Gold Nanotriangle-Assembled Nanoporous Structures for Electric Field-Assisted Surface-Enhanced Raman Scattering Detection of Adenosine Triphosphate.

A reliable, rapid, cost-effective, and simple method for the detection of biomolecules would greatly promote the research of analytical detection of single molecules. A nanopore-based analytical technique is promising for detecting biomolecules. Conventional electrochemical nanopores cannot distinguish biomolecules precisely because of their fast translocation speed and limited electrochemical information. Therefore, it is highly desirable to develop electrochemical surface-enhanced Raman scattering (SERS) nanopores to obtain multidimensional information. Herein, we designed and fabricated gold nanotriangle (AuNT)-assembled porous structures at the tip of a glass capillary using dithiol adenosine triphosphate (ATP) aptamers as cross-linking molecules. The AuNTs exhibited an edge length of 57.3 ± 6.2 nm and thickness of about 15 nm. The gold nanoporous structure (GPS) showed a strong ion rectification even at a high concentration of electrolyte (2 M) and a high SERS activity. Based on these designed structures, SERS and electrochemistry techniques were combined to control the rapid movement of ATP to the vicinity of the GPS by an applied potential of +1 V, where ATP was concentrated by ATP aptamers and the molecular signals were amplified by SERS. As a result, the GPS successfully detected ATP at a concentration as low as 10-7 M.

A Novel Indole Derivative with Superior Photophysical Performance for Fluorescent Probe, pH-Sensing, and Logic Gates.

An indole-related molecules have been considered as the potential fluorescent probes for biological and electrochemical sensing. However, most of the indole probes have been usually used in a single detection mode. Indolium probes that enable accurate detection in complex environments are rarely reported. Here, four novel indole derivatives including the phenyl group substituted with different functional moieties were designed on the basis of the donor-π-acceptor (D-π-A) concept. These derivatives exhibit positive solvatochromism owing to their varied molecular conformations upon contacting to various solvents and the different HOMO-LUMO gaps caused by the difference in electronic push-pull capability of the substituents. Their solid-state fluorescence emissions and multiple chromisms are observed due to the inherent twisted geometries and aggregation modes. In addition, these derivatives show dramatic color and fluorescence responses due to the protonation of the nitrogen and oxygen containing groups, and thus novel colorimetric pH sensors, fluorescent papers and logic gates have been designed.

A narrative review of new research progress regarding the use of airway stents in benign airway stenosis.

INTRODUCTION: Benign airway stenosis is a severe disease that can result in death with improper treatment. Clinicians must know about airway stents to choose the best one in their daily practice. AREAS COVERED: PubMed, Embase, and other electronic databases and websites were searched to identify relevant randomized controlled trials and meta-analyses. This review summarizes different types of airway stents and analyzes their advantages and disadvantages. EXPERT OPINION: Increasing attention has been given to the indications and prognosis of benign airway stenosis treated with different airway stents. With more investigations and data, better alternatives to silicone stents could be developed in the future.

Soft interface design for electrokinetic energy conversion.

The exploitation and utilization of renewable clean energy is of great significance to the sustainable development of society. Electrokinetic energy conversion (EKEC) based on micro/nanochannels is expected to provide immense potential for ocean energy harvesting, self-powered micro/nanodevices, and small portable power supplies through converting environmental energy into electrical energy. Herein, aiming to get a deeper understanding of EKEC based on micro/nanochannels, several classic theoretical models and corresponding calculation equations are introduced briefly. For high efficiency energy conversion, it is essential to clearly discuss the interface properties between the inner surface of the channel and the bulk electrolyte solution. Therefore, we put forward soft interface designs of solid-liquid and liquid-liquid interfaces, and summarize their recent progress. In addition, the different applications of EKEC, harvesting from environmental energy, are further discussed. We hope that this review will attract more scientists' attention to transform the experimental results of EKEC systems in the lab into available products on shelves.

A glass nanopore ionic sensor for surface charge analysis.

Surface charge-based nanopore characterization techniques unfold unique properties and provide a powerful platform for a variety of sensing applications. In this paper, we have proposed a nanoconfined inner wall surface charge characterization method with glass nanopores. The glass nanopores were functionalized with DNA aptamers that were designed for mercury (Hg2+) ion immobilization by forming thymine-Hg2+-thymine structures. The surface charge of the nanopores was modulated by surface chemistry and Hg2+ ion concentrations and analysed by combining zeta potential measurements on glass slides and the ionic current rectification ratio of the nanopores. Also, 1 pM Hg2+ ions could be detected by the nanopores.

Two dimensional nanomaterial-based separation membranes.

Two dimensional nanomaterials including graphene, hexagonal boron-nitride, molybdenum disulfide, etc., provide immense potentials for separation applications. However, the tradeoff between selectivity and permeability in choosing 2D nanomaterial-based membrane is inevitable, limiting the progress on separation efficiency for mass industrial applications. To target these issues, versatile strategies such as the rational design of predefined interlayer channels, membrane nanopores, and reasonable functionalization, as well as new mechanisms have been emerged. In this review, we introduce the recent progress on separation mechanisms of 2D nanomaterial-based membranes with different structures (including the interlayer channels type and the membrane nanopores type) and their inner surface functionalization. Moreover, the interface designs are discussed, in terms of employing dynamic liquid-liquid/liquid-gas interfaces, to advance the selectivity and permeability of the membranes. We further discuss the variety of separation applications based on 2D nanomaterial-based membranes. The authors hope this review will inspire the active interest of many scientists in the area of the development and application of membrane science.

