Transferrin-conjugated magnetic silica PLGA nanoparticles loaded with doxorubicin and paclitaxel for brain glioma treatment

The effective treatment of malignant brain glioma is hindered by the poor transport across the blood–brain barrier (BBB) and the low penetration across the blood-tumor barrier (BTB). In this study, transferrin-conjugated magnetic silica PLGA nanoparticles (MNP-MSN-PLGA-Tf NPs) were formulated to overcome these barriers. These NPs were loaded with doxorubicin (DOX) and paclitaxel (PTX), and their anti-proliferative effect was evaluated in vitro and in vivo. The in vitro cytotoxicity of drug-loaded NPs was evaluated in U-87 cells. The delivery and the subsequent cellular uptake of drug-loaded NPs could be enhanced by the presence of magnetic field and the usage of Tf as targeting ligand, respectively. In particular, cells treated with DOX-PTX-NPs-Tf with magnetic field showed the highest cytotoxicity as compared to those treated with DOX-PTX-NPs-Tf, DOX-PTX-NPs, DOX-PTX-NPs-Tf with free Tf. The in vivo therapeutic efficacy of drug-loaded NPs was evaluated in intracranial U-87 MG-luc2 xenograft of BALB/c nude mice. In particular, the DOX-PTX-NPs-Tf treatment exhibited the strongest anti-glioma activity as compared to the PTX-NPs-Tf, DOX-NPs-Tf or DOX-PTX-NPs treatment. Mice did not show acute toxicity after administrating with blank MNP-MSN-PLGA-Tf NPs. Overall, MNP-MSN-PLGA-Tf NPs are promising carriers for the delivery of dual drugs for effective treatment of brain glioma.     

The effect of hyperbranched polyglycerol coatings on drug delivery using degradable polymer nanoparticles

A key attribute for nanoparticles (NPs) that are used in medicine is the ability to avoid rapid uptake by phagocytic cells in the liver and other tissues. Poly(ethylene glycol) (PEG) coatings has been the gold standard in this regard for several decades. Here, we examined hyperbranched polyglycerols (HPG) as an alternate coating on NPs. In earlier work, HPG was modified with amines and subsequently conjugated to poly(lactic acid) (PLA), but that approach compromised the ability of HPG to resist non-specific adsorption of biomolecules. Instead, we synthesized a copolymer of PLA–HPG by a one-step esterification. NPs were produced from a single emulsion using PLA–HPG: fluorescent dye or the anti-tumor agent camptothecin (CPT) were encapsulated at high efficiency in the NPs. PLA–HPG NPs were quantitatively compared to PLA–PEG NPs, produced using approaches that have been extensively optimized for drug delivery in humans. Despite being similar in size, drug release profile and in vitro cytotoxicity, the PLA–HPG NPs showed significantly longer blood circulation and significantly less liver accumulation than PLA–PEG. CPT-loaded PLA–HPG NPs showed higher stability in suspension and better therapeutic effectiveness against tumors in vivo than CPT-loaded PLA–PEG NPs. Our results suggest that HPG is superior to PEG as a surface coating for NPs in drug delivery.     

Vascular toxicity of ultra-small TiO2 nanoparticles and single walled carbon nanotubes in vitro and in vivo

Ultra-small nanoparticles (USNPs) at 1–3 nm are a subset of nanoparticles (NPs) that exhibit intermediate physicochemical properties between molecular dispersions and larger NPs. Despite interest in their utilization in applications such as theranostics, limited data about their toxicity exist. Here the effect of TiO₂-USNPs on endothelial cells in vitro, and zebrafish embryos in vivo, was studied and compared to larger TiO₂-NPs (30 nm) and to single walled carbon nanotubes (SWCNTs). In vitro exposure showed that TiO₂-USNPs were neither cytotoxic, nor had oxidative ability, nevertheless were genotoxic. In vivo experiment in early developing zebrafish embryos in water at high concentrations of TiO₂-USNPs caused mortality possibly by acidifying the water and caused malformations in the form of pericardial edema when injected. Myo1C involved in glomerular development of zebrafish embryos was upregulated in embryos exposed to TiO₂-USNPs. They also exhibited anti-angiogenic effects both in vitro and in vivo plus decreased nitric oxide concentration. The larger TiO₂-NPs were genotoxic but not cytotoxic. SWCNTs were cytotoxic in vitro and had the highest oxidative ability. Neither of these NPs had significant effects in vivo. To our knowledge this is the first study evaluating the effects of TiO₂-USNPs on vascular toxicity in vitro and in vivo and this strategy could unravel USNPs potential applications.     

