Release study of polyelectrolyte layer-by-layer (LbL) microparticles (PEMP)

• Main Author: Tan, Winston Di Xian.
• Other Authors: Bjoern Holger Neu
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/39590
• Institution: Nanyang Technological University

There has been a growing trend in the research study to develop a drug delivery system that can protect and deliver the contents in a safe and sustained manner to specific target sites in vivo. In this study, the use of polyelectrolyte (PE) layer-by-layer (LbL) microparticles (PEMP) was investigated to see how the release of model macromolecule (lysozyme) can be sustained. The use of porous calcium carbonate (CaCO3) particles as the loading template for encapsulation of FITC labeled lysozyme and subsequent LbL self-adsorption of oppositely charged PE, i.e. protamine (PRM) and dextran sulphate (DXS), to fabricate the PEMP was studied to investigate the release profile under different conditions such as different number of PE layers and different pH of the release medium (PBS). CaCO3 was the chosen template because of its biocompatibility, biocompatibility, safe and simple preparation procedures and non-hazardous starting materials. In addition, CaCO3 has shown to possess a higher capacity for FITC-lysozyme encapsulation due to its porous structure. Similarly, protamine (PRM) and dextran sulphate (DXS) were chosen as the PE for layering the FITC-lysozyme-CaCO3 colloids (FLCC) because of their biocompatibility and biodegradability. Zeta potential sizing of PRM and DXS layers also showed that this combination is a stable pair and forms minimal aggregation when coated onto the FLCC. Lysozyme was labeled with fluorescein isothiocyanate (FITC) to allow quantification of amount of lysozyme released from the PEMP over time. Results from this study have shown that the release of FITC-lysozyme was sustained as the number of layers of PE in the PEMP increases and the release of FITC-lysozyme was more slightly more sustained in acidic and neutral pH conditions. Therefore, coating of the FLCC with PE layers could evidently assuage the initial burst release and control the release rate.