New Methods Based Pt Ions And Guanine Coordination Structure For Detection Of Platinum Compounds

Over the past three decades,platinum-based chemotherapeutic regimens have been widely used in the treatment of cancer.In order to study the reaction mechanism and pharmacokinetics of platinum drugs and their metabolites in vivo,it is necessary to build up a new method for the accurate quantification of Pt2+ ions in the biological sample after administration.Currently existing techniques mainly include ICPMS,spectrometry,chromatography and some combination methods.Each method has its advantages and disadvantages.ICPMS is one of the most commonly used methods because of its high sensitivity and selectivity,but it requires large instruments,high costs and long analysis time.Therefore,it is of great importance to develop a simple and selective detection method for platinum compound analysis in biological samples,and it will have a very broad application prospects.In recent years,aptamer technology has been applied for the detection of heavy metal ions,such as lead(Ⅱ)ions,mercury(Ⅱ)ions by coupling to fluorescence,electrochemical technology or colorimetry,etc.However,there are few reports about the application of this technique in the detection of platinum ions as well as the use of fluorescence quantitative PCR.As we all know,the Pt2+ ions will cross-link with guanine on the DNA strand,while the formation of a coordination structure can replace the Watson-Crick base pairs to maintain or enhance DNA duplex structural stability.Two novel methods for the detection of platinum-based compounds were established based on this,owning the advantages of high specificity,low detection limits,excellent sensitivity and reusability.The whole thesis is presented as follows:Chapter 1:IntroductionThe introduction elaborates the research purpose,significance,main content and innovation of this paper.Chapter 2:Platinum(Ⅱ)-Oligonucleotide Coordination Based Aptasensor for Simple and Selective Detection of Platinum CompoundsAn aptasensor based on coordination binding was developed for the detection of platinum-based drugs in serum or other biological samples.The aptamer sensor consists of a FITC-tagged Streptavidin aptamer sequence in which several base pairs are replaced by GG mismatches.Only in the presence of Pt2+ ions can the formation of coordination structure make the conformation of aptamer integral.Then it will bind to the streptavidin modified magnetic beads for magnetic separation,followed by adding anti-FITC modified horseradish peroxidase(HRP).After separation and washing,chemiluminescence substrate was added finally for detection.The quantitative range of the method and the detection limit is 0.12-240μM and 60 nM respectively.The method suggests excellent selectivity and has been successfully applied to the determination of Pt2+ in urine samples.Chapter 3:Fluorescence Quantitative PCR based on Coordination Structure for Detection of Platinum CompoundsCombining with fluorescence quantitative polymerase chain reaction(PCR),an innovative method was established for the detection of Pt2+ ions.The coordination binding between Pt2+ ion and the N7 positions of guanine(G)will affect the PCR amplification,resulting in less fluorescence signal.The addition of the help primer exploded this effect.Pre-reverse primers can be used as template primers to form reverse primers for subsequent PCR reactions,which means the Pt2+ ions is likely to compete with pre-reverse primers to combine with help primer.The method is simple,rapid and the detection limit can reach 10 ng/mL.