A Comprehensive Investigation of the Structural, Thermal, and Biological Properties of Fully Randomized Biomedical Polyesters Synthesized with a Nontoxic Bismuth(III) Catalyst.

Aliphatic polyesters are the most common type of biodegradable synthetic polymer used in many pharmaceutical applications nowadays. This report describes the ring-opening polymerization (ROP) of l-lactide (L-LA), ε-caprolactone (CL) and glycolide (Gly) in the presence of a simple, inexpensive and convenient PEG200-BiOct3 catalytic system. The chemical structures of the obtained copolymers were characterized by 1H- or 13C-NMR. GPC was used to estimate the average molecular weight of the resulting polyesters, whereas TGA and DSC were employed to determine the thermal properties of polymeric products. The effects of temperature, reaction time, and catalyst content on the polymerization process were investigated. Importantly, the obtained polyesters were not cyto- or genotoxic, which is significant in terms of the potential for medical applications (e.g., for drug delivery systems). As a result of transesterification, the copolymers obtained had a random distribution of comonomer units along the polymer chain. The thermal analysis indicated an amorphous nature of poly(l-lactide-co-ε-caprolactone) (PLACL) and a low degree of crystallinity of poly(ε-caprolactone-co-glycolide) (PCLGA, Xc = 15.1%), in accordance with the microstructures with random distributions and short sequences of comonomer units (l = 1.02-2.82). Significant differences in reactivity were observed among comonomers, confirming preferential ring opening of L-LA during the copolymerization process.

Synthesis of hesperetin-loaded PLGA nanoparticles by two different experimental design methods and biological evaluation of optimized nanoparticles.

Hesperetin was effectively encapsulated into poly (d,l-lactic-co-glycolic acid) nanoparticles by using experimental design methods. A seven-factor Plackett-Burman design was used in order to determine the major process parameters. A significant linear equation, which shows the effect of each process parameter on encapsulation efficiency was developed, and then the most effective factors were determined. Further investigation and optimization was carried out by applying the three-factor three-level Box-Behnken design. Significant second-order mathematical models were developed by regression analysis of the experimental data for both responses: encapsulation efficiency and nanoparticle size. The two step experimental design allowed the synthesis of the desired nanoparticle formulations with maximum encapsulation efficiency (80.5 ± 4.9%) and minimum particle size (260.2 ± 16.5 nm) at optimum process conditions: 0.5% polyvinyl alcohol (PVA) concentration, 5.13 water:organic phase ratio, and 3.59 ml min-1 flow rate of the emulsified solution into 0.1% PVA. Furthermore, the biological activity of these optimized nanoparticles were determined with antimicrobial activity and cytotoxicity studies; results were then compared to the free hesperetin. The cytotoxicity result revealed that hesperetin and hesperetin-loaded nanoparticles were biocompatible with normal cell line L929 fibroblast cells up to 184.83 and 190.88 µg ml-1 for 24 h, and up to 133.24 and 134.80 µg ml-1 for 48 h, respectively. In the antimicrobial study, the optimized nanoparticle showed inhibition activity (minimal inhibitory concentration (MIC) values were 125 µg ml-1 for Escherichia coli, and 200 µg ml-1 for Staphylococcus aureus), while the free hesperetin did not demonstrate activity in both strains (MIC value >200 µg ml-1). These in vitro results may provide useful information for the investigation of hesperetin-loaded nanoparticles in diagnostic and therapeutic applications.

Ring-Opening Polymerization of a New Diester Cyclic Dimer of Mandelic and Glycolic Acid: An Efficient Synthesis Method for Derivatives of Amorphous Polyglycolide with High Tg.

