Interaction of PLGA nanoparticles with human blood constituents

When nanoparticles are injected into the blood for drug delivery or drug detoxification, detrimental interaction of these particles with blood constituents must be avoided. In previous studies, the adsorption of albumin immunoglobulin G, and fibrinogen from blood plasma to a model hydrophobic polymer like polystyrene was investigated as was decreasing surface hydrophobicity, which quantitatively leads to decreasing amounts of adsorbed proteins on latex particles. However, the uptake of other blood constituents, such as inorganic blood electrolytes, by particles and the dispersion/coagulation characteristics of these particles in the blood stream have not been fully studied. Most importantly, the effect s of these particles on blood coagulation and hemolysis are not well known. In the present study, the poly(lactide-co-glycolide) acid(PLGA) nanoparticles were synthesized by using nanoprecipitation. The uptake of blood electrolytes from simulated blood fluid (SBF) and the stability (dispersion/aggregation) of nanoparticles in SBF was examined by using different loading amounts of PLGA and different contact time between PLGA nanoparticles and SBF. The interaction of particles with the organic components of blood was also studied by using the measurement of red blood cell hemolysis and blood clotting with raw PLGA, surfactant modified PLGA, and PEGylated PLGA.     

Protein-loaded PLGA–PEO blend nanoparticles: encapsulation, release and degradation characteristics

The aim of this work was to study the variables that affect the encapsulation and release of proteins from nanoparticles based on poly(lactic-co-glycolic acid; PLGA)–poloxamer and PLGA–poloxamine blend matrices, using bovine serum albumin (BSA) and immuno-γ-globulin (IgG) as model proteins. The nanoparticles were prepared by a solvent diffusion technique, and the studied variables were (1) PLGA molecular weight, (2) type of PEO-block copolymers, (3) protein loading, (4) pH and, (5) volume of the protein solution. Our results showed that the proteins can be efficiently incorporated into and released from the blend matrices. The type of the PEO derivative and the pH of the internal aqueous phase were the most important factors influencing protein encapsulation and release kinetics. Moreover, comparative degradation study of PLGA, PLGA–poloxamer and PLGA–poloxamine nanoparticles confirmed that the degradation and release characteristics of polyester particles can be improved by the incorporation of polyoxyethylene derivatives with different hydrophilia–lipophilia balance.     

Target-specific cellular uptake of PLGA nanoparticles coated with poly(L-lysine)-poly(ethylene glycol)-folate conjugate

Poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles with anionic surface charge were surface coated with cationic di-block copolymer, poly(L-lysine)-poly(ethylene glycol)-folate (PLL-PEG-FOL) conjugate, for enhancing their site-specific intracellular delivery against folate receptor overexpressing cancer cells. The PLGA nanoparticles coated with the conjugate were characterized in terms of size, surface charge, and change in surface composition by XPS. By employing the flow cytometry method and confocal image analysis, the extent of cellular uptake was comparatively evaluated under various conditions. PLL-PEG-FOL coated PLGA nanoparticles demonstrated far greater extent of cellular uptake to KB cells, suggesting that they were mainly taken up by folate receptor-mediated endocytosis. The enhanced cellular uptake was also observed even in the presence of serum proteins, possibly due to the densely seeded PEG chains. The PLL-PEG-FOL coated PLGA nanoparticles could be potentially applied for cancer cell targeted delivery of various therapeutic agents.     

Cross‐Platform Comparison of Therapeutic Delivery from Multilamellar Lipid‐Coated Polymer Nanoparticles

Significant efforts have been invested in finding a delivery system that can encapsulate and deliver therapeutics. Core–shell polymer‐lipid hybrid nanoparticles have been studied as a promising platform because of their mechanical stability, narrow size distribution, biocompatibility, and ability to co‐deliver diverse drugs. Here, novel core–shell nanoparticles based on a poly(lactic‐co‐glycolic acid) (PLGA) core and multilamellar lipid shell are designed, where the lipid bilayers are crosslinked between the two adjacent bilayers (PLGA‐ICMVs). The cross‐platform performance of the nanoparticles to other polymer‐lipid hybrid platforms is examined, including physicochemical characteristics, ability to encapsulate a variety of therapeutics, biocompatibility, and functionality as a vaccine delivery platform. Differential abilities of nanoparticle systems to encapsulate distinct pharmaceutics are observed, which suggest careful consideration of the platform chosen depending on the therapeutic agent and desired function. The novel PLGA‐ICMV platform herein demonstrates great potential in stably encapsulating water‐soluble agents and therefore is an attractive platform for therapeutic delivery.     

