A proximity-induced covalent fluorescent probe for selective detection of bromodomain 4

Through proximity-induced conjugation reaction, a peptide-based fluorescent probe was designed and synthesized for selective detection of bromodomain 4.     

Atom probe analysis of III-V and Si-based semiconductor photovoltaic structures.

The applicability of atom probe to the characterization of photovoltaic devices is presented with special emphasis on high efficiency III-V and low cost ITO/a-Si:H heterojunction cells. Laser pulsed atom probe is shown to enable subnanometer chemical and structural depth profiling of interfaces in III-V heterojunction cells. Hydrogen, oxygen, and phosphorus chemical profiling in 5-nm-thick a-Si heterojunction cells is also illustrated, along with compositional analysis of the ITO/a-Si interface. Detection limits of atom probe tomography useful to semiconductor devices are also discussed. Gaining information about interfacial abruptness, roughness, and dopant profiles will allow for the determination of semiconductor conductivity, junction depletion widths, and ultimately photocurrent collection efficiencies and fill factors.     

Point-of-care testing of proteins

Point-of-care testing (POCT) is a fast developing area in clinical diagnostics that is considered to be one of the main driving forces for the future in vitro diagnostic market. POCT means decentralized testing at the site of patient care. The most important POCT devices are handheld blood glucose sensors. In some of these sensors, after the application of less than 1 μl whole blood, the results are displayed in less than 10 s. For protein determination, the most commonly used devices are based on lateral flow technology. Although these devices are convenient to use, the results are often only qualitative or semiquantitative. The review will illuminate some of the current methods employed in POCT for proteins and will discuss the outlook for techniques (e.g., electrochemical immunosensors) that could have a great impact on future POCT of proteins.     

Micro- and nanofluidics for DNA analysis

Miniaturization to the micrometer and nanometer scale opens up the possibility to probe biology on a length scale where fundamental biological processes take place, such as the epigenetic and genetic control of single cells. To study single cells the necessary devices need to be integrated on a single chip; and, to access the relevant length scales, the devices need to be designed with feature sizes of a few nanometers up to several micrometers. We will give a few examples from the literature and from our own research in the field of miniaturized chip-based devices for DNA analysis, including dielectrophoresis for purification of DNA, artificial gel structures for rapid DNA separation, and nanofluidic channels for direct visualization of single DNA molecules.     

Tip-enhanced Raman spectroscopy for nanoscale strain characterization

Tip-enhanced Raman spectroscopy (TERS), which utilizes the strong localized optical field generated at the apex of a metallic tip when illuminated, has been shown to successfully probe the vibrational spectrum of today’s and tomorrow’s state-of-the-art silicon and next-generation semiconductor devices, such as quantum dots. Collecting and analyzing the vibrational spectrum not only aids in material identification but also provides insight into strain distributions in semiconductors. Here, the potential of TERS for nanoscale characterization of strain in silicon devices is reviewed. Emphasis will be placed on the key challenges of obtaining spectroscopic images of strain in actual strained silicon devices. Figure Figure Concept of Tip Enhanced Raman Spectroscopy (TERS), which utilizes the strong localized optical field generated at the apex of a metallic tip when illuminated. TERS has been demonstrated to successfully probe the vibrational spectrum of today’s and tomorrow’s state-of-the-art silicon and next generation semiconductor devices     

Suitability of Liquid Crystal Polymer substrates for high frequency acoustic devices

Polymer substrates are widely seen as a low-cost route to flexible circuits for systems incorporating displays, sensing functions and transistors. To date most polymer-based devices have involved passive components such as humidity sensors, constructed using metals and additional organic layers. The starting point of the study described here, is whether more advanced components incorporating functional materials can be integrated into devices on polymer substrates. An understanding will be required of the material factors that limit performance and, if possible, techniques developed to circumvent them so that their performance can be compared to that of standard silicon-based components.     