In this study, poly(mandelate-co-glycolate) (PMG), a modified polyglycolide (PGL), is prepared by ring-opening polymerization (ROP) of L-3-phenyl-1,4-dioxane-2,5-dione (PDD); the cyclic dimer of biobased mandelic acid and glycolic acid. The resulting polymer shows an increased glass transition temperature (Tg ) due to the incorporation of phenyl groups in the chain. High molecular weight PMG is obtained by bulk ROP at 150 °C, and it exhibits a glassy amorphous state with enhanced thermal properties such as a Tg being 35 °C higher than conventional PGL. PDD is also copolymerized with glycolide (GL) and lactide (LA), resulting in poly(mandelate-co-glycolate/glycolate) ((P(MG/GL)) with GL and poly(mandelate-co-glycolate/lactide) ((P(MG/LA)) with LA. The thermal properties of P(MG/GL) and P(MG/LA) are found to be distinctly different from PMG and conventional PGL and polylactide, and they are tunable with a changing molar ratio of PDD, GL, and LA. Therefore, PDD opens an elegant way to control and tailor the properties of biobased polyesters.

Preparation of PLGA/Rose Bengal colloidal particles by double emulsion and layer-by-layer for breast cancer treatment.

The use of colloidal particles (CPs) in the transport of drugs is developing rapidly thanks to its effectiveness and biosafety, especially in the treatment of various types of cancer. In this study Rose Bengal/PLGA CPs synthesized by double emulsion (W/O/W) and by electrostatic adsorption (layer-by-layer), were characterized and evaluated as potential breast cancer treatment. CPs were evaluated in terms of size, zeta potential, drug release kinetics and cell viability inhibition efficacy with the triple negative breast cancer cell line HCC70. The results showed that both types of CPs can be an excellent alternative to conventional cancer treatment by taking advantage of the enhanced permeation and retention (EPR) effect, manifested by solid tumors; however, the double emulsion CPs showed more suitable delivery times of up to 60% within two days, while layer-by-layer showed fast release of 50% in 90 min. Both types of CPs were capable to decrease cell viability, which encourage us to further testing in in vivo models to prove their efficacy and feasible use in the treatment of triple negative breast cancer.

Benign preparation of aqueous core poly lactic-co-glycolic acid (PLGA) microcapsules.

Poly lactic-co-glycolic acid (PLGA) has attracted considerable attention as a polymer for drug delivery carriers. However, the hydrophobic property of PLGA often leads to the use of harmful organic solvents and poor encapsulation efficiency of hydrophilic materials. To our knowledge, a preparation method of aqueous core PLGA microcapsules without using harmful organic solvents has not been proposed. In this study, we attempted to establish an encapsulation technique of hydrophilic materials in aqueous core biodegradable and biocompatible PLGA microcapsules using vegetable oil as a continuous phase. As a result, the temperature of the oil/water mixture was required to be above the glass transition temperature. In this condition, two different types of morphology were prepared. When the water volume was below the solubility limit, PLGA microcapsules with a smooth shell were formed. In contrast, when the water volume was above the solubility limit, colloidosome-like microcapsules with PLGA nanoparticles assembled at the interface were formed. The obtained microcapsules were then heated at the glass transition temperature. The result is that aqueous core PLGA microcapsules with a smooth shell were prepared using plant oil as a continuous phase. Rhodamine B used as a hydrophilic model encapsulant, was successfully encapsulated in the PLGA microcapsules.

Fabricating PLGA microparticles with high loads of the small molecule antioxidant N-acetylcysteine that rescue oligodendrocyte progenitor cells from oxidative stress.

Reactive oxygen species (ROS), encompassing all oxygen radical or non-radical oxidizing agents, play key roles in disease progression. Controlled delivery of antioxidants is therapeutically relevant in such oxidant-stressed environments. Encapsulating small hydrophilic molecules into hydrophobic polymer microparticles via traditional emulsion methods has long been a challenge due to rapid mass transport of small molecules out of particle pores. We have developed a simple alteration to the existing water-in-oil-in-water (W/O/W) drug encapsulation method that dramatically improves loading efficiency: doping external water phases with drug to mitigate drug diffusion out of the particle during fabrication. PLGA microparticles with diameters ranging from 0.6 to 0.9 micrometers were fabricated, encapsulating high loads of 0.6-0.9 µm diameter PLGA microparticles were fabricated, encapsulating high loads of the antioxidant N-acetylcysteine (NAC), and released active, ROS-scavenging NAC for up to 5 weeks. Encapsulation efficiencies, normalized to the theoretical load of traditional encapsulation without doping, ranged from 96% to 400%, indicating that NAC-loaded external water phases not only prevented drug loss due to diffusion, but also doped the particles with additional drug. Antioxidant-doped particles positively affected the metabolism of oligodendrocyte progenitor cells (OPCs) under H2 O2 -mediated oxidative stress when administered both before (protection) or after (rescue) injury. Antioxidant doped particles improved outcomes of OPCs experiencing multiple doses of H2 O2 by increasing the intracellular glutathione content and preserving cellular viability relative to the injury control. Furthermore, antioxidant-doped particles preserve cell number, number of process extensions, cytoskeletal morphology, and nuclear size of H2 O2 -stressed OPCs relative to the injury control. These NAC-doped particles have the potential to provide temporally-controlled antioxidant therapy in neurodegenerative disorders such as multiple sclerosis (MS) that are characterized by continuous oxidative stress.