Stem cell membrane vesicle–coated nanoparticles for efficient tumor‐targeted therapy of orthotopic breast cancer

Nanoparticles‐based drug delivery strategies have been widely researched for cancer therapy. However, most of them are expected to accumulate in tumor sites via the enhanced permeability and retention (EPR) effect, which is insufficient to deliver the loaded drug into tumors. Cell membrane–camouflaged nanoparticles have obtained much attention for their excellent stability and long blood circulation and reduced the macrophage cells uptake in drug delivery. Herein, bone marrow–derived mesenchymal stem cell membrane vesicle (SCV)–coated paclitaxel (PTX)–loaded poly (lactide‐co‐glycolide) (PLGA) nanoparticles (SCV/PLGA/PTX) were fabricated as the efficient orthotopic breast cancer–targeted drug delivery system. The SCV/PLGA/PTX showed excellent stability, more controlled PTX release, and more effective antitumor effect in vitro. After administration in vivo, SCV/PLGA/PTX exhibited the long‐term retention and enhanced accumulation at tumor sites due to the immune escape and mesenchymal stem cell–mimicking cancer‐targeting capacity. As expected, the SCV/PLGA/PTX could significantly suppress the primary tumor growth by increased apoptosis and necrosis areas within tumor tissues and attenuated the toxic side effects of PTX in 4T1 orthotopic breast cancer model. The study indicated the mesenchymal stem cell membrane coating strategy was highly efficient for targeted drug delivery, which provided a new insight for precise and effective breast cancer treatment.     

Internalization of PLGA nanoparticles coated with poloxamer 188 in glioma cells: A confocal laser scanning microscopy study

Internalization of poloxamer 188-coated PLGA nanoparticles (NPs) in GL261 murine glioma cells was studied using confocal laser scanning microscopy. For visualization, both poloxamer 188 (P188) and PLGA were labeled covalently with fluorescent dyes Rhodamine B and Cyanine5, respectively. The results indicated that the PLGA NPs coated with poloxamer 188 enter a cell as an integral core–shell structure, which can be helpful for gaining further insight into the in vivo performance of surfactant-coated polymeric NPs as core–shell delivery systems     

PLGA Nanoparticles Decorated with Anti-HER2 Affibody for Targeted Delivery and Photoinduced Cell Death

The effect of enhanced permeability and retention is often not sufficient for highly effective cancer therapy with nanoparticles, and the development of active targeted drug delivery systems based on nanoparticles is probably the main direction of modern cancer medicine. To meet the challenge, we developed polymer PLGA nanoparticles loaded with fluorescent photosensitive xanthene dye, Rose Bengal, and decorated with HER2-recognizing artificial scaffold protein, affibody Z_HER2:342. The obtained 170 nm PLGA nanoparticles possess both fluorescent and photosensitive properties. Namely, under irradiation with the green light of 540 nm nanoparticles, they produced reactive oxygen species leading to cancer cell death. The chemical conjugation of PLGA with anti-HER2 affibody resulted in the selective binding of nanoparticles only to HER2-overexpressing cancer cells. HER2 is a receptor tyrosine kinase that belongs to the EGFR/ERbB family and is overexpressed in 30% of breast cancers, thus serving as a clinically relevant oncomarker. However, the standard targeting molecules such as full-size antibodies possess serious drawbacks, such as high immunogenicity and the need for mammalian cell production. We believe that the developed affibody-decorated targeted photosensitive PLGA nanoparticles will provide new solutions for ongoing problems in cancer diagnostics and treatment, as well in cancer theranostics.     

