the biological performance of both bioactives is limited by their low aqueous solubility. To overcome this issue, the aim of the present investigation was to develop nanocapsule suspensions with PO as oil core for SB encapsulation, as well as assess their toxicity in vitro and radical scavenging activity. The nanocapsule suspensions were prepared by interfacial deposition of preformed polymer method. SB-loaded PO-based nanocapsules (SBNC) showed an average diameter of 157 ± 3 nm, homogenous size distribution, zeta potential of -14.1 ± 1.7 mV, pH of 5.6 ± 0.4 and SB content close to 100%. Similar results were obtained for the unloaded formulation (PONC). The nanocapsules controlled SB release at least 10 times as compared with free SB in methanolic solution. The SBNC scavenging capacity in vitro was statistically higher than free SB (p < 0.05). Cell viability in monocytes and lymphocytes was kept around 100% in the treatments with SBNC and PONC, while the SB and the PO caused a decrease around 30% at 50 µM (SB) and 724 µg/mL (PO). Protein carbonyls and DNA damage were minimized by SB and PO nanoencapsulation. Lipid peroxidation occurred in nanocapsule treatments regardless of the SB presence, which may be attributed to PO acting as substrate in reaction. The free compounds also caused lipid peroxidation. The results show that SBNC and PONC presented adequate physicochemical characteristics and low toxicity against human blood cells. Thereby, this novel nanocarrier may be a promising formulation for therapeutic applications.

Initiator-Loaded Gold Nanocages as a Light-Induced Free-Radical Generator for Cancer Therapy.

Tumor hypoxia greatly suppresses the therapeutic efficacy of photodynamic therapy (PDT), mainly because the generation of toxic reactive oxygen species (ROS) in PDT is highly oxygen-dependent. In contrast to ROS, the generation of oxygen-irrelevant free radicals is oxygen-independent. A new therapeutic strategy based on the light-induced generation of free radicals for cancer therapy is reported. Initiator-loaded gold nanocages (AuNCs) as the free-radical generator were synthesized. Under near-infrared light (NIR) irradiation, the plasmonic heating effect of AuNCs can induce the decomposition of the initiator to generate alkyl radicals (R. ), which can elevate oxidative-stress (OS) and cause DNA damages in cancer cells, and finally lead to apoptotic cell death under different oxygen tensions. As a proof of concept, this research opens up a new field to use various free radicals for cancer therapy.

Enhanced photostability, radical scavenging and antitumor activity of indole-3-carbinol-loaded rose hip oil nanocapsules.

This study aimed to develop poly(ε-caprolactone) nanocapsules loaded with indole-3-cabinol (I3C) using rose hip oil (RHO) or medium chain triglycerides (MCT) as oil core. In vitro radical scavenging activity (DPPH method), hemolysis, and antitumor effects on breast (MCF-7) and glioma (C6) cells were conducted. Preformulation evaluations revealed that RHO is suitable to prepare the nanocapsules considering the log P determination and dissolution/swelling experiments of polymer films. The nanocapsules were prepared and presented adequate physicochemical characteristics as mean size around 250nm, polydispersity index values <0.2, zeta potential negative values and I3C encapsulation efficiency around 42%, without any influence of the oil core (RHO or MCT) on these parameters. However, the photodegradation study demonstrated that RHO nanocapsules showed less degree of I3C degradation in comparison to MCT nanocapsules. The in vitro release profile showed that both nanocapsule suspensions demonstrated an initial burst effect followed by a prolonged I3C release. In addition, the formulations were considered hemocompatibles at 10µg/mL and showed an enhanced radical scavenging activity in comparison to free I3C. Moreover, nanocapsules prepared with RHO increased about two times the antitumor effect of I3C on MCF-7 and C6 cells without significant reduction of astrocyte cell viability. In conclusion, nanocapsule formulations developed in this study might be considered promising for cancer treatment.

Achyrocline satureioides essential oil-loaded in nanocapsules reduces cytotoxic damage in liver of rats infected by Trypanosoma evansi.

The aim of this study was to evaluate whether the treatment with Achyrocline satureioides essential oil-loaded in nanocapsules (AS-NC) is able to protect the hepatic tissue against cytotoxic damage caused by Trypanosoma evansi. Thus, the rats were divided into four groups (n = 6 per group): uninfected/saline, uninfected/AS-NC, infected/saline, and infected/AS-NC. At day 4 post-infection (PI), the animals were euthanized and liver and sera samples were collected to perform the hepatic cell viability assay, and to determine seric levels of reactive oxygen species (ROS) and nitric oxide metabolites (NOx). Cell viability decreased (p < 0.05) in the infected/saline group compared to uninfected/saline group, while the treatment with AS-NC avoided this alteration in infected rats. Seric ROS and NOx levels increased (p < 0.05) in the infected/saline group compared to uninfected/saline group, while the treatment with AS-NC avoided this effect on ROS levels of infected rats. In summary, the treatment with AS-NC was able to protect the liver tissue against the cytotoxic effect caused by the parasite by avoiding exacerbated production of ROS.

Toxicity Evaluation and Anti-Tumor Study of Docetaxel Loaded mPEG-Polyester Micelles for Breast Cancer Therapy.

In this work, docetaxel (DTX) was encapsulated in monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) micelles and monomethoxy poly(ethylene glycol)-poly(D, L-lactic acid) (mPEG-PLA) micelles, respectively. For the further application, the acute/genetic toxicity evaluation and pharmacokinetic/pharmacodynamic study of the two kinds of micellar nanomedicines were performed. In the study of anticancer activity in vitro and in vivo, DTX micelles showed better tumorgrowth inhibition than free DTX. The pharmacokinetic and tissue distribution studies showed that the DTX incorporated in micelles (especially in DTX-mPEG-PCL) retained significantly higher concentration in plasma and tumor tissue compared with free DTX. The acute toxicity and genotoxicity studies indicated that DTX micelles were safer than the docetaxel injection in cancer therapy and DTX-mPEG-PCL had less damage to DNA than DTX-mPEG-PLA. So the micelles had a pronounced effect on reducing acute toxicity and genotoxicity of docetaxel. In conclusion, DTX micelles were efficient and safe on breast carcinoma chemotherapy.