Dissertation
Controlling transport using surface porosity in colloidosomes
Doctor of Philosophy (Ph.D.), Drexel University
Aug 2010
DOI:
https://doi.org/10.17918/etd-3344
Abstract
Controlling the transport of encapsulants into and out of polymeric materials is important in various industries including pharmaceuticals, cosmetics, and household products. Colloidosomes are microcapsules characterized by a coating, or shell composed of self-assembled colloidal particles that can range in size from nanometers to microns. The reported hallmark of colloidosomes has been the ability to use particle size to change porosity and thus, control release of encapsulated drugsThe overall goal of this research was to synthesize and characterize hydrogel based colloidosomes using microfluidic techniques that could be useful in a broad range of applications. Previous research has been largely qualitative and has focused more on synthesis techniques. We determined experimentally that there was no dependence of particle size on release rate of small hydrophilic drugs (caffeine, aspirin, theophylline) through the colloidal shell, which was somewhat contradictory to what our collaborators had seen. Our aim was to develop theoretical models to describe transport through colloidal shells as a function of particle size, packing density, and drug properties. We determined that three mechanisms control the transport of drugs through the shell:(1) Reduction in surface area due to the presence of impenetrable colloidal particles(2) Reduced transport through the pores formed between the colloidal particles (which accounts for size exclusion)(3) Transport through the composite layerIn the case of loosely packed shells, we see no dependence of particle size on release rate of drugs due to the dominating first mechanism. For densely packed shells, there is suppression in release for small particle sizes (which accounts for size exclusion) and very large particle sizes due to the increased thickness of the shell. For buckled shells, there is a dependence of particle size on release rate, which is consistent with experimental data.
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Details
- Title
- Controlling transport using surface porosity in colloidosomes
- Creators
- Rachel Tessa Rosenberg - DU
- Contributors
- Nily Dan (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Chemical (and Biological) Engineering (1970-2026); College of Engineering (1970-2026); Drexel University
- Other Identifier
- 3344; 991014632569904721