Applications of Radio Frequency in Sensing of Biomolecules, Nanoparticles and Surfactants

Abstract

The last few decades have witnessed tremendous growth in the sensors industry, spurred by advancements in electronics, nanoscience, biotechnology and computer science. They are employed for a wide variety of applications and they possess the potential to play a pivotal role in biochemical applications. Among the various sensing modalities being explored, we have Radio Frequency based sensing. It studies the interaction between EM waves and matter and uses this interaction for qualitative and quantitative analysis. RF sensors offer a reduction in process complexity, speed, cost, portability and ease of integration with existing technology. In this work, Radio Frequency (RF) based sensing technique is applied for different biochemical applications. In particular, emphasis is given to combating two significant challenges of RF sensing, namely, specificity and reusability. In addition to that, the use of RF sensing in new sub-domains is explored, which would enable the development of a portable biochemical sensing platform. The sensors put into use in this work are Interdigitated Capacitor based sensor and Microstrip Patch based sensor. This sensor is reusable and can be put into use for diverse applications. Reusability of the sensor implies that it can not only be used several times, but the same sensor can detect different sets of analytes with equal efficiency. We have performed both computational and experimental studies on surfactants, nanoparticles and biomolecules using RF sensing. Surfactants are essentially surface-active agents that are amphiphilic. Above a specific concentration called the Critical Micelle Concentration (CMC), they self assemble to form micelles. The estimation of CMC is vital for all the varied applications of surfactants. The first application develops a fast, facile, efficient method for CMC detection that works well for all classes of surfactants. With their plethora of inherent advantages, Nanoparticles play vital roles in the biochemical and biomedical domains. Their study is essential to utilize them for diverse applications efficiently. There is a growing need to develop a methodology that performs preliminary characterization of nanoparticles in the absence of sophisticated laboratory facilities. In the second application, we study nanoparticles of various morphology and arrangements and characterize them. Our third application deals with developing a biomolecule detection platform that is rapid, portable, efficient and reusable. Gold nanoparticles are functionalized to improve the reusability and specificity aspects of conventional RF sensors. Further, the Biotin-Streptavidin binding is chosen to demonstrate the methodology