Magneto-optical and thermal characteristics of magnetite nanoparticle-embedded DNA and CTMA-DNA thin films

DNA-Nanocrystal Assemblies for Environmentally Responsive and Highly Efficient Energy Harvesting and Storage

Natural polymer-based and self-powered bioelectronic devices are attracting attention owing to an increased interest in human health monitoring and human-machine interfaces. However, obtaining both high efficiency and multifunctionality from a single natural polymer-based bioelectronics platform is still challenging. Here, molybdenum disulfide (MoS2 ) nanoparticle- and carbon quantum dot (CQDs)-incorporated deoxyribonucleic acid (DNA) nanocomposites are reported for energy harvesting, motion sensing, and charge storing. With nanomaterial-based electrodes, the MoS2 -CQD-DNA nanocomposite exhibits a high triboelectric open-circuit voltage of 1.6 kV (average) and an output power density of 275 mW cm-2 , which is sufficient for turning on hundred light-emitting diodes and for a highly sensitive motion sensing. Notably, the triboelectric performance can be tuned by external stimuli (light and thermal energy). Thermal and photon energy absorptions by the nanocomposite generate additional charges, resulting in an enhanced triboelectric performance. The MoS2 -CQD-DNA nanocomposite can also be applied as a capacitor material. Based on the obtained electronic properties, such as capacitances, dielectric constants, work functions, and bandgaps, it is possible that the charges generated by the MoS2 -CQD-DNA triboelectric nanogenerator can be stored in the MoS2 -CQD-DNA capacitor. A new way is presented here to expand the application area of self-powered devices in wearable and implantable electronics.

DNA foams constructed by freeze drying and their optoelectronic characteristics

The distinctive properties of DNA make it a promising biomaterial to use in nanoscience and nanotechnology. In the present study, DNA foam was fabricated into multi-dimensional shapes using a freeze drying process with liquid nitrogen and 3D printed molds. The physicochemical and optoelectronic properties of the fabricated DNA foams were investigated using Fourier transform infrared (FTIR) spectrum, X-ray photoelectron spectrum (XPS), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) absorption spectrum, and current-voltage (I-V) characteristics to understand the changes formed in the DNA structure and their effect on properties during the fabrication of DNA foam. The FTIR and XPS analyses confirmed that nitrogen was diffusing into the DNA structure during the DNA foam fabrication. The diffused nitrogen caused a decrease in bond lengths, strong chemical bonds, compaction of DNA structure, existence of additional carbon-nitrogen bonds, and variation in the electron density of the base elements in DNA. These changes in the DNA structure of the DNA foam were reflected in their chemical, optical, and electrical properties. Furthermore, the proper utilization of DNA foams as a template for functional materials by embedding carbon nanotubes (CNTs) and thermocolor was demonstrated.

Band gap, dielectric constant, and susceptibility of DNA layers as controlled by vanadium ion concentration

Deoxyribonucleic acid (DNA) doped with transition metal ions shows great versatility for molecular-based biosensors and bioelectronics. Methodologies for developing DNA lattices (formed by synthetic double-crossover tiles) and DNA layers (used by natural salmon) doped with vanadium ions (V3+), as well as an understanding of the physical characteristics of V3+-doped DNA nanostructures, are essential in practical applications in interdisciplinary research fields. Here, DNA lattices and layers doped with V3+ are constructed through substrate-assisted growth and drop-casting methods. In addition, enhanced physical characteristics such as the band gap energy, work function, dielectric constant, and susceptibility of V3+-doped DNA nanostructures with varying V3+ concentration ([V 3+ ]) are investigated. The critical concentration ([V 3+ ]C ) at a given amount of DNA was predicted based on an analysis of the phase transition of DNA lattices from crystalline to amorphous with specific [V 3+ ]. Generally, the [V 3+ ]C provided crucial information on the structural stability and extremum physical characteristics of V3+-doped DNA nanostructures due to the optimum incorporation of V3+ into DNA. We obtained the optical absorption spectra for energy band gap estimation; Raman spectra for identifying the preferential coordination sites of V3+ in DNA; x-ray photoelectron spectra to examine the chemical state, chemical composition, and functional groups; and ultraviolet photoelectron spectra to estimate the work function. In addition, we addressed the electrical properties (i.e. current, capacitance, dielectric constant, and storage energy) and magnetic properties (magnetic field-dependent and temperature-dependent magnetizations and susceptibility) of DNA layers in the presence of V3+. The development of biocompatible materials with specific optical, electrical, and magnetic properties is required for future applications because they must have designated functionality, high efficiency, and affordability.