| Edible or medicinal plants in nature provide a large number of biologically active substances for mankind.Meanwhile,these substances are essential for the maintenance of human life activities and for the treatment of human diseases.Thus,the detection of these substances has been playing a more and more important role in modern analytical science,and has been widely used in clinical diagnosis,treatment monitoring,food safety,drug safety evaluation and quality control,and many other fields.In these areas,we usually need to analyze one or more bioactive components in complex systems in vivo and in vitro.For example,the analysis of important functional ingredients in food,the determination of the active ingredients in Chinese herbal medicine preparations and their distribution in the body.Moreover,when the content of some biological active substances in human body changes abnormally,it often indicates some disease.Therefore,it is necessary to detect the biological active substance as a disease marker in clinical diagnosis.Simultaneously,it is also important to design new method to analyze the bioactive substances with high sensitivity,high efficiency and high selectivity.We here focused our efforts mainly on how to improve the in vivo and in vitro bioactive substances detection methods,and the main research content and results are shown as below:1.A nitrogen-doped 3D elastic carbon foam(NECF)with excellent elasticity was prepared by the direct carbonization of melamine foam(MF).The NECF had a 3D interconnected network architecture which showed the potential application in electrochemical biosensors owing to its large specific surface area,elasticity,inexpensive raw materials of MF(a kind of kitchen materials or construction materials)and simple preparation process(direct carbonization method).Furthermore,the NECF contained a large amount of nitrogen which increased active sites and provided good biological compatibility.Without any supporting materials,the NECF was employed to load GOD based on the strong adsorption between NECF and GOD for glucose biosensing,exhibiting good electrochemical performance like wide linear range,low detection limit,good stability and high sensitivity.2.The spherical porous MOF-5 microstructures supported by three-dimensional(3D)kenaf stem-derived porous carbon(KSC)(denoted as MOF-5/3D-KSC)composites were constructed for ascorbic acid(AA)sensing.The formation of MOF-5/3D-KSC was verified by scanning electron microscopy,X-ray powder diffraction and energy dispersive X-ray spectroscopy.The results showed that spherical porous MOF-5 microstructures were evenly arrayed on the surface of 3D-KSC via a simple one-step hydrothermal method,which could greatly increase the effective surface area,stability and active sites.The MOF-5/3D-KSC composites were directly used to prepare integrated MOF-5/3D-KSC electrodes for AA sensing,and the integrated electrodes showed better performance for AA detection than traditional enzyme-based sensors and nonenzymatic sensors.The sensor exhibited good stability,wide linear range(0.7 mM to 11.5 mM)and low detection limit(0.24 mM).Hence,the MOF-5/3D-KSC composites could be a potential material for sensing platforms.3.A novel open circuit potential biosensor(OCPS)composed of a working electrode and an Ag/AgCl reference electrode was designed for in vivo continuous glucose monitoring in this work.The macroporous carbon derived from kenaf stem(KSC)was used to construct a KSC microelectrode(denoted as KSCME)which was subsequently used to load glucose oxidase(GOD)as the working electrode.The resulted GOD/KSCMEs could catalyze the oxidation of glucose directly to result in the changes of open circuit potential(Voc)of the constructed OCPS.It was found that the Voc of constructed OCPS depended on the glucose concentration,showing a linear range of 0.03-10.0 mM(R=0.999)with a detection limit of 10 ?M.In addition,the OCPS exhibited a good selectivity for glucose against other common endogenous interferences.And the feasibility of the proposed OCPS for glucose detection in mice skin tumor and normal tissue homogenate samples(in vitro experiment)and rat subcutaneous glucose monitoring(in vivo experiment)was demonstrated with satisfactory results.The biosensor represents a novel example of a superficial cancer diagnostic device and the proposed OCPS also provides new ideas to develop a simple and highly selective device for continuous glucose sensing.4.Using UPLC-QTOF-MS,ultra high accuracy sample data were collected by time dependent mass spectrometry data scan mode(MSE).High-throughput analysis method for Keke capsule was established and 41 complicated compounds belonging to 8 categories identified quickly within 25 min.These main active substances were tracked after absorption pass through gastrointestinal tract and blood brain barrier in order to form impactful and integrated evaluation method for obtaining substances from capsule to blood then to brain.The transitional ingredients profile of blood and brain were depicted finally.The results provide basis for effective and safe usage of Keke capsule.5.Rapid resolution liquid chromatography-triple quadrupole mass spectrum(RRLC-MS/MS)was adopted to establish simultaneous quantitative analysis method for morphine and epimers of ephedrine and pseudoephedrine.Chromatographic separation was accomplished on a ZORBAX SB-C8 column(1.8 ?m,100 × 2.1 mm)utilizing a gradient elution profile and a mobile phase consisting of(A)acetonitrile and(B)2 mmol/L aqueous ammonium acetate containing 0.04% acetate acid.Mass spectrometric detection was performed by selected reaction monitoring mode via electrospray ionization source operating in positive ionization mode.The assay exhibited good linearity(r~2 >0.99)for all the analytes.The extraction recoveries of these alkaloids and internal standard were above 85%.The specificity,accuracy,precision,matrix effect and stability of this method were in accordance with the requirements of biological samples.The study provided the pharmacokinetics profiles and the brain regional distribution(hypothalamus,premotor cortex,striatum,hippocampus,oblongata and cerebellum)of the three active alkaloids after oral administration of Keke Capsule.The results also indicated that significant difference in pharmacokinetics parameters of the epimers was observed between ephedrine and pseudoephedrine. |
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