Pulsed Laser Deposition‐based Thin Film Microbatteries

Emerging applications for robust small format or distributed devices feature a need for power and rechargeable lithium‐ion batteries could play a significant role. This review focuses on a high precision technique to controllably grow thin‐film electrodes or full all‐solid‐state batteries, that is, pulsed laser deposition (PLD). The technique and solid‐state batteries are introduced followed by a detailed showcase of the depth of PLD‐based growth undertaken on cathodes, electrolytes, anodes and whole microbatteries. Emphasis is placed on the various characterization techniques available to study PLD grown components and devices, and how interfaces become both critical and arguably easier to probe in PLD grown films or devices. This work provides a perspective on the techniques, its opportunities for electrodes and devices, and how to probe the resulting growth and its evolution in batteries.     

核酸探针技术

本文对核酸探针技术进行了较全面的综述，介绍了核探针的制备及非放射性标记方法，并对核酸的Ｓｏｕｔｈｅｒｎ转印杂交，Ｎｏｒｔｈｅｒｎ转印杂交，ＩｎＳｉｔｕ转印杂交及斑点杂交法的原理及应用进行了简明的评述。     

Solvent induced enhancement of nonlinear optical response of graphdiyne

Flat and crystalline materials with exceptional nonlinear optical(NLO) properties are highly desirable for their potential applications in integrated NLO photonic devices.Graphdiyne(GD),a new twodimensional(2 D) carbon allotrope,has recently evoked burgeoning research attention by virtue of its tunable bandgap along with a high carrier mobility and extended π-conjugation compared with most conventional optical materials.Here,we experimentally probe the third-order nonlinear optical response of GD dispersed in several common solvents(alcohols) using a femtosecond Z-scan technique.The measured nonlinear optical refractive index is in the order of ~10^-8 cm²/W,which is approximately one order of magnitude higher than that of most 2 D materials.In particular,we find that different NLO responses can be observed from GD when dispersed in different solvents,with the strongest NLO response when dispersed in 1-propanol.It is proposed that some intrinsic properties of the solvents,such as the polarity and viscosity,could influence the NLO response of GD materials.Our experimental results confirm the assumptions on the NLO behavior in GD and demonstrate its great potential for future generations of Kerr-effect-based NLO materials and devices.     

Genotyping with microfluidic devices

In the past few years, electrophoresis microchips have been increasingly utilized to interrogate genetic variations in the human and other genomes. Microfluidic devices can be readily applied to speed up existing genotyping protocols, in particular the ones that require electric field-mediated separations in conjunction with restriction fragment analysis, DNA sequencing, hybridization-based techniques, allele-specific amplification, heteroduplex analysis, just to list the most important ones. As a result of recent developments, microfabricated electrophoresis devices offer several advantages over conventional slab-gel electrophoresis, such as small sample volume requirement, low reagent consumption, the option of system integration and easy multiplexing. The analysis speed of microchip electrophoresis is significantly higher than that of any other electric field-mediated separation techniques. State-of-the-art microfluidic bioanalytical devices already claim their place in most molecular biology laboratories. This review summarizes the recent developments in microchip electrophoresis methods of nucleic acids, particularly for rapid genotyping, that will most likely play a significant role in the future of clinical diagnostics.     

Nanoliter-scale non-invasive flow-rate quantification using micro-interferometric back-scatter and phase detection

The current trend toward miniaturization of fluid-handling systems, particularly those of micro-fluidic devices on the capillary-scale, will certainly lead to improvements in chemical and biochemical analyses. Unfortunately, when fluid volumes reach nano- and picoliter scale it is problematic to perform non-invasive fast and accurate volume flow or flow velocity measurements. Here a simple, non-invasive method is presented for detecting and measuring linear flow velocity within fluid-filled capillaries. A small fluid volume is repeatedly heated locally by means of an infrared laser diode and using the micro-interferometric back-scatter detector (MIBD) at a fixed distance downstream, a thermally induced change in refractive index is observed when the heated volume traverses the probe volume of the detector. Fluid velocity is calculated by monitoring the phase difference between the second harmonic of the heating function and the resulting MIBD output in the Fourier domain. In a probe volume of 40 nL flow rates between I and 10 microL min(-1) are quantifiable, with 3sigma detection limits determined to be 42.8 nL min(-1).     

