Empty Nanocapsules Research Articles

Adults of Sun Coral Tubastraea coccinea (Lesson 1829) Are Resistant to New Antifouling Biocides.

Biocides used in antifouling (AF) paints, such as 4,5-dichlorine-2-n-octyl-4-isothiazole-3-one (DCOIT), can gradually leach into the environment. Some AF compounds can persist in the marine environment and cause harmful effects to non-target organisms. Nanoengineered materials, such as mesoporous silica nanocapsules (SiNCs) containing AF compounds, have been developed to control their release rate and reduce their toxicity to aquatic organisms. This study aimed to evaluate the acute toxicity of new nanoengineered materials, SiNC-DCOIT and a silver-coated form (SiNC-DCOIT-Ag), as well as the free form of DCOIT and empty nanocapsules (SiNCs), on the sun coral Tubastraea coccinea. T. coccinea is an invasive species and can be an alternative test organism for evaluating the risks to native species, as most native corals are currently threatened. The colonies were collected from the Alcatrazes Archipelago, SP, Brazil, and acclimatized to laboratory conditions. They were exposed for 96 h to different concentrations of the tested substances: 3.33, 10, 33, and 100 µg L-1 of free DCOIT; 500, 1000, 2000, and 4000 µg L-1 of SiNC; and 74.1, 222.2, 666.7, and 2000 µg L-1 of SiNC-DCOIT and SiNC-DCOIT-Ag. The test chambers consisted of 500 mL flasks containing the test solutions, and the tests were maintained under constant aeration, a constant temperature of 23 ± 2 °C, and photoperiod of 12 h:12 h (light/dark). At the end of the experiments, no lethal effect was observed; however, some sublethal effects were noticeable, such as the exposure of the skeleton in most of the concentrations and replicates, except for the controls, and embrittlement at higher concentrations. Adults of T. coccinea were considered slightly sensitive to the tested substances. This resistance may indicate a greater capacity for proliferation in the species, which is favored in substrates containing antifouling paints, to the detriment of the native species.

Effects of the nanoherbicide made up of atrazine-chitosan on the primary events of photosynthesis

In this research, chitosan and alginate nanocapsules (NCs) have been synthesized and designed to act as carriers (controlled release systems) of atrazine molecules. Atrazine is an herbicide associated with relatively high chronic toxicity, which can also be accumulated as a recalcitrant substance in surface and groundwater. This effect is enhanced by the presence of adjuvants that are part of the commercial formulation. Therefore, the proposal to transport the herbicide in a nontoxic biocompatible nano-encapsulated system is particularly relevant. The nano-capsulated systems with and without the incorporated herbicide (NH, nanoherbicide and empty NCs, respectively) were characterized by scanning electron microscopy images showing an average nanocapsule size of 350 nm and a particle concentration of 4.5 × 1013/ml. The chemical composition of the NCs and NH systems was studied by Fourier Transform Infrared Spectroscopy. The OJIP transient chlorophyll fluorescence was used to evaluate the effects of the NH, commercial atrazine (At) and empty NCs on maize plants as non-target and on chicory as target plants. For the chicory plants treated with the NH and At, a decrease in the activity of the oxygen-generating complex (Fv/F0) and in the maximum quantum yield of PSII (φP0 = TR0/ABS) was observed. In addition, serious alterations in the electronic transport flux (ET0/RC), in the quantum yield for electron transport (φE0 = ET0/ABS) and in the efficiency or probability that an electron moves between plastoquinones QA and QB (ET0/TR0) were obtained for this these plants. The quantum yield of the transport stream electrons to PSI electron acceptors (φR0 = RE0/ABS) and the efficiency with which an exciton will be transferred from PSII to PSI acceptors (ψRE = RE0/TR0) also fell in the plants sprayed with the NH or commercial atrazine with respect to the control plants and those treated with the empty NCs. The photosynthetic parameters obtained for corn plants, treated with both NH and commercial atrazine, showed an inhibition of electron transport in the photosynthetic process at 24 h. These effects were reversed after seven days of treatment, due to the ability of corn plants to detoxify atrazine. Foliar damage was observed in chicory plants treated with atrazine and with NH but not concerning corn plants. Chicory or corn plants treated with the proposed carrier (NCs) showed no foliar effects, which implies that the carrier is harmless to the health of the plants.

