Bacillus subtilis DNA fluorescent sensors based on hybrid MoS2 nanosheets

Although sensor technology has advanced with better materials, biomarkers, and fabrication and detection methods, creating a rapid, accurate, and affordable bacterial detection platform is still a major challenge. In this study, we present a combination of hybrid-MoS2 nanosheets and an amine-customized probe to develop a fast, sensitive biosensor for Bacillus subtilis DNA detection. Based on fluorescence measurements, the biosensor exhibits a detection range of 23.6-130 aM, achieves a detection limit of 18.7 aM, and was stable over four weeks. In addition, the high selectivity over Escherichia coli and Vibrio proteolyticus DNAs of the proposed Bacillus subtilis sensors is demonstrated by the fluorescence quenching effect at 558 nm. This research not only presents a powerful tool for B. subtilis DNA detection but also significantly contributes to the advancement of hybrid 2D nanomaterial-based biosensors, offering substantial promise for diverse applications in biomedical research and environmental monitoring.

Recent progress in MoS2 nanostructures for biomedical applications: Experimental and computational approach

In the category of 2D materials, MoS2 a transition metal dichalcogenide, is a novel and intriguing class of materials with interesting physicochemical properties, explored in applications ranging from cutting-edge optoelectronic to the frontiers of biomedical and biotechnology. MoS2 nanostructures an alternative to heavy toxic metals exhibit biocompatibility, low toxicity and high stability, and high binding affinity to biomolecules. MoS2 nanostructures provide a lot of opportunities for the advancement of novel biosensing, nanodrug delivery system, electrochemical detection, bioimaging, and photothermal therapy. Much efforts have been made in recent years to improve their physiochemical properties by developing a better synthesis approach, surface functionalization, and biocompatibility for their safe use in the advancement of biomedical applications. The understanding of parameters involved during the development of nanostructures for their safe utilization in biomedical applications has been discussed. Computational studies are included in this article to understand better the properties of MoS2 and the mechanism involved in their interaction with biomolecules. As a result, we anticipate that this combined experimental and computational studies of MoS2 will inspire the development of nanostructures with smart drug delivery systems, and add value to the understanding of two-dimensional smart nano-carriers.

Tunable Electronic Transport of New-Type 2D Iodine Materials Affected by the Doping of Metal Elements

2D iodine structures under high pressures are more attractive and valuable due to their special structures and excellent properties. Here, electronic transport properties of such 2D iodine structures are theoretically studied by considering the influence of the metal-element doping. In equilibrium, metal elements in Group 1 can enhance the conductance dramatically and show a better enhancement effect. Around the Fermi level, the transmission probability exceeds 1 and can be improved by the metal-element doping for all devices. In particular, the device density of states explains well the distinctions between transmission coefficients originating from different doping methods. Contrary to the "big" site doping, the "small" site doping changes transmission eigenstates greatly, with pronounced electronic states around doped atoms. In non-equilibrium, the conductance of all devices is almost weaker than the equilibrium conductance, decreasing at low voltages and fluctuating at high voltages with various amplitudes. Under biases, K-big doping shows the optimal enhancement effect, and Mg-small doping exhibits the most effective attenuation effect on conductance. Contrastingly, the currents of all devices increase with bias linearly. The metal-element doping can boost current at low biases and weaken current at high voltages. These findings contribute much to understanding the effects of defects on electronic properties and provide solid support for the application of new-type 2D iodine materials in controllable electronics and sensors.

Chiral photocurrent in a Quasi-1D TiS3(001) phototransistor

The presence of in-plane chiral effects, hence spin-orbit coupling, is evident in the changes in the photocurrent produced in a TiS₃(001) field-effect phototransistor with left versus right circularly polarized light. The direction of the photocurrent is protected by the presence of strong spin-orbit coupling and the anisotropy of the band structure as indicated in NanoARPES measurements. Dark electronic transport measurements indicate that TiS₃is n-type and has an electron mobility in the range of 1-6 cm²V^-1s^-1.I-Vmeasurements under laser illumination indicate the photocurrent exhibits a bias directionality dependence, reminiscent of bipolar spin diode behavior. Because the TiS₃contains no heavy elements, the presence of spin-orbit coupling must be attributed to the observed loss of inversion symmetry at the TiS₃(001) surface.

