Poly[lactic-co-glycolic] Acid Nanospheres Research Articles

PLGA Nanospheres as Delivery Platforms for Eimeria mitis 1a Protein: A Novel Strategy to Improve Specific Immunity.

The infections of chicken coccidiosis impact the welfare of chickens and the economical production of poultry. Eimeria mitis is ubiquitous in chicken coccidiosis, and E. mitis infection can significantly affect the productivity of birds. Up to now, few efficient vaccines against E. mitis have been reported, whereas the recombinant subunit vaccines delivered by nanomaterials may elicit an encouraging outcome. Thus, in this study, we chose E. mitis 1a (Em1a) protein as the candidate antigen to generate Em1a preparations. The recombinant Em1a (rEm1a) protein was encapsulated with poly lactic-co-glycolic acid (PLGA) and chitosan (CS) nanospheres. The physical characterization of the rEm1a-PLGA and rEm1a-CS nanospheres was investigated, and the resulting nanospheres were proven to be nontoxic. The protective efficacy of rEm1a-PLGA and rEm1a-CS preparations was evaluated in E. mitis-challenged birds in comparison with two preparations containing rEm1a antigen emulsified in commercially available adjuvants. ELISA assay, flow cytometry analysis, and quantitative real-time PCR (qPCR) analysis indicated that vaccination with rEm1a-loaded nanospheres significantly upregulated the secretions of antibodies and cytokines and proportions of CD4+ and CD8+ T lymphocytes. Compared with the other three preparations, rEm1a-PLGA nanosphere was more effective in improving growth performance and inhibiting oocyst output in feces, indicating that the PLGA nanosphere was associated with optimal protection against E. mitis. Collectively, our results highlighted the advantages of nanovaccine in eliciting protective immunity and may provide a new perspective for developing effective vaccines against chicken coccidiosis.

With Chitosan and PLGA as the Delivery Vehicle, Toxoplasma gondii Oxidoreductase-Based DNA Vaccines Decrease Parasite Burdens in Mice.

Toxoplasma gondii (T. gondii) is an intracellular parasitic protozoan that can cause serious public health problems. However, there is no effectively preventive or therapeutic strategy available for human and animals. In the present study, we developed a DNA vaccine encoding T. gondii oxidoreductase from short-chain dehydrogenase/reductase family (TgSDRO-pVAX1) and then entrapped in chitosan and poly lactic-co-glycolic acid (PLGA) to improve the efficacy. When encapsulated in chitosan (TgSDRO-pVAX1/CS nanospheres) and PLGA (TgSDRO-pVAX1/PLGA nanospheres), adequate plasmids were loaded and released stably. Before animal immunizations, the DNA vaccine was transfected into HEK 293-T cells and examined by western blotting and laser confocal microscopy. Th1/Th2 cellular and humoral immunity was induced in immunized mice, accompanied by modulated secretion of antibodies and cytokines, promoted the maturation and MHC expression of dendritic cells, and enhanced the percentages of CD4+ and CD8+ T lymphocytes. Immunization with TgSDRO-pVAX1/CS and TgSDRO-pVAX1/PLGA nanospheres conferred significant immunity with lower parasite burden in the mice model of acute toxoplasmosis. Furthermore, our results also lent credit to the idea that TgSDRO-pVAX1/CS and TgSDRO-pVAX1/PLGA nanospheres are substitutes for each other. In general, the current study proposed that TgSDRO-pVAX1 with chitosan or PLGA as the delivery vehicle is a promising vaccine candidate against acute toxoplasmosis.

Investigating dual drug loaded PLGA nanocarriers for improved efficacy in endometritis therapeutics

Modern endometritis therapeutics may require an extremely precise and controlled drug release system. Poly lactic-co-glycolic acid (PLGA) microspheres loaded with two different drugs like amoxicillin and vancomycin were prepared and their efficacy in management of endometritis in murine model was examined. Such biological nanocarriers are need of the hour since they are biodegradable, cytocompatible, hemocompatible and easily formulated. The sizes of the drug loaded PLGA microspheres ranged from 65–100 nm. The electron microscopy images depicted them as uniform spherical structures. The zeta potential and polydispersity index were calculated and the in vitro release investigation indicated steady drug release over a period of 50 h at effective dosage. The drug loaded nanocarriers were found with be cytocompatible and hemolysis test elaborated that they met with hemolysis rate safety requirements. The murine models were induced with endometritis by intravaginal administration of bovine uterine isolates. The mice were sacrificed and histopathogical examination of the endometrial slides stained with haematoxylin and eosin revealed that the drug loaded PLGA nanospheres helped in reducing acute endometritis in mice in a very short time. This study thereby demonstrated well described synthesis approach of drug loaded PLGA nanospheres which may be further be transferred to preclinical laboratory studies.

