Date of Award
Doctor of Philosophy (PhD)
Micro and Nanoscale Systems
In this dissertation, the fabrication, characterization, and application examples of 3D multicomponent nanocomposite micropatterns (MNMs) with precise spatial arrangements are described. The ability to produce such small-scale 3D structures with versatility in composition and structure is a new development based on the integration of nanoscale layer-by-layer (LbL) self-assembly and microscale photolithographic patterning, enabling construction of surfaces with microscale patterns that possess nanotopographies. The techniques used here are analogous to surface micromachining, except that the deposition materials are polymers, biological materials, and colloidal nanoparticles used to produce 3D MNMs. A key feature of the resulting 3D MNMs is that the physical and chemical properties of the multilayer nanofilms may be finely tuned using the versatile LbL assembly process, which makes them attractive for many applications requiring polymeric structures with small features.
The work presented here involves development of techniques for the fabrication, characterization, and applications of 3D MNMs, and evaluation of the process parameters involved in the developed techniques. These results clearly demonstrate the feasibility of the polymer 3D MNMs for biotechnological applications; specifically, they have potential as tailored surfaces for direct comparison of cell-material interactions on a single substrate, and for co-culture systems. In reality, the approach described here may enable study of and control over cell-biomaterial and cell-cell interactions in a whole new fashion. The techniques developed in this work represent a major advancement of nanoscale engineering through the integration of nanoscale LbL self-assembly and microscale photolithographic patterning for constructing 3D MNMs with varying physical and chemical properties in precise spatial arrangements. A major finding of this work, related to the applicability of the developed techniques, is that most of the seemingly harsh processes involved in constructing the 3D MNMs have minimal or no deleterious effects on the biological models used here. The exception is the resist developer (MF319), which due to its highly basic nature, results in disintegration of nanofilms exposed to it directly. Nevertheless, the methods developed here are not limited by the photoresists and resist developers used here; biocompatible photoresists and aqueous base developers could potentially be used.
This work has pursued the development of organic and inorganic nanofilm scaffolds which can eventually be combined to achieve functionality desired for specific applications. It is anticipated that the 3D MNMs developed in this work will provide general platforms for studying biological processes, which will not only impact stem cell research in general but also provide useful information in support of biomedical device development, and tissue engineering. Although the intended purpose for developing 3D MNMs is to produce novel bioactive systems, their applicability is more general and may find use in a broad range of applications including electronics, photonics, optoelectronics, and chemical and biochemical sensors.
Shaikh Mohammed, Javeed, "" (2006). Dissertation. 566.