Polyethyleneimine-mediated synthesis of folic acid-targeted iron oxide nanoparticles for in vivo tumor MR imaging

We report a facile polyethyleneimine (PEI)-mediated approach to synthesizing folic acid (FA)-targeted magnetic iron oxide nanoparticles (Fe₃O₄ NPs) for in vivo magnetic resonance (MR) imaging of tumors. In this study, stable PEI-coated Fe₃O₄ NPs were prepared by a one-pot hydrothermal route. The aminated Fe₃O₄ NPs with PEI coating enabled covalent conjugation of fluorescein isothiocyanate (FI) and folate-conjugated polyethylene glycol (PEG) with one end of carboxyl groups (FA-PEG-COOH). Followed by final acetylation, FA-targeted PEGylated Fe₃O₄ NPs (Fe₃O₄-PEI-Ac-FI-PEG-FA NPs) were formed. The formed multifunctional Fe₃O₄ NPs were characterized via different techniques. We show that the PEI-mediated approach along with the PEGylation conjugation enables the generation of water-dispersible and stable multifunctional Fe₃O₄ NPs, and the particles are quite cytocompatible and hemocompatible in the given concentration range as confirmed by in vitro cytotoxicity assay, cell morphology observation, and hemolysis assay. In addition, flow cytometry and confocal microscopy data show that the multifunctional Fe₃O₄ NPs are able to target a model cancer cell line (KB cells) overexpressing FA receptors in vitro. Importantly, the FA-targeted Fe₃O₄ NPs are able to be used as an efficient nanoprobe for MR imaging of cancer cells in vitro and a xenografted tumor model in vivo via an active FA targeting pathway. With the facile PEI-mediated formation strategy and PEGylation conjugation chemistry, the Fe₃O₄ NPs may be multifunctionalized with other biological ligands for MR imaging of different biological systems.     

Oral delivery of shRNA and siRNA via multifunctional polymeric nanoparticles for synergistic cancer therapy

Galactose modified trimethyl chitosan-cysteine (GTC) conjugates with various galactose grafting densities were developed for oral delivery of Survivin shRNA-expression pDNA (iSur-pDNA) and vascular endothelial growth factor (VEGF) siRNA (siVEGF) in the synergistic and targeted treatment of hepatoma. iSur-pDNA and siVEGF loaded GTC nanoparticles (NPs) were prepared via electrostatic complexation and showed desirable stability in physiological fluids and improved intestinal permeation compared to naked genes. Galactose grafting density of GTC NPs significantly affected their in vitro and in vivo antitumor activities. GTC NPs with moderate galactose grafting density, termed GTC2 NPs, were superior in facilitating cellular uptake, promoting nuclear distribution, and silencing target genes, leading to notable inhibition of cell growth. In tumor-bearing mice, orally delivered GTC2 NPs could effectively accumulate in the tumor tissues and silence the expression of Survivin and VEGF, evoking increased apoptosis, inhibited angiogenesis, and thus the most efficient tumor regression. Moreover, compared with single gene delivery, co-delivery of iSur-pDNA and siVEGF showed synergistic effects on inhibiting in vitro cell proliferation and in vivo tumor growth. This study could serve as an effective approach for synergistic cancer therapy via oral gene delivery, and highlighted the importance of ligand grafting density in the rational design of targeted nanocarriers.     

Synergistic inhibition of breast cancer by co-delivery of VEGF siRNA and paclitaxel via vapreotide-modified core–shell nanoparticles

