Radiopaque iodinated copolymeric nanoparticles for X-ray imaging applications

Recently we described iodinated homopolymeric radiopaque nanoparticles of 28.9 ± 6.3 nm dry diameter synthesized by emulsion polymerization of 2-methacryloyloxyethyl(2,3,5-triiodobenzoate) (MAOETIB). The nanoparticle aqueous dispersion, however, was not stable and tended to agglomerate, particularly at weight concentration of dispersed nanoparticles above 0.3%. The agglomeration rate increases as the concentration of nanoparticles in aqueous phase rises and prevents the potential in vivo use as contrast agent for medical X-ray imaging. Here we describe efforts to overcome this limitation by synthesis of iodinated copolymeric nanoparticles of 25.5 ± 4.2 nm dry diameter, by emulsion copolymerization of the monomer, MAOETIB, with a low concentration of glycidyl methacrylate (GMA). The surface of resulting copolymeric nanoparticles is far more hydrophilic than that of polyMAOETIB (PMAOETIB) nanoparticles. Therefore, P(MAOETIB-GMA) nanoparticles are significantly more stable against agglomeration in aqueous continuous phase. After intravenous injection of P(MAOETIB-GMA) nanoparticles in rats and mice (including those with a liver cancer model) CT-imaging revealed a significant enhanced visibility of the blood pool for 30 min after injection. Later, lymph nodes, liver and spleen strongly enhanced due to nanoparticle uptake by the reticuloendothelial system. This favorably enabled the differentiation of cancerous from healthy liver tissue and suggests our particles for tumor imaging in liver and lymph nodes.     

Anti-biofouling conducting polymer nanoparticles as a label-free optical contrast agent for high resolution subsurface biomedical imaging

Optical coherence tomography (OCT) is a modern high resolution subsurface medical imaging technique. Herein we describe: (i) the synthesis of a thiophene-functionalized oligo(ethylene glycol) methacrylate (OEGMA)-based statistical copolymer, denoted poly(2TMOI–OEGMA); (ii) the preparation of sterically-stabilized polypyrrole (PPy) nanoparticles of approximately 60 nm diameter; (iii) the evaluation of these nanoparticles as a NIR-absorbing optical contrast agent for high-resolution OCT imaging. We show that poly(2TMOI–OEGMA)-stabilized PPy nanoparticles exhibit similar optical properties to poly(vinyl alcohol) (PVA)-stabilized PPy nanoparticles of comparable size prepared using commercially available PVA. Spectroscopic measurements and Mie calculations indicate that both types of PPy nanoparticles strongly absorb NIR radiation above 1000 nm, suggesting their potential use as OCT contrast agents. In vitro OCT studies indicate that both types of PPy nanoparticles reduce NIR backscattering within homogeneous intralipid tissue phantoms, offering almost identical contrast performance in this medium. However, PVA-stabilized PPy nanoparticles became colloidally unstable when dispersed in physiological buffer and immersed in a solid biotissue phantom and hence failed to generate a strong contrast effect. In contrast, the poly(2TMOI–OEGMA)-stabilized PPy nanoparticles remained well-dispersed and hence exhibited a strong rapid onset contrast effect within the biotissue phantom under identical physiological conditions. Ex vivo studies performed on excised chicken and porcine skin tissue demonstrated that topical administration of a low concentration of poly(2TMOI–OEGMA)-stabilized PPy nanoparticles rapidly enhances OCT image contrast in both cases, allowing key tissue features to be readily identified.     

Engineered protein nanoparticles for in vivo tumor detection

Two different protein nanoparticles that are totally different in shape and surface structure, i.e. Escherichia coli DNA-binding protein (eDPS) (spherical, 10 nm) and Thermoplasma acidophilum proteasome (tPTS) (cylindrical, 12 × 15 nm) were engineered for in vivo optical tumor detection: arginine–glycine–aspartic acid (RGD) peptide (CDCRGDCFC) was genetically inserted to the surface of each protein nanoparticle, and also near-infrared fluorescence dye was chemically linked to the surface lysine residues. The specific affinity of RGD for integrin (α_vβ₃) facilitated the uptake of RGD-presenting protein nanoparticles by integrin-expressing tumor cells, and also the protein nanoparticles neither adversely affected cell viability nor induced cell damage. After intravenously injected to tumor-bearing mice, all the protein nanoparticles successfully reached tumor with negligible renal clearance, and then the surface RGD peptides caused more prolonged retention of protein nanoparticles in tumor and accordingly higher fluorescence intensity of tumor image. In particular, the fluorescence of tumor image was more intensive with tPTS than eDPS, which is due presumably to longer in vivo half-life and circulation of tPTS that originates from thermophilic and acidophilic bacterium. Although eDPS and tPTS were used as proof-of-concept in this study, it seems that other protein nanoparticles with different size, shape, and surface structure can be applied to effective in vivo tumor detection.     