The effect of poly (lactic-co-glycolic) acid composition on the mechanical properties of electrospun fibrous mats.

The aim of this study was to investigate the influence of polymer molecular structure on the electrospinnability and mechanical properties of electrospun fibrous mats (EFMs). Polymers with similar molecular weight but different composition ratios (lactic acid (LA) and glycolic acid (GA)) were dissolved in binary mixtures of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). The intrinsic viscosity and rheological properties of polymer solutions were investigated prior to electrospinning. The morphology and mechanical properties of the resulting EFMs were characterized by scanning electron microscope (SEM) and dynamic mechanical analysis (DMA). Sufficiently high inter-molecular interactions were found to be a prerequisite to ensure the formation of fibers in the electrospinning process, regardless the polymer composition. The higher the amount of GA in the polymer composition, the more ordered and entangled molecules were formed after electrospinning from the solution in THF-DMF, which resulted in higher Young's modulus and tensile strength of the EFMs. In conclusion, this study shows that the mechanical properties of EFMs, which depend on the polymer molecule-solvent affinity, can be predicted by the inter-molecular interactions in the starting polymer solutions and over the drying process of electrospinning.

Co-delivery of paclitaxel and tetrandrine via iRGD peptide conjugated lipid-polymer hybrid nanoparticles overcome multidrug resistance in cancer cells.

One of the promising strategies to overcome tumor multidrug resistance (MDR) is to deliver anticancer drug along with P-glycoprotein (P-gp) inhibitor simultaneously. To enhance the cancer cellular internalization and implement the controlled drug release, herein an iRGD peptide-modified lipid-polymer hybrid nanosystem (LPN) was fabricated to coload paclitaxel (PTX) and tetrandrine (TET) at a precise combination ratio. In this co-delivery system, PTX was covalently conjugated to poly (D,L-lactide-co-glycolide) polymeric core by redox-sensitive disulfide bond, while TET was physically capsulated spontaneously for the aim to suppress P-gp in advance by the earlier released TET in cancer cells. As a result, the PTX+TET/iRGD LPNs with a core-shell structure possessed high drug loading efficiency, stability and redox-sensitive drug release profiles. Owing to the enhanced cellular uptake and P-gp suppression mediated by TET, significantly more PTX accumulated in A2780/PTX cells treated with PTX+TET/iRGD LPNs than either free drugs or non-iRGD modified LPNs. As expected, PTX+TET/iRGD LPNs presented the highest cytotoxicity against A2780/PTX cells and effectively promoted ROS production, enhanced apoptosis and cell cycle arrests particularly. Taken together, the co-delivery system demonstrated great promise as potential treatment for MDR-related tumors based on the synergistic effects of P-gp inhibition, enhanced endocytosis and intracellular sequentially drug release.

Next Generation Precision-Polyesters Enabling Optimization of Ligand-Receptor Stoichiometry for Modular Drug Delivery.