Preparation of Poly[lactic-co-glycolic] Acid Nanospheres and Its Role in Hepatoma Cells.

Poly[lactic-co-glycolic] acid (PLGA) targeting nanoparticles AFP/PLGA/Dt386, loaded with Dt386 plasmid of diphtheria toxin gene, modified by Alpha fetoprotein (AFP) monoclonal antibody, is prepared. Its physical and chemical properties and its effect on HepG2 cells are studied. Firstly, Dt386 expression plasmid pET11a/Dt386 is constructed and PLGA nanoparticles are prepared by emulsion solvent evaporation (ESE). Scanning electron microscope (SEM) is used to observe its morphology. Laser Particle Sizer is used to measure the particle size. In addition, the encapsulation efficiency, drug loading and in vitro release rate of PLGA nanoparticles are measured. Carboxy fluorescein and rhodamine fluorescein are used to double label IgG/PLGA/Dt386 and AFP/PLGA/Dt386 nanospheres, respectively, the entry of nanospheres into HepG2 cells are observed at 3 h and 12 h. The effect of AFP/PLGA/Dt386 nanospheres on the migration of HepG2 cells is examined by wounding healing assay. Transwell chamber experiment is used to detect the effect of AFP/PLGA/Dt386 nanospheres on the invasion of HepG2 cells. MTT method is utilized to determine the inhibitory activity of nanoparticles on HepG2 cell proliferation. After treated with IgG/PLGA/Dt386 and AFP/PLGA/Dt386 nanoparticles for 48 hours, flow cytometry is used to detect the apoptosis rate and cell cycle of HepG2 cells in each group. The results show that the prepared nanospheres have regular morphology, flat surface, average particle size of 265.72±12.46 nm, zeta potential of -18.15 mV. The average entrapment efficiency and drug loading are 78.48±1.71% and 3.16±0.35%, respectively. The nanoparticles release slowly and stably in vitro. At the 10th day, the release rate reaches 75.13%. PLGA nanospheres can effectively protect DNA from nuclease degradation. The results show that AFP/PLGA/Dt386 nanospheres have biological targeting effect and can be enriched in cells. AFP/PLGA/Dt386 nanoparticles can significantly inhibit the migration, invasion and proliferation of HepG2 cells, and promote apoptosis.

Conjugation of vascular endothelial growth factor to poly lactic-co-glycolic acid nanospheres enhances differentiation of embryonic stem cells to lymphatic endothelial cells.

ObjectivePluripotent stem cell-derived lymphatic endothelial cells (LECs) show great promise in their therapeutic application in the field of regenerative medicine related to lymphatic vessels. We tested the approach of forced differentiation of mouse embryonal stem cells into LECs using biodegradable poly lactic-co-glycolic acid (PLGA) nanospheres in conjugation with growth factors (vascular endothelial growth factors [VEGF-A and VEGF-C]).MethodsWe evaluated the practical use of heparin-conjugated PLGA nanoparticles (molecular weight ~15,000) in conjugation with VEGF-A/C, embryoid body (EB) formation, and LEC differentiation using immunofluorescence staining followed by quantification and quantitative real-time polymerase chain reaction analysis.ResultsWe showed that formation and differentiation of EB with VEGF-A/C-conjugated PLGA nanospheres, compared to direct supplementation of VEGF-A/C to the EB differentiation media, greatly improved yield of LYVE1(+) LECs. Our analyses revealed that the enhanced potential of LEC differentiation using VEGF-A/C-conjugated PLGA nanospheres was mediated by elevation of expression of the genes that are important for lymphatic vessel formation.ConclusionTogether, we not only established an improved protocol for LEC differentiation using PLGA nanospheres but also provided a platform technology for the mechanistic study of LEC development in mammals.

Novel 20% doxycycline-loaded PLGA nanospheres as adjunctive therapy in chronic periodontitis in type-2 diabetics: randomized clinical, immune and microbiological trial.