Surface modification of poly(lactide-co-glycolide) nanoparticles by d-α-tocopheryl polyethylene glycol 1000 succinate as potential carrier for the delivery of drugs to the brain

The potential health benefits of vitamin E (d-α-tocopheryl polyethylene glycol 1000 succinate, TPGS), particularly, in curing of the neurological symptoms associated with vitamin E deficiency have been reported. Hence, vitamin E containing carriers for delivery of drugs to the brain might be useful from different points of view. Herein, in order to obtain desired surface morphology and particle size of poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) and high emulsifying effects, TPGS-modified PLGA NPs were optimized as a potential carrier for the delivery of drugs to the brain. The particle sizes, surface morphology, phase composition correlated with different emulsifiers and different stirring times were characterized. Also, the in vitro cytotoxicity of the samples using PC12 cell line was investigated. According to the obtained results, by increasing the percentages of TPGS, the average particle size decreased and the distribution of particle diameters came closer by further addition, and the larger particles did not create. In addition, no obvious cytotoxicity was observed at various TPGS amounts, and the modified PLGA NPs were considered biocompatible since they show little decrease in cellular viability. With the increase of TPGS ratio, more effective in vitro therapeutic effects could be observed, which achieved the highest cell viability, because the degradation of NPs may release the most amounts of TPGS components that have synergistic activity. Furthermore, it was found that TPGS as a water-soluble derivative of natural source of vitamin E could be a perfect emulsifier for making PLGA NPs as potential carrier for delivery of drugs to the brain.     

Preparation and characterization novel polymer-coated magnetic nanoparticles as carriers for doxorubicin

The poly(lactide-co-glycolide)-coated magnetic nanoparticles (PLGA MNPs) were prepared as carriers of doxorubicin (PLGA-DOX MNPs) through water-in-oil-in-water (W/O/W) emulsification method. The characteristics of PLGA-DOX MNPs were measured by using transmission electron microscopy (TEM) and vibrating-sampling magnetometry (VSM). It was found that the synthesized nanoparticles were spherical in shape with an average size of 100 ± 20 nm, low aggregation and good magnetic responsivity. Meanwhile, the drug content and encapsulation efficiency of nanoparticles can be achieved by varying the feed weight ratios of PLGA and DOX particles. These PLGA-DOX MNPs also demonstrated sustained release of DOX at 37 °C in buffer solution. Besides, influence of drug-loaded nanoparticles on in vitro cytotoxicity was determined by MTT assay, while cellular apoptosis was detected by Annexin V-FITC apoptosis detection kit. The results showed that PLGA-DOX MNPs retained significant antitumor activities. Therefore, PLGA-DOX MNPs might be considered a promising drug delivery system for cancer chemotherapy.     

Fabrication of poly(lactide‐co‐glycolide) scaffold embedded spatially with hydroxyapatite particles on pore walls for bone tissue engineering

Poly(lactide‐co‐glycolide) (PLGA) scaffolds embedded spatially with hydroxyapatite (HA) particles on the pore walls (PLGA/HA‐S) were fabricated by using HA‐coated paraffin spheres as porogens, which were prepared by Pickering emulsion. For comparisons, PLGA scaffolds loaded with same amount of HA particles (2%) in the matrix (PLGA/HA‐M) and pure PLGA scaffolds were prepared by using pure paraffin spheres as porogens. Although the three types of scaffolds had same pore size (450–600 µm) and similar porosity (90%–93%), the PLGA/HA‐S showed the highest compression modulus. The embedment of the HA particles on the pore walls endow the PLGA/HA‐S scaffold with a stronger ability of protein adsorption and mineralization as well as a larger mechanical strength against compression. In vitro culture of rat bone marrow stem cells revealed that cell morphology and proliferation ability were similar on all the scaffolds. However, the alkaline phosphatase activity was significantly improved for the cells cultured on the PLGA/HA‐S scaffolds. Therefore, the method for fabricating scaffolds with spatially embedded nanoparticles provides a new way to obtain the bioactive scaffolds for tissue engineering. Copyright © 2011 John Wiley & Sons, Ltd.     

