Light-Amplified CISS-Based Hybrid QD-DNA Impedimetric Device for DNA Hybridization Detection

Area of Science:

• Spintronics
• Nanotechnology
• Biosensing

Background:

• The chiral-induced spin selectivity (CISS) effect offers a unique mechanism for spin-based detection.
• Detecting DNA hybridization with high sensitivity is crucial for diagnostics.
• Integrating spintronic effects with electrochemical methods presents new sensing opportunities.

Purpose of the Study:

• To develop a novel electrochemical impedimetric device for DNA hybridization detection.
• To investigate the amplification of the chiral-induced spin selectivity (CISS) effect using light.
• To establish a highly sensitive DNA sensor based on spin-polarized current.

Main Methods:

• Fabrication of a hybrid quantum dot (QD)-DNA monolayer on a ferromagnetic (FM) Ni/Au thin film.
• Utilizing electrochemical impedance spectroscopy to measure charge-transfer resistance.
• Applying spin currents with opposite polarities and illuminating the device with 532 nm light.

Main Results:

• A large differential change in charge-transfer resistance (ΔRct) of ~100 ohms was observed for both spin polarities.
• Illumination with light amplified the ΔRct by threefold to ~270 ohms due to an enhanced CISS effect.
• Spin polarization yield increased from 6% in the dark to 13% under illumination.
• A spin-based DNA hybridization sensor with a limit of detection of 10 fM was achieved.

Conclusions:

• Light significantly amplifies the CISS effect in a hybrid QD-DNA system.
• This amplified effect enables highly sensitive impedimetric DNA hybridization detection.
• The developed sensor shows potential for next-generation point-of-care diagnostic devices.