Light-Driven Modulation of Electrical Current through DNA Sequences: Engineering of a Molecular Optical Switch

Abstract

Designing a molecular switch with bistable on/off states is of particular interest in molecular electronics. Motivated by experimental studies of molecular conductors, interplays of photons and electrons and their effects on electrical properties are studied theoretically. We have tried to model a molecular optical switch based on DNA sequences of the hepatitis delta virus and Toxocara canis parasite. The electrical response of chains to the light irradiation was examined to optimize the function of an optical switch. The switch turns on when the amplitude of incident irradiation and its frequency approach to 0.3 at the unit of (ℏc)/(er 0) and 2 THz, respectively. We can modulate the switching of the system via the simultaneous variation of effective factors and obtain different islands in the parameter settings. The appearance of different islands in the parameter surface relates to the on/off states of electrical current, which can be verified and estimated through the multifractal analysis.

Base-Pairs’ Correlated Oscillation Effects on the Charge Transfer in Double-Helix B-DNA Molecules

“…Quite interestingly, the electrical response of biological dsDNA chains to light irradiation has been recently investigated in order to engineer a DNA based molecular switch. In these experiments, it was observed that the electrical current turns on when the frequency of the incident light is above the 2 THz threshold [64], a value that coincides with that listed for ν ϕρ in Table 2. On the other hand, it is worth mentioning that the ν HS frequency value listed in Table 2 is smaller than the 2.83 and 3.04 THz frequencies experimentally observed by optical Kerr-effect spectroscopy in ds-GGCGGCCCGCGCGGGCCGCC and ds-ATTATTATTATATTA oligonucleotides, respectively.…”

Synchronized Oscillations in Double-Helix B-DNA Molecules with Mirror-Symmetric Codons

“…Since ρ n,n±1 = ρ n ± p n,n±1 = 2ρ n , we see that all the bps in the codon move in phase. A similar solution describing a modulated oscillation in opposite phase is obtained by choosing ρ n = p n,n±1 as the particular solution to the inhomogeneous differential Equation (38). In this case, we get a larger high frequency value γ + = 1.774 THz.…”

“…For the sake of comparison, the transition times reported for intrastrand hole transfer in ds-GT n GGG oligonucleotides, range from τ = 0.5 ps for n = 1 to τ = 315 ps for n = 4 [37]. Remarkably, recent studies on the electrical response of biological dsDNA chains to light irradiation, performed to engineer a DNA-based molecular switch, have unveiled that electrical current turns on for incident light frequencies above the 2 THz threshold [38], a figure very close to that listed for ν ϕSH in Table 2, a frequency involving energy enough to activate all the fundamental interactions present in the system Hamiltonian in a coupled way.…”

“…The general solution to the dynamical equations for polyXX'-polyX'X polymers can be obtained from the knowledge of the general solution to the homogeneous version of Equation (38) given by π n = A 0 cos(Γ ± t + δ 0 ), plus the particular solution ansatz ρ n = −p n,n±1 , leading to the differential equationp n,n±1 + Γ 2 ∓ p n,n±1 = 0, whose solution readsπ n = B 0 cos(Γ ∓ t + δ 0 ). For the sake of simplicity, we adopt the initial conditionṡ ρ n (0) =ρ n±1 (0) = 0, and ρ n (0) = −p n,n±1 (0), so that we get:…”

A many-body approach to transport in quantum systems: From the transient regime to the stationary state

“…In addition to the massive speed-up in processing power that arises from reduced spatial dimensions, molecular junctions can produce a massive speedup in clock speed by harnessing THz intramolecular transport processes [11,12]. The advanced temporal resolution of molecular devices also has applications in frequency doublers and detectors [13,14] and switches for fast memory storage [15][16][17][18]. Experimental advances in miniaturization of integrated devices in electrical circuits, potentially utilizing the nextgeneration nanoscale components operational in the GHz-THz regime, have prompted remarkable interest in the theoretical description of these systems.…”