The success of receptor-mediated drug delivery primarily depends on the ability to optimize ligand-receptor stoichiometry. Conventional polyesters such as polylactide (PLA) or its copolymer, polylactide-co-glycolide (PLGA), do not allow such optimization due to their terminal functionality. We herein report the synthesis of 12 variations of the PLA-poly(ethylene glycol) (PEG) based precision-polyester (P2s) platform, permitting 5-12 periodically spaced carboxyl functional groups on the polymer backbone. These carboxyl groups were utilized to achieve variable degrees of gambogic acid (GA) conjugation to facilitate ligand-receptor stoichiometry optimization. These P2s-GA combined with fluorescent P2s upon emulsification form nanosystems (P2Ns) of size <150 nm with GA expressed on the surface. The P2Ns outclass conventional PLGA-GA nanosystems in cellular uptake using caco-2 intestinal model cultures. The P2Ns showed a proportional increase in cellular uptake with an increase in relative surface GA density from 0 to 75%; the slight decline for 100% GA density was indicative of receptor saturation. The intracellular trafficking of P2Ns in live caco-2 cells demonstrated the involvement of endocytic pathways in cellular uptake. The P2Ns manifest transferrin receptor (TfR) colocalization in ex vivo intestinal tissue sections, despite blocking of the receptor with transferrin (Tf) noncompetitively, i.e., independently of receptor occupation by native ligand. The in vivo application of P2Ns was demonstrated using cyclosporine (CsA) as a model peptide. The P2Ns exhibited modular release in vivo, as a function of surface GA density. This approach may contribute to the development of personalized dose regimen.

PLGA nanoparticles for the oral delivery of nuciferine: preparation, physicochemical characterization and in vitro/in vivo studies.

This article reports a promising approach to enhance the oral delivery of nuciferine (NUC), improve its aqueous solubility and bioavailability, and allow its controlled release as well as inhibiting lipid accumulation. NUC-loaded poly lactic-co-glycolic acid nanoparticles (NUC-PLGA-NPs) were prepared according to a solid/oil/water (s/o/w) emulsion technique due to the water-insolubility of NUC. PLGA exhibited excellent loading capacity for NUC with adjustable dosing ratios. The drug loading and encapsulation efficiency of optimized formulation were 8.89 ± 0.71 and 88.54 ± 7.08%, respectively. NUC-PLGA-NPs exhibited a spherical morphology with average size of 150.83 ± 5.72 nm and negative charge of -22.73 ± 1.63 mV, which are suitable for oral administration. A sustained NUC released from NUC-PLGA-NPs with an initial exponential release owing to the surface associated drug followed by a slower release of NUC, which was entrapped in the core. In addition, ∼77 ± 6.67% was released in simulating intestinal juice, while only about 45.95 ± 5.2% in simulating gastric juice. NUC-PLGA-NPs are more efficient against oleic acid (OA)-induced hepatic steatosis in HepG2 cells when compared to naked NUC (n-NUC, *p < 0.05). The oral bioavailability of NUC-PLGA-NPs group was significantly higher (**p < 0.01) and a significantly decreased serum levels of total cholesterol (TC), triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C), as well as a higher concentration of high-density lipoprotein cholesterol (HDL-C) was observed, compared with that of n-NUC treated group. These findings suggest that NUC-PLGA-NPs hold great promise for sustained and controlled drug delivery with improved bioavailability to alleviating lipogenesis.

Strategy for constructing vascularized adipose units in poly(l-glutamic acid) hydrogel porous scaffold through inducing in-situ formation of ASCs spheroids.

