Physico-Chemical nanomaterials science

Desorption of doxorubicin from the surface of magnetite nanoparticles into DNA and bovine serum albumin solutions 
Pesina D. A., Dukhopelnikov E. V., Gladkovskaya N. A., Bereznyak E. G.
O.Ya.Usikov Institute for Radiophysics and Electronics NAS of Ukraineю
Akad. Proskury Str., 12, Kharkiv, 61085, Ukraine.
E-mail: darynapesina@gmail.com

Doxorubicin hydrochloride (DOX), an anthracycline antibiotic, is a highly effective anti-neoplastic agent used in the chemotherapy of a variety of cancers. Its successful use is hampered by severe toxic side effects such as cardiotoxicity. This side effect, as well as the effective concentration of the drug, can be significantly reduced if being loaded onto the magnetic nanoparticles (MNPs) it is directly targeted to the tumor and then retained there under external magnetic field. 
The biological action of DOX results from its intercalation into DNA. However, before targeting to its receptor, the drug can bind transport proteins like serum albumin. The aim of the present work is to evaluate the influence of DNA and bovine serum albumin (BSA) molecules on the desorption of DOX previously loaded onto the superparamagnetic Fe3O4 nanoparticles.
Three suspensions containing Fe3O4 nanoparticles prepared in trisodium citrate and DOX were processed by ultrasound dispersion for 2 hours. The obtained colloid solutions were placed on the samarium-cobalt magnet for 10 minutes in order for nanoparticles with the bound drug to precipitate. The supernatant then was removed from each tube, and distilled water, DNA and BSA solutions in equal volumes were added to each of the sorbent residues. At given time intervals the released drug concentration in the supernatant was determined from its adsorption spectra. The spectra were recorded in the visible region by spectrophotometer “Specord M40”. 
Our results show that DOX molecules do not practically release into the water. The initial percentage of bound DOX molecules (~90%) does not change over time. DNA greatly facilitates the desorption of the drug from MNPs. After 200 min only ~50% of DOX molecules remained bound with nanoparticles. BSA also facilitated DOX desorption, although not as efficiently as DNA. After the same time up to 83% of DOX molecules were adsorbed on MNPs in the presence of BSA. The desorption of DOX into DNA solution also had a higher rate than into BSA one. 
Thus, we show that physiologically-relevant molecules like DNA and BSA desorb DOX from the magnetite nanoparticle surface, which is an important point to consider for in vivo drug delivery and controlled release studies.