A Novel Turn on Fluorescence Sensor for Determination Enoxaparin, a Low Molecular Weight Heparin

Detection of protamine based on competitive adsorption onto the surface of functionalized multi-walled carbon nanotubes

This study developed an adsorption-based determination system for protamine. A multi-walled carbon nanotube (MWCNT), which is a strong adsorbent, was used. The competitive adsorption process between dyes and protamine formed the basis of the sensor system. The adsorption process was followed over the dyes by UV-Vis. absorption spectroscopy. This sensor system was developed using the thermodynamic parameters. Transmission electron microscopy and Fourier-transform infrared spectroscopy techniques were used for the characterization of the sensor system. It was determined that the sensor system remained stable at physiological temperature and pH range. Limit of detection values of PyB-COO-MWCNT and PyY-COO-MWCNT systems were found to be 1.32 and 1.12 ng mL-1 , respectively. The applicability of the sensor systems was demonstrated using bovine serum solutions.

A Highly Selective and Sensitive Peptide-Based Fluorescent Ratio Sensor for Ag. J Fluoresc 2020;31:237-246. [PMID: 33215317 DOI: 10.1007/s10895-020-02653-5]

A fluorescence ratio sensor based on dansyl-peptide, Dansyl-Glu-Cys-Glu-Glu-Trp-NH₂ (D-P5), was efficiently synthesized by Fmoc solid phase peptide synthesis. The sensor exhibits high selectivity and sensitivity for Ag⁺ over 16 metal ions in 100 mM sodium perchlorate and 50 mM 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid buffer solution by fluorescence resonance energy transfer. The 1:1 binding stoichiometry of the sensor and Ag⁺ is measured by fluorescence ratio response and the job's plot. The dissociation constant of the sensor with Ag⁺ was calculated to be 6.4 × 10^-9 M, which indicates that the sensor has an effective binding affinity for Ag⁺. In addition, the limit of detection of the sensor for Ag⁺ was determined to be 80 nM, which also indicates that the sensor has a high sensitivity to Ag⁺. Result showed that the sensor is an excellent Ag⁺ sensor under neutral condition. Furthermore, this sensor displays good practicality for Ag⁺ detection in river water samples without performing tedious sample pretreatment, as well as for silver chloride detection.