Vascularization is of great importance to adipose tissue regeneration. Here we introduced a paradigm that using scaffold to induce ASC spheroids, so to promote vascularized adipose tissue regeneration. Poly (l-glutamic acid) (PLGA) was activated by EDC, followed by being cross-linked by Adipic dihydrazide (ADH) to form a homogeneous hydrogel. Lyophilization was then carried out to create porous structure. The PLGA hydrogel scaffold possessed a significant swollen hydrophilic network to weaken cell-scaffold adhesion but drive ASCs to aggregate to form spheroids. Increase of seeding cell density was proved to result in the increase of spheroid size, upregulating angiogenic genes (VEGF and FGF-2) expression by enhancing the hypoxia-induced paracrine secretion. Also, the adipogenic differentiation of ASCs was achieved in spheroids in vitro. Moreover, the in vivo vascularized adipose tissue regeneration was evaluated in the dorsum of nude mice. After 12weeks post-implantation, the significant angiogenesis was found in both adipogenic induced and non-induced engineered tissue. In adipogenic induced group, the clear ring-like morphology, the large vacuole in the middle of the cell and the Oil red O staining demonstrated adipose tissue formation. STATEMENT OF SIGNIFICANCE: Vascularization is of great importance to adipose tissue regeneration. Adipose derived stem cell (ASC) spheroids possessed not only the high efficiency of vascularization, but also the improved differentiation ability. Several research works have illustrated the advantage of ASC spheroids in vascularization. However, in adipose regeneration, ASC spheroid was rarely used. Even so, it is reasonable to believe that ASC spheroids hold a great promise in vascularized adipose tissue engineering. Thus in the present study, we introduced a method to create lots of ASC spheroids that acted as lots of individual adipogenesis and angiogenesis units inside of a porous hydrogel scaffold. Then, the scaffold carrying ASC spheroids was implanted subcutaneously in nude mice to preliminarily evaluate the adipose tissue generation and blood vessel formation.

Promoting bioengineered tooth innervation using nanostructured and hybrid scaffolds.

The innervation of teeth mediated by axons originating from the trigeminal ganglia is essential for their function and protection. Immunosuppressive therapy using Cyclosporine A (CsA) was found to accelerate the innervation of transplanted tissues and particularly that of bioengineered teeth. To avoid the CsA side effects, we report in this study the preparation of CsA loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles, their embedding on polycaprolactone (PCL)-based scaffolds and their possible use as templates for the innervation of bioengineered teeth. This PCL scaffold, approved by the FDA and capable of mimicking the extracellular matrix, was obtained by electrospinning and decorated with CsA-loaded PLGA nanoparticles to allow a local sustained action of this immunosuppressive drug. Dental re-associations were co-implanted with a trigeminal ganglion on functionalized scaffolds containing PLGA and PLGA/cyclosporine in adult ICR mice during 2weeks. Histological analyses showed that the designed scaffolds did not alter the teeth development after in vivo implantation. The study of the innervation of the dental re-associations by indirect immunofluorescence and transmission electron microscopy (TEM), showed that 88.4% of the regenerated teeth were innervated when using the CsA-loaded PLGA scaffold. The development of active implants thus allows their potential use in the context of dental engineering. STATEMENT OF SIGNIFICANCE: Tooth innervation is essential for their function and protection and this can be promoted in vivo using polymeric scaffolds functionalized with immunosuppressive drug-loaded nanoparticles. Immunosuppressive therapy using biodegradable nanoparticles loaded with Cyclosporine A was found to accelerate the innervation of bioengineered teeth after two weeks of implantation.

Preparation of Aqueous Core-Poly(d,l-Lactide-co-Glycolide) Shell Microcapsules With Mononuclear Cores by Internal Phase Separation: Optimization of Formulation Parameters.

Previously, our group employed the internal phase separation method to produce aqueous core-PLGA [poly(d,l-lactide-co-glycolide)] shell microcapsules with polynuclear core morphologies. This report describes the preparation of the more desired and challenging architecture with mononuclear cores. Optimization of formulation parameters including (1) varying the composition of the internal phase and (2) incorporating selected organic solvents (dichloromethane, chloroform, methanol, and acetonitrile) into the internal phase was systematically evaluated. Varying the composition of the internal phase (i.e., PLGA and water levels) failed to produce mononuclear microcapsules. However, incorporating methanol or acetonitrile into the internal phase produced microcapsules with mononuclear cores as confirmed by phase-contrast microscopy, transmission electron microscopy, and scanning electron microscopy. Stability of the prepared emulsions (internal phase of PLGA, acetone, acetonitrile, and water) was optimized by evaluating different types of surfactants with varying concentrations. Among them, lecithin in the range of 0.5%-5% wt/wt provided the best emulsion stability. Interestingly, increasing lecithin concentrations led to the production of microcapsules with smaller sizes (from 2.4 ± 1.6 to 1.1 ± 0.8 µm) and higher percentage of mononuclear cores. The resulting aqueous core-PLGA shell microcapsules are expected to have interesting applications in drug delivery systems with controlled release for hydrophilic drugs and proteins.