Polymeric Lids for Microcontainers for Oral Protein Delivery

Oral delivery of proteins and peptides is one of the main challenges in pharmaceutical drug development. Microdevices have the possibility to protect the therapeutics until release is desired, avoiding losses by degradation. One type of microdevice is polymeric microcontainers. In this study, lysozyme is chosen as model protein and loaded into microcontainers with the permeation enhancer sodium decanoate (C10). The loaded microcontainers are sealed and functionalized by applying polymeric lids onto the cavity of the devices. The first lid is poly(lactic‐co‐glycolic) acid (PLGA) and on top of this either polyethylene glycol (PEG) or chitosan is applied (PLGA+PEG or PLGA+chitosan, respectively). The functionalization is evaluated in vitro for morphology, drug release, and mucoadhesive properties. These are coupled with in vitro and ex vivo studies using Caco‐2 cells, Caco‐2/HT29‐MTX‐E12 co‐cultures, and porcine intestinal tissue. PLGA+chitosan shows slower release compared to PLGA+PEG or only PLGA in buffer and the transport of lysozyme across cell cultures is not enhanced compared to the bulk powder. Microcontainers coated with chitosan or PEG demonstrate a three times stronger adhesion during ex vivo mucoadhesion studies compared to samples without coatings. Altogether, functionalized microcontainers with mucoadhesive properties and tunable release for oral protein delivery are developed and characterized.     

Use of a polycation spacer for noncovalent immobilization of albumin on thermally modified virus particles

The noncovalent immobilization of the protein bovine serum albumin on the surface of spherical nanoparticles 330 ± 60 nm in diameter is described. These nanoparticles are prepared by the thermal treatment of tobacco mosaic virus and are preliminarily covered with a layer of the cationic polymer poly(N-ethyl-4-vinylpyridinium bromide). The electrostatic adsorption of the polycation on the surface of negatively charged spherical nanoparticles (on average 1.2 × 10⁴ macromolecules per particle) is accompanied by recharging of the surface; as a result, the negatively charged protein bovine serum albumin can be adsorbed on it in an amount of 1.7 × 10⁴ molecules per particle. The modification of spherical nanoparticles with the polycation and protein does not cause the aggregation of particles. The spherical-nanoparticle-polycation-protein ternary complex demonstrates increased stability in salt solutions relative to the spherical-nanoparticle-polycation binary complex. Because of the simplicity of the method used to modify the surface of spherical nanoparticles, it shows promise for preparation of functionally active complexes.     

Biocompatible APTES–PEG Modified Magnetite Nanoparticles: Effective Carriers of Antineoplastic Agents to Ovarian Cancer

Magnetite nanoparticles are particularly attractive for drug delivery applications because of their size-dependent superparamagnetism, low toxicity, and biocompatibility with cells and tissues. Surface modification of iron oxide nanoparticles with biocompatible polymers is potentially beneficial to prepare biodegradable nanocomposite-based drug delivery agents for in vivo and in vitro applications. In the present study, the bare (10 nm) and polyethylene glycol (PEG)–(3-aminopropyl)triethoxysilane (APTES) (PA) modified (17 nm) superparamagnetic iron oxide nanoparticles (SPIO NPs) were synthesized by coprecipitation method. The anticancer drugs, doxorubicin (DOX) and paclitaxel (PTX), were separately encapsulated into the synthesized polymeric nanocomposites for localized targeting of human ovarian cancer in vitro. Surface morphology analysis by scanning electron microscopy showed a slight increase in particle size (27?±?0.7 and 30?±?0.45 nm) with drug loading capacities of 70 and 61.5 % and release capabilities of 90 and 93 % for the DOX- and PTX-AP-SPIO NPs, respectively (p?<?0.001). Ten milligrams/milliliter DOX- and PTX-loaded AP-SPIO NPs caused a significant amount of cytotoxicity and downregulation of antiapoptotic proteins, as compared with same amounts of free drugs (p?<?0.001). In vivo antiproliferative effect of present formulation on immunodeficient female Balb/c mice showed ovarian tumor shrinkage from 2,920 to 143 mm³ after 40 days. The present formulation of APTES–PEG-SPIO-based nanocomposite system of targeted drug delivery proved to be effective enough in order to treat deadly solid tumor of ovarian cancer in vitro and in vivo.     

