| Anti-cancer drugs are widely used for human cancertherapy. However, theprolonged clinical usage of anti-cancer drugs will birng some side effects. Forexample it may kill the healthy body cells and cause the organ toxicity to human body，such as cardiotoxicity, hepatotoxicity and marrow toxicity, et al. Quercetin, as anatural flavonoid anti-tumor compounds, can effectively inhibits the proliferation andmetastasis of tumor cells, reverse the multidrug resistance of tumor cells, andenhanced the effectiveness of anti-cancer drugs. Daunorubicin (DNR) is ananthracyclinederived nonspecific anticancer drug. By inserting DNR into DNA, it willhinder the synthesis of DNA and the DNA-dependent RNA. DNR has been widelyused in the treatment of leukemia, as well as many other kinds of cancer such asmalignant lymphoma. The annual sale is reach1billion. However, as an anti-cancerdrug, DNR also birng some side effects. It produces a potentially fatalcardiotoxicityand marrow toxicity which is dependents on the total cumulative dose administered.Therefore, the accurate control of drug concentration, together with thepharmacokinetic supported rational and customized dosage regimen, will greatlyreduce its side effects and at the same time enhance the effectiveness of anti-cancerdrugs.So far, HPLC along with some other means such as fluorescence spectrometry,capillary electrophoresis etc, are the most popular methods for cancer drugsdetection.Among all these methods，using the electrochemical sensors for anti-cancer drugsdetection is most promising, and it has many advantages: portable, fast, sensitive, andeconomic. Consequently，highly sensitive electrochemical sensor is essential for theevaluation and administration of anticancer drugs.Mesoporous silica (SBA-15) exhibits good bio-compatibility and has large surface area due to its mesoporons structure. SBA-15bonded to the surface of glassycarbon electrode will extensively increase surface area of electrode, p-cyclodextirn(P_CD)，as supermolecule, is widely used for drug embedding molecules. Spatialelectrochemical signal will be observed when the hydrophobic part of DNR entrappedinto the cavities of P-CD. Gold nanoparticles(GNPs) exhibit good electron transferactivity, high surface area and uniformity. Chemicals which contain thiol group, tendto bind with GNPs by Au-S strong electrostatic interaction，and therefore the surfaceof electrode can be easily modiifed with hydrosulfuryl consist of electro-activematerials by a simple self-assembly operation. This makes GNPs a good nanomateiralas electrochemical sensors.Cysteine (Cys) is a common amino acid. Poly-cysteine iflm can be obtainedeasily by electro-polymerization technology. The resultingpoly-cysteine layersexhibited good biological compatibility and electrocatalytic activity. Single-wallcarbon nanotubes (SWNT) with a two-dimensional tubular structure formed by asingle layer of carbon atoms possess a good electronic conductivity, surface area,stability and biocompatibility. Modiifed glassy carbon electrode based onpoly-cysteine and SWNT exhibited very good electro-conductivity andelectro-catalytic activity, making it widely used in the field of sensor.In the present study, a novel electrochemical sensor for anticancer drug detecitonwas develop with nanomaterials (SBA-15, SWNT and GNPs etc.) by applying thelayer-by-layer self-assembly technique. The research ideas behind this were outlinedas follows:1) Gold nanoparticles and mesoporous silica with larger surface area andgood biocompatibility were combined with new sensitive mateiral, in the aim ofdeveloping a electrochemical sensors with high sensitivity, stability and goodanti-jamming ability;2) Due to the good performance of carrier, its excellentelectronic conductivity and biocompatibility, electrochemical sensors with single-wallcarbon nanotube and cysteine was prepared to get higher-selectivity and largerresponse signal for quercetin detection. Three aspects of the work in the present theses have been carried out and are summarized as follows:1Sensor Based on Mesoporous silica/β-cyclodextrin Modified GCE for Deterination of DNRA novel electrochemical sensor for DNR detection based on mesoporous silica/β-cyclodextrin modified GCE was developed. The nanostructure of synthesized mesoporous silica and fabricated electrods were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Atomic Force Microscope (AFM), Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments were carried out to investigate the electrochemical properties of the modified electrode. The sensor exhibits good amperometric response towards daunorubicin (DNR) due to the large specific area and Specific binding with DNR of mesoporous silica and β-cyclodextrin. Under optimum conditions, The current response of the sensor increases linearly with the concentration of DNR from1.0×10-6～5.0×10-5mol/L (with a relative coefficient R=0.9950) and5.0×10-5～2.5×10-4mol/L(with a relative coefficient R=0.9990). The detection limit is2.0×10-7mol/L (S/N=3). The results indicate that this modified electrode has a very good performance in reproducibility, stability and interference experiments.2Daunorubicin Sensor Based on Gold Nanoparticles/Mercapto-β-cydodextrinA sensitive electrochemical sensor for low concentration DNR detection was prepared by following steps:Gold nano particles(GNPs) were first deposited onto the surface of glassy carbon electrode, and then mercapto-p-cyclodextrin was immobilized on GNPs. Field emission scanning electron microscopy (FESEM) was used to characterize the morphology of the modified electrode. The electrochemical property of the modified electrode and DNR was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the sensor exhibits good amperometric response and high sensitivity towards DNR because of the excellent conductivity of GNPs. Under the optimal expeirmental conditions, thecurrent is linear with the concentration of DNR in the range rfom l.OxlO"7mol/L tol6x.OlO*5mol/L, with two parts included： l.OxlO"7?L0xl(Tmol/L(R=0.9990);1.0x10’6~1x.010"5mol/L(R=0.9985). The limit of detection is5.0xlO"8mol/L (S/N=3).3Quercetin Sensor Modiifed with Poly-cysteine, Single-wail Carbon NanotubesA novel sensor for Quercetin (Qu) detection was developed by the combinationof functionalized SWNT together with poly-L-cysteine (L-cys). FunctionalizedSWNT and L-cys were immobilized onto the surface of a glassy carbon electrode byelectrochemical technology. The electrochemical property of the Qu electrochemicalsensor was investigated by cyclic voltammetry and electrochemical impedancespectroscopy. The sensor was found exhibit good amperometric response towards Qu.The SWNT polymer membrane can promote the electro-active property at theelectrode-solution interface, enhance the reactivity of catalytic and selectivelyincrease the active area of electrode. Under the optimal experimental conditions, thecurrent was linear with the concentration of Qu in the range rfoml’.OxlO7mol/L to2.0x10"4mol/L with a relative coefficient of0.9990. The detection limit was found tobe2-.0xl08mo!/L(S/N=3),... |
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