Preparation, physicochemical properties and biocompatibility of PBLG/PLGA/bioglass composite scaffolds.

In this study, novel poly(γ-benzyl l-glutamate)/poly(lactic-co-glycolic acid)/bioglass (PBLG/PLGA/BG) composite scaffolds with different weight ratios were fabricated using a negative NaCl-templating method. The morphology, compression modulus and degradation kinetics of the scaffolds were characterized. The results showed that the PBLG/PLGA/BG composite scaffolds with a weight ratio of 5:5:1, namely PBLG5PLGA5BG composite scaffolds, displayed a pore size range of 50-500µm, high compressive modulus (566.6±8.8kPa), suitable glass transition temperature (46.8±0.2°C) and low degradation rate (>8weeks). The in vitro biocompatibility of the scaffolds was evaluated with MC3T3-E1 cells by live-dead staining, MTT and ALP activity assays. The obtained results indicated that the PBLG5PLGA5BG composite scaffolds were more conducive to the adhesion, proliferation and osteoblastic differentiation of MC3T3-E1 cells than PBLG and PBLG/PLGA composite scaffolds. The in vivo biocompatibility of the scaffolds was evaluated in both SD rat subcutaneous model and rabbit tibia defect model. The results of H&E, Masson's trichrome and CD34 staining assays demonstrated that the PBLG5PLGA5BG composite scaffolds allowed the ingrowth of tissue and microvessels more effectively than PBLG/PLGA composite scaffolds. The results of digital radiography confirmed that the PBLG5PLGA5BG composite scaffolds significantly improved in vivo osteogenesis. Collectively, the PBLG5PLGA5BG composite scaffolds could be a promising candidate for tissue engineering applications.

Preparation and physicochemical characterization of T-OA PLGA microspheres.

As the carrier of water-insoluble drugs, microspheres can play a role in increasing solubility and delaying releasing essence. The objective of this study was to improve the solubility and to delay the release of a newly discovered antitumor compound 3ß-hydroxyolea-12-en-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester (T-OA). Early-stage preparation discovery concept (EPDC) was employed in the present study. The preparation, physicochemical characterization, and drug release properties of PLGA microspheres were evaluated. T-OA-loaded PLGA microspheres were prepared by an oil-in-water (O/W) emulsification solvent evaporation method. Characterization and release behaviors of the T-OA PLGA microspheres were evaluated by X-ray diffract (XRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and high performance liquid chromatography (HPLC). The results demonstrated that T-OA-loaded PLGA microspheres could be successfully obtained through solvent evaporation method with appropriate morphologic characteristics and high encapsulation efficiency. The XRD analysis showed that T-OA would be either molecularly dispersed in the polymer or distributed in an amorphous form. The DSC and FTIR analysis proved that there were interactions between T-OA and PLGA polymer. SEM observations displayed the morphology of the microspheres was homogeneous and the majority of the spheres ranged between 50 and 150 µm. The drug release behavior of the microspheres in the phosphate buffered saline medium exhibited a sustained release and the duration of the release lasted for more than 23 days, which was fit with zero-order release pattern with r2 = 0.9947. In conclusion, TOA-loaded PLGA microspheres might hold great promise for using as a drug-delivery system in biomedical applications.

Design of smart GE11-PLGA/PEG-PLGA blend nanoparticulate platforms for parenteral administration of hydrophilic macromolecular drugs: synthesis, preparation and in vitro/ex vivo characterization.

