There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

The layer-by-layer (LbL) adsorption technique offers an easy and inexpensive process for multilayer formation and allows a variety of materials to be incorporated within the film structures. Therefore, the LbL assembly method can be regarded as a versatile bottom-up nanofabrication technique. Research fields concerned with LbL assembly have developed rapidly but some important physicochemical aspects remain uninvestigated. In this review, we will introduce several examples from physicochemical investigations regarding the basics of this method to advanced research aimed at practical applications. These are selected mostly from recent reports and should stimulate many physical chemists and chemical physicists in the further development of LbL assembly. In order to further understand the mechanism of the LbL assembly process, theoretical work, including thermodynamics calculations, has been conducted. Additionally, the use of molecular dynamics simulation has been proposed. Recently, many kinds of physicochemical molecular interactions, including hydrogen bonding, charge transfer interactions, and stereo-complex formation, have been used. The combination of the LbL method with other fabrication techniques such as spin-coating, spraying, and photolithography has also been extensively researched. These improvements have enabled preparation of LbL films composed of various materials contained in well-designed nanostructures. The resulting structures can be used to investigate basic physicochemical phenomena where relative distances between interacting groups is of great importance. Similarly, LbL structures prepared by such advanced techniques are used widely for development of functional systems for physical applications from photovoltaic devices and field effect transistors to biochemical applications including nano-sized reactors and drug delivery systems.

Layer-by-Layer Assembly as a Versatile Bottom-Up Nanofabrication Technique for Exploratory Research and Realistic Application

Mushrooms have been valued as edible and medicinal resources, and antitumor substances have been identified in many mushroom species. Polysaccharides are the best known and most potent mushroom-derived substances with antitumor and immunomodulating properties. Although the isolation process, structural characterization and antitumor activity of mushroom polysaccharides have been extensively investigated in the past three decades, the relationship between the antitumor activity and the chemical composition as well as the high order structure of their active components is still not well established. These studies are still in progress in many laboratories, and the role of polysaccharides as antitumor agent is especially under intense debate. The purpose of the present review is to summarize the available information, and to reflect the current status of this research area with a view for future direction.

Antitumor polysaccharides from mushrooms: a review on their isolation process, structural characteristics and antitumor activity

Titanium Dioxide Nanomaterials for Sensor Applications

Ultrathin films of titanium oxide gel imprinted with 4-(4-propyloxyphenylazo)benzoic acid (C3AzoCO2H) were prepared by repeated immersion of a gold-coated quartz crystal microbalance (QCM) electrode or a quartz plate in solutions of C3AzoCO2H and titanium butoxide (Ti(O-nBu)4) in toluene/ethanol. Regular film growth was confirmed by frequency decrement in QCM measurements and by the appearance of the azobenzene absorption in UV−vis spectroscopy. The template molecule could be completely removed upon treatment with 1% aqueous ammonia. The resulting films showed saturation binding of the template molecule in acetonitrile in less than 1 min. Binding of the template molecule was greatest among aromatic carboxylic acids that are structurally related to the template. A related ester showed a significant reduction in the binding efficiency. The surface sol-gel process provides a powerful tool for molecular imprinting in ultrathin metal oxide films.

Molecular imprinting of azobenzene carboxylic acid on a TiO2 ultrathin film by the surface sol-gel process

https://iopscience.iop.org/article/10.1088/2040-8986/aac68d/pdf

Biomedical application of optical fibre sensors

The development of reliable, affordable and efficient sensors is a key step in providing tools for efficient monitoring of critical environmental parameters. This review focuses on the use of tapered optical fibres as an environmental sensing platform. Tapered fibres allow access to the evanescent wave of the propagating mode, which can be exploited to facilitate chemical sensing by spectroscopic evaluation of the medium surrounding the optical fibre, by measurement of the refractive index of the medium, or by coupling to other waveguides formed of chemically sensitive materials. In addition, the reduced diameter of the tapered section of the optical fibre can offer benefits when measuring physical parameters such as strain and temperature. A review of the basic sensing platforms implemented using tapered optical fibres and their application for development of fibre-optic physical, chemical and bio-sensors is presented.

Seung-Woo Lee

Papers

Molecular imprinting of azobenzene carboxylic acid on a TiO2 ultrathin film by the surface sol-gel process

Biomedical application of optical fibre sensors

Tapered Optical Fibre Sensors: Current Trends and Future Perspectives

Optical fibre long period grating with a nanoporous coating formed from silica nanoparticles for ammonia sensing in water

Molecular imprinting in ultrathin titania gel films via surface sol-gel process