Kheireddine El-Boubbou

Hyaluronic acid immobilized magnetic nanoparticles for active targeting and imaging of macrophages

Imaging and targeted delivery to macrophages are promising new approaches to study and treat a variety of inflammatory diseases such as atherosclerosis. In this manuscript, we have designed and synthesized iron oxide based magnetic nanoparticles bearing hyaluronic acid (HA) on the surface to target activated macrophages. The HA-coated nanoparticles were prepared through a co-precipitation procedure followed by postsynthetic functionalization with HA and fluorescein. The nanoparticles were characterized by transmission electron microscopy, thermogravimetric analysis, elemental analysis, dynamic light scattering, and high-resolution magic angle spinning NMR and were biocompatible with cells and colloidally stable in the presence of serum. The HA immobilized on the nanoparticles retained their specific biological recognition with the HA receptor CD44, which is present on activated macrophages in high-affinity forms. Cell uptake studies demonstrated significant uptake of HA nanoparticles by activated macrophage cell line THP-1, which enabled magnetic resonance imaging of THP-1 cells. The uptake of nanoparticles was found to be both HA and CD44 dependent. Interestingly, Prussian blue staining showed that the magnetite cores of the HA-coated nanoparticles were only transiently present inside the cells, thus reducing the potential concerns of nanotoxicity. Furthermore, fluorescein on the nanoparticle was found to be delivered to the cell nucleus. Therefore, with further development, these HA functionalized magnetic nanoparticles can potentially become a useful carrier system for molecular imaging and targeted drug delivery to activated macrophages.

Development of multifunctional hyaluronan-coated nanoparticles for imaging and drug delivery to cancer cells

Currently, there is high interest in developing multifunctional theranostic platforms for cancer monitoring and chemotherapy. Herein, we report hyaluronan (HA)-coated superparamagnetic iron oxide nanoparticles (HA-SPION) as a promising system for targeted imaging and drug delivery. When incubated with cancer cells, HA-SPIONs were rapidly taken up and the internalization of HA-SPION by cancer cells was much higher than the NPs without HA coating. The high magnetic relaxivity of HA-SPION coupled with enhanced uptake enabled magnetic resonance imaging of cancer cells. Furthermore, doxorubicin (DOX) was attached onto the nanoparticles through an acid responsive linker. While HA-SPION was not toxic to cells, DOX-HA-SPION was much more potent than free DOX to kill not only drug-sensitive but also multi-drug-resistant cancer cells. This was attributed to differential uptake mechanisms and cellular distributions of free DOX and DOX-HA-SPION in cancer cells.

CD44 Targeting Magnetic Glyconanoparticles for Atherosclerotic Plaque Imaging

PurposeThe cell surface adhesion molecule CD44 plays important roles in the initiation and development of atherosclerotic plaques. We aim to develop nanoparticles that can selectively target CD44 for the non-invasive detection of atherosclerotic plaques by magnetic resonance imaging.MethodsMagnetic glyconanoparticles with hyaluronan immobilized on the surface have been prepared. The binding of these nanoparticles with CD44 was evaluated in vitro by enzyme linked immunosorbent assay, flow cytometry and confocal microscopy. In vivo magnetic resonance imaging of plaques was performed on an atherosclerotic rabbit model.ResultsThe magnetic glyconanoparticles can selectively bind CD44. In T2* weighted magnetic resonance images acquired in vivo, significant contrast changes in aorta walls were observed with a very low dose of the magnetic nanoparticles, allowing the detection of atherosclerotic plaques. Furthermore, imaging could be performed without significant delay after probe administration. The selectivity of hyaluronan nanoparticles in plaque imaging was established by several control experiments.ConclusionsMagnetic nanoparticles bearing surface hyaluronan enabled the imaging of atherosclerotic plaques in vivo by magnetic resonance imaging. The low dose of nanoparticles required, the possibility to image without much delay and the high biocompatibility are the advantages of these nanoparticles as contrast agents for plaque imaging.

A simple method for the synthesis of hyaluronic acid coated magnetic nanoparticles for highly efficient cell labelling and in vivo imaging

Highly stable colloidal hyaluronic acid coated magnetic nano-particles were prepared via a ligand exchange method. These particles exhibited excellent cell labeling efficiencies and superior potential as MRI contrast agents, which are useful to target tumor cells expressing hyaluronic acid receptors such as CD44.

Lipoic acid glyco-conjugates, a new class of agents for controlling nonspecific adsorption of blood serum at biointerfaces for biosensor and biomedical applications.