Nanocarried antioxidants in freezing extenders for boar spermatozoa.

Post-thawing cryoinjuries in boar spermatozoa due to oxidative stress may be reduced by adding nanoencapsulated antioxidants to freezing extenders. This study evaluated post-thawing kinetics, structural and biochemical functions of boar spermatozoa frozen with extenders including resveratrol and vitamin E loaded into polymeric nanocapsules. Resveratrol was added at 0 (control), 5, 10, 20, 40 and 80µg/ml, whereas Vitamin E was added at 0 (control), 50, 100, 200 and 400µg/ml. Both antioxidants were tested in free and nanoencapsulated presentations. In contact with empty nanocapsules, some sperm kinetics parameters were impaired compared to the control (p<.05), whereas lipoperoxidation declined (p<.05). With inclusion of 40µg/ml nanoencapsulated resveratrol, some sperm kinetics parameters were improved (p<.01), but sperm motility, structural and biochemical functions did not differ from the control (p>.05). No improvement in sperm quality occurred with inclusion of vitamin E, although sperm kinetics with 400µg/ml nanoencapsulated vitamin E was reduced compared to the control (p<.01). Inclusion of 40µg/ml nanoencapsulated resveratrol benefitted boar sperm kinetics after thawing, but no improvement resulted from inclusion of vitamin E.

Calcium-Carbonate Nanocapsules Improve the Efficacy of BEZ235 in Lymphoma a Cell Line: A Promising New Technology of Drug Delivery

Nanotechnology is a promising branch of the medical field, directed to improve diagnostic and therapeutics strategies, applying nanovectors as drug delivery systems. Efficient encapsulation of anticancer drugs in nanocolloids and microcapsules was recently developed by G. Ciccarella research group (1). Based on our collaboration with the Nantional Nanotechnology Laboratory of the University of Salento and our previous experience with target therapies, we encapsulated BEZ235, a phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin inhibitor (mTOR). BEZ235 efficiently blocks the dysfunctional activation of the PI3K/mTOR pathway in cellular and in vivo settings, thus inhibiting the growth and proliferation of various cancer cells, and phase I/II clinical trials were open in solid cancer. However the scarse solubility limited further development of this promising compound. In order to overcome the solubility issue BEZ235-loaded nanocapsules were generated by the stepwise adsorption of oppositely charged polyelectrolytes into biocompatible CaCO3 cores. First nanocapsules were tested for biocompatibility. The exposition of lymphoma cell lines to empty nanocapsules up to 48 hours, did not induce any cititoxicity, confirming their biocompatibility. Second, encapsulated BEZ235 was compared with free-drug to test the cytotoxicity in a T lymphoma cell line (HUT78) by MTT assay (Fig. 1). The results suggested that nanoencapsulated-BEZ235 was extremely efficient compared with free-BEZ235, reaching IC50 just after 5 hours of exposure compared with an IC65% at 48 hours with the free drug. A validated LC-MS/MS method was developed in order to quantify intracellular concentration of BEZ235 over time. Intracellular concentration of BEZ235 in the lymphoma cell line was consistent with biological results since the internalization kinetic and efficiency was increased by the coating. In order to confirm that the encapsuled-BEZ235 was still effective on cell apoptosis, we tested free BEZ and encapsulated BEZ235 at a concentration of 1µM in T cell lymphoma cell lines. Encapsulated-BEZ235 induced apoptosis evidenced by the cleavage of caspase 8, 9 and 3 at an earlier time point compared with free BEZ235 and at significantly lower concentration.We also confirmed that the encapsulated-BEZ235 maintained its effect on the target mTOR/AKT pathway: p-AKT was dephosphorylated at 5h while the free BEZ235 operates at least after 24 hours at concentrations 100 times higher, as previously demonstrated (2).Keeping in mind a future clinical application of these polymeric particles/capsules, our data can be regarded as a promising new nanotechnology-based strategy to improve the efficacy and bioavailability of old and new drugs. Functional biological studies of BEZ235-encapsulated carrier and its mechanism of internalization are already under way, and animal in vivo studies to evaluated toxicity and distribution of the nanocapsuled compound are ongoing.1 F. Baldassare et al., Macromolecular Bioscience, Volume 12, Issue 5, pages 656-665, 20122 Civallero M, Cosenza M, Marcheselli L, Pozzi S, Sacchi S. Expert Opin Investig Drugs. 2012 Nov;21(11):1597-606. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Modulation of antioxidant and detoxifying capacity in fish Cyprinus carpio (Cyprinidae) after treatment with nanocapsules containing lipoic acid

