Investigating protein adsorption at solid-liquid interfaces towards the development of functional biomaterial coatings

• Main Author: Park, Jae Hyeon
• Other Authors: Cho Nam-Joon
• Format: Theses and Dissertations
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Materials::Biomaterials; DRNTU::Science::Chemistry::Analytical chemistry::Proteins
• Online Access: https://hdl.handle.net/10356/87467; http://hdl.handle.net/10220/46777
• Institution: Nanyang Technological University

Surface and interfacial science is an essential field of study in determining the structure-property design parameters of materials. The fundamental knowledge is especially important in modern days whereby many practical applications rely on the compatibility of organic and inorganic substances. Protein adsorption is one of such areas of research that has been considered highly necessary and relevant for various applications, yet much of its details remain under vigorous scrutiny due to its complexity. Protein adsorption is the first step in the acute biological reaction to an exposed surface, in which the functionalities or properties of a material in query could possibly be altered or even contaminated depending on the biomaterials accumulated on the surface. The protein-surface interaction occurs spontaneously and almost at random but the detailed process can be broken down into step-by-step phases whereby a certain level of higher governance is embedded within the system that dictates its kinetics and trends. The major factors can be largely classified into extrinsic and intrinsic factors, which include many other subfactors that are cross-interdependent of one another. Therefore, even with highly sophisticated computerized simulations, the theoretical studies are limited without the inclusion of systematic studies emphasizing data-driven empirical analysis. With the emphasis on the empirical establishment of fundamental insights, this dissertation dives in to the interfacial science of protein-surface interactions using carefully structured experimental designs and intuition-based analyses to form fresh arguments to explain protein adsorption. While most of the experimental layouts are in reference to past studies, the methods were reinforced with modern techniques, and speculations were minimized through data verification via complimentary pairing of analytical devices. The project is presented as a three-part series starting from a broad macroscopic view of the protein adsorption in ensemble, which then gradually narrows down to the sub-molecular level of protein-surface interactions. Thorough investigations revealed that protein adsorption is indeed reliant on the environmental conditions (through control of ionic strength), but more specifically by factors that directly intervene with the conformational stability of the proteins. However, it was further revealed that the extrinsic controls were insufficient in determining the final outcome, ultimately guided by the protein’s potential entropic energy that is confined within the malleable structure. Finally, based on the insights and the unexpected and/or expected observations from the series of studies, scientific and practical solutions were discussed for relevant applications, particularly in regards to achieving an efficient and optimized surface passivation protocol. Revealing the need for a disruptive solution condition for the effective tuning of stable protein layers was especially critical considering the implications that it may have on the many relevant surface passivation applications that were considered common practice. This is only one such example, and clearly there is more room for improvement as there is much to be uncovered from the study of protein adsorption.