Biocatalytic and antibacterial visualization of green synthesized silver nanoparticles using Hemidesmus indicus

In the present investigation, we described the green synthesis of silver nanoparticles using plant leaf extract of Hemidesmus indicus. The synthesized silver nanoparticles were characterized by UV–visible spectroscopy, fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). TEM images proved that the synthesized silver nanoparticles were spherical in shape with an average particle size of 25.24 nm. To evaluate antibacterial efficacy, bacteria was isolated from poultry gut and subjected to 16S rRNA characterization and confirmed as Shigella sonnei. The in vitro antibacterial efficacy of synthesized silver nanoparticles was studied by agar bioassay, well diffusion and confocal laser scanning microscopy (CLSM) assay. The H. indicus mediated synthesis of silver nanoparticles shows rapid synthesis and higher inhibitory activity (34 ± 0.2 mm) against isolated bacteria S. sonnei at 40 μg/ml.     

Core Cross-Linking Enhances the Anti-Inflammatory Performance of Oxidation-Sensitive Polymeric Micelles

Nanomaterials able to scavenge biologically relevant oxidants (reactive oxygen species, ROS) can directly act as anti-inflammatory agents. Here, micelles made of amphiphilic poly(ethylene glycol)(PEG)-polysulfide block copolymers are focused on; the polysulfide blocks are responsible of ROS-scavenging and are composed of propylene sulfide and ethylene sulfide units in ratios of 20:0, 15:5, 10:10. These polymers can be intramicellarly cross-linked through thermal thiol-yne reaction of terminal alkynes (trithiol cross-linker). Self-assembled and cross-linked micelles are virtually identical in size and scavenging kinetics, but greatly differ in stability against dilution (critical aggregation concentration (CAC) respectively of ≈0.1 and <0.01 mg mL⁻¹) and in the final state after oxidation (soluble polymers vs cross-linked nanoparticles). Most importantly, self-assembled micelles have significant toxicity and damage cell membranes already at 0.5 mg mL⁻¹, which seriously hampers their anti-inflammatory activity. On the contrary, cross-linked micelles do not appreciably harm cells at least up to 1 mg mL⁻¹, and effectively inhibit the production of inflammatory cytokines in activated macrophages. In this study, a detailed interpretation of the morphological evolution of the two types of micelles during oxidation is provided and it is proved that core cross-linking significantly widens the therapeutic window.     

Size-Controlled Synthesis of Soluble-Conjugated Polymeric Nanoparticles in Dendritic Mesoporous Silica Nanospheres

A size-controlled method has been exploited to synthesize 20 kinds of soluble-conjugated polymeric nanoparticles (SCPNs) through cross-coupling polymerizations between various combinations of symmetrical multifunctional monomers (A_x+B_y, x > 2, y ≥ 2). Unlike the classical polycondensation of these kinds of monomers where infinite polymer networks and insoluble polymeric products are typically formed, this confined polymerization in palladium nanoparticles-loaded dendritic mesoporous silica nanospheres produced SCPNs with good to high yields, narrow particle size distribution, and high solubility in common organic solvents. The controlled size of SCPNs characterized with gel permeation chromatography shows narrow distribution and various molecular weight ranging from 2164 to 14 234 Da, transmission electron microscopy and dynamic light scattering analyses range from 5 to 15 nm, suggesting the confined polymerization occurring inside of the mesopores. By simply adjusting the monomer structure and selecting an appropriate cross-coupling polymerization method among Suzuki, Stille, Sonogashira, and direct arylation polymerizations, the obtained SCPNs show bright fluorescence emission varying from blue to red. The SCPNs with long alkyl chain substituents in monomer units show good processability and smooth polymer films are formed by the simple spin-casting method. The repeatable and straightforward synthesis of SCPNs endows them with wide application prospects in light-emission, fluorescence sensing, and bioimaging.     