A somatostatin analog, vapreotide (VAP), can be used as a ligand for targeting drug delivery based on its high affinity to somatostatin receptors (SSTRs), which is overexpressed in many tumor cells. RNA interference plays an important role on downregulation of vascular endothelial growth factor (VEGF), which is important for tumor growth, progression and metastasis. To improve tumor therapy efficacy, the vapreotide-modified core–shell type nanoparticles co-encapsulating VEGF targeted siRNA (siVEGF) and paclitaxel (PTX), termed as VAP-PLPC/siRNA NPs, were developed in this study. When targeted via somatostatin receptors to tumor cells, the VAP-PLPC/siRNA NPs could simultaneously delivery siVEGF and PTX into cells and achieve a synergistic inhibition of tumor growth. Interestingly, in vitro cell uptake and gene silencing experiments demonstrated that the targeted VAP-PLPC/siRNA NPs exhibited significant higher intracellular siRNA accumulation and VEGF downregulation in human breast cancer MCF-7 cells, compared to those of the non-targeted PEG-PLPC/siRNA NPs. More importantly, in vivo results further demonstrated that the targeted VAP-PLPC/siRNA NPs had significant stronger drug distribution in tumor tissues and tumor growth inhibition efficacy via receptor-mediated targeting delivery, accompany with an obvious inhibition of neovascularization induced by siVEGF silencing. These results suggested that the co-delivery of siRNA and paclitaxel via vapreotide-modified core–shell nanoparticles would be a promising approach for tumor targeted therapy.     

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.     

Iron/iron oxide core/shell nanoparticles for magnetic targeting MRI and near-infrared photothermal therapy

The development of photothermal agents (PTAs) with good stability, low toxicity, highly targeting ability and photothermal conversion efficiency is an essential pre-requisite to near-infrared photothermal therapy (PTT) in vivo. Herein, we report the readily available PEGylated Fe@Fe₃O₄ NPs, which possess triple functional properties in one entity – targeting, PTT, and imaging. Compared to Au nanorods, they exhibit comparable photothermal conversion efficiency (∼20%), and much higher photothermal stability. They also show a high magnetization value and transverse relaxivity (∼156 mm⁻¹ s⁻¹), which should be applied for magnetic targeting MRI. With the Nd-Fe-B magnet (0.5 T) beside the tumour for 12 h on the xenograft HeLa tumour model, PEGylated Fe@Fe₃O₄ NPs exhibit an obvious accumulation. In tumour, the intensity of MRI signal is ∼ three folds and the increased temperature is ∼ two times than those without magnetic targeting, indicating the good magnetic targeting ability. Notably, the intrinsic high photothermal conversion efficiency and selective magnetic targeting effect of the NPs in tumour play synergistically in highly efficient ablation of cancer cells in vitro and in vivo.     

Substrate-mediated nanoparticle/gene delivery to MSC spheroids and their applications in peripheral nerve regeneration

Substrate-derived mesenchymal stem cell (MSC) spheroids show greater differentiation capacities than dispersed single cells in vitro. During spheroid formation, nanoparticles (NPs)/genes may be delivered into the cells. In this study, MSCs were conveniently labeled with superparamagnetic Fe₃O₄ NPs, or transfected with brain-derived neurotrophic factor (BDNF) gene, by the substrate-mediated NP/gene uptake. With the promising in vitro data showing the beneficial effect on neural development and neurotrophic factor expression, MSCs were combined with a polymeric nerve conduit to bridge a 10 mm transection gap of rat sciatic nerve. High-resolution (7-T) magnetic resonance imaging (MRI) was used to track the transplanted cells. Nerve regeneration was assessed by functional recovery and histology. Results revealed that Fe₃O₄ NP-labeled MSCs were successfully visualized by MRI in vivo. Animals receiving BDNF-transfected MSC spheroids demonstrated the shortest gap bridging time (<21 days), the largest regenerated nerve, and the thickest myelin sheath at 31 days. Compared to MSC single cells, the pristine or BDNF-transfected MSC spheroids significantly promoted the functional recovery of animals, especially for the BDNF-transfected MSC spheroids. The transplanted MSCs were incorporated in the regenerated nerve and differentiated into non-myelinating Schwann cells after 31 days. This study suggests that the substrate-mediated gene delivery and NP labeling may provide extra values for MSC spheroids to carry therapeutic/diagnostic agents in cell-based therapy.     