Lipoic acid (LA) is a water- and lipid-soluble molecule with capacity to pass through cell membranes and with several antioxidant properties. Previous studies have shown that polymeric nanocapsules with LA favor the protection of this antioxidant, increasing their physical and chemical stability compared to formulations containing free LA. The aim of this study was to evaluate and compare the effect of free LA and LA-nanocapsules on antioxidant enzymes, the concentration of reduced glutathione (GSH) and a by-product of lipid peroxidation (malondialdehyde), as well as the expression of gene coding for different forms of glutathione-S-transferase (GST) in model fish. For this, carp Cyprinus carpio (Cyprinidae) were exposed (i.p.) to different forms of LA (free and in nanocapsules) for different times (48h, 96h and 1week) and the brain, liver and muscle were analyzed. Results indicated that the organs respond differently depending on the time and form in which LA was delivered. After 96h and 1week, a better antioxidant response was found generally in the formulation with nanocapsules. The nanocapsule composition showed to be a factor to be considered in future studies, because in some organs and exposure times empty nanocapsules promoted an antioxidant effect and in others a pro-oxidant effect.

Monitoring pH-Triggered Drug Release from Radioluminescent Nanocapsules with X-ray Excited Optical Luminescence

One of the greatest challenges in cancer therapy is to develop methods to deliver chemotherapy agents to tumor cells while reducing systemic toxicity to noncancerous cells. A promising approach to localizing drug release is to employ drug-loaded nanoparticles with coatings that release the drugs only in the presence of specific triggers found in the target cells such as pH, enzymes, or light. However, many parameters affect the nanoparticle distribution and drug release rate, and it is difficult to quantify drug release in situ. In this work, we show proof-of-principle for a "smart" radioluminescent nanocapsule with an X-ray excited optical luminescence (XEOL) spectrum that changes during release of the optically absorbing chemotherapy drug, doxorubicin. XEOL provides an almost background-free luminescent signal for measuring drug release from particles irradiated by a narrow X-ray beam. We study in vitro pH-triggered release rates of doxorubicin from nanocapsules coated with a pH-responsive polyelectrolyte multilayer using HPLC and XEOL spectroscopy. The doxorubicin was loaded to over 5% by weight and released from the capsule with a time constant in vitro of ∼36 days at pH 7.4 and 21 h at pH 5.0, respectively. The Gd₂O₂S:Eu nanocapsules are also paramagnetic at room temperature with similar magnetic susceptibility and similarly good MRI T₂ relaxivities to Gd₂O₃, but the sulfur increases the radioluminescence intensity and shifts the spectrum. Empty nanocapsules did not affect cell viability up to concentrations of at least 250 μg/mL. These empty nanocapsules accumulated in a mouse liver and spleen following tail vein injection and could be observed in vivo using XEOL. The particles are synthesized with a versatile template synthesis technique which allows for control of particle size and shape. The XEOL analysis technique opens the door to noninvasive quantification of drug release as a function of nanoparticle size, shape, surface chemistry, and tissue type.

Semi-solid topical formulations containing nimesulide-loaded nanocapsules showed in-vivo anti-inflammatory activity in chronic arthritis and fibrovascular tissue models

