Chemiresistive/SERS dual sensor based on densely packed gold nanoparticles

Abstract

SummaryChemiresistors are a class of sensitive electrical devices capable of detecting (bio)chemicals by simply monitoring electrical resistance. Sensing based on surface enhanced Raman scattering (SERS) represents a radically different approach, in which molecules are optically detected according to their vibrational spectroscopic fingerprint. Despite different concepts are involved, one can find in the literature examples from both categories reporting sensors made of gold nanoparticles. The same building blocks appear because both sensor classes share a common principle: nanometric interparticle gaps are needed, for electron tunneling in chemiresistors, and for enhancing electromagnetic fields by plasmon coupling in SERS-based sensors. By exploiting such nano-gaps in self-assembled films of gold nanoparticles, we demonstrate the proof of concept of a dual electrical/optical sensor, with both chemiresistive and SERS capabilities. The proposed device is realized by self-assembling 15 nm gold nanoparticles into few micrometers-wide strips across commercially available interdigitated electrodes. The dual-mode operation of the device is demonstrated by the detection of a biologically relevant model analyte, 4-mercaptophenyl boronic acid.

Engineering Defects in Graphene Oxide for Selective Ammonia and Enzyme-Free Glucose Sensing and Excellent Catalytic Performance for para-Nitrophenol Reduction

“…Therefore, there is urgent need to develop a fast, convenient, highly selective and sensitive ammonia sensor that can detect low concentrations of ammonia in air, which is critical for environmental monitoring. A lot of work has been reported in the literature for the detection of toxic and explosive gases using various oxides such as α-Fe 2 O 3 , ZnO, SnO 2 , WO 3 , NiO, In 2 O 3 , and so forth owing to their several advantages such as high sensitivity to a large variety of gases, low detection limit, fast response and recovery, superb stability, low fabrication cost, and simple preparation. , However, the oxide-based materials require external stimuli such as high temperature, ultraviolet (UV) light activation, and so forth for the sensor response and/or recovery, which restricts their further application. − Hence, these materials are power-consuming sensors. Therefore, great efforts are being taken to solve the great challenge by developing advanced sensors that can effectively detect ammonia at room temperature.…”

Gold vs. Silver Colloidal Nanoparticle Films for Optimized SERS Detection of Propranolol and Electrochemical-SERS Analyses

“…It is also interesting to note that gold surfaces are preferred over silver for many EC-SERS applications due to their wider hydrogen overpotential and, thus, a wider range of operational potentials and higher overall chemical and electrochemical inertness. Finally, as demonstrated by previous works, such self-assembled nanoparticle films could also be used for electrical resistance-based chemical sensing [47] or deformation sensing [48], pointing toward interesting possibilities for developing multi-stimuli-responsive sensing devices.…”

Gold nanoparticle surface engineering strategies and their applications in biomedicine and diagnostics

“…For instance, Boca et al have demonstrated dual signal-based electrical/optical proof of concept biosensing prototype exploiting the nano-gaps formed during the self-assembly of AuNPs. This showed excellent SERS capabilities and chemi-resistivity of nano-gap AuNPs for the detection of 4-mercaptophenyl boronic acid (Boca et al 2015). In another report, an aptamer-based AuNP-functionalized biosensor has been developed showing high sensitivity (20 nM) for biomolecular analysis using avidin as a model compound.…”