Dihydroartemisinin and transferrin dual-dressed nano-graphene oxide for a pH-triggered chemotherapy

Dihydroartemisinin (DHA) is a unique anti-malarial drug isolated from the plant Artemisia annua. Recently, it has been studied as an alternative modality for cancer therapy, utilizing its reactive oxygen species (ROS) yielding mechanism from interacting with Ferrous ion (Fe (Ⅱ)). In this work, a novel nanodrug (DHA-GO-Tf) is constructed based on nanoscale Graphene oxide (GO) dual-dressed with DHA and Transferrin (Tf). Tf dually functions as a pilot for the nanoparticle to target tumor cell with over expressed Transferrin receptor (TfR) and a ferric ion carrier. Upon tumor cellular endocytosis, Ferric ion (Fe(Ⅲ)) is released from the Tf, triggered by the low pH in the lysosomes of the tumor cell. The intracellular Fe (Ⅲ) is reduced to Fe (Ⅱ) and interacts with DHA to increase its cytotoxicity. The potential of this alternative anti-tumor modality is demonstrated both in vitro and in vivo. Comparing with DHA alone, the nanodrug DHA-GO-Tf resulted in a significantly enhanced tumor delivery specificity and cytotoxicity, and achieved a complete tumor cure in mice with minimal side-effects.     

Controllable synthesis of monodispersed silver nanoparticles as standards for quantitative assessment of their cytotoxicity

Silver nanoparticles (Ag NPs) are appealing due to their excellent antibacterial/antivirus properties. At the meantime, the wide applications of Ag NPs as antibacterial/antivirus agents arise the concern of Ag NPs’ toxicity. However, quantitative understanding of the cytotoxicity of Ag NPs is minimum since that the Ag NPs in current studies have wide size distributions, in which the size effect of Ag NPs on cytotoxicity was unable to be accurately evaluated. In this work, unprecedentedly monodispersed Ag NPs with sizes of 25, 35, 45, 60 and 70 nm were obtained, respectively, by using an optimized polyol method with poly(vinyl pyrrolidone) (PVP) as surfactant. It was found that the reaction temperature, reaction time, concentration of the surfactant and reactants are playing important roles in determining the size and size distribution of Ag NPs. With the monodispersed Ag NPs as standard samples, the size- and dose- dependent cytotoxicity of Ag NPs against Human lung fibroblast (HLF) cells was accurately accomplished in terms of cell viability, apoptosis and necrosis, reactive oxygen species, etc. We expect that the monodispersed Ag NPs will act as the standard samples for quantitatively characterizing the toxicity of Ag NPs in vitro and in vivo.     

Tumor-specific penetrating peptides-functionalized hyaluronic acid-d-α-tocopheryl succinate based nanoparticles for multi-task delivery to invasive cancers

Poor site-specific delivery and incapable deep-penetration into tumor are the intrinsic limitations to successful chemotherapy. Here, the tumor-homing penetrating peptide tLyP-1-functionalized nanoparticles (tLPTS/HATS NPs), composed of two modularized amphiphilic conjugates of tLyP-1-PEG-TOS (tLPTS) and TOS-grafted hyaluronic acid (HATS), had been fabricated for tumor-targeted delivery of docetaxel (DTX). The prepared tLPTS/HATS NPs had about 110 nm in mean diameter, high drug encapsulation efficiency (93%), and sustained drug release behavior. In vitro studies demonstrated that the tLPTS/HATS NPs exhibited enhanced intracellular delivery and much better anti-invasion ability, cytotoxicity, and apoptosis against both invasive PC-3 and MDA-MB-231 cells as compared to the non-tLyP-1-functionalized HATS NPs. The remarkable penetrability and inhibitory effect on both PC-3 and MDA-MB-231 multicellular tumor spheroids were also identified for the tLPTS/HATS NPs. In vivo biodistribution imaging demonstrated the tLPTS/HATS NPs possessed much more lasting accumulation and extensive distribution throughout tumor regions than the HATS NPs. The higher in vivo therapeutic efficacy with lower systemic toxicity of the tLPTS/HATS NPs was also verified by the PC-3 xenograft model in athymic nude mice. These results suggested that the designed novel tLPTS/HATS NPs were endowed with tumor recognition, internalization, penetration, and anti-invasion, and thus might be a promising anticancer drug delivery vehicle for targeted cancer therapy.     

