Fluorescent chemosensors for ions and neutral analytes have been widely applied in many diverse fields such as biology, physiology, pharmacology, and environmental sciences. The field of fluorescent chemosensors has been in existence for about 150 years. In this time, a large range of fluorescent chemosensors have been established for the detection of biologically and/or environmentally important species. Despite the progress made in this field, several problems and challenges still exist. This tutorial review introduces the history and provides a general overview of the development in the research of fluorescent sensors, often referred to as chemosensors. This will be achieved by highlighting some pioneering and representative works from about 40 groups in the world that have made substantial contributions to this field. The basic principles involved in the design of chemosensors for specific analytes, problems and challenges in the field as well as possible future research directions are covered. The application of chemosensors in various established and emerging biotechnologies, is very bright.

Recent developments in the design of bifunctional and activatable photo sensitizers rejuvenate the aging field of photodynamic sensitization and photodynamic therapy. While systematic studies have uncovered new dyes that can serve as potential photosensitizers, the most promising results have come from studies aimed at gaining precise control over the location and rate of cytotoxic singlet oxygen generation. As a consequence, higher selectivities and efficiencies in photodynamic treatment protocols are now within reach. This feature article highlights the variety of approaches that have been pur sued to improve photodynamic therapy and to transform simple photosensi tizers into smarter theranostic agents.

The field of molecular logic gates originated 25 years ago, when A. P. de Silva published a seminal article in Nature. Stimulated by this ground breaking research, scientists were inspired to join the race to simulate the workings of the fundamental components of integrated circuits using molecules. The rules of this game of mimicry were flexible, and have evolved and morphed over the years. This tutorial review takes a look back on and provides an overview of the birth and growth of the field of molecular logics. Spinning-off from chemosensor research, molecular logic gates quickly proved themselves to be more than intellectual exercises and are now poised for many potential practical applications. The ultimate goal of this vein of research became clearer only recently - to "boldly go where no silicon-based logic gate has gone before" and seek out a new deeper understanding of life inside tissues and cells.

Cataloged from PDF version of article.The in silico design of tetraradical S 1 states was validated experimentally through synthesis, followed by characterization including phosphorescence measurements, use of trap molecules, and cell culture studies, leading to a series of orthogonal dimers of Bodipy chromophores with remarkable singlet oxygen efficiencies (see picture). A new path for the rational development of efficient photosensitizers is thus revealed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A novel distyryl-substituted boradiazaindacene (BODIPY) dye displays interesting properties as a sensitizer in DSSC systems, opening the way to further exploration of structure-efficiency correlation within this class of dyes.

Following a highly influential paper by de Silva, 1 there have been many reported examples of individual molecular logic gates, 2 and molecular equivalents of even more complex digital designs were presented in recent years, such as half adder, 3 half-subtractor 4 and multiplexer. 5 Nevertheless, the unresolved issues of individual addressability and input-output heterogeneity remain to be important handicaps, making molecular logic gates very difficult to integrate for the implementation of more advanced digital operations. However, in recent years, there have been important advances toward finding practicality in molecular logic gates, such as, identification tags for small objects, 6 molecular keypad lock, 7 laboratory on molecule, 8 and pro-drug activation. 9 RNA-based logic devices were also shown to be promising in vitro, yielding fluorescent proteins, 10 or potentially important DNA antisense drug sequences as outputs. 11 In this Communication, we will put forward the idea that in essence, a comparison between the silicon-based digital electronics and "chemical" logic gates is mostly unfair, chemical logic systems are inherently more capable than they are given credit for, and the potential of the chemical logic gates is yet largely untapped. The chemical logic gates and the biomolecules in living systems, including ourselves, speak the same language. It may be challenging to integrate two molecular logic gates; however, they can be easily integrated into the control processes of healthy or pathological biochemistry.Photodynamic therapy is a noninvasive methodology used for the treatment malignant tumors and age related macular degeneration. The treatment requires a combined application of red to near IR light and a sensitizer. The cytotoxic agent thus produced within the target region is singlet oxygen.A few years ago, O'Shea published 12 a report, where it was shown that singlet oxygen generation rate could be modulated by pH. This effect is directly related to PET efficiency; excited-state molecules can relax through a number of different pathways including two competing processes, intersystem crossing and photoinduced electron transfer. Blocking of PET process by protonation of the amine PET donor, shuts down one channel of deactivation, and thus enhances intersystem crossing efficiency and the rate of singlet oxygen generation.Recent works by Nagano 13 and us 14 have demonstrated that appropriately decorated bodipy 15 dyes can be very efficient generators for singlet oxygen, and thus act as satisfactory photodynamic agents. As a bonus, the dyes synthesized in our laboratory absorbed very strongly at 660 nm which is considered to be well within the therapeutic window of mammalian tissue. We are aware of the fact that PET process can be manipulated by a large variety of modulators other than pH: cations, anions, carbohydrates, phosphates, among others. 16 So, combining our earlier experience in molecular logic gates and rational design of photodynamic agents, we proposed a photodynamic therapy agent t...

Highly versatile BODIPY dyes proved themselves to be very useful as photosensitizers. These dyes can be derivatized to absorb essentially anywhere in the visible the near IR region of the spectrum. As a result of their diverse reactivity, singlet oxygen generation efficiency can be modulated very precisely, leading to a number of selective photosensitizers for photodynamic therapy. Among the biologically relevant modulators, glutathione concentration and pH received particular attention. In this review, we highlight modulatable BODIPY-based photodynamic photosensitizers, and various synthetically useful chemical reactions triggered by singlet oxygen and other reactive oxygen species generated by BODIPY-based photosensitizers.

Remarkably versatile chemistry of Bodipy dyes allows the design and straightforward synthesis of multivalent-multitopic derivatives, which, with judicious selection of metal ion-ligand pairs based on known affinities, affords control and manipulation of photoinduced electron transfer and internal charge transfer processes as desired. We have demonstrated that metal ions acting as modulators (or inputs, in digital design parlance) can generate absorbance changes in accordance with the operation of a halfadder. In addition, an AND logic gate in the emission mode was delivered using a different binucleating arrangement of ligands. A molecular equivalent of a three-input AND logic gate was also obtained exploiting differential binding affinities of metal ions for different ligands. The results suggest that different metal ions can be used as nonannihilating inputs, selectively targeting various ligands incorporated within a single fluorophore, and with careful design, diverse photophysical processes can be selectively modulated, resulting in a range of signals, useful in molecular logic design, and offering an enticing potential for multianalyte chemosensors.