To evaluate the anti-inflammatory activity of topical gel containing nimesulide-loaded nanocapsules using experimental models in vivo, and to compare the anti-inflammatory activity of two nimesulide preparations. Male Wistar rats (200-250g) treated with gel containing empty nanocapsules (GEN); gel containing nimesulide in the free form (GNFF) or gel containing nimesulide-loaded nanocapsules (GNN). Nanoprecipitation methods were used to prepare the colloidal suspension. In-vivo experimental models of paw edema, acute and chronic arthritis, and granuloma formation were used. The gels were applied topically in all models. The nanocapsules had an average particle size of 344.6nm±4.33 and a polydispersity index of 0.251±0.002. The models of acute inflammation (paw edema and arthritis) showed that GNFF and GNN were able to inhibit the inflammatory process with similar efficacy. Moreover, nanoencapsulation significantly increased the anti-inflammatory activity of nimesulide in two chronic inflammation models (chronic arthritis and granuloma). The GNFF- and GNN-induced inhibition of inflammation in the chronic arthritis model were 27.75 and 81.5%, respectively. Similarly, GNFF and GNN reduced granuloma formation by 2.82 and 36.66%. Nanoencapsulation increased the anti-inflammatory activity of topical nimesulide in chronic inflammation models.

Effect on Cerebral Blood Flow of Orally Administered Indomethacin-loaded Poly(isobutylcyanoacrylate) and Poly(DL-lactide) Nanocapsules

Nanocapsules, containing indomethacin, were prepared either by interfacial polymerization of isobutylcyanoacrylate monomers or by interfacial deposition of a performed (DL-lactide) polymer. In-vitro release of indomethacin from nanocapsules was dependent on the pH of the sink solution and was enhanced by addition of albumin. A decrease in cerebral blood flow was noted 15 min after oral administration to rats of indomethacin nanocapsules (5 mg kg-1) and lasted over 3 h. Empty nanocapsules had no effect. Since release of indomethacin from nanocapsules is unlikely to occur in the lumen of the stomach, due to unsuitable pH conditions, and nanocapsules have been previously shown to be able to cross the intestinal barrier, to reach the villi vessels intact and to protect against the ulcerating effect of the free drug, it is suggested that the rapid onset of the pharmacological effect was sufficiently induced by free indomethacin released in the plasma following absorption of the intact nanocapsules.

Physicochemical Characteristics and Preliminary in Vivo Biological Evaluation of Nanocapsules Loaded with siRNA Targeting Estrogen Receptor Alpha

Specific siRNAs that target estrogen receptor alpha (ERalpha) were encapsulated in nanocapsules (NCs). We produced small (approximately 100-200 nm) ERalpha-siRNA NCs with a water core by incorporating two mixed duplexes of specific ERalpha-siRNAs (ERalpha-mix-siRNA) into NCs. The encapsulation yield that was obtained with poly(iso-butylcyanoacrylate) (PIBCA) NCs was low, whereas no release of trapped siRNA was observed for poly(ethylene)glycol-poly(D,L-lactide-co-glycolide) (PEG-PLGA) NCs. High levels of ERalpha-siRNA incorporation into PEG-epsilon-caprolactone-malic acid (PEG-PCL/MA) NCs (3.3 microM in a polymer solution at 16 mg/mL) were observed (72% yield). No difference in size or zeta potential was observed between siRNA NCs that were based on PEG-PCL/MA and empty NCs. Fluorescence quenching assays confirmed the incorporation of siRNA into the NC core. A persistent loss of ERalpha (90% over 5 days) was observed in MCF-7 human breast cancer cells that were exposed to PEG-PCL/MA NCs that were loaded with ERalpha-siRNA. The intravenous injection of these NCs into estradiol-stimulated MCF-7 cell xenografts led to a significant decrease in tumor growth and a decrease in ERalpha expression in tumor cells. These data indicate that a novel strategy, based on ERalpha-siRNA delivery, could be developed for the treatment of hormone-dependent breast cancers.

Improvement of the inhibitory effect of xanthones on NO production by encapsulation in PLGA nanocapsules

