Development and applications of electrochemical dna biosensors for the study of selective estrogen receptor modulators (SERM) raloxifene

"Development and Applications of Electrochemical DNA Biosensors for the Study of Selective Estrogen Receptor Modulators (SERM) Raloxifene (Ralo) ([6-hydroxy-2-(4-hydroxyphenyl)-1- benzothiophen-3-yl]-[4-(2-piperidine-1-ylethoxy)phenyl]methanone), is a selective estrogen receptor modulator (SERM) that is used in the treatment of cancer. Estrogen receptors have two different structures: alpha and beta. SERM substances bind to these receptors and have antagonist and agonist effects. SERMs are nonsteroidal compounds that cause estrogen agonist and antagonist effects in some tissues using the 3- dimensional conformation. The most well-known SERMs are Ralo and tamoxifen (TAM). TAM affects the estrogen receptors and causes therapeutic and side effect-producing mechanisms in the body. Tam acts as an estrogen antagonist in breast cells, but it stimulates the endometrium by acting as an estrogen agonist in the uterus. On the other hand, RALO affects breast cell estrogen receptors as an antagonist and it doesn't stimulate the uterus. This thesis investigated the interaction between Ralo and DNA by using disposable electrochemical biosensor. Firstly, the electrochemical behaviour of Ralo was examined with cyclic and square wave voltammetry in aqueous solutions over the pH range of 2.0-12.0. The detection limit of Ralo was calculated as 5.63 µM (2.66 µg/mL) (linearity range from 1.25 to 50 µg/mL). In addition, an electrochemical biosensor was designed for interaction between Ralo and DNA sequences by using pencil graphite electrode (PGE). Consequently, the developed biosensor provides a suitable stage for the analysis of Ralo-DNA interaction sensitively. In the present study, the interaction of the anticancer drug was investigated with the DNA-modified electrodes. The binding mechanism of the anticancer drug Ralo with DNA was determined by using electrochemical voltammetry methods. For this purpose, DNA-modified electrodes were prepared and interacted with Ralo then measured by electrochemical analysis. In summary, it was shown that the label-free detection of Ralo–DNA interaction could be done with sensitive, faster, and less laborious techniques by using disposable electrochemical biosensors.