Visible-light-excited and europium-emissive nanoparticles for highly-luminescent bioimaging in vivo

Europium(III)-based material showing special milliseconds photoluminescence lifetime has been considered as an ideal time-gated luminescence probe for bioimaging, but is still limited in application in luminescent small-animal bioimaging in vivo. Here, a water-soluble, stable, highly-luminescent nanosystem, Ir–Eu–MSN (MSN = mesoporous silica nanoparticles, Ir–Eu = [Ir(dfppy)₂(pic–OH)]₃Eu·2H₂O, dfppy = 2-(2,4-difluorophenyl)pyridine, pic–OH = 3-hydroxy-2-carboxypyridine), was developed by an in situ coordination reaction to form an insoluble dinuclear iridium(III) complex-sensitized-europium(III) emissive complex within mesoporous silica nanoparticles (MSNs) which had high loading efficiency. Compared with the usual approach of physical adsorption, this in-situ reaction strategy provided 20-fold the loading efficiency (43.2%) of the insoluble Ir–Eu complex in MSNs. These nanoparticles in solid state showed bright red luminescence with high quantum yield of 55.2%, and the excitation window extended up to 470 nm. These Ir–Eu–MSN nanoparticles were used for luminescence imaging in living cells under excitation at 458 nm with confocal microscopy, which was confirmed by flow cytometry. Furthermore, the Ir–Eu–MSN nanoparticles were successfully applied into high-contrast luminescent lymphatic imaging in vivo under low power density excitation of 5 mW cm⁻². This synthetic method provides a universal strategy of combining hydrophobic complexes with hydrophilic MSNs for in vivo bioimaging.     

The effects of graphene nanostructures on mesenchymal stem cells

We report the effects of two-dimensional graphene nanostructures; graphene nano-onions (GNOs), graphene oxide nanoribbons (GONRs), and graphene oxide nanoplatelets (GONPs) on viability, and differentiation of human mesenchymal stem cells (MSCs). Cytotoxicity of GNOs, GONRs, and GONPs dispersed in distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)] (DSPE-PEG), on adipose derived mesenchymal stem cells (adMSCs), and bone marrow-derived mesenchymal stem cells (bmMSCs) was assessed by AlamarBlue and Calcein AM viability assays at concentrations ranging from 5 to 300 μg/ml for 24 or 72 h. Cytotoxicity of the 2D graphene nanostructures was found to be dose dependent, not time dependent, with concentrations less than 50 μg/ml showing no significant differences compared to untreated controls. Differentiation potential of adMSCs to adipocytes and osteoblasts, – characterized by Oil Red O staining and elution, alkaline phosphatase activity, calcium matrix deposition and Alizarin Red S staining – did not change significantly when treated with the three graphene nanoparticles at a low (10 μg/ml) and high (50 μg/ml) concentration for 24 h. Transmission electron microscopy (TEM) and confocal Raman spectroscopy indicated cellular uptake of only GNOs and GONPs. The results lay the foundation for the use of these nanoparticles at potentially safe doses as ex vivo labels for MSC-based imaging and therapy.     

NIR photothermal therapy using polyaniline nanoparticles

Developing a biocompatible and efficient photothermal coupling agent with appropriate size is a prerequisite for the development of near-infrared (NIR) light-induced photothermal therapy (PTT). In the present study, polyaniline nanoparticles (PANPs) with a size of 48.5 ± 1.5 nm were fabricated and exhibited excellent dispersibility in water by a hydrothermal method and further surface functionalization by capping with F127. The developed F127-modified PANPs (F-PANPs) had a high molar extinction coefficient of 8.95 × 10⁸ m⁻¹ cm⁻¹, and high NIR photothermal conversion efficiency of 48.5%. Furthermore, combined with NIR irradiation at 808 nm and injection of F-PANP samples, in vivo photothermal ablation of tumor with excellent treatment efficacy was achieved. In vitro transmission electron microscopy (TEM) images of cells, methyl thiazolyl tetrazolium (MTT) assay, histology, and hematology studies revealed that the F-PANPs exhibit low toxicity to living systems. Therefore, F-PANPs could be used as PTT agents for ablating cancer, and the concept of developing polyaniline-based nanoparticles can serve as a platform technology for the next generation of in vivo PTT agents.     