For the first time the inhibitory effect of xanthone and 3-methoxyxanthone on nitric oxide (NO) production by IFN-γ /LPS activated J774 macrophage cell line is reported. A remarkable improvement of this effect promoted by encapsulation of these compounds in nanocapsules of poly (dl-lactide-co-glycolide) (PLGA) is also demonstrated. A weak inhibitory effect of 3.6% on NO production by activated macrophages was observed for xanthone at the highest studied concentration (100 μM). This effect was slightly higher for 3-methoxyxanthone at the same concentration, producing a reduction of 16.5% on NO production. In contrast, equivalent concentrations of xanthone and 3-methoxyxanthone incorporated in nanocapsules produced a significant decrease on NO production of 91.8 and 80.0%, respectively. Empty nanocapsules also exhibited a slight NO inhibitory activity, which may be due to the presence of soybean lecithin in the composition of the nanosystems. The viability of the macrophages was not affected either by free or nanoencapsulated xanthones. Fluorescence microscopy analysis confirmed that a phagocytic process was involved in the macrophage uptake of xanthone- and 3-methoxyxanthone-loaded PLGA nanocapsules. Phagocytosis might be the main mechanism responsible for the enhancement of the intracellular delivery of both compounds and consequently for the improvement of their biological effect.

Prophylactic Oral Administration of Metabolically Active Insulin Entrapped in Isobutylcyanoacrylate Nanocapsules Reduces the Incidence of Diabetes in Nonobese DiabeticMice

Nonebese diabetic (NOD) mice develop an autoimmune disease with a long prodromal period and constitute a model for investigating the prevention of human type 1 diabetes. Since prophylactic insulin injections reduced the incidence of diabetes in NOD mice, we tested a new prophylactic strategy to prevent diabetes in NOD mice consisting of oral administration of insulin, protected in polyalkylcyanoacrylate nanocapsules from degradation in the gastrointestinal tract. In humans, this form of prophylactic insulin administration would be less constraining than insulin injections. Ninety female NOD mice were randomized at weaning and fed once a week (from 60 to 300 days of age) with insulin nanocapsules (100 U/kg) or empty nanocapsules. Within the group fed with insulin nanocapsules, the incidence of diabetes was reduced (38% vs 75%; P<0.02), the onset of disease was delayed ( P<0.02), and the severity of lymphocytic inflammation of endogenous islets was reduced ( P<0.03). Although the oral treatment was stopped at 300 days of age, the incidence of diabetes at 360 days remained lower in mice previously fed insulin nanocapsules ( P<0.02). Previous feedings with insulin nanocapsules did not protect against cyclophosphamide-induced diabetes, since final incidence of diabetes (sum of the incidence during the initial 360 days and the further CY-induced incidence) reached the final incidence obtained in mice previously fed empty nanocapsules and treated with cyclophosphamide. Intestinal absorption of insulin nanocapsules was evidenced by HPLC separation of human insulin in NOD sera. During cotransfer, T splenocytes from mice fed insulin nanocapsules were able to reduce the capacity of T cells from diabetic donors to adoptively transfer the disease ( P<0.01). Antigens for islet-cell autoantibodies (ICA) in pancreata from both NOD groups were compared by immunofluorescence with the same ICA-positive human sera to ensure that differences were due to quantitative changes in antigen. These antigens, which could serve as an index of possibly more extended antigen β-cell rest, were decreased ( P<0.02) and pancreatic insulin content was reduced ( P<0.05) in mice fed with insulin nanocapsules, suggesting a mechanism of ‘β cell rest’. To summarize, early feeding with insulin nanocapsules reduces diabetes and insulitis in the NOD mouse model that mimics human type 1 diabetes. This may be due both to generation of cellular mecahnisms that actively suppress disease and a decrease in antigens which makes beta cells less vulnerable to autoimmune aggression.

Evaluation of indomethacin nanocapsules for their physical stability and inhibitory activity on inflammation and platelet aggregation

Indomethacin nanocapsules were investigated for their physical stability and anti-inflammatory activity in the carrageenan paw oedema tests in rats and also for their inhibitory activity on platelet aggregation induced by ADP. From the physical stability view point, there was a marked difference for the extent of drug loss between the indomethacin nanocapsules which were stored for 12 months at ambient temperature when freeze-dried and in the form of suspension. The indomethacin content of the freeze-dried nanocapsules and in the suspension from decreased by 52.8% and by 17.5% respectively. Compared to free indomethacin the anti-inflammatory activity of indomethacin increased 10 times when it was prepared as nanocapsules and the inhibition of platelet aggregation also increased with nanocapsulated indomethacin. But empty nanocapsules also showed an inhibition in the platelet aggregation because of their isobutylcyanoacrylate content.