Single-step, portable biosensors based on the integration of optical, electronic materials, and bioreceptors

Abstract

The recent emergence of an aging society has given rise to a growing interest in healthy futures and improved quality of life in aging, as well as early disease diagnosis, treatment, and prevention. For achieving this goal, known as point-of-care (POC) testing, the development of biosensors for on-site and early diagnosis that can be used by individuals anytime and anywhere is considered to be an essential element. However, current diagnostic technologies must be used by well-trained experts because these diagnostic methods involve multi-step processes and/or require sophisticated equipment. Hence, there is a high demand for POC biosensors that can be used by non-experts and satisfy the high sensitivity, specificity, single-step procedure, and portability requirements. Despite the intense research efforts devoted to the development of POC biosensors, biosensors fulfilling these four key requirements have not yet been reported. Furthermore, with the development of smart devices, the healthcare system will also converge with smart systems in the future, leading to smart healthcare. Due to this strong trend, POC biosensors must also be integrated with electronics. In this dissertation, single-step, portable POC biosensors were evaluated based on functiona l substrates fabricated using engineered optical/electrical materials and the functionalization of these material with bioreceptors (Chapters 2 and 3). Additionally, an approach for the integration of biosensors and electronics that do not require power supplies or batteries is suggested (Chapter 4). As a result, highly sensitive POC biosensors were developed from the converging perspectives of m aterials science and engineering, and analytical, surface, and bio chemistry. Considering that all single-step and one-pot biosensors showed sensitivities toward the targets that were similar to or even higher than those previously reported for conventional multi-step or/and solution-phase biosensors, fabrication of functional solid substrates is a highly effective approach for the development of future POC biosensors. Additionally, a simple combination of a p-n junction photodetector and colorimetric reaction showed superior sensitivity toward glucose in real sample, and such a simple approach led to far better results than those achieved by complicated self-powered biosensors reported previously. Hence, it is important to mention that the simpler approach carried out by converging various well-developed techniques in diverse academic fields may be a better approach for the development of future POC biosensors.