Surface‐Mediated Interconnections of Nanoparticles in Cellulosic Fibrous Materials toward 3D Sensors

Abstract

Fibrous materials serve as an intriguing class of 3D materials to meet the growing demands for flexible, foldable, biocompatible, biodegradable, disposable, inexpensive, and wearable sensors and the rising desires for higher sensitivity, greater miniaturization, lower cost, and better wearability. The use of such materials for the creation of a fibrous sensor substrate that interfaces with a sensing film in 3D with the transducing electronics is however difficult by conventional photolithographic methods. Here, a highly effective pathway featuring surface‐mediated interconnection (SMI) of metal nanoclusters (NCs) and nanoparticles (NPs) in fibrous materials at ambient conditions is demonstrated for fabricating fibrous sensor substrates or platforms. Bimodally distributed gold–copper alloy NCs and NPs are used as a model system to demonstrate the semiconductive‐to‐metallic conductivity transition, quantized capacitive charging, and anisotropic conductivity characteristics. Upon coupling SMI of NCs/NPs as electrically conductive microelectrodes and surface‐mediated assembly (SMA) of the NCs/NPs as chemically sensitive interfaces, the resulting fibrous chemiresistors function as sensitive and selective sensors for gaseous and vaporous analytes. This new SMI–SMA strategy has significant implications for manufacturing high‐performance fibrous platforms to meet the growing demands of the advanced multifunctional sensors and biosensors.

Flexible Plasmonic Biosensors for Healthcare Monitoring: Progress and Prospects

“…This sensing mechanism is based on the change of resistivity (ΔR) of the film by adsorbing the analyte to the chemically sensitive Au NP film, which exhibits high sensitivity for both liquid and gas detections. , It is noteworthy that the selection of thiols on the NP surface plays an important role in the sensitivity and selectivity of Au NP based chemiresistors, which have been widely exercised to optimize the properties of chemiresistors. − …”

Where Nanosensors Meet Machine Learning: Prospects and Challenges in Detecting Disease X

“…Another emerging biosensing technique is surface-enhanced Raman scattering (SERS) based nanosensors, which utilize plasmonic nanoparticles such as Ag and Au to harness incoming light excitation, concentrate surface plasmon resonances, and boost the Raman vibrational signatures of biomarkers for ultrasensitive detection . There are also other types of nanosensors used in biosensing, such as electrochemical nanosensors and chemiresistors, which use conducting and semiconducting nanomaterials to measure electrical signals instead of optical signals. , Importantly, nanosensors are flexible in that they can be applied to sense a variety of disease biomarkers such as small-molecule metabolites, surface proteins, or genetic material within diverse noninvasive biological matrices such as exhaled breath, sweat, and urine. − However, conventional data analysis strategies involving statistical approaches often perform poorly with convoluted analyte signals arising from biological matrices containing a multitude of interfering species and correlated information. , They also require a large amount of time and effort to parse through large volumes of data. This warrants the use of machine learning (ML) algorithms, which are smart programs based on logic and mathematics, to facilitate pattern recognition and multiplex correlative data processing of convoluted output signals .…”

“…17 There are also other types of nanosensors used in biosensing, such as electrochemical nanosensors and chemiresistors, which use conducting and semiconducting nanomaterials to measure electrical signals instead of optical signals. 18,19 Importantly, nanosensors are flexible in that they can be applied to sense a variety of disease biomarkers such as small-molecule metabolites, surface proteins, or genetic material within diverse noninvasive biological matrices such as exhaled breath, sweat, and urine. 20−24 However, conventional data analysis strategies involving statistical approaches often perform poorly with convoluted analyte signals arising from biological matrices containing a multitude of interfering species and correlated information.…”

A Low-Current and Multi-Channel Chemiresistor Array Sensor Device

“…The nanostructured chemiresistor array coupling and device integration require high sensitivity, rapid response, low power-supply, and high durability. Molecularly-linked thin film assemblies of nanoparticles on interdigitated microelectrode platforms feature enhanced sensitivity, selectivity, detection limit, and response time via controlling size, composition, functional group, and spatial properties [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], offering the promise for potential applications of the sensors in healthcare and environmental monitoring. However, a key problem for the coupling of the detection electronics with the nanostructured chemiresistor devices is that the measurement current of most commercial instruments is too high for maintaining a good stability of the sensors.…”