Layered GeI2: A wide-bandgap semiconductor for thermoelectric applications–A perspective

Layered GeI2 is a two-dimensional wide-bandgap van der Waals semiconductor, which is theorized to be a promising material for thermoelectric applications. While the value of the experimentally extrapolated indirect optical bandgap of GeI2 is found to be consistent with the existing theoretical calculations, its potential as a thermoelectric material still lacks experimental validation. In this Perspective, recent experimental efforts aimed towards investigating its dynamical properties and tuning its bandgap further, via intercalation, are discussed. A thorough understanding of its dynamical properties elucidates the extent of electron-phonon scattering in this system, knowledge of which is crucial in order to open pathways for future studies aiming to realize GeI2-based thermoelectric devices.

Edge, size, and shape effects on WS2, WSe2, and WTe2 nanoflake stability: design principles from an ab initio investigation

The magic nanoflakes, obtained by the evaluation of the relative stability function, are n = 9 and 14 for all chemical compositions, whereas n = 12 is a magic number for WS₂ and WSe₂.

Optical properties of the crumpled pattern of selectively layered MoS2

Crumple-structured two-dimensional MoS₂ was evaluated as an essential element for future optoelectronic and stretchable devices owing to its interesting optical properties. This Letter reports the characteristics of the crumpled structure of MoS₂ directly layered on a MoS₂ sheet by chemical vapor deposition. The crumpling structure is presented as a method for selectively layering MoS₂ with crumpled layered patterning and tunable optical properties as a crumpled structure on a single substrate. Optical analysis by the fast Fourier transform revealed the distribution characteristics of the crumple structure, and a Raman, photoluminescence, and optical absorption analysis confirmed the change in peak shift and intensity according to the degree of the crumpled structure. This material has potential future optoelectronic applications.

Effects of a magnetic field on the optoelectronic properties of mono- and bi-layer transition metal dichalcogenides

We report a theoretical study on the effects of an external magnetic field on the electronic and optical properties of mono- and bi-layer MoS₂, and bilayer MoS₂/WS₂ heterostructures. The direction of an applied magnetic field determines (i) the strength of the coupling between the atomic orbital moments of the structure and the field, and (ii) Zeeman contribution to the splitting of the VB and CB levels with the amplitude of the applied field. Whereas for a magnetic field applied perpendicular to the structure, calculated real part of optical conductivity reveals optical transitions red-shifted compared to zero magnetic field case, conductivity is unaffected by the the amplitude of an in-plane applied magnetic field. We show that through modifying atomic d-orbitals conduction and valence band states by an applied electric field, we can determine and control the impact of a magnetic field on the optical response of these materials. We employ our parametrized tight-binding model with non-orthogonal sp³d⁵ orbitals and spin-orbit coupling, which was advanced to include the effects of an external magnetic field through Peierls substitution in the wave vector and the Zeeman energy term.

In situ topotactic synthesis of a porous network Zn2Ti3O8 platelike nanoarchitecture and its long-term cycle performance for a LIB anode

Porous network Zn₂Ti₃O₈ platelike nanoarchitecture was prepared by an ion exchange reaction and further in situ topotactic transformation, and it exhibited an enhanced reversibility capacity of 408 mA h g⁻¹ after 1000 cycles at a current density of 1 Ag⁻¹.

First principles study of electronic transport properties in novel FeB2 flake-based nanodevices

First-principles calculations provide theoretical support for the promising applications of innovative two-probe devices based on FeB₂ flakes and reveal the superiority of devices with FeB₂ flakes at temperatures not above 1000 K in transport properties.