Targeting and imaging cancer cells by Folate-decorated,quantum dots (QDs)- loaded nanoparticles of biodegradable polymers

We developed a new strategy to prepare folate-decorated nanoparticles of biodegradable polymers for Quantum dots (QDs) formulation for targeted and sustained imaging for cancer diagnosis at its early stage. Poly(lactide)-vitamin E TPGS (PLA-TPGS) copolymer and vitamin E TPGS-carboxyl (TPGS-COOH) copolymer were synthesized. Their blend at various weight ratio was used to prepare folate-decorated nanoparticles (NPs) for QDs formulation to improve their imaging effects and reduce their side effects. The TPGS-COOH on the NP surface was designed to conjugate folate-NH₂ with advantage to make the targeting effect adjustable. The size of such NPs was found in the range of 280–300 nm. In vitro cellular uptakes of such NPs were investigated with confocal laser scanning microscopy (CLSM), which demonstrated much higher internalization of the folate-decorated QDs-loaded PLA-TPGS/TPGS-COOH NPs by MCF-7 breast cancer cells which are of over-expression of folate receptors than the cellular uptake by NIH 3T3 fibroblast cells which are of low expression of folate receptors. Compared with the free QDs, the QDs formulated in the PLA-TPGS/TPGS-COOH NPs showed lower in vitro cytotoxicity for both of MCF-7 cells and NIH 3T3 cells. Additionally, our findings indicated that under same conditions, cytotoxicity of QDs formulated in the PLA-TPGS/TPGS-COOH NPs is lower for normal cells such as NIH 3T3 cells than that for breast cancer such as MCF-7 breast cancer cells due to folate targeting effect. Targeted imaging by QDs formulated in folate-decorated PLA-TPGS/TPGS-COOH nanoparticles with better effects and less side effects is feasible.     

An oligopeptide ligand-mediated therapeutic gene nanocomplex for liver cancer-targeted therapy

The epidermal growth factor receptor (EGFR) is over-expressed in a wide variety of epithelial-derived cancer cells. In this study, EGFR-targeted gene carriers were designed to complex the therapeutic acetylcholinesterase gene (AChE gene), which suppresses cell proliferation via inactivating mitogen-activated protein kinase and PI3K/Akt pathways in cells, for treatment of EGFR-positive liver cancers. Different amounts of target ligand YC21 (an oligopeptide composed of 21 amino acid units) were coupled with the PEI₆₀₀-CD (PC) vectors composed of β-cyclodextrin (β-CD) and low-molecular-weight polyethylenimine (PEI, Mw 600) to form the EGFR-targeted gene vectors (termed as YPCs). The YPC vectors possessed the highly efficient gene delivery ability to the EGFR-positive liver cancer cells. YPCs could effectively promote AChE gene expression. The YPC/AChE complexes produced excellent gene transfection abilities in EGFR-positive liver cancer cells in vitro and in vivo.     

Intra-articular delivery of kartogenin-conjugated chitosan nano/microparticles for cartilage regeneration

We developed an intra-articular (IA) drug delivery system to treat osteoarthritis (OA) that consisted of kartogenin conjugated chitosan (CHI-KGN). Kartogenin, which promotes the selective differentiation of mesenchymal stem cells (MSCs) into chondrocytes, was conjugated with low-molecular-weight chitosan (LMWCS) and medium-molecular-weight chitosan (MMWCS) by covalent coupling of kartogenin to each chitosan using an ethyl(dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) catalyst. Nanoparticles (NPs, 150 ± 39 nm) or microparticles (MPs, 1.8 ± 0.54 μm) were fabricated from kartogenin conjugated-LMWCS and –MMWCS, respectively, by an ionic gelation using tripolyphosphate (TPP). The in vitro release profiles of kartogenin from the particles showed sustained release for 7 weeks. When the effects of the CHI-KGN NPs or CHI-KGN MPs were evaluated on the in vitro chondrogenic differentiation of human bone marrow MSCs (hBMMSCs), the CHI-KGN NPs and CHI-KGN MPs induced higher expression of chondrogenic markers from cultured hBMMSCs than unconjugated kartogenin. In particular, hBMMSCs treated with CHI-KGN NPs exhibited more distinct chondrogenic properties in the long-term pellet cultures than those treated with CHI-KGN MPs. The in vivo therapeutic effects of CHI-KGN NPs or CHI-KGN MPs were investigated using a surgically-induced OA model in rats. The CHI-KGN MPs showed longer retention time in the knee joint than the CHI-KGN NPs after IA injection in OA rats. The rats treated with CHI-KGN NPs or CHI-KGN MPs by IA injection showed much less degenerative changes than untreated control or rats treated with unconjugated kartogenin. In conclusion, CHI-KGN NPs or CHI-KGN MPs can be useful polymer-drug conjugates as an IA drug delivery system to treat OA.     