Oligomeric nanoparticles functionalized with NIR-emitting CdTe/CdS QDs and folate for tumor-targeted imaging

We report herein the facile surface-functionalization of one type of biocompatible, oligomeric nanoparticles 1-NPs with NIR-emitting CdTe/CdS QDs and folate for tumor-targeted imaging in vivo. The –NH₂ and –SH groups of cysteine residues on the 1-NPs were utilized to covalently conjugate CdTe/CdS QDs and Mal-FA to prepare the hybrid nanoparticles 1-NPs-QDs-FA. As-prepared 1-NPs-QDs-FA showed NIR-fluorescence emission at 734 nm, selective uptake by FR-overexpressing tumor cells in vitro, and selective FR-overexpressing tumor-targeted imaging in vivo. This first example of oligomeric/inorganic hybrid nanoparticles provides people with new type of biomaterials for tumor-targeted imaging with high selectivity.     

Hyaluronic acid-modified hydrothermally synthesized iron oxide nanoparticles for targeted tumor MR imaging

We report a polyethyleneimine (PEI)-mediated approach to synthesizing hyaluronic acid (HA)-targeted magnetic iron oxide nanoparticles (Fe₃O₄ NPs) for in vivo targeted tumor magnetic resonance (MR) imaging applications. In this work, Fe₃O₄ NPs stabilized by PEI were first synthesized via a one-pot hydrothermal method. The formed PEI-stabilized Fe₃O₄ NPs were then modified with fluorescein isothiocyanate (FI) and HA with two different molecular weights to obtain two different Fe₃O₄ NPs (Fe₃O₄–PEI–FI–HA_6K and Fe₃O₄–PEI–FI–HA_31K NPs) with a size of 15–16 nm. The formed HA-modified multifunctional Fe₃O₄ NPs were characterized via different techniques. We show that the multifunctional Fe₃O₄ NPs are water-dispersible and colloidal stable in different aqueous media. In vitro cell viability and hemolysis studies reveal that the particles are quite cytocompatible and hemocompatible in the given concentration range. Furthermore, confocal microscopy and flow cytometry data demonstrate that HA-targeted Fe₃O₄ NPs are able to be uptaken specifically by cancer cells overexpressing CD44 receptors, and be used as efficient probes for targeted MR imaging of cancer cells in vitro and xenografted tumor models in vivo. With the tunable amine-based conjugation chemistry, the PEI-stabilized Fe₃O₄ NPs may be functionalized with other biological ligands or drugs for diagnosis and therapy of different biological systems.     

Core-Shell type lipid/rPAA-Chol polymer hybrid nanoparticles for in vivo siRNA delivery

Our previous study had reported that cholesterol-grafted poly(amidoamine) (rPAA-Chol polymer) was able to self-assemble into cationic nanoparticles and act as a potential carrier for siRNA transfection. In this study, the core–shell type lipid/rPAA-Chol hybrid nanoparticles (PEG-LP/siRNA NPs and T7-LP/siRNA NPs) were developed for improving in vivo siRNA delivery by modifying the surface of rPAA-Chol/siRNA nanoplex core with a lipid shell, followed by post-insertion of polyethylene glycol phospholipid (DSPE-PEG) and/or peptide (HAIYPRH, named as T7) modified DSPE-PEG-T7. The integrative hybrid nanostructures of LP/siRNA NPs were evidenced by dynamic light scattering (DLS), confocal laser scanning microscope (CLSM), cryo-transmission electron microscope (Cryo-TEM) and surface plasmon resonance (SPR) assay. It was demonstrated that the T7 peptide modified LP/siRNA NPs (T7-LP/siRNA NPs) exhibited uniform and spherical structures with particle size of 99.39 ± 0.65 nm and surface potential of 42.53 ± 1.03 mV, and showed high cellular uptake efficiency and rapid endosomal/lysosomal escape ability in MCF-7 cells. Importantly, in vitro gene silencing experiment demonstrated that both of pegylated and targeted LP/siEGFR NPs exhibited significantly stronger downregulation of EGFR protein expression level in MCF-7 cells, compared to that of the physical mixture of siRNA lipoplexes and rPAA-Chol/siRNA nanoplexes. In vivo tumor therapy on nude mice bearing MCF-7 tumors further confirmed that the targeted T7-LP/siEGFR NPs exhibited the greatest inhibition on tumor growth via transferrin receptor-mediated targeting delivery, without any activation of immune responses and significant body weight loss following systemic administration. These findings indicated that the core-shell type T7-LP/siRNA nanoparticles would be promising siRNA delivery systems for in vivo tumor-targeted therapy.     

