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Label-free Thrombin Detection Using a Tapered Fiber-optic Interferometric Aptasensor
摘要： Aptamer biosensor for label-free thrombin detection based on a tapered fiber-optic interferometer has been proposed and demonstrated. The biosensor probe can be easily fabricated by tapering a commercial double-cladding fiber down to 5 μm in diameter and it provides a high refractive index sensitivity of 1660 nm/RIU. The changes are determined by tracing the wavelength shift of the dip in the transmission spectrum with variable surrounding refractive index. With the help of surface functionalization of thrombin-binding aptamers, the proposed fiber-optic biosensor proves its capability in label-free detection of thrombin with a lowest detectable concentration of 0.1 μM, together with high specificity in various concentrations of pure and mixed thrombin solutions.
关键词： Fiber-optic biosensor,tapered fiber interferometer,aptamer,thrombin detection
更新于2025-09-23 15:21:01
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Green fluorescent carbon quantum dots functionalized with polyethyleneimine, and their application to aptamer-based determination of thrombin and ATP
摘要： Brightly fluorescent carbon quantum dots coated with polyethylenimine (PEI-CDs) were prepared using malic acid and PEI as the precursors. The PEI-CDs have a high quantum yield (41%) and green emission (peaking at 502 nm under 430 nm excitation), both of which are not affected by high ionic strength. The PEI-CDs have a positive charge at physiological pH values and can electrostatically bind aptamers with their negative charge. This is shown for aptamers binding thrombin or ATP. Binding of aptamers results in quenching of fluorescence. If thrombin or ATP are introduced, the respective aptamer will bind them, and the complex is then released from the PEI-CDs. Fluorescence increases in proportion to the analyte concentration. Under optimized conditions, thrombin and ATP can be sensitively and selectively detected by fluorometry with lower detection limits of 1.2 and 13 nM, respectively. The assay was successfully applied to the determination of thrombin and of ATP in spiked serum samples.
关键词： Aptamer sensor,Thrombin detection,Serum analysis,Green luminescent,PEI-CDs,Malic acid,Polyethylenimine,Fluorescence assay,ATP detection,Hydrothermal reaction
更新于2025-09-19 17:13:59
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Supersandwich Nanowire/Quantum Dots Sensitization Structure-Based Photoelectrochemical a??Signal-Ona?? Platform for Ultrasensitive Detection of Thrombin
摘要： A new photoelectrochemical (PEC) “signal-on” sensing platform based on photoactive material Bi2O3-ZnO and CdS quantum dots (QDs) sensitizer were fabricated for ultrasensitive determination of thrombin by constructing supersandwich nanowires. The CdS/ZnO/Bi2O3 sensitization structure with excellent energy level arrangement remarkably improved photoelectric conversion efficiency due to efficient separation of electron-hole. Moreover, the DNA supersandwich nanowire is ingeniously synthesized in one step by simple dislocation hybridization, which could carry a large amount of sensitized material CdS QDs. More importantly, with Exo III-assisted multiple amplification, the proposed “signal-on” platform demonstrated a detection range of 10 fM to 1 μM with the detection limit of 1.41 fM for thrombin. Impressively, the PEC platform can successfully detect human serum samples with good accuracy. Above all, the CdS/ZnO/Bi2O3 sensitization photoelectric biosensing platform by using DNA nanowire in combination with Exo III-multiple amplification open new sensitized amplification paths for supersensitive biosensing and bioanalysis.
关键词： photoelectrochemical,CdS quantum dots,signal-on,thrombin detection,Bi2O3-ZnO,supersandwich nanowires,Exo III-assisted multiple amplification
更新于2025-09-19 17:13:59