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Boron doped carbon dots as a multifunctional fluorescent probe for sorbate and vitamin B12
摘要： Boron doped carbon dots (B-CD) were synthesized by a one-step hydrothermal method using phenylboronic acid as the starting material. They have an average size of about 3.3 nm, with excitation/emission wavelength of 247/323 nm and a quantum yield of 12%. The B-CD is shown to be viable fluorescent probe for sorbate (PS) and vitamin B12 (VB12). The fluorescence (FL) of the B-CD is quenched in the presence of PS or VB12 mainly coming from inner filter effect (IFE), but F?rster resonance energy transfer (FRET) from the B-CD (as a donor) to PS/VB12 (as an acceptor) cannot be excluded. The probe enables PS to be detected by fluorometry with a linear response in the 0.20–24 μM concentration range and a 6.1 nM detection limit (at 3σ/slope). For VB12, the data are 0.20–30 μM and 8.0 nM.
关键词： Fluorescent probe,Sorbic acid,Fluorescence quenching ratios,Intra-day precision,Selectivity,Inter-day precision,Quenching mechanism,Real sample analysis
更新于2025-09-23 15:23:52
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Highly Sensitive Optical Biosensing of Staphylococcus aureus with an Antibody/Metal-Organic Framework Bioconjugate
摘要： In this research, a new luminescent bioprobe was developed for the detection of S. aureus based on bio-conjugation of an amine functionalized metal-organic framework (NH2-MIL-53(Fe)) with an anti-S. aureus antibody (Ab). The formation of the desired bioprobe (Ab/NH2-MIL-53), in its liquid phase, has been verified with several spectroscopic and structural characterizations. The bioprobe was incubated with varying concentrations of S. aureus bacteria. The resulting antibody conjugated bioprobe (Ab/NH2-MIL-53) maintained a strong inverse correlation in which decreases in fluorescence intensity were accompanied by increase in bacterial count. Thus, the potential of the herein developed probe has been successfully demonstrated for the detection of S. aureus with a low limit of detection (85 CFU/mL) over a wide concentration range (40 × 102 - 4 × 108 CFU/mL). It was further found to be reliable with regard to inter-/intra- precision assays and long-term stability. The feasibility of the method was further supported through the detection of S. aureus spiked in environmental samples (e.g., river water and cream pastry).
关键词： bacteria,real sample analysis,S. aureus,fluorescent sensor,Metal-organic framework
更新于2025-09-19 17:15:36
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A boronate-modified molecularly imprinted polymer labeled with a SERS-tag for use in an antibody-free immunoassay for the?carcinoembryonic antigen
摘要： An antibody-free immunoassay that makes use of a boronate affinity molecularly imprinted polymer (MIP) and surface enhanced Raman scattering (SERS) tags is described. It was applied to the specific determination of the carcinoembryonic antigen (CEA) in human serum. For the preparation of the boronate affinity array, a polymer capable of adsorbing glycoproteins was first synthesized on the surface of a glass slide with four spots using 4-vinylbenzeneboronic acid (VPBA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and ethylene glycol and cyclohexanol as porogens. The surface of the VPBA-Co-EGDMA can bind target glycoproteins. After specific capture of the glycoprotein, a “MIP-target glycoprotein-SERS tag” sandwich structure was formed by covalent interaction between the SERS nanotag (consisting of gold nanoparticles and 4-mercaptophenylboronic acid [MPBA]). CEA can be quantified in spiked serum with a detection limit of 0.1 ng·mL?1 via the specific Raman band at 1098 cm?1.
关键词： MIP array,Sandwich structure,Nanoprobes,Biomarker,Real sample analysis
更新于2025-09-12 10:27:22
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Phenanthrene-imidazole-based fluorescent sensor for selective detection of Ag+ and F? ions: real sample application and live cell imaging
摘要： 4-Methyl-2,6-bis(1H-phenanthro[9,10-d]imidazol-2-yl)phenol (probe-MPIP) conjugate has been designed as a selective fluorescent probe for silver (Ag+) ions. The probe-MPIP exhibits selectivity towards Ag+ in DMSO-H2O (1:9 v/v) in 50 mM HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) at pH 7.4. Moreover, the detection of probe-MPIP towards Ag+ ions could be realized with a “naked eye” with a color conversion from greenish yellow to orange. The linear relationship between fluorescence intensity and Ag+ ion concentration indicates that probe-MPIP can be used for quantification of Ag+ ions. The probe-MPIP can be used in a broad range of pH from 3 to 11. The limit of detection (LOD) and association constant (Ka) of MPIP-Ag+ complex have been determined and found to be 1.8 nM and 8.24 × 105 M?1, respectively, according to fluorescence titrations. Moreover, the binding ratio of probe-MPIP and Ag+ was found to be 1:1 by Job’s method. Furthermore, MPIP-Ag+ complex subsequently acted as a secondary fluorescent turn-on probe for fluoride (F?) ion recognition among the other anions. To assess the real-world efficacy of probe-MPIP and MPIP-Ag+ complex, a real water sample of silver and fluoride ions (Ag+ and F?) was evaluated. Furthermore, probe-MPIP and MPIP-Ag+ complex have been successfully applied to cell imaging studies.
关键词： Fluorescent probe,Silver and fluoride ion detection,Binding constant,In vitro cell imaging,Real sample analysis
更新于2025-09-10 09:29:36
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Aluminum(III) triggered aggregation-induced emission of glutathione-capped copper nanoclusters as a fluorescent probe for creatinine
摘要： Glutathione-capped copper nanoclusters (CuNCs) are presented that display aggregation-induced emission (AIE). This feature was exploited for selective and sensitive quantification of creatinine (CRN) which is an important diagnostic parameter. In the presence of Al3+ ions, such CuNCs rapidly aggregate, and this induces enhanced a red emission. The AIE nature of CuNCs was proven via TEM and fluorimetry. On addition of CRN, the coordination between CRN and Al3+ ions led to the quenching of fluorescence due to weakening the AIE. The best fluorescence intensity was measured at excitation/emission peaks of 360/585 nm. Quenched fluorescence intensity showed a linear dependence on the concentrations of CRN in the range of 2.5–34 μgL?1 with a detection limit of 0.63 μgL?1. The sensing mechanism of probe for CRN detection is discussed. The probe was applied to the determination of CRN in spiked human serum samples and gave satisfactory results.
关键词： Nanosensor,Renal biomarker,Serum analysis,Fluorescent nanomaterials,Metal nanoclusters,Nanoprobe,Paired t-test,Fluorometry,Real sample analysis
更新于2025-09-04 15:30:14