Ultrasonically Assisted Preparation of Polysaccharide Microcontainers for Hydrophobic Drugs
0
Citation
0
Reference
20
Related Paper
Abstract:
Stable polysaccharide microcontainers are fabricated by ultrasonically assisted procedure. Ultrasound induces formation of permanent microcontainer shell due to interaction between chitosan and xanthan gum. The obtained system has a core-shell structure with high loading capacity for hydrophobic molecules. The permanent polymer shell thickness of 7-10 nm allows to maintain the microcontainer stability for more than 4 months. The microcontainers in a wide size range of 350-7500 nm were obtained by changing an overall emulsion viscosity. Uptake of the microcontainers by mouse melanoma M3 cells was studied by flow cytometry and confocal microcscopy.Cite
Abstract An elaborate control of fibroin self‐assembly is critical in determining the size, structure, and release properties of a microcapsule. This report describes the preparation of microspheres in the submicron range using an aqueous fibroin solution nanoemulsified in decane with a mixed detergent solution of Tween 80 and Span 80. Nanodispersed water droplets containing fibroin molecules were dried under vacuum to facilitate the coalescence of fibroin and then transformed to suspended particles in the range of 200–1200 nm in diameter. The method was also applied to encapsulate dextran and fluorescein isothiocyanate‐dextran (FITC‐dextran), producing core–shell structured microcapsules as identified by scanning electron microscopy and confocal scanning laser microscopy. The microcapsule yield was in the range of 82–85% per fibroin consumed. The encapsulation efficiency was 64% for the microcapsules fabricated from a nanoemulsion containing 0.1 mg of FITC‐dextran per mg fibroin. Approximately 70.5% of the core material was released within 2 weeks. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fibroin
Cite
Citations (8)
Deposition
Cite
Citations (4)
In order to address preserved protein bioactivities and protein sustained-release problems, a method for preparing double-walled microspheres with a core (protein-loaded nanoparticles with a polymer-suspended granule system-formed core) and a second shell (a polymerformed shell) for controlled drug release and preserved protein bioactivities has been developed using (solid-in-oil phase-in-hydrophilic oil-in-water (S/O/O h /W)) phases.The method, based on our previous microsphere preparation method (solid-in-oil phase-in-hydrophilic oil-in-water (S/O/O h /W), employs different concentric poly(D,L-lactide-co-glycolide), poly(D,L-lactide), and protein-loaded nanoparticles to produce a suspended liquid which then self-assembles to form shell-core microspheres in the hydrophilic oil phase, which are then solidified in the water phase.Variations in the preparation parameters allowed complete encapsulation by the shell phase, including the efficient formation of a poly(D,L-lactide) shell encapsulating a protein-loaded nanoparticle-based poly(D,L-lactide-co-glycolide) core.This method produces core-shell doublewalled microspheres that show controlled protein release and preserved protein bioactivities for 60 days.Based upon these results, we concluded that the core-shell double-walled microspheres might be applied for tissue engineering and therapy for chronic diseases, etc.
Cite
Citations (37)
Polyelectrolyte capsules fabricated by layer-by-layer (LbL) technique are introduced as a simple and efficient carrier system for spontaneous deposition of proteins and low molecular water soluble drug. The objective of the work was to investigate the applicability of polyelectrolyte capsules as vehicles for sustained or controlled delivery of drugs. Two different polymeric systems composed of weak and strong polyelectrolytes were chosen to study the loading and release behavior in order to meet the requirements of biomedical applications.
In the first system, the wall permeability of weak polyelectrolyte (PAH/PMA) capsules could be readily manipulated from open to closed state by simply varying the pH. The open and closed state of the capsules could be attributed to the charge density variation of weak polyelectrolytes, which induces the capsule wall to undergo a transition from continuous to nanoporous morphology due to phase segregation. Bovine Serum Albumin (BSA) was spontaneously deposited in the hollow capsules and deposition was investigated by CLSM, SEM and AFM techniques. The driving force for spontaneous deposition was electrostatic interaction between the preloaded polystyrene sulfonate (PSS) and BSA. The deposition was uniform and concentration of BSA in the capsule interior reached a few hundred times greater than that of bulk. The amount of loading was significantly influenced by the loading pH, loading concentration and charge density of substance to be loaded at the corresponding pH. The deposition was successful up to the isoelectric point of BSA (pH = 4.8) and there was no loading observed above that, since the deposition is based on electrostatic attraction between PSS and BSA. During the release at physiological pH of 7.4, charge reversal of BSA occurred which induced electrostatic repulsion between PSS and BSA thereby triggering the movement of BSA from the interior to the bulk. Release continued up to 5 h in water and a total release of 63 % was observed which increased to 72 % when release was performed in PBS.
