Sequence-controlled chiral induced spin selectivity effect in ds-DNA

Abstract

In this research, we explore sequence-dependent chiral-induced spin selectivity (CISS) in double-stranded (ds)-DNA using time-correlated single-photon counting and electrochemical impedance spectroscopy supplemented by tight-binding calculations of the phenomenon for the first time. The average lifetime of the photo-excited electrons in a Quantum Dot-DNA system is influenced by the CISS effect generated by the DNA molecule, and the difference in average time decay of electrons was found to be 345 ps for opposite polarity (“UP” and “DOWN”) of spins due to the CISS effect. Moreover, the yield of spin-polarized electrons due to the CISS effect was reduced by more than 35% from perfect DNA to DNA with point mutations. Remarkably, by employing a tight binding method combined with Green’s function formalism for transport, simulations of the process support the observed experimental trends. Our results provide a basic understanding of the sequence-specific spin-dependent electron transfer through ds-DNA. These results would help to build spin-based next-generation DNA sensors.

Chiral Induced Spin Selectivity

“…The spin-specific change in charge transport through chiral molecules in electrochemical tunnel junctions, be that through monitoring changes in current or charge transfer rate, likely arise from the same phenomenon: spin-dependent changes in resistance for charge transport. This supposition is supported by recent impedance measurements made on DNA coated ferromagnetic electrodes, in which an equivalent circuit model analysis is used to extract the charge transfer resistance as a function of applied magnetic field. − For the DNA assemblies, deviations in charge transfer resistance with magnetization orientation are observed, owing to the CISS effect; however, in achiral systems the charge transfer resistance is unaffected by the magnetic field orientation.…”

“…DNA (see refs , , , , , − , , − ) and α-helical oligopeptides (see refs , , − , , , , , , − , , , , , , , , , − ) have been widely used to explore the CISS effect and its connection with molecular properties. Having been investigated by spin-dependent photoemission, transport, electrochemical, and spin-dependent polarization experiments, they comprise testbed systems for comparisons between methods.…”

Chiral-Induced Spin Selectivity Modulated Time-Correlated Single-Photon Counting for DNA Hybridization Detection

“…15 In our recently published work, we investigated sequence-specific spin selectivity through several dsDNA using time-correlated single-photon counting (TCSPC) measure-ments. 16 It was observed that there exists an asymmetry in the average decay lifetime of excitons for two directions of the magnetic field due to the CISS effect which (differential average lifetime) reduced to approximately 83% with a point mutation in DNA. Note that besides DNA, achiral and chiral quantum dot assemblies show different average decay lifetimes when excited with clockwise (CW) and counterclockwise (CCW) circularly polarized light for either L-or D-cysteine-coupled quantum dots.…”

“…The PL decay curves of QD-DNA were fitted by a three-exponential function. The equation is given by , I ( t ) = prefix∑ i = 1 3 A i normale − t / τ i where t is time and A i is the weighting parameter associated with each decay time. An average amplitude-weighted lifetime is defined as ⟨ τ ⟩ = prefix∑ i = 1 3 A i τ i 2 A i τ i The nonradiative average decay lifetime of optically excited states for the QD-ssDNA system was calculated using eq and was found to be ∼8.98 ± 0.4 and ∼8.82 ± 0.4 ns for the magnetic field in the “UP” and “DOWN” directions, respectively.…”

“…The nonradiative average decay lifetime of the QD-dsDNA system was calculated to be ∼12.97 ± 0.7 and ∼15.18 ± 0.7 ns for UP and DOWN directions of the magnetic field, respectively. The largest observed decay lifetime difference to date is ∼2.21 ns, achieved in the QD-dsDNA system with different magnetic field orientations. ,,, We calculated the yield of spin polarization using the spin-based nonradiative average decay time of optically excited states of the QD-DNA system. In particular, the yield of spin polarization | P s | was determined by the following equation: | P s | = ⟨ τ ↑ ⟩ + ⟨ τ ↓ ⟩ ⟨ τ ↑ ⟩ − ⟨ τ ↓ ⟩ × 100 where ⟨τ ↑ ⟩ is the nonradiative average decay lifetime when the magnetic field is in an upward direction and ⟨τ ↓ ⟩ is the nonradiative average decay lifetime when the magnetic field is in the downward direction.…”