Dynamic Curvature Nanochannel-Based Membrane with Anomalous Ionic Transport Behaviors and Reversible Rectification Switch.

Biological nanochannels control the movements of different ions through cell membranes depending on not only those channels' static inherent configurations, structures, inner surface's physicochemical properties but also their dynamic shape changes, which are required in various essential functions of life processes. Inspired by ion channels, many artificial nanochannel-based membranes for nanofluidics and biosensing applications have been developed to regulate ionic transport behaviors by using the functional molecular modifications at the inner surface of nanochannel to achieve a stimuli-responsive layer. Here, the concept of a dynamic nanochannel system is further developed, which is a new way to regulate ion transport in nanochannels by using the dynamic change in the curvature of channels to adjust ionic rectification in real time. The dynamic curvature nanochannel-based membrane displays the advanced features of the anomalous effect of voltage, concentration, and ionic size for applying simultaneous control over the curvature-tunable asymmetric and reversible ionic rectification switching properties. This dynamic approach can be used to build smart nanochannel-based systems, which have strong implications for flexible nanofluidics, ionic rectifiers, and power generators.

Interface Design of Nanochannels for Energy Utilization.

Nanochannels offer a variety of significant advantages for innovative applications, such as biosensing, filtering, and energy utilization. In this Perspective, we highlight the interface design and applications of nanochannels for energy utilization and discuss further challenges in the development of nanochannels for energy conversion, energy conservation, and energy recovery.

Tunable Microscale Porous Systems with Dynamic Liquid Interfaces.

Solid microscale porous material systems have attracted more attention in recent years due to their various potential applications, such as energy source transportations, biomedical devices, wastewater treatments, phase separations, etc. However, such systems are still plagued with many issues including fouling, mechanical fragility, inability to self-heal, and low recyclability that restrict them for further industrial applications. Dynamic liquid-based microscale porous material systems, especially porous surfaces and membranes, provide a new opportunity for resolving these issues and possess many benefits, such as antifouling, slippery, transparent, recovery, self-healing, and recycling properties. This Concept is mainly concerned with how to obtain tunable microscale porous systems with dynamic liquid interfaces, and their applications from the surfaces to membranes. The authors hope this concept will attract interest of scientists in areas related to the rapid development and application of various liquid-based porous systems.

Tunicate-Inspired Gallol Polymers for Underwater Adhesive: A Comparative Study of Catechol and Gallol.

Man-made glues often fail to stick in wet environments because of hydration-induced softening and dissolution. The wound healing process of a tunicate inspired the synthesis of gallol-functionalized copolymers as underwater adhesive. Copolymers bearing three types of phenolic groups, namely, phenol, catechol, and gallol, were synthesized via the methoxymethyl protection/deprotection route. Surprisingly, the newly synthesized copolymers bearing gallol groups exhibited stronger adhesive performances (typically 7× stronger in water) than the widely used catechol-functionalized copolymers under all tested conditions (in air, water, seawater, or phosphate-buffered saline solution). The higher binding strength was ascribed to the tridentate-related interfacial interaction and chemical cross-linking. Moreover, gallol-functionalized copolymers adhered to all tested surfaces including plastic, glass, metal, and biological material. In seawater, the performance of gallol-functionalized copolymer even exceeds the commercially available isocyanate-based glue. The insights from this study are expected to help in the design of biomimetic materials containing gallol groups that may be utilized as potential bioadhesives and for other applications. The results from such a kind of comparable study among phenol, catechol, and gallol suggests that tridentate structure should be better than bidentate structure for bonding to the surface.

One-pot stirring-free synthesis of silver nanowires with tunable lengths and diameters via a Fe3+ & Cl- co-mediated polyol method and their application as transparent conductive films.

The properties of nanomaterials are highly dependent on their size, shape and composition. Compared with zero-dimensional nanoparticles, the increased dimension of a one-dimensional silver nanowire (AgNW/Ag NW) leads to extra challenges on synthesizing it with controllable sizes. Here, a convenient way for the synthesis of AgNWs with tunable sizes has been developed simply by adjusting the amount of salt additives, i.e., ferric chloride (FeCl3), or Fe(NO3)3 & KCl. The average diameter and length of nanowires are readily tailored within 45-220 nm and 10-230 µm, respectively. The distinctive roles of Fe3+ and Cl- played during the growth stages of Ag NWs were revealed by comparative experiments and a heterogeneous nucleation model with the assistance of oxidative etching was proposed to elucidate the growth mechanism. Afterwards, transformations in XRD patterns from nanometer-size effects and quantitative relation for size-dependent peak wavelength of surface plasmon resonances (SPRs) in UV-vis spectroscopy of these nanowires were studied. In addition, as transparent conductive materials (TCMs), these metal nanowires were utilized to fabricate transparent conductive films (TCFs), and the effects of their diameters and lengths were elucidated. Very/ultra-long nanowires with a high aspect ratio up to 1600 achieved impressive properties of R = 12.4 ohm sq-1 at T% = 90.1% without any post treatment. This facile method for the size-tunable growth of uniform AgNWs with high yield is attractive and ready to be home-made, which is believed to promote research in their potential applications, especially in optoelectronic devices and flexible electronics.