Oxygen radical-driven surface modification of polycaprolactone-filled glass microfiber media: Probing the surface chemistry of wicking microfluidic devices

Cost and complexity are key factors in designing microfluidic devices for broad application. Therefore, the development of a simple, inexpensive, and easily manufactured fabrication technique that does not require expensive chemicals or instruments is necessary. We have successfully demonstrated the use of long-lived oxygen radicals for the fabrication of membrane-based microfluidic devices on polycaprolactone (PCL)-filled glass microfiber (GMF) membranes. These devices may incorporate complex multidimensional (2D and 3D) microfluidic pathways on a single PCL-filled GMF membrane. Selective exposure to oxygen radicals generated in a homebuilt oxygen plasma exposure system was employed to pattern the flow path; radical exposure of the polymer-filled substrate altered the physical and chemical properties of the surface, affecting wettability. To the best of our knowledge, this is the only wicking microfluidic device fabrication technology that is capable of generating both 2D and 3D microfluidic pathways in a single membrane; hence, it has many potential applications. Investigations were conducted to probe the effects of oxygen radical exposure in order to provide a more quantitative understanding of the process. These findings will help expand the utility of the selective oxygen radical exposure–driven fabrication technology.     

Polymeric electrochromics

Conducting polymers are excellent candidates for applications in displays, mirrors, windows, light-emitting diodes, photovoltaics, near-infrared devices and electrochromic devices. From these potential applications, in this article, we will focus on the electrochromic polymers and devices. Although several objective studies have been conducted in the last decade, bringing to light many advantages over other types of electrochromics, polymeric electrochromics have not yet received the industrial attention that they deserve. One of the most important and dazzling advantages of polymers over the other types of electrochromics is the ease of modification of a polymer's backbone, that changes almost the entire properties of the material and switches many disadvantages into advantages. Our recent completion of the deficient third leg of additive primary colour space was a very good example of tailoring the polymer backbone. This discovery could be considered as one of the milestones of commercialization of polymeric electrochromics. In this article, we will also discuss the completion of the additive primary colours, red, green and blue (RGB), in polymeric electrochromics and their ways of commercialization.     

Applications and limitations of uranyl ion as a photophysical probe

Uranyl ion has a long-lived luminescent excited state, which can be used as a probe for the aggregation behaviour in a variety of surfactant and polymeric systems. The general spectroscopy and photophysics of this species are discussed, and the applications to specific micellar, microemulsion, vesicular and liquid crystalline systems presented. It is shown that both dynamic and structural information can be obtained from spectral and kinetic data. Examples of applications of uranyl probe studies to technologically important mesoscopic and mesoporous systems involving metal oxides, or their salts, and to humic acids and soils will also be reviewed. Emphasis will be given to both the advantages and restrictions on the use of this useful photophysical probe.     

Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces

Investigation into nanostructured organic films has served many purposes, including the design of functionalized surfaces that may be applied in biomedical devices and tissue engineering and for studying physiological processes depending on the interaction with cell membranes. Of particular relevance are Langmuir monolayers, Langmuir–Blodgett (LB) and layer-by-layer (LbL) films used to simulate biological interfaces. In this review, we shall focus on the use of vibrational spectroscopy methods to probe molecular-level interactions at biomimetic interfaces, with special emphasis on three surface-specific techniques, namely sum frequency generation (SFG), polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and surface-enhanced Raman scattering (SERS). The two types of systems selected for exemplifying the potential of the methods are the cell membrane models and the functionalized surfaces with biomolecules. Examples will be given on how SFG and PM-IRRAS can be combined to determine the effects from biomolecules on cell membrane models, which include determination of the orientation and preservation of secondary structure. Crucial information for the action of biomolecules on model membranes has also been obtained with PM-IRRAS, as is the case of chitosan removing proteins from the membrane. SERS will be shown as promising for enabling detection limits down to the single-molecule level. The strengths and limitations of these methods will also be discussed, in addition to the prospects for the near future.     