Label-free quantitative analysis for studying the interactions between nanoparticles and plasma proteins

A shotgun proteomics approach was used to compare human plasma protein binding capability with cationic liposomes, DNA–cationic lipid complexes (lipoplexes), and lipid–polycation–DNA (LPD) complexes. Nano-high-performance liquid chromatography coupled with a high-resolution LTQ Orbitrap XL mass spectrometer was used to characterize and compare their protein corona. Spectral counting and area under curve methods were used to perform label-free quantification. Substantial qualitative and quantitative differences were found among proteins bound to the three different systems investigated. Protein variety found on lipoplexes and LPD complexes was richer than that found on cationic liposomes. There were also significant differences between the amounts of protein. Such results could help in the design of gene-delivery systems, because some proteins could be more selectively bound rather than others, and their bio-distribution could be driven in vivo for more efficient and effective gene therapy.     

Morphological and thermal behavior of porous biopolymeric nanoparticles

The aim of the present work is to design, develop and characterize biodegradable polymeric nanoparticles having well defined size and porous morphology. Poly(dl-lactide-co-glycolide) (PLGA) and poly(l-lactide) (PLLA) nanoparticles (NPs) were prepared by double emulsion method with subsequent solvent evaporation. NPs were characterized by electron microscopes, dynamic light scattering, XRD and thermal properties by differential scanning calorimetry and thermogravimetry. Finally, the in vitro degradation analysis was also performed. Biodegradable NPs display a spherical surface structure with a homogeneous size distribution, and an average diameter of 180 nm for PLLA and 218 nm for the PLGA. The NP nanoporous structure was analyzed by an innovative thermal method: thermoporosimetry, providing information about nanopore dimensions. In vitro degradation studies demonstrate the gradual surface aggregation and degradation of NPs and the effects on polymer properties. Biopolymeric porous nano-systems may offer promise properties for revolutionary improvements in tissue engineering, diagnosis and targeted drug delivery systems.     

Development and validation of an HPLC method for the quantitation of 1,3-dihydroxy-2-methylxanthone in biodegradable nanoparticles

A rapid and simple high-performance liquid chromatographic method for the analysis of 1,3-dihydroxy-2-methylxanthone (DHMXAN) in biodegradable poly(D,L-lactide-co-glycolide) (PLGA) nanosphere and nanocapsule formulations is developed and validated. The method does not require any complex sample extraction procedure. Chromatographic separation is made with a reversed-phase C18 column, using methanol-water (90:10, v/v) containing 1% (v/v) acetic acid as a mobile phase at a flow rate of 1 mL/min. Identification is made by UV detection at 237 nm. The isocratic system operates at ambient temperature and requires 7.5 min of chromatographic time. The developed method is statistically validated according to ICH guidelines and USP 29 for its specificity, linearity, accuracy, and precision. The assay method proposed in this study is specific for DHMXAN in the presence of nanosphere and nanocapsule excipients. Diode-array analyses confirm the purity of DHMXAN peak in stress conditions (> 99.0%). The method is shown to be linear (r > or = 0.999) over the concentration range of 0.25-3.0 microg/mL. Recovery ranges from 99.0% to 102.7% (RSD: 1.49%) and from 98.3% to 101.6% (RSD: 1.07%) for nanospheres and nanocapsules, respectively. Repeatability (intra-assay precision) and intermediate precision is acceptable with RSD values ranging from 0.6% to 1.9% and from 0.3% to 2.0%, respectively. The method is shown to be suitable for the evaluation of DHMXAN content entrapped in PLGA nanoparticles.     

Microencapsulation of protein‐loaded polysaccharide particles within poly(D,L‐lactic‐co‐glycolic acid) microspheres using S/O/W: characterization and release studies

