Time filter

Source Type

Xiamen, China

Moon S.,Catholic University of Korea | Yang S.-G.,Meet You | Yang S.-G.,Inha University | Na K.,Catholic University of Korea
Biomaterials | Year: 2011

Gemcitabine (Gem) eluting metal stents were prepared for potential application as drug delivery systems for localized treatment of malignant tumors. Pullulan, a natural polysaccharide, was chemically acetylated (pullulan acetate; PA) by different degrees (1.18, 1.71, and 2.10 acetyl groups per glucose unit of pullulan), layered on polytetrafluoroethylene (PTFE), and applied as part of a Gem-loaded controlled-release membrane for drug-eluting non-vascular stents. PA with a higher degree of acetylation had greater drug-loading capacity with more extended release of Gem over 30 days. The released Gem accumulated in CT-26 colon cancer without systemic exposure inducing total regression of tumors. The long-term biological activity of the released Gem and apoptosis of tumor tissues following localized delivery were confirmed by annexin V binding assays and histology. The controlled release of Gem from PA-PTFE covered drug-eluting stents (DES) may increase the patency of these stents for the treatment of malignant gastrointestinal cancer as well as cancer-related stenosis. © 2011 Elsevier Ltd. Source

Modern breakthroughs in the fields of proteomics and DNA micro-arrays have widened the horizons of nanotechnology for applications with peptides and nucleic acids. Hence, biomimetic interest in the study and formulation of nanoscaled bio-structures, -materials, -devices and -therapeutic agent delivery vehicles has been recently increasing. Many of the currently-investigated functionalized bio-nanosystems draw their inspiration from naturally-occurring phenomenon, prompting the integration of molecular signals and mimicking natural processes, at the cell, tissue and organ levels. Technologically, the ability to obtain spherical nanostructures exhibiting combinations of several properties that neither individual material possesses on its own renders colloidal core-shell architectured nanosystems particularly attractive. The three main developments presently foreseen in the nanomedicine sub-arena of nanobiotechnology are: sensorization (biosensors/biodetection), diagnosis (biomarkers/bioimaging) and drug, protein or gene delivery (systemic vs. localized/targeted controlled-release systems). Advances in bio-applications such as cell-labelling/cell membrane modelling, agent delivery and targeting, tissue engineering, organ regeneration, nanoncology and immunoassay strategies, along the major limitations and potential future and advances are highlighted in this review. Herein, is an attempt to address some of the most recent works focusing on bio-inspired and -functional polymeric-based core-shell nanoparticulate systems aimed for agent delivery. It is founded, mostly, on specialized research and review articles that have emerged during the last ten years. © 2010 by the authors. Source

Joo V.,Meet You | Ramasamy T.,Meet You | Haidar Z.S.,Meet You | Haidar Z.S.,University of Utah
Polymers | Year: 2011

Soft nanogels are submicron-sized hydrophilic structures engineered from biocompatible polymers possessing the characteristics of nanoparticles as well as hydrogels, with a wide array of potential applications in biotechnology and biomedicine, namely, drug and protein delivery. In this work, nanogels were obtained using the physical self-assembly technique or 'layer-by-layer' which is based on electrostatic interactions. Liposomal vesicles were coated with alternating layers of hyaluronic acid and chitosan yielding a more viscous hydrogel formulation that previously reported core-shell nanoparticulate suspension, via simply modifying the physico-chemical characteristics of the system. Structural features, size, surface charge, stability and swelling characteristics of the nanogel were studied using scanning electron microscopy and dynamic light scattering. With a specific cranio-maxillofacial application in mind, the hydrogel was loaded with recombinant human (rh) bone morphogenetic protein-7, also known as osteogenic protein-1 or rhOP-1 and release was monitored over an extended period of 60 days. This preliminary study reports promising results on the formulation of a novel core-shell polymeric nanogel. © 2011 by the authors. Source

Maeng J.H.,Meet You | Lee D.-H.,Meet You | Jung K.H.,Inha University | Bae Y.-H.,Meet You | And 12 more authors.
Biomaterials | Year: 2010

To develop a drug delivery system with enhanced efficacy and minimized adverse effects, we synthesized a novel polymeric nanoparticles, (YCC-DOX) composed of poly (ethylene oxide)-trimellitic anhydride chloride-folate (PEO-TMA-FA), doxorubicin (DOX) and superparamagnetic iron oxide (Fe3O4) and folate. The efficacy of the nanoparticles was evaluated in rats and rabbits with liver cancer, in comparison with free-DOX (FD) and a commercial liposome drug, DOXIL®. YCC-DOX showed the anticancer efficacy and specifically targeted folate receptor (FR)-expressing tumors, thereby increasing the bioavailability and efficacy of DOX. The relative tumor volume of the YCC-DOX group was decreased two- and four-fold compared with the FD and DOXIL® groups in the rat and rabbit models, respectively. Furthermore, YCC-DOX showed higher MRI sensitivity comparable to a conventional MRI contrast agent (Resovist®), even in its lower iron content. In the immunohistochemical analysis, YCC-DOX group showed the lower expression of CD34 and Ki-67, markers of angiogenesis and cell proliferation, respectively, while apoptotic cells were significantly rich in the YCC-DOX group in terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. These results indicate that YCC-DOX is a promising candidate for treating liver cancer and monitoring the progress of the cancer using MRI. © 2010. Source

Ramasamy T.G.,Meet You | Haidar Z.S.,Meet You | Haidar Z.S.,University of Utah
Journal of Bionanoscience | Year: 2011

Lipid-based carriers have been extensively explored in the pharmaceutical industry showing superior advantages for topical applications over conventional colloidal carriers. Indeed, solid lipid nanoparticles (SLN) are effective carriers for the delivery of proteins or peptides. Yet, a system with high protein encapsulation capacity and sustained release profile remains a challenge. Herein, a hybrid release-controlled delivery system consisting of a suspension of core-shell nanocapsules was prepared. The nanocapsules are composed cationic SLN core and a bi-layered shell constructed via the layer-by-layer self-assembly of alternate coats of anionic alginate (AL) and cationic chitosan (CH). Compact, spherical, monodisperse, cytocompatible and stable SLN (AL- CH) nanocapsules (<150 nm) resulted. High cargo loading accompanied with modulated release of load (bovine serum albumin, as a model protein) dosages is demonstrated. The system offers compartments for protein entrapment including core and within the polyelectrolyte layers of shell. To the best of our knowledge, this is the first report describing the step-wise build-up of a tunable polymeric shell on a SLN core. Copyright © 2011 American Scientific Publishers. Source

Discover hidden collaborations