A new angle on pluronic additives: advancing droplets and understanding in digital microfluidics

Biofouling in microfluidic devices limits the type of samples which can be handled and the duration for which samples can be manipulated. Despite the cost of disposing fouled devices, relatively few strategies have been developed to tackle this problem. Here, we have analyzed a series of eight amphiphilic droplet additives, Pluronic coblock polymers of poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO), as a solution to biofouling in digital microfluidics using serum-containing cell culture media as a model fluid. Our analysis shows that species with longer PPO chains are superior for enabling droplet motion and reducing biofouling. Two of the tested species, L92 and P105, were found to lengthen device lifetimes by 2-3 times relative to additives used previously when used at optimal concentrations. Pluronics with low PEO content such as L92 were found to be cytotoxic to an immortalized mammalian cell line, and therefore we recommend that Pluronic additives with greater or equal to 50% PEO composition, such as P105, be used for digital microfluidic applications involving cells. Finally, contact angle measurements were used to probe the interaction between Pluronic-containing droplets and device surfaces. Strong correlations were found between various types of contact angle measurements and the capacity of additives to reduce biofouling, which suggests that contact angle measurements may be useful as a tool for rapidly screening new candidates for the potential to reduce biofouling. We propose that this study will be useful for scientists and engineers who are developing digital microfluidic platforms for a wide range of applications involving protein-containing solutions, and in particular, for applications involving cells.     

Applications of Tamm plasmon-liquid crystal devices

ABSTRACT

The Tamm-plasmon-polariton (TPP) occurs at the interface between a metallic film and the photonic-crystal (PC) substrate. Unlike conventional surface-plasmon-polariton (SPP), TPP can be directly excited by both the transverse electric (TE) and transverse magnetic (TM) electromagnetic waves without using additional coupling optics. The fact that the optical functionality of most plasmonics devices is determined after fabrication limits their applications. Tunable SPP devices by applying liquid crystals (LCs) have been widely demonstrated due to their large birefringence and easy controllability via external stimuli. However, actively tuning TPP is difficult because the localised electric field is between the metallic film and PC substrate, the change of refractive index above the metallic film has only small influences on TPP. This article is intended to briefly review recent progress towards using LCs for actively tuning TPP devices. Not only TPP devices can gain benefits from LCs, we will also discuss the applications of TPP for measuring the anisotropy of the alignment films of LC devices. The sensitivity of the proposed scheme will be discussed.     

3D‐Printed Microfluidics

The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite‐element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia.     

Organic electronic devices and their functional interfaces.

A most appealing feature of the development of (opto)electronic devices based on conjugated organic materials is the highly visible link between fundamental research and technological advances. Improved understanding of organic material properties can often instantly be implemented in novel device architectures, which results in rapid progress in the performance and functionality of devices. An essential ingredient for this success is the strong interdisciplinary nature of the field of organic electronics, which brings together experts in chemistry, physics, and engineering, thus softening or even removing traditional boundaries between the disciplines. Naturally, a thorough comprehension of all properties of organic insulators, semiconductors, and conductors is the goal of current efforts. Furthermore, interfaces between dissimilar materials-organic/organic and organic/inorganic-are inherent in organic electronic devices. It has been recognized that these interfaces are a key for device function and efficiency, and detailed investigations of interface physics and chemistry are at the focus of research. Ultimately, a comprehensive understanding of phenomena at interfaces with organic materials will improve the rational design of highly functional organic electronic devices.     

In situ studies: electrochemistry and scattering

Given the global relevance of sustainable energy and energy security, the study of electrochemistry and the development of energy storage devices is a very active area of research. As researchers attempt to overcome issues with current energy storage devices, innovative methods are required to probe deeper into the working mechanisms of devices. The ability to study electrochemistry as it takes place in electrochemical energy storage devices has been enabled by continuous developments in instrumentation, improved accessibility for researchers and also innovations in data collection and cell design. In this short review, we highlight several studies that make use of innovations in data collection, data interpretation, or device design, to study electrochemical energy storage devices using scattering methods.