This report demonstrates a process to form polysaccharide glassy particles without water–oil or water–air interfaces as well as ionic polymers and its application in formulating sustained‐release dosage forms for structurally delicate proteins. When a co‐solution containing dextran and polyethylene glycol (PEG) was subjected to freeze‐drying, the dextran separated out of the solution to form dispersed phases surrounded by a PEG‐rich continuous phase and was solidified during subsequent lyophilization to fine glassy particles, 1–2 µm in diameter. Water‐soluble proteins can easily be loaded in these glassy particles due to preferential partition and become resistant to organic solvents simply by adding them into the dextran‐PEG co‐solution. After washing away the PEG continuous phase with organic solvents, the protein‐containing glassy particles can be suspended in a hydrophobic polymer solution and formulated into various pharmaceutical dosage forms and medical devices for sustained‐release protein delivery. In the present study, myoglobin, bovine serum albumin (BSA), and β‐galactosidase (β‐gal) were formulated in PLGA mcirospheres and as model proteins using this glassy particulate approach, and subjected to a series of assays for release kinetics, structural integrity, and bioactivity. The experimental results indicated that this system offered well preserved protein integrity and bioactivity as well as significantly improved protein release kinetics. Copyright © 2008 John Wiley & Sons, Ltd.     

Stabilizer‐Free Poly(lactide‐co‐glycolide) Nanoparticles Conjugated with Quantum Dots as a Potential Carrier Applied in Human Mesenchymal Stem Cells

We report that human mesenchymal stem cells (hMSCs) were successfully labeled with poly(lactide‐co‐glycolide) nanoparticles (PLGA NPs) surface‐conjugated quantum dots (QDs) (PLGA‐QD NPs) via endocytosis pathway. These NPs were not toxicity even treated with PLGA‐QD NPs at high concentrations for at least four weeks. Besides, PLGA‐QD NPs‐labeled hMSCs did not change their proliferation and differentiation capability toward the cell fates of adipocytes, osteocytes, and chrondrocytes. It's known that PLGA has been widely employed to act as delivery carrier which encapsulates drugs and releases them under a controlled way. Currently, we have also demonstrated that FITC‐loaded PLGA‐QD NPs degraded in hMSCs to achieve intracellular release of FITC. The aim of this research is to investigate viability, proliferation and differentiation capability and the potential for gene delivery of MSCs labeled with PLGA‐QD NPs. In addition to PLGA‐QD NPs, QDs alone were used to serve as a control set for comparison.     

Enhanced transdermal delivery of indomethacin-loaded PLGA nanoparticles by iontophoresis

Nanoparticles effectively deliver therapeutic agent by penetrating into the skin. Indomethacin (IM) and coumarin-6 were loaded in PLGA nanoparticles with an average diameter of 100 nm. IM and coumarin-6 were chosen as a model drug and as a fluorescent marker, respectively. The surfaces of the nanoparticles were negatively charged. Permeability of IM-loaded PLGA nanoparticles through rat skin was studied. Higher amount of IM was delivered through skin when IM was loaded in nanoparticles than IM was free molecules. Also, iontophoresis was applied to enhance the permeability of nanoparticles. When iontophoresis with 3 V/cm was applied, permeability of IM was much higher than that obtained by simple diffusion of nanoparticles through skin. The combination of charged nanoparticle system with iontophoresis is useful for effective transdermal delivery of therapeutic agents.     

Layer by layer surface engineering of poly (lactide-co-glycolide) nanoparticles: A versatile tool for nanoparticle engineering for targeted drug delivery

Recent work regarding the Layer by Layer (LbL) engineering of poly(lactide-co-glycolide) nanoparticles (PLGA NPs) is reviewed here.The LbL engineering of PLGA NPs is applied as a means of generating advanced drug delivery devices with tailored recognition,protection,cargo and release properties.LbL in combination with covalent chemistry is used to attach PEG and folic acid to control cell uptake and direct it towards cancer cells.LbL coatings composed of chitosan and alginate show low protein interactions and can be used as an alternative to Pegylation.The assembly on top of LbL coatings of lipid layers composed of variable percentages of 1,2-dioleoyl-sn-glycero-3-choline (DOPC) and 1,2-dioleoyl-sn-glycero-3-phosphoL-serine (DOPS) increases NP uptake and directs the NPs towards the endoplasmic reticulum.The antibody anti-TNF-α is encapsulated forming a complex with alginate that is assembled LbL on top of PLGA NPs.The antibody is released in cell culture following first order kinetics.The release kinetics of encapsulated molecules inside PLGA NPs are studied when the PLGA NPs are coated via LbL with different polyelectrolytes.The intracellular release of encapsulated Doxorubicin is studied in the HepG2 cell line by means of Fluorescence Lifetime Imaging.