The carbohydrate-derived lipoic acid derivatives were studied as protein and cell resistant biomaterials. Six types of carbohydrates were examined for their abilities to reduce nonspecific adsorption of human serum and Hela cell using quartz crystal microbalance. Our data suggested that the structures of carbohydrates play an important role in resisting nonspecific binding. Specifically, the resistance was found to increase in the order lipoic fucose < lipoic mannose < lipoic N-acetyl glucosamine < lipoic glucose < lipoic sialic acid < lipoic galactose, where lipoic galactose derivative resisted most nonspecific adsorption. Furthermore, the combination of lipoic galactose and BSA was the most effective in reducing the adsorption of even undiluted human serum and the attachment of Hela cells while allowing specific binding. Several control experiments have demonstrated that the resistant-ability of mixed lipoic galactose and BSA was comparable to the best known system for decreasing nonspecific adsorption.

Magnetic Fluorescent Nanoformulation for Intracellular Drug Delivery to Human Breast Cancer, Primary Tumors, and Tumor Biopsies: Beyond Targeting Expectations

We report the development of a chemotherapeutic nanoformulation made of polyvinylpyrrolidone-stabilized magnetofluorescent nanoparticles (Fl-PMNPs) loaded with anticancer drugs as a promising drug carrier homing to human breast cancer cells, primary tumors, and solid tumors. First, nanoparticle uptake and cell death were evaluated in three types of human breast cells: two metastatic cancerous MCF-7 and MDA-MB-231 cells and nontumorigenic MCF-10A cells. While Fl-PMNPs were not toxic to cells even at the highest concentrations used, Dox-loaded Fl-PMNPs showed significant potency, effectively killing the different breast cancer cells, albeit at different affinities. Interestingly and superior to free Dox, Dox-loaded Fl-PMNPs were found to be more effective in killing the metastatic cells (2- to 3-fold enhanced cytotoxicities for MDA-MB-231 compared to MCF-7), compared to the normal noncancerous MCF-10A cells (up to 8-fold), suggesting huge potentials as selective anticancer agents. Electron and live confocal microscopy imaging mechanistically confirmed that the nanoparticles were successfully endocytosed and packaged into vesicles inside the cytoplasm, where Dox is released and then translocated to the nucleus exerting its cytotoxic action and causing apoptotic cell death. Furthermore, commendable and enhanced penetration in 3D multilayered primary tumor cells derived from primary lesions as well as in patient breast tumor biopsies was observed, killing the tumor cells inside. The designed nanocarriers described here can potentially open new opportunities for breast cancer patients, especially in theranostic imaging and hyperthermia. While many prior studies have focused on targeting ligands to specific receptors to improve efficacies, we discovered that even with passive-targeted tailored delivery system enhanced toxic responses can be attained.

Magnetic Nanocarriers Enhance Drug Delivery Selectively to HumanLeukemic Cells

Selective drug delivery to human leukemia cells using a nanoparticulate chemotherapeutic formulation is hugely needed. In this work, we report the development of a magnetic nanocarrier made of PVP-stabilized magnetic iron oxide nanoparticles (PMNP) loaded with the anticancer drug Doxorubicin (Dox) as a promising selective drug carrier to different types of human leukemia and normal cells. Our results revealed that while the unloaded MNPs were not potent to any of the cells, Dox@PMNPs showed significant toxicities, effectively killing the different leukemia cells, albeit at different inhibitory concentrations. Interestingly and superior to free Dox, Dox@PMNPs showed enhanced and significant inhibition towards the human monocytic THP-1 cells compared to human promyelocytic leukemia cells HL-60 (2-fold enhanced cytotoxicities), with the least potency towards the normal peripheral blood mononuclear cell (PBMC) cells (up to 6-fold). Nonetheless, free Dox was found to be concurrently less toxic to all the three cell lines tested. The cytotoxic effects obtained were further confirmed by live confocal imaging and electron microscopy. Both imaging techniques confirmed distinct morphological changes (membrane blebbing, shrinkage, and condensation) corresponding to typical apoptotic features in the treated leukemia cells compared to normal PBMC cells. The observed enhanced cytotoxic effects of Dox@PMNPs is mostly dependent upon the selective and differential endocytic uptake of Dox@PMNPs, with subsequent release of Dox intracellularly to the cytoplasm after 6 h, which then translocates to the nucleus after 24 h, causing apoptotic cell death. Importantly, magnetic Dox nanocarrier described here reduces the unwanted diffusive side effects of the free drug and allows selective drug delivery to leukemic cells, allowing its potential use for leukemic patients’ theranostics.