Investigation On Interaction And Sonodynamic Damage Of Several Fluorescein Derivatives To Serum Albumins

In this paper, we selected the fluorescein and its derivatives to study the interaction and sonodynamic damage between these fluorescein derivatives to biological macromolecules-Bovine serum albumin (BSA) and Human serum albumin (HSA). Because the structure of selected fluorescein derivatives included 4,5-Dibromofluorescein (DBF),2,4,5,7-Tetrabromofluorescein(TBF), 4,5-Dibromo-2,7-dinitrofluorescein (DBDNF), Fluorescein (FLU), 4,5-Dichlorofluorescein (DCF),4,5-Dinitrofluorescein (DNF) is planar, belonging to the xanthones dyes. Both their extinction coefficient and fluorescence quantum yield in the water are high, so these fluorescein derivatives have better sonodynamic activity and antitumor activity. Due to above reasons, we chose these fluorescein derivatives as sonosensitizers. The targeted molecular serum albumins chosed in this paper are BSA and HSA. Because the serum albumin is the most abundant protein in blood plasma and also is the direct expression of genetic traits, occupying an important position in the cell, so we chosed the serum albumins as targeted molecular to explore the sonosensitizer combining and damaging the BSA and HSA. In addition, because the tertiary structure of HSA has two different subdomains:subdomainⅡA and subdomainⅢA, so we used two probe compounds WAR and IBU through the competition reaction to further explore the combination subdomains and damage subdomains of probe compounds to HSA. In brief, this paper mainly discussed the interaction between fluorescein derivatives with BSA and HSA and further studied their sonodynamic damage to BSA and HSA. At last, we also discussed the sonodynamic damage mechanism of fluorescein derivatives to serum albumins.This paper mainly consists of two parts as following:1.We chose the interaction between fluorescein without any group(FLU), fluorescein with two chlorine atoms(DCF) and fluorescein with two nitro(DNF) to HSA, use the fluorescence spectrum as means of verification, and discussed the the combination mechanism of these three kinds of fluorescein derivatives to HSA. We used the three dimensional fluorescence spectrum and contour spectra to discuss the changes of HSA conformation of secondary structure under the condition of with or without fluorescein derivatives. The binding sites between three kinds of fluorescein derivatives and HSA were studied by the method of synchronous fluorescence spectroscopy and synchronous quenching rate and the damage sites of ultrasonic irradiation to HSA were discussed by changing the ultrasonic irradiation time and synchronization quenching rate curve. Using the compounds WAR and IBU as probe, Fluorescence spectroscopy explored the combining subdomain and damage subdomains of FLU, DCF and DNF to HSA and discussed and compared the damaging degree. At last, the conformation change impacted by FLU, DCF and DNF under ultrasonic irradiation was also studied by the method of circular dichroism.2. We chose the interaction between fluorescein with two bromine atoms (DBF), four bromine atoms (TBF) and with two bromine and two nitro (DBDNF) to BSA, through the fluorescence spectrum. And we discussed the the combination mechanism of these three kinds of fluorescein derivatives to BSA. The ultraviolet, fluorescein and circular dichroism spectrum of with or without fluorescein derivatives were also studied before and after ultrasonic irradiation. In additon, the influence of ultrasonic irradiation time on sonodynamic damage was disscused.The research results of this paper may provide some valuable information for treatment of tumor in clinical medical as well as for the exploitment and development of sonosensitizer in future.