Formation and Electrical Evaluation of a Single Metallized DNA Nanowire in a Nanochannel

Fabrication of a Deoxyribonuclease Sensor Based on the Electrical Characteristics of DNA Molecules

In this study, we developed a sensing device that can detect deoxyribonuclease (DNase) based on the electrical properties of deoxyribonucleic acid (DNA). We estimated the equivalent circuit between the electrodes with immobilized DNA and investigated whether the characteristics of the electrodes change before and after the DNase reaction. This method detects DNase by simply evaluating the electrical properties of DNA without using a fluorescent reagent. Therefore, inexpensive and highly accurate measurements can be performed with simple operations. However, detection sensitivity must be increased for practical feasibility. Hence, we investigated whether DNA immobilization is restricted by changing the shape of the electrode to a triangle with sharp edges, which may improve the sensitivity of DNase. Additionally, we attempted to detect DNase from an extremely small amount of sample solution using a microchannel. The device was able to quantitatively analyze DNase I activity with a detection limit of 5.5 × 10^-5 unit/μL. The results demonstrate the effectiveness of the proposed sensing device for various medical applications.

Naphthalene diimides: perspectives and promise

In this review, we describe the developments in the field of naphthalene diimides (NDIs) from 2016 to the presentday. NDIs are shown to be an increasingly interesting class of molecules due to their electronic properties, large electron deficient aromatic cores and tendency to self-assemble into functional structures. Almost all NDIs possess high electron affinity, good charge carrier mobility, and excellent thermal and oxidative stability, making them promising candidates for applications in organic electronics, photovoltaic devices, and flexible displays. NDIs have also been extensively studied due to their potential real-world uses across a wide variety of applications including supramolecular chemistry, sensing, host-guest complexes for molecular switching devices, such as catenanes and rotaxanes, ion-channels, catalysis, and medicine and as non-fullerene accepters in solar cells. In recent years, NDI research with respect to supramolecular assemblies and mechanoluminescent properties has also gained considerable traction. Thus, this review will assist a wide range of readers and researchers including chemists, physicists, biologists, medicinal chemists and materials scientists in understanding the scope for development and applicability of NDI dyes in their respective fields through a discussion of the main properties of NDI derivatives and of the status of emerging applications.

Highly Conductive Thin Uniform Gold-Coated DNA Nanowires

Over the past decades, DNA, the carrier of genetic information, has been used by researchers as a structural template material. Watson-Crick base pairing enables the formation of complex 2D and 3D structures from DNA through self-assembly. Various methods have been developed to functionalize these structures for numerous utilities. Metallization of DNA has attracted much attention as a means of forming conductive nanostructures. Nevertheless, most of the metallized DNA wires reported so far suffer from irregularity and lack of end-to-end electrical connectivity. An effective technique for formation of thin gold-coated DNA wires that overcomes these drawbacks is developed and presented here. A conductive atomic force microscopy setup, which is suitable for measuring tens to thousands of nanometer long molecules and wires, is used to characterize these DNA-based nanowires. The wires reported here are the narrowest gold-coated DNA wires that display long-range conductivity. The measurements presented show that the conductivity is limited by defects, and that thicker gold coating reduces the number of defects and increases the conductive length. This preparation method enables the formation of molecular wires with dimensions and uniformity that are much more suitable for DNA-based molecular electronics.