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Peptide-Functionalized Quantum Dots for Rapid Label-Free Sensing of 2,4,6-Trinitrotoluene
摘要： Explosive compounds, such as 2,4,6-trinitrotoluene (TNT), pose a great concern in terms of both global public security and environmental protection. There are estimated to be hundreds of TNT contaminated sites all over the world, which will affect the health of humans, wildlife, and the ecosystem. Clearly, the ability to detect TNT in soils, water supplies, and wastewater is important for environmental studies but also important for security, such as in ports and boarders. However, conventional spectroscopic detection is not practical for on-site sensing because it requires sophisticated equipment and trained personnel. We report a rapid and simple chemical sensor for TNT by using TNT binding peptides which are conjugated to fluorescent CdTe/CdS quantum dots (QDs). QDs were synthesized in the aqueous phase, and the peptide was attached directly to the surface of the QDs by using thiol groups. The fluorescent emission from the QDs was quenched in response to the addition of TNT. The response could even be observed by the naked eye. The limit of detection from fluorescence spectroscopic measurement was estimated to be approximately 375 nM. In addition to the rapid response (within a few seconds), selective detection was demonstrated. We believe this label-free chemical sensor contributes to progress for the on-site explosive sensing.
关键词： quantum dots (QDs),explosive detection,2,4,6-trinitrotoluene (TNT),label-free sensing,peptide-functionalized
更新于2025-11-14 15:23:50
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Fingerprints mapping and biochemical sensing on smartphone by electrochemiluminescence
摘要： Electrochemiluminescence (ECL) is a kind of optical radiation process triggered by electrochemistry, which has been one of the most important strategies in analytical chemistry and biosensing. Recently, smartphone, as one of the widely-used mobile device, has provided a attractive solution as simple yet powerful sensing platform to satisfy the needs of on-site inspection. Here, ECL on smartphone was put forward for fingerprints mapping and biochemical sensing. The smartphone-based system integrated both electrochemical excitation and optical analysis by built-in functional modules “all in one phone”. Typical enhanced luminescence analysis of nicotine, quenched luminescence analysis of trinitrotoluene (TNT) demonstrated the availability of the phone-based ECL system for biochemical sensing. Furthermore, multimode imaging analysis including color induction, gray processing, and binary extraction on smartphone were used for fingerprints mapping. The grain information of fingerprints was clearly displayed on the luminescence images, even the sweat pores on fingerprints were visible to naked eyes. Finally, in situ sensing of exogenous substances on fingerprints, such as nicotine and TNT were also accomplished by the phone. Results indicated the remarkable performances of the system in ECL, especially in the fields of biochemical sensing and imaging analysis. Because fingerprints were widely used to unlock phones, the combination of fingerprints imaging and sensing on smartphone would be contributed to the development of personal medicine, public health monitoring, and mobile care testing.
关键词： Nicotine,Smartphone,Electrochemiluminescence (ECL),Trinitrotoluene (TNT),Fingerprints mapping
更新于2025-09-23 15:23:52
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A Rapid and Sensitive Quantitative Analysis Method for TNT using Raman Spectroscopy
摘要： Raman spectroscopy as a rapid and sensitive qualitative detection method has been applied in many fields; however, it is rarely used for the quantitative purpose due to poor reproducibility of peak area. Here, 2,4,6-trinitrotoluene (TNT) and its two byproducts, 2,4-dinitrotoluence (DNT) and 2,6-DNT, were firstly qualitatively analyzed by Raman spectroscopy and the characteristic parameters were extracted. Then, in the range of 2 %–9 % and 10 %–90 %, the standard curves were established between the area ratio of the characteristic peaks and the content of 2,4-DNT or 2,6-DNT using silver nanoflowers as the enhancing substrate. The fitting correlation for TNT/2,4-DNT or TNT/2,6-DNT system is around 0.99. The peak area ratio of the components exhibits much better data reproducibility than peak area, and the relative error does not exceed 9.3 % for at least six groups of parallel experiments.
关键词： TNT,Quantitative analysis,2,4-DNT,2,6-DNT,Raman spectroscopy
更新于2025-09-23 15:22:29
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On-Demand Electromagnetic Hotspot Generation in Surface Enhanced Raman Scattering Substrates via “Add-On” Plasmonic Patch
摘要： Electromagnetic hotspots at the interstices of plasmonic assemblies are recognized to be the most potent sites for surface enhanced Raman scattering (SERS). We demonstrate a novel “add-on” electromagnetic hotspot formation technique, which significantly improves the sensitivity of conventional SERS substrates comprised of individual plasmonic nanostructures. The novel approach demonstrated here involves the transfer of “plasmonic patch”, a transparent, flexible and conformal elastomeric film adsorbed with plasmonic nanostructures, onto a conventional SERS substrate. The addition of plasmonic patch onto conventional SERS substrate following the analyte capture results in the formation of electromagnetic hotspots and hence large SERS enhancement. The application of plasmonic patch improves the sensitivity and limit of detection of conventional SERS substrates by upto ~100-fold. The transfer of plasmonic patch also effectively transforms the SERS-inactive gold mirror to a highly SERS-active “particle-on-mirror” system. Furthermore, we demonstrate that the “add-on” technique can be effectively utilized for the vapor phase detection of explosives such as trinitrotoluene (TNT) using peptide recognition elements. We believe that the on-demand hotspot formation approach presented here represents a highly versatile and ubiquitously applicable technology readily expandable to any existing SERS substrate without employing complicated modification.
关键词： Trinitrotoluene (TNT),On-Demand Electromagnetic Hotspots,Surface Enhanced Raman Scattering (SERS),Plasmonic Patch,Plasmonic Nanostructures
更新于2025-09-11 14:15:04
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Porous Halide Perovskite–Polymer Nanocomposites for Explosive Detection with a High Sensitivity
摘要： A porous halide perovskite–polymer nanocomposite is developed using a freeze-drying process. Such a composite shows strong fluorescence quenching after exposure to explosive nitroaromatics, nitroamines, and nitrate esters with a sensitivity of a few nanograms. In addition, this composite is robust against moisture and solvents, showing negligible change in fluorescence intensities after submersion in water, alcohol, and acid, base, and salt solutions. Transient absorption spectroscopy studies further disclose that the explosive chemical introduces more trap states into the perovskite that contributes to fluorescence quenching of the perovskite.
关键词： explosive detection,TNT,perovskite,composites
更新于2025-09-09 09:28:46