Sensing Nanomaterials Based on Host–Guest Interactions

Nanostructures capable of sensing analytes have revolutionized the chemicals-based detection process and enabled chemists to design several cutting-edge technologies applicable in medicine, material science, environmental monitoring, agriculture, energy, and defense sector. The analyte-sensor-transducer-amplifier paradigm employed by chemists in the design of nanosensors have taken chemical detention limits to new limits than that was previously possible with single-molecule detection approach due to the assembling of functional units that serve one of those mentioned roles. In addition, the nanosensing paradigm also allows for the synthesis of low-cost sensing devices. Within the realm of nanosensors, a subset of sensors designed based on the utilization of macrocyclic cavitands that engage in host–guest dynamics is gaining attraction. Cavitands are cyclic oligomeric structures that could encapsulate other smaller molecules within their cavities. which allows for the construction of specific, complex, and functional macroscale devices such as nanosensors. This chapter presents the supramolecular chemistry fundamentals of macrocyclic cavitands and their structural features that render them useful tools in the hands of a nanochemist in designing sensors. Representative examples of nanosensors designed based on the inclusion of complexation dynamics at the heart of its sensing process are discussed. Instances of nanosensors designed with diverse sets of macrocycles such as cyclodextrins, cucurbiturils, calixarenes, and pillarenes are discussed, and their utility in medical diagnostics, thermal sensing, smart materials, and food quality control are given. Toward the end, the chapter presents an envisioned future of the role that macrocyclic cavitands and host–guest chemistry could play in realizing the potential of nanosensors in the aforementioned and newer areas of technology.