Transport Properties of a Molybdenum Disulfide and Carbon Dot Nanohybrid Transistor and Its Applications as a Hg²⁺ Aptasensor

Abstract

Unique electronic, optical, and mechanical properties of molybdenum disulfide (MoS2) hold great potential and can be harnessed as a key component in novel applications in electronics, optoelectronics, high-performance sensing material, and photodetection. Carbon quantum dots (CDs) have attracted a great deal of attention because of their biocompatibility, high quantum yield, and tunable light-emission band for biological and photodetector applications. In this research, we used these two materials for the Hg2+ sensor. First, the sensing layer of MoS2 and carbon dots were prepared through sequential solvent exchange and hydrothermal methods, respectively; then, they were characterized. Since mercury, as one of the most harmful pollutants in water, has a significant negative impact on human health and its detection is of great significance, the proposed MoS2 field-effect transistor sensor functionalized with the DNA–CD hybrid was fabricated for the ultrasensitive detection of the Hg2+ ion in an aqueous environment. Specific T-rich DNA was used in the hybrid structure as the capture probe for label-free detection. The DNA-CD/MoS2 hybrid aptasensor was capable of the detection of Hg2+ in a concentration range from 1 aM to 10 pM with a detection limit of 0.65 aM. The effect of the DNA presence in Hg2+ detection was investigated, and the specificity of the aptasensor response to the Hg2+ ion was also evaluated in the presence of other common cations in the aqueous medium. Finally, the aptasensor was used for Hg2+ detection from samples of tap and mineral water with satisfactory results.

Two-Dimensional Field-Effect Transistor Sensors: The Road toward Commercialization

“…Ion sensors have attracted extensive attention for food safety, environmental analysis, human health, and industrial production control . Notable advances have been made in 2D ion sensitive field effect transistors (ISFETs) during the past decade. ,− This section discusses their differences and generalities in operation principle and then presents a survey of the latest advances in 2D ISFETs.…”

Recent Advances in Aptamer Sensors

“…The electrochemical aptasensors were modified with various nanomaterials such as carbon-based nanomaterials, metal–organic frameworks (MOFs), AuNPs, and polymers for signal amplification [ 164 , 165 , 166 , 167 ]. The aptamers were immobilized on the electrode surface via π–π interactions, hydrogel grafts, biotin–avidin interactions, thiol–gold self-assembly, and carboxyl–amine covalent reactions [ 168 , 169 , 170 , 171 , 172 , 173 ].…”

“…Because of the formation of the Au-S bond between the AuNPs and the modified thiol aptamer, competition on the surface of the GCE occurs between the amoxicillin and its aptamer, achieving a detection sensitivity of 0.5-3 nM and a LOD of 0.2 nM [191]. for signal amplification [164][165][166][167]. The aptamers were immobilized on the electrode surface via π-π interactions, hydrogel grafts, biotin-avidin interactions, thiol-gold self-assembly, and carboxyl-amine covalent reactions [168][169][170][171][172][173].…”

Vertically aligned carbon nanotubes, MoS2–rGo based optoelectronic hybrids for NO2 gas sensing

“…Therefore, efficient detection of the NO 2 gas and development of the high performance semiconductor based sensors as promising candidates are crucial for protection of human health 3 . Atomic thickness and high surface-to-volume ratio of two-dimensional (2d) materials make them good candidates for gas sensing applications because their electronic transport properties are highly dependent on the surrounding atmosphere [4][5][6] . Despite the introduction of many new 2d materials, graphene as the first material discovered, is still used in many ongoing sensing studies thanks to its high electrical conductivity, large detection surface area, and high sensitivity potentials 7,8 .…”