On Correlation Effect of the Van-der-Waals and Intramolecular Forces for the Nucleotide Chain - Metallic Nanoparticles - Carbon Nanotube Binding

The tertiary system of nucleotide chain (NC) - gold nanoparticles (NPs) - carbon nanotube (CNT) represents a great interest in the modern research and application of the bio-nano-technologies. The application aspects include, for example, the development of electronic mobile diagnostic facilities, nanorobotic design for a drug delivery inside living cell, and so on. The small NC chain represents an important stage in the understanding of the interaction mechanism of a full DNA or RNA molecule with NP and CNT. In this regard, one has to mention the development of the DNA-CNT devices for the purposes of diagnostic applications in the chemical or drug delivery.

For the NC-NP-CNT system, we have built up a series of the molecular dynamics (MD) models with different NC-NP configurations and performed their MD analysis. The entire system (the NC chain, gold NPs and CNT) was allowed to interact with each other by the only VdW forces. The Lennard-Jones short-ranged interaction was assumed between the NC, NP and CNT. For the CNT a many body Tersoff potential having a quantum-chemistry nature was used. So far, the so-called hybrid MD approach was realized, where the quantum-chemistry potential in combination with a classical trajectory calculation applied .

The peculiarities of the NC-NP interaction and bond formation inside of a CNT matrix were investigated along with the structural and dynamical behavior. The correlation effects between the weak Van der Waals (VdW) forces and intramolecular vibrations were enlighten for the molecular system consisting of a small nucleotide chain (NC), gold nanoparticles (NPs) and carbon nanotube (CNT) using molecular dynamics (MD) simulation method.

The NC intermolecular motions were estimated from MD data thereby building the distance distributions, the angular and dihedral (torsional) bond energy graphs versus simulation time at different temperatures from T=100 K up to 300 K. The MD simulation results have shown that depending on the relative NC-NP position a different scenario of bonding between the NC-NP, within CNT matrix, is possible. We have observed the possibilities of formation of weak, strong and intermediate bonds between the NP-NC, which are overestimated by a presence of CNT matrix as confined environment. The NC chain can form with a particular gold atom a close contact, while with another under the same positional and temperature conditions the weak resultant bonding formation might be possible. We estimated the fluctuations in the NP-NC bonding processes for a single gold atomic case (models 1-3, NC-1NP-CNT), for the two (model 4-6, NC-2NP-CNT) and three (model 7, NC-3NP-CNT) gold particle ones. Thus, a concurrent effect between the NC intramolecular vibrations and a weak VdW interaction between the NC and gold NP were studied in detail.