Spectrofluorimetric study on in vitro interaction between calcium phosphate nanoparticle and salmon testis DNA

摘要

At present, calcium phosphate nanoparticle (CPNP) is considered as a potential vector of nucleic acids into cells. However, the mode of interaction between CPNP and DNA is quite unknown. This communication throws some light on this. For the investigation, we synthesized CPNP using calcium nitrate and di-ammonium hydrogen phosphate as precursors and Na-citrate as stabilizer. Characterization of the NPs by the techniques of scanning and transmission electron microscopies, electron diffraction X-ray spectroscopy, and X-ray diffraction spectroscopy signified that the particles were about 45 nm in size, spherical in shape, and composed of the hydroxyapatite form of calcium phosphate. The most interesting feature of CPNP was that it had fluorescence with excitation and emission at 254 and 310 nm, respectively. Analysis of the results of different fluorescence-based experiments revealed that the CPNP had specifically bound at the grooves of DNA forming a ground state complex with 1:1 stoichiometry, and the interaction was exothermic, spontaneous, and enthalpy-driven in nature.