Functionalization of Biomaterials with Atomic Layer Deposition for Tunable Performance Enhancements

Biomaterials are engineered to interact with biological systems for therapeutic and diagnostic clinical applications. These materials are used in medical devices and modern medicines. Biomaterials can be synthesized in the laboratory or can be directly obtained from natural resources, and they constitute whole or part of a biomedical device or a living structure that can be utilized to execute, improve, enhance or restore a natural function. The surface of a biomaterial controls the interactions occurring at the interface between the biomaterial surface and its surrounding living environment. Hence, successful performance of a biomaterial relies on its surface properties. Many biomaterials do not have the appropriate surface functions and properties to cater to specific needs and applications. It would also be more effective and less time-consuming to modify selected surface properties. Therefore, appropriate surface modification and functionalization leading to significantly improved performance of biomaterials would be highly desirable and sought after. In modern surface science and engineering, nanotechnology is a potent tool to functionalize surfaces incorporating nanometer size thin films and nano-structural features into materials. In particular, thin films and coatings of functional metal oxides/metals can be used to nano-functionalize surfaces of biomaterials. Among the available deposition techniques, atomic layer deposition (ALD) offers unique advantages in yielding conformal thin films of metal oxides or metals (from a few Å to hundreds of nm thick), uniform coating on three-dimensional complex nano-structures, with precise control over thickness and stoichiometry of film at atomic or molecular level. Therefore, the performance and functionality of ALD functionalized biomaterials could be selectively altered, optimized and controlled as needed. This thesis primarily focuses on the development and optimization of low temperature ALD processes to improve functionalities of different biomaterials (e.g., collagen and polydimethylsiloxane), by depositing very thin film of metals/metal oxides (e.g., titania, platinum) at room or near room temperature. Several surface characterization techniques were utilized to investigate the physico-chemical surface properties of the ALD functionalized biomaterials followed by preliminary applications to assess the enhanced performance of those surface functionalized biomaterials, as a proof of concept. As a result of these studies, applications in prosthodontics, orthopedics and cardiology/heart surgery are being pursued.