Preparation Of Magnetic MMT And ZnAl-LDH Drug Delivery System Via LbL Method

Natural clay montmorillonite(MMT) and synthetic layered double hydroxide(LDH) have been intensively studied in biomedicine-related fields due to their lamellar and planar structures in which plenty of drugs can be accomodated. But constructing stable and reliable interfaces around pseudo two-dimensional clay materials is a key process in achieving advanced and reliable performance of related propertice. Layer-by-layer(Lb L) technique is a widely explored facile nanofabrication method in construction of such functional devices or systems which involves the alternative deposition of species with complementary groups for chemical interactions.In the present work, interfacial modification of MMT and LDH by covalently assembled Lb L multilayers is performed to stablize the suspensions of MMT and LDH. The formed assemblies were multifunctional particles with target delivery ability. The main work of the present dissertation is.(1) MMT was stabilized by alternative deposition of poly(acrylic acid)(PAA) and poly-(allylamine hydrochloride)(PAH) via layer-by-layer technique and then the polymer multilayers were covalent cross-linked by photosensitive cross-linker to give DAS-(PAA/PAH)5-MMT for loading drugs. The formed nanocomposite not only can accomudate ample organic species in its space of interlayers but also is stable even in extreme conditions such as in basic(p H=14) solutions. In addition, the composite possesses the release ability to model drug “methyl blue”.(2) Stable magnetic DAS-(PAA/PAH)10-LDH system was prepared via the same method for preparation of DAS-(PAA/PAH)5-MMT. Then the LDH layers were etched by adjusting the p H of the solution to give assemblies with different drug loading ability because LDH is sensitive to acid. The formed assemblies were stable in high p H solutions(p H=11-12) and acidic solution(p H=2-3) for 1 hour. The as prepared assemblis have adjusted ability to drug loading capacity and release behavior.