Biomedical subjects

Jingwei Xie

Publications and source records attributed to Jingwei Xie.

5 recordsLinked to original sources

PubMed2007

Encapsulation of proteins in biodegradable polymeric microparticles using electrospray in the Taylor cone-jet mode.

Solvent extraction (or evaporation from a W(1)/O/W(2)-dispersion), coacervation, and spray drying methods are commonly employed to encapsulate protein drugs in polymeric microparticles for sustained delivery applications. To overcome the limitations of these methods, a novel electrospray method was developed to encapsulate a model protein drug-bovine serum albumin (BSA) in biodegradable polymeric microparticles and examine the feasibility of the process in not denaturing the protein. Microparticles of approximately 20 microm diameter with corrugated surfaces and smooth surfaces were observed by scanning electron microscope. Confocal laser scanning microscope images showed that BSA was distributed evenly in microparticles. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was employed to investigate the protein integrity of BSA released from the polymer matrix after 38 days. No protein degradation was observed during the 38 days release. The secondary structure of released BSA was characterized by Fourier transform infrared (FTIR) and circular dichroism (CD), which suggested that the released BSA was almost identical to native BSA. The encapsulation efficiency could reach 76% by adjusting the amount of the additive Pluronic F127 and processing parameters. The release profile could be tailored by the fabrication process and the sustained release of BSA could endure for more than 1 month. More than 80% of the bioactivity of BSA (evaluated by BSA ELISA kit) could be maintained after releasing from polymer matrix. Findings of the present study demonstrate that this novel electrospray method is a promising approach to encapsulate bioactive materials such as proteins, enzymes, antibiotics, and DNA fragments in biodegradable polymeric particles.

Absorbable Implants↗

PubMed2006

Electrohydrodynamic atomization for biodegradable polymeric particle production.

Electrohydrodynamic atomization (EHDA) has many applications such as electrospray ionization in mass spectroscopy, electrospray deposition of thin films, pharmaceutical productions, and polymeric particle fabrications for drug encapsulation. In the present study, EHDA was employed to produce biodegradable polymeric micro- and nanoparticles. The effects of processing parameters such as polymer concentration, flow rate, surfactants, organic salt, and setup configurations on the size and morphology of polymeric particles were investigated systematically. By changing the various processing parameters, controllable particle shape and size can be achieved. PLGA nanoparticles with size of around 250 nm can be obtained by using organic salts to increase the conductivity of the spraying solution even at a relatively high flow rate. A higher flow rate has the advantage of producing a stable cone spray and can be easily reproduced. Solid and porous particles can be fabricated using different experimental setups to control the organic solvent evaporation rate. Also, paclitaxel, a model antineoplastic drug, was encapsulated in polymeric particles which can be employed for controlled release applications. In short, EHDA is a promising technique to fabricate polymeric micro- or nanoparticles which can be used in drug delivery systems.

Electrochemistry↗

PubMed2006

Microparticles developed by electrohydrodynamic atomization for the local delivery of anticancer drug to treat C6 glioma in vitro.

This study aims to fabricate biodegradable polymeric particles by electrohydrodynamic atomization (EHDA) for applications in sustained delivery of anticancer drug-paclitaxel to treat C6 glioma in vitro. Controllable morphologies such as spheres, doughnut shapes and corrugated shapes with sizes from several tens of microns to hundred nanometers of particles were observed by scanning electron microscopy (SEM) and field emission electron microscope (FSEM). The differential scanning calorimetry (DSC) study indicated that paclitaxel could be either in an amorphous or disordered-crystalline phase of a molecular dispersion or a solid solution state in the polymer matrix after fabrication. The X-ray photoelectron spectroscopy (XPS) result suggested that some amount of paclitaxel could exist on the surface layer of the microparticles. The encapsulation efficiency was around 80% and more than 30 days in vitro sustained release profile could be achieved. Cell cycling results suggested that paclitaxel after encapsulation by EHDA could keep its biological function and inhibit C6 glioma cells in G2/M phase. The cytotoxicity of paclitaxel-loaded biodegradable microparticles to C6 glioma cells could be higher than Taxol in the long-term in vitro tests evaluated by MTS assay. The drug delivery devices developed by EHDA in this study could be promising for the local drug delivery to treat malignant glioma.

