The supramolecular interaction between the water-soluble pillar[5]arene (WP[5]) as host and dopamine hydrochloride (DH) as guest was studied by spectrofluorometry . The fluorescence intensity of DH gradually decreased with increasing WP[5] concentration, and the possible interaction mechanism between WP[5] and DH was confirmed by 1 H NMR, 2D NOESY , and molecular modelling. Based on significant DH fluorescence, a highly sensitive and selective method for DH determination was developed for the first time. The fluorescence intensity was measured at 312 nm, with excitation at 285 nm. The effects of pH, temperature, and reaction time on the fluorescence spectra of the WP[5]-DH complex were investigated. A linear relationship between fluorescence intensity and DH concentration in the range of 0.07–6.2 μg mL − 1 was obtained. The corresponding linear regression equation is Δ F = 25.76 C + 13.56 (where C denotes the concentration in μg mL − 1 ), with the limit of detection equal to 0.03 μg mL − 1 and the correlation coefficient equal to 0.9996. This method can be used for the determination of dopamine in injection and urine samples. In addition, the WP[5]-DH complex has potential applications in fluorescent sensing and pharmacokinetics studies of DH.
Shengling Li,Duanlin Cao,Xianjiao Meng,Zhiyong Hu,Zhichun Li,Changchun Yuan,Tao Zhou,Xinghua Han,Wenbing Ma
In this study, a novel schiff base fluorescent probe (E)- N' -(3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzylidene)-7-(diethylamino)-2-oxo-2 H -chromene-3-carbohydrazide ( CHS ) was synthesized for sequential detection of Al 3+ and pyrophosphate ions (PPi) in a DMSO/HEPES (4:1 v/v, pH = 7.4) buffer system and characterized by 1 H NMR, 13 C NMR, ESI-HR-MS and DFT calculation. Its detection limit was determined to be 0.16 μM for Al 3+ and 0.18 μM for PPi in a pH range of 4∼8, respectively. The Job’ s plot showed that the stoichiometric ratio to Al 3+ was 1:1, and CHS -Al 3+ showed highly selective recognition of PPi. The sensor CHS could also recognize Al 3+ and PPi and exhibited fluorescence enhancement and quenching properties in HeLa cells.
He Liu,Shuang Zheng,Xuan Yang,Wenbo Liao,Can Wang,Weining Miao,Jiayue Tang,Dianyu Wang,Ye Tian
Multifunctional droplets manipulation devices are in urgent need for various laboratory operations such as chemical reaction and biological analysis. However, most current techniques that achieved a controllable droplet transport system mainly rely on passive diffusion for mixing, limiting their practical applications. Here, we develop a magnetic controlled dimple on slippery surface (MCDSS) that enables arbitrary direction or even uphill droplet transport through the synergy between gravitational force and asymmetrical droplet deformation. Further experiments demonstrate that our system could also be used for stirring microdroplets and accelerating the mixing speed by more than one hundred times. In addition, the microstir strategy could help to avoid locally uneven production of precipitation or gas in heterogeneous reactions. This combination of droplet delivery and agitation may have a promising future for application in various fields, for example, laboratory-on-a-chip platforms and microengines.
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