Calcium phosphate nanoparticles: a study of their synthesis, characterization and mode of interaction with salmon testis DNA

Abstract

Calcium phosphate nanoparticles (CPNPs) are presently emerging as a second generation vector for efficient delivery and stabilization of nucleic acids inside cells, although the detailed mode of interaction between CPNPs and DNA is still obscure. This study discloses some features of the interaction. For this study, we synthesized CPNPs by a modified co-precipitation method and characterized the particles by different techniques such as dynamic light scattering, X-ray diffraction, electron dispersive spectroscopy, Fourier transform infra-red spectroscopy, differential thermal and thermo-gravimetric analysis, and atomic force, scanning and transmission electron microscopy. The characterization studies showed that the nanoparticles were spherical in shape, about 45 nm in size and were composed of the hydroxyapatite form of calcium phosphate; almost 90% of the starting materials were converted to nanoparticles (NPs). The different aspects of the interaction between CPNPs and salmon testis DNA were investigated using techniques such as UV-Vis spectrophotometry, circular dichroism, Fourier transform infra-red spectrometry, thermal denaturation, microviscometry, agarose gel electrophoresis, cyclic voltammetry and atomic force microscopy. The results revealed that CPNPs interacted with DNA with ~1 : 3.3 stoichiometry with a binding constant of the order of 10(4) M(-1) through groove-interacting mode and a single nanoparticle covered about 6.2 base pairs of the DNA chain. Moreover, the binding interaction was spontaneous, cooperative, exothermic and enthalpy-driven and some electrostatic nature of the binding was also evident; however, the non-polyelectrolyte contribution was dominant. The binding interaction finally caused an increase in the melting temperature of DNA from 70.8 °C to 75 °C and alteration of its secondary structure from the naturally occurring B-form to C-form.

Natural‐Based Nanocomposites for Bone Tissue Engineering and Regenerative Medicine: A Review

“…CaP nanopowders/nanoparticles have been produced using a large number of methods, such as wet chemical precipitation, sol‐gel synthesis, hydrothermal synthesis, mechanochemical synthesis, microwave irradiation‐assisted processing, and the spray‐drying method . Among them, the wet chemical process, also known as aqueous precipitation, is the most extensively investigated technique for CaP nanoparticle synthesis, followed by heat treatment according to the desired CaPs structure.…”

Tetracycline-loaded calcium phosphate nanoparticle (Tet-CPNP): Rejuvenation of an obsolete antibiotic to further action

“…The reason behind the large difference in size of the particles, measured by DLS instrument and TEM, was that the DLS-measured size was principally the hydrodynamic size i.e., the size of a core particle, together with the thick hydration layer around it and so this size was always larger than the real size of core particle measured by TEM. Our earlier report also showed such large difference in size of CPNP alone, determined by DLS and TEM [36].…”

“…The Tet-CPNP was synthesized by a co-precipitation method of preparation of CPNP [36], where tetracycline was added at the stage of formation of the NPs, so that the antibiotic got loaded within the particles formed. The method of synthesis of CPNP was based on a simple, quick, co-precipitation method of preparation of stable, dispersed CPNP using calcium nitrate and di-ammonium hydrogen phosphate as precursors and Na-citrate as stabilizer [36,44]. When the precursors were allowed to react at different temperatures, amorphous…”

“…In purification stage of the synthesized NPs, the obtained centrifuged pellet of NP suspension was dried in a lyophilizer A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 6 (Heto, DW-3). From lyophilized powder, FTIR sample was prepared as described in [36] and spectroscopy was done in FTIR instrument (Perkin Elmer L 120-000A).…”

“…For this study, sample was prepared on carbon-coated copper grid (Applied Biosystems, India), as described in [36] and analysis was performed in HR-TEM (JEOL, JEM-2010), operated at an acceleration voltage of 200 kV.…”