The formation of G-quadruplex at the telomeric end can prevent telomere elongation by inhibiting activity of telomerase enzyme, which is activated in 80–85% cancer cells. We studied the interactions between the [Pd 3 (C 12 H 8 C=NO) 6 ] with G-quadruplex DNA using UV–Vis absorption spectroscopy. The results showed that the palladium complex can effectively induce and stabilize G-quadruplex structure. According to the results, the binding constant between the Pd (II) complex and G-quadruplex was found to be (1.03×10 7 M ?1 ) while binding constant between the Pd (II) complex and duplex DNA was obtained (1.3×10 5 M -1 ). The results indicated that the selectivity of the complex for binding to the G-quadruplex is larger than that to the duplex DNA. The method of continuous variation analysis (Job plot) was used to determine the number of Pd (II) complex binding to G-quadruplex. The UV-denaturation experiments were carried out to examine the stability of the Pd(II) complex induced G-quadruplex, The thermodynamic parameters were measured by thermal denaturation experiment and according to results ?H°, ?G°, and ?S° were found to be -17/86, -10/3 kcal mol ?1 , and -54/92 kcal k -1 mol ?1 , respectivily . Bovine serum albumin and cellulose nanoparticles were synthesized, then the complex was loaded on the nanoparticles and were investigated interaction between G-quadruplex DNA and the complex -NPs. Also the realese of complex from anoparticles were studied. In order to investigate morphology of nanoparticles, the SEM image was taken from the Pd(II) complex loaded NPs. The biological activity showed that the complex has significant antitumor activities against MCF7 (breast cancer) cells.