Active drug targeting and controlled release of hydrophilic macromolecular drugs represent crucial points in designing efficient polymeric drug delivery nanoplatforms. In the present work EGFR-targeted polylactide-co-glycolide (PLGA) nanoparticles were made by a blend of two different PLGA-based polymers. The first, GE11-PLGA, in which PLGA was functionalized with GE11, a small peptide and EGFR allosteric ligand, able to give nanoparticles selective targeting features. The second polymer was a PEGylated PLGA (PEG-PLGA) aimed at improving nanoparticles hydrophilicity and stealth features. GE11 and GE11-PLGA were custom synthetized through a simple and inexpensive method. The nanoprecipitation technique was exploited for the preparation of polymeric nanoparticles composed by a 1:1weight ratio between GE11-PLGA and PEG-PLGA, obtaining smart nanoplatforms with proper size for parenteral administration (143.9±5.0nm). In vitro cellular uptake in EGFR-overexpressing cell line (A549) demonstrated an active internalization of GE11-functionalized nanoparticles. GE11-PLGA/PEG-PLGA blend nanoparticles were loaded with Myoglobin, a model hydrophilic macromolecule, reaching a good loading (2.42% respect to the theoretical 4.00% w/w) and a prolonged release over 60days. GE11-PLGA/PEG-PLGA blend nanoparticles showed good in vitro stability for 30days in physiological saline solution at 4°C and for 24h in pH 7.4 or pH 5.0 buffer at 37°C respectively, giving indications about potential storage and administration conditions. Furthermore ex vivo stability study in human plasma using fluorescence Single Particle Tracking (fSPT) assessed good GE11-PLGA/PEG-PLGA nanoparticles dimensional stability after 1 and 4h. Thanks to the versatility in polymeric composition and relative tunable nanoparticles features in terms of drug incorporation and release, GE11-PLGA/PEG-PLGA blend NPs can be considered highly promising as smart nanoparticulate platforms for the treatment of diseases characterized by EGFR overexpression by parenteral administration .

Preparation and characterization of Chinese yam polysaccharide PLGA nanoparticles and their immunological activity.

This paper first provides that Chinese yam polysaccharide (CYP) is encapsulated by PLGA using a double emulsion solvent evaporation method and aims to screen the optimal preparation of CYP-PLGA nanoparticles (CYPP) using response surface methodology (RSM). The volume ratio of the internal water phase to the organic phase (W1:O), the volume ratio of the primary emulsion to the external water phase (PE:W2) and the concentration of Poloxamer 188 (F68) are deemed key variables for the encapsulation efficiency of CYPP. The results demonstrated that the data were accurately fitted into the RSM model. According to the RSM, the optimal scheme was a volume ratio of W1:O of 1:9, a volume ratio of PE: W2 of 1:10 and a concentration of F68 (W/V) of 0.7%. TEM and SEM images demonstrated that the nanoparticles had a spherical shape and smooth surface. The CYP and CYPP in vitro release studies demonstrated that the CYPP showed a release rate 53.41% lower than the release rate of CYP after 48h. The result of pro-proliferation and flow cytometry emerged that the CYPP were more effective compared with the free CYP and blank PLGA nanoparticles in promoting lymphocyte proliferation and triggering the transformation of T lymphocytes into Th cells.

Preparation and Preclinical Evaluation of Inhalable Particles Containing Rapamycin and Anti-Tuberculosis Agents for Induction of Autophagy.

PURPOSE: Mycobacterium tuberculosis (Mtb) inhibits host defense mechanisms, including autophagy. We investigated particles containing rapamycin (RAP) alone or in combination with isoniazid (INH) and rifabutin (RFB) for: targeting lung macrophages on inhalation; inducing autophagy; and killing macrophage-resident Mtb and/or augmenting anti-tuberculosis (TB) drugs. METHODS: PLGA and drugs were spray-dried. Pharmacokinetics, partial biodistribution (LC-MS/MS) and efficacy (colony forming units, qPCR, acid fast staining, histopathology) in mice following dry powder inhalation were evaluated. RESULTS: Aerodynamic diameters of formulations were 0.7-4.7 µm. Inhaled particles reached deep lungs and were phagocytosed by alveolar macrophages, yielding AUC0-48 of 102 compared to 0.1 µg/ml × h obtained with equivalent intravenous dose. RAP particles induced more autophagy in Mtb-infected macrophages than solutions. Inhaled particles containing RAP alone in daily, alternate-day and weekly dosing regimens reduced bacterial burden in lungs and spleens, inducing autophagy and phagosome-lysosome fusion. Inhalation of particles containing RAP with INH and RFB cleared the lungs and spleens of culturable bacteria. CONCLUSIONS: Targeting a potent autophagy-inducing agent to airway and lung macrophages alone is feasible, but not sufficient to eliminate Mtb. Combination of macrophage-targeted inhaled RAP with classical anti-TB drugs contributes to restoring tissue architecture and killing Mtb.

