The physicochemical behavior of temozolomide stabilized on folic acid−targeted−gold−thiol modified surface via covalent conjugation towards cancer cells

Abstract

Conjugation via covalent bonding on nanocarriers is an effective strategy to stabilize drugs and prodrugs, improve their efficiency and decrease their side effects. In this study, temozolomide (TMZ) is used as a prodrug and stabilized via covalent conjugation on folic acid−targeted−gold−thiol modified surface, and then, the physicochemical behavior of the integrated system towards cancer cells is studied by surface techniques, votammetric methods, electrochemical impedance spectroscopy (EIS), and quartz crystal microbalance (QCM). The voltammetric and ATR−FTIR studies revealed that the conjugated TMZ is stable at least for 48 h. The adsorption behavior of A2780 cancer cells onto the system is well described by Freundlich adsorption isotherm with adsorption capacity of 50.11 and adsorption intensity of 1/n = 0.15. The process is controlled by a first order kinetic model with rate constant of 0.036 ± 0.002 min−1 and t1/2 of 18 ± 1 min. To our knowledge, this is the first time that the physicochemical behavior of the TMZ prodrug integrated onto Au−thiol SAM nanostructures is studied by EIS and QCM concerning cancer cells. The results of this research are noteworthy and can improve our physicochemical insights into anticancer drugs in conjunction with gold targeted nanocarriers, regarding the stability of prodrugs, mixed molecular nanostructures, adsorption kinetics and isotherms for sensing and capture of cancer cells.