This study evaluated the clinical, microbiological, and immunological results of poly lactic-co-glycolic acid (PLGA) nanospheres containing 20% doxycycline (DOXY) in the treatment of type-2 diabetic patients (DM-2) with chronic periodontitis (CP). A parallel, double-blind, randomized, placebo-controlled clinical trial was conducted in DM-2 presenting severe and generalized CP. All patients received one-stage full-mouth ultrasonic debridement (FMUD) and they were randomly divided into two groups: PLAC (n = 20)-local application of placebo PLGA nanospheres, and DOXY (n = 20)-local application of doxycycline-loaded nanospheres; both in six non-contiguous sites. Clinical, metabolic (fasting plasma glucose level-FPG and glycated hemoglobin-HbA1c), cytokine pattern (multiplexed bead immunoassay) and microbiological assessments were performed at baseline, and 1, 3, and 6months after treatment. Both groups showed clinical improvement in all parameters after treatment (p < 0.05). Deep pockets showed improvements in bleeding on probing-BoP (3 and 6months), PD (at 3months), and CAL gain (at 1 and 3months) favoring DOXY (p < 0.05). The percentage of sites presenting PD reduction and CAL gain ≥ 2mm was higher in DOXY at 3months (p < 0.05). DOXY group exhibited a significant increase in the levels of anti-inflammatory interleukin (IL)-10 and a reduction in IL-8, IFN-y, IL-6, and IL-17 (p < 0.05), significant reduction in periodontal pathogens (p < 0.05), and a lower mean percentage of HbA1C at 3months (p < 0.05). DOXY nanospheres may be considered a potential adjunct to mechanical debridement in the therapy of periodontitis in DM-2, offering additional benefits in deep pockets, improving the cytokine profile, and reducing periodontal pathogen levels. The use of locally applied doxycycline nanospheres may represent an adjunctive therapeutic approach in the treatment of periodontal disease in type-2 diabetic patients, achieving additional benefits in the local modulation of cytokines, microbial reduction, and clinical parameters, especially in deep pockets.

Anticancer Activity of Curcumin-Loaded PLGA Nanoparticles on PC3 Prostate Cancer Cells.

Curcumin (Cur) has been found to be very efficacious against many different types of cancer cells. However, the major disadvantage associated with the use of Cur is its low systemic bioavailability. Our present work investigated the toxic effect of encapsulation of Cur in PLGA (poly lactic-coglycolic acid) nanospheres (NCur) on PC3 human cancer prostate cell. In the present study, we have investigated the effects of NCur on growth, autophagia, and apoptosis in PC3 cells, respectively, by MTT assay, fluorescence microscopy, and Flow cytometry. MTT assays revealed that the NCur at the concentration of 25 µg/mL for 48 h were able to exert a more pronounced effect on the PC3 cells as compared to free Cur. Apoptotic index was significantly increased in NCur-treated cells compared to free Cur. The percentage of autophagic cells (LC3-II positive cells) was also significantly increased in NCur treatment in comparison to free Cur. These data indicate that the NCur has considerable cytotoxic activity more than Cur on PC3 cell lines, which is mediated by induction of both apoptotic and autophagic processes. Thus, NCur has high potential as an adjuvant therapy for clinical application in prostate cancer.

PLGA (85:15) nanoparticle based delivery of rL7/L12 ribosomal protein in mice protects against Brucella abortus 544 infection: A promising alternate to traditional adjuvants.

There is a compelling need for the development of suitable adjuvants for human use to enhance the efficacy of the upcoming vaccines for the prevention of life threatening infections. In the current study, we have tried to explore the immunogenic potential of nanoparticles (NPs) made of PLGA (poly lactic-co-glycolic acid), a biodegradable and biocompatible polymer approved by FDA for human use after entrapping rL7/L12 protein, an immunodominant antigen of Brucella. Adjuvant properties were exhibited by the formulation as it elicited high IgG antibody titers just after first immunization which increased significantly after the booster administration. A good elicitation of the Th1 cytokines especially IFN-γ was recorded. Amongst the IgG antibody subclasses, IgG1 remained the predominant subclass to be elicited in mice serum after immunization; however IgG1/2a ratio showed a mixed profile of Th1/Th2 response. Lymphocyte proliferation assay as a marker of amplification in cellular immunity demonstrated that the splenocytes of the immunized mice had a high proliferation index with reference to the control, revealing that L7/L12 entrapping PLGA nanoparticles are potent inducer of inflammatory cell response indispensable to combat Brucella infection. Enumeration of splenic CFU after 14 days of infection with Brucella abortus 544 showed a significant reduction in log CFU of splenic bacteria in the vaccinated mice as compared to the control group. Therefore it is evident that PLGA nano formulations delivering the entrapped vaccine candidate in mice elicit specific humoral as well as cellular responses specific to the entrapped Brucella antigen. So there is much promise in this approach and this work by highlighting the adjuvant properties of the PLGA nanospheres will accelerate the development of improved vaccines safe for human as well as veterinary use.