One‐Pot Preparation of Core–Shell,Organic–Inorganic,Hybrid Latexes by In Situ Nanoparticle Precipitation in Pickering Emulsion Polymerization

A one‐pot emulsion polymerization process to produce silica nanoparticles fixed on polymer particles is presented. Simultaneous nanoparticle formation/monomer emulsification and later polymerization of monomers prevent the agglomeration of silica particles and result in hybrid organic–inorganic, core–shell latexes. The emulsion polymerization of methyl methacrylate is performed using nascent silica nanoparticles, cetyltrimethylammonium bromide, and ammonium persulfate as Pickering surfactant, cosurfactant, and initiator, respectively. The effects of parameters like temperature, initiator type and concentration, and cosurfactant and silica precursor amounts on the polymerization, coagulation percentage, and morphology of hybrid particles are determined using SEM and TEM.     

One-Pot/Simultaneous Synthesis of PHPMA-G-PLA Copolymers via Metal-Free Rop/Raft Polymerization and their Self-Assembly from Micelles to Thermoresponsive Vesicles

The present article reports a simple and straightforward approach to access thermoresponsive graft copolymers based on lactide (LA) and a methacrylic monomer, 2-hydroxypropyl methacrylate (HPMA), using a synthesized carboxy-functionalized trithiocarbonate-based chain transfer agent. One protocol involves a metal-free simultaneous synthesis through a combination of reversible addition-fragmentation chain transfer polymerization and organic acid-catalyzed ring-opening polymerization, which follows first-order kinetics. The resulting copolymers with a controlled structure exhibit remarkably narrow molecular weight distributions (Р< 1.10). Within this framework, the self-assembly of PHPMA-g-PLA graft copolymers (GCs) into nanoparticles (NPs) is demonstrated at concentrations of 0.2 and 0.5 wt.%, respectively. The displacement method, based on the rapid injection of the organic solvent (acetone) into an aqueous medium under vigorous stirring, produces spherical NPs such as micelles, vesicles, or non-spherical “lumpy rods”. The presence of a pseudo-thermoresponsive segment (PHPMA) in GCs facilitates stimulus-responsive self-assembly behavior. Well-defined spherical NPs—primarily vesicles of substantial size—develop upon heating above the glass transition temperature (T_g ≈35–36 °C) of the GCs in an acetone–water (80/20 wt.%) mixture. Last, specific interactions between the obtained PHPMA-g-PLA nano-objects and blood proteins in human plasma are studied using isothermal calorimetry.     

The combined effects of size and surface chemistry on the accumulation of boronic acid-rich protein nanoparticles in tumors

The high drug concentration and long-acting time within tumor tissues are a key challenge in cancer treatment. Here we prepare the boronic acid-rich bovine serum albumin nanoparticles with the size of 70 nm, 110 nm and 150 nm, and subsequently decorate particle surface with polyethyleneimine–polyethylene glycol copolymer and cRGD peptide. We demonstrated that the drug accumulation and particle residence time at tumor site can be significantly improved by incorporating boronic acid group into the bovine serum albumin nanoparticles, optimizing particle size and decorating particle surface. We show that the size- and surface chemistry-driven dual-actions lead to the doxorubicin accumulation at tumor site go beyond 12% injected dose per gram of tumor through such delivery system, which is 16-fold higher than that of free doxorubicin injected. Based on the systemic, tissue and cell level analysis, we demonstrated that the incorporated boronic acid group into the nanoparticles enhances the recognition ability of nanoparticles to cancer cells, and prolongs the action time of nanoparticles at tumor sites since the boronic acid group can reversibly and rapidly react with sialic acid residues which are overexpressed in cancer cells. These features make that this drug delivery system not only has significantly superior ability in impeding tumor growth, but also induces distinct shrinkage and apoptosis of tumor.     

