Fabrication Of Inkjet-Printed Enzyme-Based Biosensors Towards Point-Of-Care Applications
Abstract
In the recent years, point-of-care (POC) devices are continuously being demanded in the healthcare field due to the advantages of low-cost, easy-to-use, rapid and on-site detection. Among all kinds of POC devices, electrochemical biosensors are superior candidates because of the miniaturization simplicity, fast analysis and high selectivity nature to the sensing analytes. Traditional fabrication method of electrochemical biosensors by drop-casting process suffers from uneven thickness of functionalization layer and low reproducibility. Nowadays, inkjet printing has been a promising technique for biosensor fabrication. The merits, such as precise position, micro-dispensing, minimum contamination, less waste and potentiality for mass production as valuable features of inkjet printing, have attracted significant attention by researchers. However, there are still some issues that need to be addressed to promote inkjet printing technique for the POC applications. The most important problems include: 1. deficient investigation towards the effect of inkjet printing on the sensing element of biosensor, which is critical for the improvement of the sensor performance; 2. inadequate printing strategy for multi-functional layers printing, which is essential for the development of a stable and sensitive biosensor ; 3. lack of demonstration for the construction of inkjet-printed biosensor system towards point-of-care testing, which will be significant for the development of POC devices.
To bridge these gaps, I firstly studied the influence of mechanical stress on the biological materials of enzymes based on the pressure wave propagation mechanism. Then, based on the first enzyme printing study, a reagentless enzyme-based biosensor was fabricated through a novel multi-layer printing strategy. In the end, to demonstrate the inkjet-printed biosensor for point-of-care analyte detection, a smartphone-supported biosensor system was constructed, consisting of a smartphone, an Android APP, a portable potentiostat and a functionalized scree-printed electrode (SPE) via inkjet printing.
In general, the investigation of inkjet printing technique towards fabrication of POC devices opens a door for further research and development of an increasing variety of inkjet-printed POC devices. Through the work presented in this dissertation, I thoroughly investigated the effect of printing on enzymes, and substantially build upon the multi-layer printing strategy and biosensor system for inkjet-printed POC devices. The work in this research paves a way toward creating high performance, low-cost, easy-to-use and rapid POC diagnostic devices.