Spontaneous deposition of low molecular weight, water soluble drug, ciprofloxacin hydrochloride was performed in the same manner and its release profile was studied. Controlling diffusion of smaller drug molecules is extremely difficult in drug delivery applications. Cross linking of capsule wall components could be used to control the release rates of smaller drug molecules. Cross linking density is dependent on the cross linking time and increases the stiffness of the capsule wall. Release of ciprofloxacin hydrochloride was possible even up to 6 h after cross linking. Antibacterial studies showed that the drug released even after 25 h has a significant effect on the bacterial pathogen E.coli.
The second system included weak and strong polyelectrolytes (PAH & DS) and a novel route was employed to fabricate optically addressable capsules that could be laser activated for delivery of drugs. This approach involved a combination of LbL assembly and polyol reduction method wherein PEG was…
Polystyrene sulfonate
Bovine serum albumin
Nanoporous
Cite
Citations (0)
Gelatin
Glutaraldehyde
Cite
Citations (19)
Capsules containing a dye were prepared by the LbL method with iron oxide nanoparticles (50 nm) in different layers of the shell.The capsules were dispersed in a gel and subjected to focused ultrasonic irradiation at three different powers and exposure times.It was found that the inclusion of iron oxide magnetic nanoparticles in any of the polyelectrolyte shells (4, 6, 8 and 10) strengthened the capsules with respect to capsules without nanoparticles. Incorporation of nanoparticles in shell 8 provided the most resistance to fragmentation under focused ultrasonic irradiation. The relative degree of capsule stability is dependent on both the power of the ultrasound and the exposure time.The presence of iron oxide nanoparticles not only conferred more resistance to fragmentation but also provided a route to protein labelled dye release through sonoporation that was not present for capsules without nanoparticles.
Iron oxide nanoparticles
Capsule
Fragmentation
Cite
Citations (6)
Poly(methyl-methacrylate) (PMMA) is a biocompatible and non-biodegradable polymer widely used as biomedical material. PMMA microcapsules with suitable dimension and porosity range are proposed to encapsulate live cells useful for tissue regeneration purposes. The aim of this work was to evaluate the feasibility of producing cell-loaded PMMA microcapsules through "high efficiency vibrational technology" (HEVT). Preliminary studies were conducted to set up the process parameters for PMMA microcapsules production and human dermal fibroblast, used as cell model, were encapsulated in shell/core microcapsules. Microcapsules morphometric analysis through optical microscope and scanning electron microscopy highlighted that uniform microcapsules of 1.2 mm with circular surface pores were obtained by HEVT. Best process conditions used were as follows: frequency of 200 Hz, voltage of 750 V, flow rate of core solution of 10 mL/min, and flow rate of shell solution of 0.5 bar. Microcapsule membrane allowed permeation of molecules with low and medium molecular weight up to 5900 Da and prevented diffusion of high molecular weight molecules (11,000 Da). The yield of the process was about 50% and cell encapsulation efficiency was 27% on total amount. The cell survived and growth up to 72 h incubation in simulated physiologic medium was observed.
Cell encapsulation
Cite
Citations (6)
PLGA
Superparamagnetism
Microparticle
Cite
Citations (25)
PLGA
Dispersity
Cite
Citations (174)
Here, we report the preparation and characterization of hollow polymer microspheres based on the preprecipitation of porous calcium carbonate cores with an average size of 5 μm and their use for encapsulation of living microorganisms. The microspheres filled with individual living E. coli cells were prepared by layer-by-layer (LbL) deposition of different polyelectrolytes and proteins onto the porous calcium carbonate cores leading to the formation of matrix-like complexes of the compounds followed by calcium carbonate core dissolution using EDTA. Both the influence of the encapsulation process as well as of the used polyelectrolytes on the survival rate of the cells were determined by confocal laser scanning microscopy (CLSM) and microtiter plate fluorescence tests. After the encapsulation process ~40% of the cells were alive. Cultivation tests indicated that the lag phase of cells treated with polyelectrolytes increases and the encapsulated E. coli cells were able to produce green fluorescent protein inside the microcapsules.
Cell encapsulation
Calcium alginate
Encapsulation
Cite
Citations (33)