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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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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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A Novel Rare Earth Ion Fluorescent Probe towards the Trace Detection of 2,4,6-Trinitrotoluene Based on Fluorescence Resonance Energy Transfer
摘要： This paper reports a resonance energy transfer-fluorescence quenching of the core-shell structure of CaMoO4:Tb3+@SiO2 modified by amino group on the surface for the ultrasensitive and ultratrace detection of 2,4,6-trinitrotoluene (TNT) in solution environments. Organic amine was covalently modified onto the surface of silica shell to form a hybrid monolayer of amino group. The particle can specifically bind TNT species by the charge-transfer complexing or acid-base pairing interactions between electron-rich amine ligands and electron-deficient aromatic rings. The resultant TNT-amine complexes bound at the silica surface can strongly suppress the fluorescence emission of the chosen dye by the fluorescence resonance energy transfer (FRET) from CaMoO4:Tb3+ fluorescence donor to the irradiative TNT-amine acceptor through intermolecular polar-polar interactions at spatial proximity. The nanoparticle can sensitively detect down to 1 nM TNT with the use of only 10 μL of solution (2 pg TNT). The simple FRET-based nanoparticle sensors reported here exhibit a high and stable fluorescence brightness, strong analyte affinity and good assembly flexibility and can thus find many applications in the detection of ultratrace analytes.
关键词： Fluorescence quenching,FRET,Ultratrace detection,2,4,6-Trinitrotoluene,Rare earth ion
更新于2025-09-11 14:15:04
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An Ultrastable Magnesium–Organic Framework as Multi-responsive Luminescent Sensor for Detecting Trinitrotoluene and Metal ions with High Selectivity and Sensitivity
摘要： A pH and thermal stable three dimensional framework [Mg(ATDC)(H2O)2]n (1) (H2ATDC = 2'-amino-1,1':4',1''-terphenyl-4,4''-dicarboxylate) with blue fluorescence has been successfully synthesized and characterized. The Mg-MOF contains 2D [Mg(COO)2]n sheet, which links ATDC2- to generate 3D framework with accessible -NH2 groups, which could be beneficial to impact the reorganization on specific small molecules. Importantly, it is the first reported highly selective fluorescence Mg-MOF for sensing 2,4,6-Trinitrotoluene (TNT), and have the highest sensitivity for detecting Chromium(III) simultaneously through fluorescence quenching. Furthermore, the quenching mechanisms are mainly attributed to the photo-induced electron transfer and competitive absorptions between the excitation/emission of Mg-MOF and analytes, rather than the interactions between –NH2 and analytes.
关键词： Metal organic frameworks,Metal ions,Fluorescence sensing,2,4,6-Trinitrotoluene
更新于2025-09-09 09:28:46