Curcumin-loaded into PLGA nanoparticles

The incorporation of the curcumin into poly(lactic-co-glycolic)acid (PLGA) nanospheres by the nanoprecipitation technique, the characterization of the nanoparticles and the schistosomicidal activity of the curcumin-loaded into PLGA nanospheres were reported. The incorporation process occurred with high efficiency and the images of field-emission scanning electron microscopy (FESEM) revealed the production of spherically shaped particles. According to the dynamic light scattering measurements, the particles are nanometric and monodisperse. The curcumin-loaded PLGA nanoparticles (50 and 100 μM) caused the death of all worms and a separation between 50% and 100% of Schistosoma mansoni couples at concentrations from 30 μM. Moreover, the curcumin-loaded PLGA nanoparticles also decreased the motor activity and caused partial alterations in the tegument of adult worms. This study marks the first time that schistosomicidal activity has been reported for curcumin-loaded PLGA nanoparticles.

Surface modification of Mitoxantrone-loaded PLGA nanospheres with chitosan

The purpose of this research was to develop polylactic-co-glycolic acid (PLGA) nanospheres surface modified with chitosan (CS). Mitoxantrone- (MTO-) loaded PLGA nanospheres were prepared by a solvent evaporation technique. The PLGA nanospheres surface was modified with CS by two strategies (adsorption and covalent binding). PLGA nanospheres of 248.4 ± 21.0 nm in diameter characterized by the laser light scattering technique, scanning electron microscopy (SEM) are spherical and its drug encapsulation efficiency is 84.1 ± 3.4%. Zeta potential of unmodified nanospheres was measured to be negative −21.21 ± 2.13 mV. The positive zeta potential of modified nanospheres reveals the presence of CS on the surface of the modified nanospheres. Modified nanospheres were characterized for surface chemistry by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR). FT-IR spectra exhibited peaks at 3420 cm −1 and 1570 cm −1, XPS spectra shows the N 1s (atomic orbital 1s of nitrogen) region of the surface of the nanospheres, corresponding to the primary amide of CS. In vitro drug release demonstrated that CS-modified nanospheres have many advantages such as prolonged drug release property and decreased the burst release over the unmodified nanospheres, and the modified nanospheres by covalent binding method could achieve the release kinetics of a relatively constant release. These data demonstrate high potential of CS-modified PLGA nanospheres for the anticancer drug carrier.

Particle size and temperature effect on the physical stability of PLGA nanospheres and microspheres containing Bodipy

The purpose of this study was to investigate the effect of particle size, storage temperature, and duration of storage on the physical stability and morphology of polylactic-co-glycolic acid (PLGA) nanospheres and microspheres. PLGA nanospheres and microspheres containing the fluorescent dye, Bodipy, were prepared in varying sizes by controlling the method and degree of agitation during the emulsification phase of preparation. Mean diameters of the particles were measured by dynamic light scattering. To evaluate the effect of storage temperature and duration of storage on the extent of aggregation, nanospheres and microspheres were stored at 4 degrees C, 25 degrees C, 37 degrees C, and 50 degrees C for 6 days and then monitored using both confocal and scanning electron microscopy. The mean +/- SD diameters of PLGA particles containing Bodipy were: 266.9 +/- 2.8, 351.6 +/- 1.8, 988.8 +/- 14.1, and 1865.9 +/- 67.0 nm. The extent of aggregation of the particulate delivery system decreased as the mean diameter increased, and increased as the storage temperature increased. The maximum extent of aggregation was observed with the smallest (266 nm) nanospheres. Microspheres did not aggregate. The aggregation of nanospheres was significantly reduced by introducing an additional evaporation step during preparation, suggesting that migration of residual dichloromethane from within the nanospheres may have dissolved the PLGA on the surface. The extent of aggregation of nanospheres increased as the temperature was increased from 4 degrees C to 50 degrees C, and decreased as particle size increased. To avoid aggregation, PLGA nanospheres should be stored at 4 degrees C.