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An AND logic gate-based fluorescence probe for the detection of homovanillic acid, an indicator of the tumor
摘要： Homovanillic acid (HVA) is one of the major metabolites of catecholamine in human. An elevated level of HVA in urine and blood has been associated with many diseases, including catecholamine-secreting tumors. Consequently, detection of the biomarker HVA in urine is an effective strategy to detect cancer precursors and early stage cancers. In this study, a fluorescence probe is designed and fabricated by integrating lanthanide ions with metal-organic frameworks (MOFs). The fluorescence probe shows distinguished response toward HVA and exhibits ratiometric detection of HVA, rendering it an excellent candidate for sensing devices. Thus, we have designed logic gate operation integrating the probe with logical operations for the intelligent sensing of HVA. Furthermore, this type of luminesce based sensors integrated with logic gate augur for the further application in real-time early diagnosis of tumors in the future.
关键词： Rare earth,Homovanillic acid,Fluorescent probe,Logic gate,Ratiometric sensing,Metal-organic frameworks
更新于2025-11-19 16:56:35
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Encapsulation of Dual Emitting Giant Quantum Dots in Silica Nanoparticles for Optical Ratiometric Temperature Nanosensors
摘要： Accurate temperature measurements with a high spatial resolution for application in the biomedical fields demand novel nanosized thermometers with new advanced properties. Here, a water dispersible ratiometric temperature sensor is fabricated by encapsulating in silica nanoparticles, organic capped PbS@CdS@CdS “giant” quantum dots (GQDs), characterized by dual emission in the visible and near infrared spectral range, already assessed as efficient fluorescent nanothermometers. The chemical stability, easy surface functionalization, limited toxicity and transparency of the silica coating represent advantageous features for the realization of a nanoscale heterostructure suitable for temperature sensing. However, the strong dependence of the optical properties on the morphology of the final core–shell nanoparticle requires an accurate control of the encapsulation process. We carried out a systematic investigation of the synthetic conditions to achieve, by the microemulsion method, uniform and single core silica coated GQD (GQD@SiO2) nanoparticles and subsequently recorded temperature-dependent fluorescent spectra in the 281-313 K temperature range, suited for biological systems. The ratiometric response—the ratio between the two integrated PbS and CdS emission bands—is found to monotonically decrease with the temperature, showing a sensitivity comparable to bare GQDs, and thus confirming the effectiveness of the functionalization strategy and the potential of GQD@SiO2 in future biomedical applications.
关键词： silica shell,QD functionalization,nanothermometers,optical sensor,ratiometric sensing
更新于2025-09-23 15:19:57
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On the combination of luminescent rare earth MOF and rhodamine dopant with two sensing channels for picric acid
摘要： The present paper reported a hybrid structure for the optical recognition of PA (picric acid). This dye-MOF structure, named as R6h@EuBTC, consisted of a supporting matrix based on rare earth MOF and a sensing probe based on rhodamine dye, which was con?rmed using XRD, IR, thermal and photophysical analysis. R6h@EuBTC's rhodamine absorption in visible region was enhanced by increasing PA concentrations, showing obvious color change and consequently colorimetric sensing. R6h@EuBTC's rhodamine emission component was increased by increasing PA concentrations, while its Eu emission component was slightly quenched by increasing PA concentrations, which offered self-calibrated sensing signals for ratiometric ?uorescent sensing. Linear response and good selectivity were observed for both sensing channels with LOD of 3.9 μM. R6h@EuBTC's sensing mechanism towards PA was the combination of two procedures, which were the emission turn on effect of rhodamine component triggered by PA-released protons and the emission turn off effect of Eu component caused by its electron transfer procedure to PA, respectively. R6h@EuBTC's novelty was its two sensing channels and the practicability of naked eye detection.
关键词： Ratiometric sensing,Optical sensing,Explosive detection,Naked eye detection
更新于2025-09-19 17:15:36
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Rapid, facile, reagentless, and room-temperature conjugation of monolayer MoS2 nanosheets with dual-fluorophore-labled flares as Nanoprobes for ratiometric sensing of TK1 mRNA in living cells
摘要： Direct loading of fluorophore-labeled DNA molecules (named as flares) on gold nanoparticles (AuNPs) is a controllable and straightforward approach for intracellular imaging of target DNA molecules. However, the modification of AuNPs with flares requires a tedious and time-consuming procedure, additional reagents, or adenosine-rich DNA molecules. Here, we developed a rapid, simple, reagentless, and room-temperature approach for the modification of monolayer molybdenum disulfide nanosheets (M-MoS2 NSs) with dual-fluorophore-labeled flares, which were implemented for ratiometric imaging of TK1 mRNA in living cells. The duplexes were prepared by hybridizing thiolated single-stranded DNA (ssDNA) to 6-carboxyfluorescein (FAM)- and 5-carboxytetramethylrhodamine (TAMRA)-labeled flares. Fabrication of the nanoflares was conducted by conjugating the formed duplexes to the surface sulfur vacancy sites of the M-MoS2 NSs. The time for preparing the nanoflares was found to be completed within 1 h. In the nanoflares, FAM stays away from TAMRA, leading to inefficient fluorescence resonance energy transfer (FRET). The presence of perfectly matched DNA (DNApm) molecules induces the liberation of the flares from the nanoflares. The liberated flares fold into hairpin-shaped structures, causing high FRET efficiency from FAM to TAMRA and efficient FAM-TAMRA static quenching. Following this mechanism, the nanoflares provided an effective platform for ratiometric sensing of DNApm molecules with the limit of detection (at a signal-to-noise ratio of 3) of 8 nM and the linear range of 25?500 nM. Confocal microscopy experiments demonstrated that the nanoflares can be used to ratiometrically image TK1 mRNA in HeLa and MCF-7 cells.
关键词： ratiometric sensing,monolayer MoS2 nanosheets,TK1 mRNA,dual-fluorophore-labeled flares,living cells
更新于2025-09-16 10:30:52