Recent advances in engineered graphene and composites for detection of volatile organic compounds (VOCs) and non-invasive diseases diagnosis

Recent Advances in Sensing Applications of Graphene Assemblies and Their Composites

“…A thin, transparent, flexible, incredibly fast humidity sensor that showed great response and recovery time was reported in 2014 . Graphene‐based field‐effect transistors also present exciting and bright prospects for sensing applications due to their high sensitivity and stronger selectivity, while graphene‐based real‐time diagnostic detectors for biomarkers that indicate the early state of disease have also been extensively studied . Recently, a graphene composite‐based magnetic sensor has been developed which is 200 times more sensitive than traditional sensor‐based silicon …”

“…Graphene‐based gas and vapor sensors have been drawn significant attentions from scientific community for a range of practical applications including human health, public safety, environmental monitoring, and so on . Self‐assembled graphene structures are considered as promising candidates for high‐performance sensing, and they will potentially replace traditional analysis instruments based on semiconductors and gas chromatography mass spectrometry .…”

“…The sensors function by detecting intermolecular interactions of analytes with the active center. These methods have several advantages in terms of portability, remote monitoring, and electromagnetic immunity . The colors of the optical sensors array are affected by interactions between the analytes and colorant dyes such as Lewis acid–base reactions, Brønsted acidity/basicity, redox properties, π–π interactions, and local polarity .…”

“…Unfortunately, due to their chemical inertness and relatively low dispersion in most of the solvents, the use of these hybrid composites for fabrication of chemical sensor devices is still challenging. In addition, the lack of bonds or functional groups on their surface is likely to limit their sensitivity as chemical gas/vapor sensors, as gas molecules cannot readily be adsorbed onto their surface . A solution to this was the use of PILs for the functionalization of CNTs and graphene resulting in the generation of CNT/PIL/rGO composites.…”

Colorimetric Nanofibers as Optical Sensors

“…In contrast to electrical signals, optical signals are more straightforward and easier to interpret, especially in the case of warning signals. Additionally, optical sensors do not show electromagnetic interference, neither do they need electric contacts . As there is no need for electrodes or sophisticated equipment, optical nanofibrous sensors are easily portable or wearable and enable the production of large‐scale sensors that are capable of monitoring large areas, yet resulting in local signaling if desired.…”