Design And Synthesis Of A Novel Calcium Ion Fluorescent Probe And Its Application In The Detection Of Calcium-Containing Foods

Calcium(Ca)is one of the most abundant elements on the earth,and it is also an essential trace element for the human body,which is of great significance for maintaining human vital signs.Calcium deficiency and calcium excess can induce the occurrence and development of certain diseases,thus threatening the life and health of the human body.Food is an important source of our daily intake of calcium.There are many calcium-supplemented foods on the market,but the effect of calcium-supplementation is uneven.Therefore,a rapid,highly sensitive and highly selective detection method has been developed to accurately supplement calcium-supplemented foods.Calcium effect assessment is important.Fluorescent probes are considered to be the most effective molecular detection tools due to their many advantages,such as excellent optical properties,low cost,high sensitivity,fast transient response,and simplicity.In this paper,a small molecule Ca2+near-infrared(NIR)fluorescent probe and a Ca2+NIR nano-fluorescent probe were rationally designed and constructed,and their structures were characterized.The spectral response properties of the two probes to different calcium ion concentrations were studied by ultraviolet and fluorescence spectroscopy.At the same time,the rapid detection and analysis of the Ca2+concentration in the serum of calcium supplemented mice was carried out,and the detection and imaging of Ca2+ were carried out in vivo.analyze.The experimental results show that these two probes exhibit excellent optical properties and recognition performance.Among them,the new Ca2+ nano-NIR fluorescent probe has good biocompatibility and can be used for in vivo imaging,detection and the change of Ca2+concentration in blood samples of animal models.Determination and evaluation of calcium supplementation effect.The specific research work is as follows:1.A novel NIR fluorescent probe(Probe-adamantane)was constructed for the in vitro detection of Ca2+.The probe Probe-adamantane consists of two parts:an adamantane-labeled NIR fluorophore and a Ca2+ recognition group ethylenedioxybis(o-phenylene nitrilo)tetraacetic acid(BAPTA),where BAPTA has strong light The fluorescence intensity of NIR fluorophore is weakened due to Photo induced electron transfer(PET).When the probe Probe-adamantane was incubated with different concentrations of Ca2+,the absorption peak and fluorescence emission peak were significantly enhanced at 615 nm and 725 nm,respectively,with the increasing Ca2+concentration,and the Ca2+concentration was in the range of 0～0.2 μM It exhibited a good linear relationship with the detection limit as low as 18.6 nM,while other interfering substances did not significantly interfere with the response performance of the probe.This shows that Probe-adamantane has the advantages of excellent optical properties,specific selectivity and good sensitivity.Although Probe-adamantane exhibits excellent optical properties,high selectivity and high sensitivity for Ca2+,due to the four carboxyl groups Due to the strong negative charge,it has poor biocompatibility and cannot penetrate the cell membrane.Therefore,it cannot be used for the detection,imaging and assessment of calcium ions in animal models.2.Based on the above consideration of the strong negative charge effect of the carboxyl group,a nano-fluorescent probe was constructed by self-assembly of the probe Probe-adamantane with a biocompatible and water-soluble β-cyclodextrin(β-CD)polymer through host-guest interaction.Needle(NIRCD-Ca)for in vitro and in vivo detection of Ca2+,imaging analysis and evaluation of calcium supplementation effect of calcium supplementation oral solution.Firstly,the spectral response of NIRCD-Ca to Ca2+was investigated,and its UV-Vis and fluorescence spectra with different concentrations of Ca2+were measured.With the increasing concentration of Ca2+,the absorption and fluorescence intensities were observed at 615 nm and 725 nm,respectively.significantly increased,with an approximately 18-fold increase in its fluorescence intensity and a detection limit as low as 9.7 nM.The experimental results show that NIRCD-Ca exhibits excellent water solubility,good biocompatibility and very low background fluorescence interference,and can be used for the detection and imaging analysis of Ca2+in cells,blood samples and mice.Therefore,the probe was used for the detection of Ca2+in food samples,and the probe was finally used to evaluate the calcium supplementation in mice,both showed satisfactory results.