Cationic, amphiphilic copolymer micelles as nucleic acid carriers for enhanced transfection in rat spinal cord.

Spinal cord injury commonly leads to permanent motor and sensory deficits due to the limited regenerative capacity of the adult central nervous system (CNS). Nucleic acid-based therapy is a promising strategy to deliver bioactive molecules capable of promoting axonal regeneration. Branched polyethylenimine (bPEI: 25kDa) is one of the most widely studied nonviral vectors, but its clinical application has been limited due to its cytotoxicity and low transfection efficiency in the presence of serum proteins. In this study, we synthesized cationic amphiphilic copolymers, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP), by grafting low molecular weight PLGA (4kDa) to bPEI (25kDa) at approximately a 3:1 ratio as an efficient nonviral vector. We show that PgP micelle is capable of efficiently transfecting plasmid DNA (pDNA) and siRNA in the presence of 10% serum in neuroglioma (C6) cells, neuroblastoma (B35) cells, and primary E8 chick forebrain neurons (CFN) with pDNA transfection efficiencies of 58.8%, 75.1%, and 8.1%, respectively. We also show that PgP provides high-level transgene expression in the rat spinal cord in vivo that is substantially greater than that attained with bPEI. The combination of improved transfection and reduced cytotoxicity in vitro in the presence of serum and in vivo transfection of neural cells relative to conventional bPEI suggests that PgP may be a promising nonviral vector for therapeutic nucleic acid delivery for neural regeneration. STATEMENT OF SIGNIFICANCE: Gene therapy is a promising strategy to overcome barriers to axonal regeneration in the injured central nervous system. Branched polyethylenimine (bPEI: 25kDa) is one of the most widely studied nonviral vectors, but its clinical application has been limited due to cytotoxicity and low transfection efficiency in the presence of serum proteins. Here, we report cationic amphiphilic copolymers, poly (lactide-co-glycolide)-graft-polyethylenimine (PgP) that are capable of efficiently transfecting reporter genes and siRNA both in the presence of 10% serum in vitro and in the rat spinal cord in vivo. The combination of improved transfection and reduced cytotoxicity in the presence of serum as well as transfection of neural cells in vivo suggests PgP may be a promising nucleic acid carrier for CNS gene delivery.

Synergistic Effect of Cold Atmospheric Plasma and Drug Loaded Core-shell Nanoparticles on Inhibiting Breast Cancer Cell Growth.

Nano-based drug delivery devices allowing for effective and sustained targeted delivery of therapeutic agents to solid tumors have revolutionized cancer treatment. As an emerging biomedical technique, cold atmospheric plasma (CAP), an ionized non-thermal gas mixture composed of various reactive oxygen species, reactive nitrogen species, and UV photons, shows great potential for cancer treatment. Here we seek to develop a new dual cancer therapeutic method by integrating promising CAP and novel drug loaded core-shell nanoparticles and evaluate its underlying mechanism for targeted breast cancer treatment. For this purpose, core-shell nanoparticles were synthesized via co-axial electrospraying. Biocompatible poly (lactic-co-glycolic acid) was selected as the polymer shell to encapsulate anti-cancer therapeutics. Results demonstrated uniform size distribution and high drug encapsulation efficacy of the electrosprayed nanoparticles. Cell studies demonstrated the effectiveness of drug loaded nanoparticles and CAP for synergistic inhibition of breast cancer cell growth when compared to each treatment separately. Importantly, we found CAP induced down-regulation of metastasis related gene expression (VEGF, MTDH, MMP9, and MMP2) as well as facilitated drug loaded nanoparticle uptake which may aid in minimizing drug resistance-a major problem in chemotherapy. Thus, the integration of CAP and drug encapsulated nanoparticles provides a promising tool for the development of a new cancer treatment strategy.