The effect of autophagy inhibitors on drug delivery using biodegradable polymer nanoparticles in cancer treatment

Nanoparticles of biodegradable polymers (NPs) have been widely used for drug delivery. However, there has been little research on their fate after internalized into the cells. We show in this research by using docetaxel as a model anticancer drug, which is formulated in the cholic acid conjugated nanoparticles of poly(lactic-co-glycolic acid (PLGA NPs) that the NPs induce autophagy of the cancer cells and thus may hinder the advantages of the nanomedicine. Moreover, we show both in vitro and in vivo that co-administration of autophagy inhibitors such as 3-methyladenine (3-MA) and Chloroquine (CQ) could greatly enhance the therapeutic effects of the nanoparticle formulation. The IC₅₀ values of the drug formulated in the PLGA NPs after 24 h treatment with no autophagy inhibitor or in combination with 10 mm 3-MA or 30 μm CQ are 38.27 ± 1.23, 6.7 ± 1.05, 4.78 ± 1.75 μg/mL, which implie 5.7 or 8,0 fold efficient by the autophagy inhibition respectively. Moreover, both the volume and the weight of the shrunk tumor of the mice after 20 day treatment with the PLGA NPs formulation combined with 3-MA or CQ are found to be only about a half in comparison with the treatment with the PLGA NPs formulation alone. In this research, we reported such a new mechanism of cancer cells to have PLGA NPs captured and degraded by auto-lysosomes. The findings provide advanced knowledge for development of nanomedicine for clinical application.     

Effects of mannose density on in vitro and in vivo cellular uptake and RNAi efficiency of polymeric nanoparticles

To evaluate the effects of mannose density on in vitro and in vivo cellular uptake and RNA interference (RNAi) efficiency of polymeric nanoparticles (NPs) in macrophages, mannose-modified trimethyl chitosan-cysteine (MTC) conjugates with mannose densities of 4%, 13%, and 21% (MTC-4, MTC-13, and MTC-21) were synthesized. Tumor necrosis factor-alpha (TNF-α) siRNA loaded MTC NPs with particle sizes of ∼150 nm exhibited desired structural stability and effectively protected siRNA from enzymatic degradation. Generally, cellular uptake and RNAi efficiency were affected by mannose density. As expected, MTC-21 NPs presented the maximum in vitro uptake and RNAi efficacy in Raw 264.7 cells among all NPs tested. However, MTC-4 NPs exhibited the optimal in vivo uptake by peritoneal exudate cell macrophages (PECs). In the inflammation model of acute hepatic injury, orally delivered MTC-4 and MTC-13 NPs worked better in silencing TNF-α expression and alleviating liver damage than MTC-21 NPs. As for the ulcerative colitis model, MTC-4 NPs outperformed MTC-13 and MTC-21 NPs with respect to TNF-α knockdown and therapeutic efficacy following oral administration. These results highlighted the importance of ligand density in cellular uptake and RNAi efficiency, which could serve as a guideline in the rational design of targeted nanocarriers for anti-inflammation therapy.     

Endothelial targeting of nanocarriers loaded with antioxidant enzymes for protection against vascular oxidative stress and inflammation

Endothelial-targeted delivery of antioxidant enzymes, catalase and superoxide dismutase (SOD), is a promising strategy for protecting organs and tissues from inflammation and oxidative stress. Here we describe Protective Antioxidant Carriers for Endothelial Targeting (PACkET), the first carriers capable of targeted endothelial delivery of both catalase and SOD. PACkET formed through controlled precipitation loaded ∼30% enzyme and protected it from proteolytic degradation, whereas attachment of PECAM monoclonal antibodies to surface of the enzyme-loaded carriers, achieved without adversely affecting their stability and functionality, provided targeting. Isotope tracing and microscopy showed that PACkET exhibited specific endothelial binding and internalization in vitro. Endothelial targeting of PACkET was validated in vivo by specific (vs IgG-control) accumulation in the pulmonary vasculature after intravenous injection achieving 33% of injected dose at 30 min. Catalase loaded PACkET protects endothelial cells from killing by H₂O₂ and alleviated the pulmonary edema and leukocyte infiltration in mouse model of endotoxin-induced lung injury, whereas SOD-loaded PACkET mitigated cytokine-induced endothelial pro-inflammatory activation and endotoxin-induced lung inflammation. These studies indicate that PACkET offers a modular approach for vascular targeting of therapeutic enzymes.     

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.