Antineoplastic Agents↗

PubMed2006

Electrospun micro- and nanofibers for sustained delivery of paclitaxel to treat C6 glioma in vitro.

PURPOSE: The present study aims to develop electrospun PLGA-based micro- and nanofibers as implants for the sustained delivery of anticancer drug to treat C6 glioma in vitro. METHODS: PLGA and an anticancer drug--paclitaxel-loaded PLGA micro- and nanofibers were fabricated by electrospinning and the key processing parameters were investigated. The physical and chemical properties of the micro- and nanofibers were characterized by various state-of-the-art techniques, such as scanning electron microscope and field emission scanning electron microscope for morphology, X-ray photoelectron spectroscopy for surface chemistry, gel permeation chromatogram for molecular weight measurements and differential scanning calorimeter for drug physical status. The encapsulation efficiency and in vitro release profile were measured by high performance liquid chromatography. In addition, the cytotoxicity of paclitaxel-loaded PLGA nanofibers was evaluated using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide MTT) assay on C6 glioma cell lines. RESULTS: PLGA fibers with diameters of around several tens nanometers to 10 microm were successfully obtained by electrospinning. Ultrafine fibers of around 30 nm were achieved after addition of organic salts to dilute polymer solution. The encapsulation efficiency for paclitaxel-loaded PLGA micro- and nanofibers was more than 90%. DSC results suggest that the drug was in the solid solution state in the polymeric micro- and nanofibers. In vitro release profiles suggest that paclitaxel sustained release was achieved for more than 60 days. Cytotoxicity test results suggest that IC50 value of paclitaxel-loaded PLGA nanofibers (36 microg/ml, calculated based on the amount of paclitaxel) is comparable to the commercial paclitaxel formulation-Taxol. CONCLUSIONS: Electrospun paclitaxel-loaded biodegradable micro- and nanofibers may be promising for the treatment of brain tumour as alternative drug delivery devices.

Antineoplastic Agents, Phytogenic↗

PubMed2005

Self-assembled biodegradable nanoparticles developed by direct dialysis for the delivery of paclitaxel.

PURPOSE: The main objective of this study was to obtain self-assembled biodegradable nanoparticles by a direct dialysis method for the delivery of anticancer drug. The in vitro cellular particle uptake and cytotoxicity to C6 glioma cell line were investigated. METHODS: Self-assembled anticancer drugs--paclitaxel-loaded poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLA) nanoparticles--were achieved by direct dialysis. The physical and chemical properties of nanoparticles were characterized by various state-of-the-art techniques. The encapsulation efficiency and in vitro release profile were measured by high-performance liquid chromatography. Particle cellular uptake was studied using confocal microscopy, microplate reader, and flow cytometry. In addition, the cytotoxicity of this drug delivery system was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on C6 glioma cell line to predict the possible dose response of paclitaxel-loaded PLGA and PLA nanoparticles. RESULTS: PLGA and PLA nanoparticles with or without vitamin E tocopherol polyethylene glycol succinate (TPGS) as an additive were obtained, in which the sustained release of paclitaxel of more than 20 days was achieved. The coumarin6-loaded PLGA and PLA nanoparticles could penetrate the C6 glioma cell membrane and be internalized. The cytotoxicity of paclitaxel-loaded nanoparticles seemed to be higher than that of commercial Taxol after 3 days incubation when paclitaxel concentrations were 10 and 20 microg/ml. CONCLUSIONS: Direct dialysis could be employed to achieve paclitaxel-loaded PLGA and PLA nanoparticles, which could be internalized by C6 glioma cells and enhance the cytotoxicity of paclitaxel because of its penetration to the cytoplasm and sustained release property.

Antineoplastic Agents, Phytogenic↗