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

Abstract

We design and build a novel light-amplified electrochemical impedimetric device based on the CISS effect to detect DNA hybridization using a hybrid quantum dot (QD)-DNA monolayer on a ferromagnetic (FM) Ni/Au thin film for the first time. Using spin as a detection tool, the current research considers the chiral-induced spin selectivity (CISS) phenomenon. After injecting a spin current into the QD-DNA system with opposite polarities (up and down), the impedimetric device revealed a large differential change in the charge-transfer resistance (ΔR ct ) of ∼100 ohms for both spins. Nearly, a threefold increase in the ΔR ct value to ∼270 ohms is observed when light with a wavelength of 532 nm is illuminated on the sample, owing to the amplified CISS effect. The yield of spin polarization as extracted from the Nyquist plot increases by a factor of more than 2 when exposed to light, going from 6% in the dark to 13% in the light. The impact of light on the CISS effect was further corroborated by the observation of the spin-dependent asymmetric quenching of photoluminescence (PL) in the same hybrid system. These observations are absent in the case of a noncomplementary QD-DNA system due to the absence of a helical structure in DNA. Based on this, we develop a spin-based DNA hybridization sensor and achieve a limit of detection of 10 fM. These findings open a practical path for the development of spin-based next-generation impedimetric DNA sensors and point-ofcare devices.

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.…”

“…For instance, incorporation of spin polarization in bioelectronic mimetics may increase the specificity and sensitivity of biorecognition elements in sensors. Indeed, CISS-based sensing platforms are beginning to be developed. ,,,, Moreover, the living cell can be viewed as a miniaturized information processor or computer; cells input information through intermolecular interactions, use proteins for intracellular communication, and store information as DNA. The cell performs these tasks more effectively than conventional computers .…”

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

“…This has been demonstrated by several different methods, including electrochemical, Mott polarimeter, conductive atomic force microscopy, etc. − The CISS effect describes the spin-filtering ability of chiral molecules made up of C, N, or O, despite their very low spin–orbit coupling (∼3 meV) constants compared to 3d-group ferromagnetic materials such as Fe, Co, or Ni (∼800 meV). The phenomenon of spin-filtering has been reported for a range of molecular structures, including amino acids, peptides, polymers, proteins, and dsDNA. ,− Among these, the spin filtering efficacy of dsDNA has been shown to reach noteworthy levels, as high as 60%, despite the fact that the inherent spin–orbit coupling constant of dsDNA is quite low, theoretically estimated to be around 10 meV. , The CISS phenomenon exhibits a wide range of applications, encompassing several fields such as molecular spintronics, water splitting, and DNA biosensing. − In DNA biosensors, the detection of DNA hybridization plays a pivotal role that finds applications in genomics, drug discovery, diagnosis of hereditary diseases, detection of infectious agents, and the discovery of gene-targeted drugs . In our recently published work, we investigated sequence-specific spin selectivity through several dsDNA using time-correlated single-photon counting (TCSPC) measurements .…”

Photo-enhanced electrochemical and colorimetric dual-modal aptasensing for aflatoxin B1 detection based on graphene–gold Schottky contact

“…5,6 Prashant et al designed a light-amplified EC impedimetric device based on a hybrid quantum dot (QD)-DNA structure yielding 7% more spinpolarized electrons under light, which offered an enlarged variation in the charge-transfer resistance (DR ct ). 7 Wang et al found that the current response of ascorbic acid (AA) increases by 1.3fold due to hot electron effective transport of plasmonic gold nanostars (AuNSs). 8 The construction of photoactive nanostructures with high carrier concentration and specific electron transport is crucial for amplifying EC signals.…”