Spontaneous Deposition Of Enzyme And Drugs In Polyelectrolyte Multilayer Microcapsules And Control Release Thereof

In recent years, polyelectrolyte multiplayer (PEM) microcapsules prepared by layer-by-layer adsorption of oppositely charged polyelectrolytes have received considerable attention. However, desirable substances should be encapsulated into these capsules at first in order to meet the different applications in the fields like biotechnology, chemical engineering and pharmacy. The novel finding that some PEM capsules can introduce spontaneous deposition of various substances provides a brand-new way of encapsulation. The main objective of this thesis is to explore the deposition properties of different substances as well as their release behaviors.First, the deposition properties of horseradish peroxidase (HRP) and its activity after deposition are investigated in this article. Confocal laser scanning microscopy (CLSM), atomic force microscopy [AFM][ and transmission verified the occurrence of the deposition. After HRP deposition, majority of its initial activity was lost; However, the left part which still remains the activity has the high resistance to denaturation environments like high temperature, long incubation time and organic solvent exposure.In this thesis, the deposition properties and the release behavior after deposition of a low molecular model drug (rhodamine B) and four kinds of anti-cancer drugs (daunorubicin (DNR), adroamycin (ADM), cisplatin and carboplatin) have been examined. CLSM, AFM and TEM testified the deposition of these drugs and the experiments carried out in (1) different initial incubation concentration, (2) different temperature, (3) different NaCl concentration and (4) different pH revealed that the drugs have a relative high deposition efficiency in the high initial incubation concentration, high temperature, high NaCl concentration and high pH environment, and relatively stable release properties in the low initial incubation concentration, low temperature, high NaCl concentration and low pH environment. Many factors discussed in the article like the static force between the drugs and melamine formaldehyde/poly(styrene sulfonate sodium salt) (MF/PSS) complex inside the capsules, the concentration balance between outside and inside the capsules, and the drugs' solubility will affect the deposition and release behaviors.