Abstract:
Breast cancer (BC) is one of the leading causes of cancer related deaths in women. Many
factors are involved behind the development of BC, for example, abnormal hormonal activity,
environmental factors, genetic disorders, lifestyle, and epigenetic regulations. Tamoxifen
(TAM), a chemotherapeutic drug, was used in 1960s for the first time for breast cancer
treatment. BC is developed by irregular activity of estrogens in body and TAM releases an antiestrogen
metabolite i.e., 4-hydroxy tamoxifen to control this sort of tumor. However, TAM
detection is necessary for monitoring the treatment of BC as well as to detect the root source
of some diseases triggered by excessive amount of TAM in body. In the present study, TAM
was electrochemically detected in aqueous media by modifying glassy carbon electrode (GCE)
with the nanocomposite of reduced graphene (rGO) and manganese 5,10,15,20-tetrakis (4-
chlorophenyl) porphyrin (MnTClPP). Nanocomposite was manufactured by π-π interaction
between rGO and MnTClPP in 1:3. Fourier transform infrared spectroscopy (FTIR),
ultraviolet-visible spectroscopy (UV-Vis), X-Ray diffraction (XRD), scanning electron
microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS) and nuclear magnetic
resonance spectroscopy (NMR) were performed for the confirmation of successful fabrication
of synthesized materials. Moreover, electrochemical analysis of the various modified
electrodes was done via cyclic voltammetry (CV), electrochemical impedance spectroscopy
(EIS) and differential pulse voltammetry (DPV). A very suitable sensor showing significant
anodic peaks of current towards analyte, working at a scan rate of 50mV/s on pH 7, was
developed having remarkable values of LoD and LoQ as 0.037nM and 0.124nM, respectively.
This sensor was able to perform linearly on a wide range of concentrations of TAM i.e., 1μM-
3mM as well as on large scale of scan rates i.e., 5mV/s – 100mV/s. Various interfering agents
i.e., common ions and biomolecules present in body were not able to affect the electrochemical
activity of the modified sensor. The sensor also showed admirable reproducibility, stability,
sensitivity, and repeatability. The sensor was also capable of performing well in real life
samples. This developed sensor also showed extraordinary results for TAM sensing among all
the sensors formerly developed for this purpose.
