Electrochemical study of doxorubicin on the surface of SBA-15 modified screen -printed carbon electrode

Doxorubicin (DOX), has been nearly recognized as the ‘‘gold standard’’ for the treatment of various cancers including solid breast, ovarian, lung and liver tumors. However, the side effects such as systemic toxicity, cardiotoxicity and drug resistance gradually appear during the therapy. Therefore, there is an emergent need for rapid, easy and sensitive techniques for analysis of DOX .The performance of sensors can be significantly improved by using different nanomaterials. One of these materials is mesoporous silica SBA-15. SBA-15 is a promising candidate for the immobilization of various materials and can be used to create stable biosensing. Sensors based on the SBA-15 have shown high sensitivity and good detection limit through promoting electron transfer reaction and enhancing electrochemical signal. In this project, a simple and novel sensor is developed for study of clinical DOX concentration based on SBA-15 on the surface of SPE .The SBA-15 modified screen printed electrode (SPE) was fabricated to monitor the DOX in phosphate buffer solution (pH 6.0). A droplet of 9μL SBA-15 was placed on the working electrode surface, followed by air-drying for 1.0 h. The interaction of SBA-15 on the working electrode surface with DOX was investigated in the drug solution. The electrochemical behavior of DOX was observed at the surface of SBA-15-modified SPE by cyclic voltammetry (CV) and electrochemical impedance spectroscopy. The effect of pH and scan rate on the reduction current of DOX was studied using cyclic voltammetry. From the obtained results, pH 6.0 was obtained as the optimum pH. Also scan rate showed that the reduction peak current increased with increasing in scan rate from 10 to 400 mV s-1. From the calculated results, the electron transfer coefficient was obtained 0.49. Under optimized condition, the measured reduction peak current of DOX by differential pulse voltammetry exhibited a good linear relationship with the increasing of the DOX concentration in the range of 0.002 μM to 2μM. The detection limit was founded to be5.4×10-6μM.