Various techniques for fabrication of multilayer organic films onto solid templates have been studied. The development of thin film technologies for surface modification and construction of multilayer structures is the key step for the creation of novel materials for emerging applications. Multilayer films constructed by a technique called "Layer-by-Layer (LbL) electrostatic self assembly" based on consecutive adsorption of oppositely charged polyelectrolytes onto a solid template LbL provides a simple approach to fabricate multicomponent films of nanometer thickness with tailored architecture....[ Read more ]

Various techniques for fabrication of multilayer organic films onto solid templates have been studied. The development of thin film technologies for surface modification and construction of multilayer structures is the key step for the creation of novel materials for emerging applications. Multilayer films constructed by a technique called "Layer-by-Layer (LbL) electrostatic self assembly" based on consecutive adsorption of oppositely charged polyelectrolytes onto a solid template LbL provides a simple approach to fabricate multicomponent films of nanometer thickness with tailored architecture.

This thesis presents applications of LbL thin films in the areas of bioengineering and bioanalytics. The construction of polyelectrolyte multilayer microcapsule with tailored permeability was applied for the development of microcapsule polymerase chain reaction (PCR), Microcapsule-PCR. The PCR mixture was entrapped in matrix microbeads followed by LbL coating. During the PCR, small molecular weight nucleotides were supplied externally and diffused through the permeable capsule wall, while the high molecular weight PCR products were accumulated in the interior of the microcapsule. The microcapsule-PCR technique provides a new approach to perform high numbers of parallel PCRs.

In the area of bioanalytics, the LbL technology was employed for the encapsulation of electrochemical signal generating microcrystals (ferrocene microcrystals). The encapsulated microcrystals were conjugated with antibody molecules and utilized as a probe for immunoassays. The microcrystal based label system provided a high signal molecule to antibody (S/P) ratio of 10⁴ to 10⁵. The sensitivity of the microcrystals based immunoassay for the detection of mouse immunoglobulin G (M-IgG) was found to be 3.93 nA μg^-1 L^-1 with microcrystals having antibody surface coverage of 5.05 mg m^-2.

In the area of bioengineering, a new approach for cell surface engineering of living yeast cells (Arxula sp.) by using LbL technology to extend the substrate spectrum was demonstrated. Arxula surfaces were modified with polyelectrolyte and enzyme layers. The outer enzyme (lactate oxidase) layer provides an addition biological function for the modified Arxula to convert an unfavourable substrate (lactate) into a favourable substrate (pyruvate), thus extending the substrate spectrum of the Arxula. The activity of the enzyme conjugate on individual modified Arxula cell was calculated to be about 12.3 picounits.