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

Abstract

The chiral-induced spin selectivity (CISS) effect can distinguish between the spin of electrons as they pass through chiral molecules by backscattering one of the spin components. Herein, we explore the role of the CISS effect in time-correlated single-photon counting measurements to detect DNA hybridization. We observe that the average lifetime of optical excited states of quantum dots attached to doublestranded DNA (dsDNA) varies with directions of the applied magnetic field. Specifically, the difference in the nonradiative average decay lifetime for the two orientations of the applied magnetic field is 2.21 ns in the case of hybridized strands, which is 130 times higher than that observed with quantum dots attached to single-strand DNA. Additionally, we investigate the application of Fourier transform infrared (FTIR) spectroscopy for detecting double-stranded DNA in the presence of a magnetic field, establishing a theoretical framework to substantiate the experimental evidence of magnetic field-dependent FTIR spectroscopy for dsDNA.

Enhanced spin-polarization and detection limit in a spin-based optoelectrochemical DNA hybridization sensor induced by circularly polarized light

“…Peak number 1 observed at around 1070 cm −1 for the CFA/ss-DNA/QD and CFA/ds-DNA/QD devices represents the CO stretching. 10,25 Peaks observed at around 1114 cm −1 and 1270 cm −1 (marked as 2) both represent the asymmetric and symmetric groups belonging to the phosphodiester backbone (PO 4 − group). 10,25 The C4C5 vibrations at 1470 cm −1 are represented by peak 3.…”

“…10,25 Peaks observed at around 1114 cm −1 and 1270 cm −1 (marked as 2) both represent the asymmetric and symmetric groups belonging to the phosphodiester backbone (PO 4 − group). 10,25 The C4C5 vibrations at 1470 cm −1 are represented by peak 3. Peak 4 at around 1580 cm −1 in Fig.…”

“…6(a-ii)). 10 As a result, to balance the charge and spin density of states generated in the system, electrons migrate from the CFA thin film towards the counter electrode via the ds-DNA bridge (as depicted in Fig. 6(a-iii)).…”

“…10 μM primer or the single-stranded DNA (ss-DNA), modified with amide and thiol groups, was immobilized onto the CFA thin film using the drop-casting method. 10 Subsequently, it was subjected to a wet environment for 24 hours to facilitate the immobilization of self-assembled monolayers (SAMs) of the ssDNA. To affix core–shell CdSe/ZnS quantum dots (QDs) onto the SAMs of the ss-DNA, a toluene solution of CdSe/ZnS core–shell quantum dots (0.5 μM) was formed.…”

“…6 However, the limitations of conventional EIS can be effectively addressed or overcome with the emergence of the chiral-induced spin selectivity (CISS) effect, facilitating the advancement of spin-based DNA biosensor technology. 7–10…”