Novel Biomaterial for NCT - “Rigid” Particles of (DNA-gadolinium) Liquid-Crystalline Dispersions

Abstract

The formation and physico-chemical properties of biomaterial, based on double-stranded (ds) DNA molecules and bearing high concentration of gadolinium, is described. This “rigid” biomaterial demonstrate a few unique properties: (i) the ds DNA molecules forming complexes with gadolinium are fixed in the spatial structure of “rigid” particles, (ii) an abnormal negative band in the circular dichroism spectrum permits to follow the formation of this biomaterial; (iii) local concentration gadolinium in the content of biomaterial can reach 40%. These properties show that we are dealing with a novel type of biomaterial strongly enriched by gadolinium. This opens a gateway for practical application of this biomaterial for neutron-capture reactions. A first attempt to apply this material for neutron-capture reaction in combination with neutron generator of thermal neutron flux was performed. Positive result obtained at destruction of CHO cells allows one to state that the advantages of this biomaterial are a simple manipulation with it, a possibility to adjust its gadolinium content, long-term stability of its physico-chemical properties, as well as a reduced cost of neutron-capture experiment

Physicochemical and nanotechnological approaches to the design of 'rigid' spatial structures of DNA

“…Liquid DNA CLCD particles transform into rigid (gel-like) particles. 32 As in the above case, rigid DNA particles can exist in the absence of the osmotic pressure of the PEG-containing solution, which supports their immobilization on the nuclear membrane filter surface ( Fig.5 a,b). The particles are independent objects with uncompensated surface charges, which prevent their aggregation.…”

DNA Liquid-Crystalline Dispersion Particles as a Platform for Creation of “RIGID” Spatial Structures

“…Such cations efficiently neutralize the negative charges of the DNA phosphate groups, the complexes of the cations with the phosphate groups being nearly insoluble (for example, the solubility constant of gadolinium phosphate is ~10 -12 M). It was shown [17,19] that the amplitude of the negative abnormal band in the CD spectrum of the cholesteric DNA LCD formed in PEG-containing solution increases at a high gadolinium concentration, at which Na + ions are replaced by gadolinium (Gd 3+ ) cations in nearest environment of ds DNA molecules (Fig. 6). )…”

“…The very high-molecular mass of such structure and its insolubility makes this system incompatible with the PEG-containing solution. Hence, "liquid" DNA CLCD particles are transformed into "rigid" (gel-like) constructions ("rigid" particles) [19].…”

“…An application of rigid particles formed by (DNA-Gd 3+ ) complexes as gadolinium carriers in the neutron capture therapy was described and experimentally tested in a set of our papers [4, 17,19,[23][24][25][26][27][28][29][30][31][32][33].…”

“…It was shown [19] that that the irradiation of Chinese hamster ovary (CHO) adherent cells ( The presence of strongly deformed cells (collapsed cells) allows one to suppose, that although concrete reasons for an appearance of these cells were not investigated carefully, that irradiation of CHO cells in presence of (ds DNA-Gd 3+ ) rigid particles is accompanied by a few processes:…”