Nitric Oxide Detection Using a Corona Phase Molecular Recognition Site on Chiral Single-Walled Carbon Nanotubes

Near-Infrared Fluorescent Single-Walled Carbon Nanotubes for Biosensing

The objective of this article is to provide a comprehensive overview of the recent advancements in biosensing using near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs). SWCNTs are cylindrical structures formed by rolling up a graphene layer, with their chiral index (n,m) defining their diameter and electronic, mechanical, and optical properties, making them metallic, semimetallic, or semiconducting. The semiconducting variants feature NIR fluorescence, which offers significant advantages for biological imaging and sensing due to deep tissue penetration and minimal background interference. Moreover, SWCNTs are highly photostable, demonstrating resistance to photobleaching and blinking. Owing to these unique optical properties, SWCNTs have been widely used as optical probes for monitoring a broad spectrum of biological analytes, ranging from small molecules to macromolecules. This review explores the photophysics of SWCNTs, their suitability for biosensing, and strategies for developing effective SWCNT-based sensors. This review begins with their photophysical properties, highlighting their relevance to biosensing, followed by key technical concepts. Additionally, biosensing principles, methods for optimizing functionalized SWCNTs, and diverse sensing approaches are also covered. Overall, this review intends to provide a foundational understanding of SWCNT-based biosensing, equipping readers with the knowledge needed to explore and apply these powerful nanomaterials in diverse biosensing applications.

Dynamic Tracking of Biological Processes Using Near-Infrared Fluorescent Single-Walled Carbon Nanotubes

Biological processes are characterized by dynamic and elaborate temporal patterns driven by the interplay of genes, proteins, and cellular components that are crucial for adaptation to changing environments. This complexity spans from molecular to organismal scales, necessitating their real-time monitoring and tracking to unravel the active processes that fuel living systems and enable early disease detection, personalized medicine, and drug development. Single-walled carbon nanotubes (SWCNTs), with their unique physicochemical and optical properties, have emerged as promising tools for real-time tracking of such processes. This perspective highlights the key properties of SWCNTs that make them ideal for such monitoring. Subsequently, it surveys studies utilizing SWCNTs to track dynamic biological phenomena across hierarchical levels─from molecules to cells, tissues, organs, and whole organisms─acknowledging their pivotal role in advancing this field. Finally, the review outlines challenges and future directions, aiming to expand the frontier of real-time biological monitoring using SWCNTs, contributing to deeper insights and novel applications in biomedicine.

Monitoring Enzyme Activity Using Near-Infrared Fluorescent Single-Walled Carbon Nanotubes

Enzymes serve as pivotal biological catalysts that accelerate essential chemical reactions, thereby influencing a variety of physiological processes. Consequently, the monitoring of enzyme activity and inhibition not only yields crucial insights into health and disease conditions but also forms the basis of research in drug discovery, toxicology, and the understanding of disease mechanisms. In this context, near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) have emerged as effective tools for tracking enzyme activity and inhibition through diverse strategies. This perspective explores the physicochemical attributes of SWCNTs that render them well-suited for such monitoring. Additionally, we delve into the various strategies developed so far for successfully monitoring enzyme activity and inhibition, emphasizing the distinctive features of each principle. Furthermore, we contrast the benefits of SWCNT-based NIR probes with conventional gold standards in monitoring enzyme activity. Lastly, we highlight the current challenges faced in this field and suggest potential solutions to propel it forward. This perspective aims to contribute to the ongoing progress in biodiagnostics and seeks to engage the wider community in developing and applying enzymatic assays using SWCNTs.