PLA-b-SMA as an Amphiphilic Diblock Copolymer for Encapsulation of Lipophilic Cargo

The encapsulation of active pharmaceutical ingredients (APIs) within drug delivery systems such as polymeric nanoparticles (PNPs) vastly improves the therapeutic efficiency of the incorporated APIs. PNPs synthesized using amphiphilic block copolymers are efficient drug delivery systems as the hydrophobic block facilitates the encapsulation of lipophilic components and the hydrophilic block constitutes the hairy corona of the PNP that stabilizes the nanocarriers against aggregation in solution. Poly(styrene-alt-maleic acid) (SMA) is an attractive polymer for the hydrophilic corona of PLA-based nanoparticles as it allows for post polymerization functionalization and aids in the prevention of NP aggregation. The synthesis of a novel PLA-b-SMA block copolymer, via sequential ring opening polymerization (ROP) and reversible addition–fragmentation chain transfer (RAFT) polymerization, is presented. PLA macro-CTAs, synthesized via ROP, can be chain extended via RAFT copolymerization of styrene and maleic anhydride to yield PLA-b-SMAnh and via RAFT polymerization of N-vinylpyrrolidone to yield PLA-b-PVP block copolymers. Controlled hydrolysis of the anhydride moieties converts PLA-b-SMAnh into PLA-b-SMA. Monodisperse PLA-b-SMA and PLA-b-PVP nanoparticles (NPs) ranging in diameter between 60 and 220 nm are prepared. The lipophilic fluorescent dye DiI is encapsulated within the NPs successfully and these fluorescent NPs are used in a preliminary cell uptake study.     

Amphiphilic carboxymethyl chitosan-quercetin conjugate with P-gp inhibitory properties for oral delivery of paclitaxel

An amphiphilic carboxymethyl chitosan-quercetin (CQ) conjugate was designed and synthesized for oral delivery of paclitaxel (PTX) to improve its oral bioavailability by increasing its water solubility and bypassing the P-gp drug efflux pumps. CQ conjugate had low critical micelle concentration (55.14 μg/mL), and could self assemble in aqueous condition to form polymeric micelles (PMs). PTX-loaded CQ PMs displayed a particle size of 185.8 ± 4.6 nm and polydispersity index (PDI) of 0.134 ± 0.056. The drug-loading content (DL) and entrapment efficiency (EE) were 33.62 ± 1.34% and 85.63 ± 1.26%, respectively. Moreover, PTX-loaded CQ PMs displayed similar sustained-release profile in simulated gastrointestinal fluids (pH 1.2/pH 6.8) and PBS (pH 7.4). In situ intestinal absorption experiment showed that PTX-loaded CQ PMs significantly improved the effective permeability of PTX as compared to verapamil (P < 0.01). Likewise, PTX-loaded CQ PMs significantly enhanced the oral bioavailability of PTX, resulting in strong antitumor efficacy against tumor xenograft models with better safety profile as compared to Taxol^® and Taxol^® with verapamil. Overall, the results implicate that CQ PMs are promising vehicles for the oral delivery of water-insoluble anticancer drugs.     

Magnetic Poly(PEGMA–MAA) Nanoparticles: Photochemical Preparation and Potential Application in Drug Delivery

Poly(PEGMA–MAA)-coated superparamagnetic nanoparticles were synthesized by in situ photochemical polymerization in magnetite aqueous suspension under UV irradiation. The magnetic poly(PEGMA–MAA) nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), photo correlation spectroscopy (PCS) and vibration sample magnetometry (VSM), respectively. The results indicated that the magnetic poly(PEGMA–MAA) nanoparticles were of regularly spherical shape and remained monodisperse. The average size measured in aqueous media was 96.4 nm, which was much bigger than that in dry state, the nanoparticles behaved superparamagnetic with saturated magnetization of 64.8 emu/g, the zeta potential was ?18.3 mV at physiological pH 7.2, and the magnetic poly(PEGMA–MAA) nanoparticles had a high stability in vitro. A typical anti-inflammatory drug, ibuprofen, was used for drug loading, and the release behavior of ibuprofen in a simulated body fluid (SBF, pH 7.4) was studied. The results indicated that these novel magnetic nanoparticles had a high drug-loading capacity and favorable release properties for ibuprofen. The magnetic poly(PEGMA–MAA) nanoparticles are very promising for application in drug delivery.     

Multilayer nanoparticles for sustained delivery of exenatide to treat type 2 diabetes mellitus

A method for the sustained delivery of exenatide was proposed using nanoparticles (NPs) with a core/shell structure. The interactions between lipid bilayers and Pluronics were utilized to form various NPs using a layer-by-layer approach. Transmittance electron microscopy and dynamic light scattering were used to examine the morphology of the NPs. The in vitro release pattern was observed as a function of changes in the structure of the NPs, and the structural integrity of exenatide released was examined by SDS–PAGE analysis. Pharmacokinetics and antidiabetic effects were also observed with the structural change of NPs using in vivo animal models. In vitro–in vivo correlation was discussed in relation to manipulation of the NP structures.