Journal of Photochemistry and Photobiology C: Photochemistry Reviews最新文献

Mitochondria is the cell's energy powerhouse and regulate most of the metabolism process through the inherent mitochondrial genes (mtDNA). The control of mtDNA replication and transcription is known to be mediated by noncanonical forms of guanine-rich nucleotides G-quadruplexes (G4s). These putative and transient guanine-based structures and their dynamics are closely associated with mtDNA deletion breakpoints pertaining to fatal diseases such as cancers, hypertension, diabetes, etc. The precise reason for the origin of G4s at deletion breakpoints in the heavy strand and during the replication process has not yet been identified, owing to its complex biochemical phenomenon. Biomolecular structure, typically having a size of 5–10 nm with an average life span of seconds, strongly demands high-end instruments to explore the precise biochemical mechanism and dynamics (folding or unfolding) in biological systems. In that sense, since the last decade, tremendous efforts have been kept in X-ray crystallography, circular dichroism spectroscopy (CD), nuclear magnetic resonance spectroscopy (NMR), immunofluorescence, and the mtG4-ChIP methods to recognize and characterize the G4s structures in physiological conditions. Owing to their non-invasiveness, robustness, and high spatio-temporal resolution at the molecular level, fluorescence methods have been exploited to recognize noncanonical forms of nucleic acids even at the subcellular level. In light of this, from 2015 until today, the documentation of photophysical and bioanalytical capabilities of mtG4s recognizing small and quencher-free fluorescent probes has not yet been reported. Considering the plethora of G4s propensity with mtDNA replication, transcription, oxidative phosphorylation, glycolysis etc. In the current article, we have systematically documented small fluorescent probes that have been exclusively used to recognize mtG4 in cellular conditions with photophysical and biophysical properties. Furthermore, the probe's designing rationale binding mechanism, readout system, cellular localization, and cytotoxicity were tabulated.

Triplet-triplet annihilation photon up-conversion (TTA-PUC) has gained immense attention among the scientific community in the last decade due to its application in the fields of energy, biology, and photocatalytic organic synthesis. One of the main aims to improve the efficiency of these low-to-high photon-energy conversion is to reduce energy losses during the intersystem crossing (ISC). Since 2015, many strategies have been reported to address this challenge and a significant update has been noticed in this field. This review is aimed to critically analyze these updates and provide an outlook for the future. A detailed mechanism of ISC in thermally activated delayed-fluorescence (TADF) molecules that possess a small singlet−triplet energy gap, is discussed with a focus on its deeper understanding and the impact of molecular design. In this context, a range of selected organic and inorganic TADF molecules are thoroughly evaluated. Osmium(II) complexes that exhibit a spin-forbidden metal-to-ligand charge-transfer (³MLCT) transition in their Vis-NIR-IR absorption spectra and can be excited directly into their triplet state, thereby bypassing the energy loss during ISC, are also debated in sufficient detail for their advantages as well as shortcomings in being used in TTA-PUC. This work aims at reviewing the latest progress in this field, understanding the fundamental ISC mechanism of these photosensitizers, and critically addressing the challenges that are faced in this field. This review is anticipated to serve as a helpful script for identifying future directions and designing molecular sensitizers for TTA-PUC, which can sensitize the triplet state with minimum energy loss during ISC and can be helpful for increasing the anti-Stokes shift in TTA-PUC.

Bottom-up strategies have allowed the synthesis of “molecular” nanographenes with full control over size, shape and functionality. In recent years, the progress on wet chemical approaches, oxidative cyclodehydrogenation amongst all, has been the foundation to the synthesis of an impressive number of soluble and well-defined molecular nanographenes. The level of control over nanographene syntheses has allowed a fine-tuning of the photophysical and electrochemical properties and, in turn, has a compelling potential in the field of material science. In this regard, understanding and harnessing the competition between electron transfer and energy transfer in nanographenic systems is of utmost importance. However, a comprehensive structure-property relationship remains still an open aspect. In the present review we describe a large variety of hexa-peri-hexabenzocoronene (HBC)-based nanographenes obtained through wet chemical strategies and linked – either covalently or non-covalently – to porphyrins, rylenes, fullerenes, etc. Particular attention was placed on the optical, electrochemical and excited-state properties.

A review regarding the studies of light-sensitive systems based on bacteriorhodopsin is presented. Briefly given are modern ideas about bacteriorhodopsin and its molecular properties, about the photocycle of its transformation. The possibilities and ways of bacteriorhodopsin modifications are shown, in particular, such as dehydration, modification using chemical additives, changing the primary protein sequence by use of genetic mutants of bacteriorhodopsin, replacing the chromophore with its synthesized analogues. Such modifications can optimize the use of bacteriorhodopsin to create photosensitive recording media. Particular attention is paid to various areas of possible applications of light-sensitive materials of this type, in particular, polymer films based on bacteriorhodopsin and its derivatives, the so-called Biochrome films. The possibilities of using BR-based polymer films not only as a photochromic material for multiple recording, but also as a material for write-once recording and permanent memory (the so-called material for write-once recording of optical information) are also considered.

Spectral microscopy provides information about the spatial distribution and physiological functional states of pigment-protein complexes in photosynthetic organisms. This can be used to complement the newly developed techniques, such as cryogenic electron microscopy and atomic force microscopy, which are less effective in functional analysis of photosynthesis, despite having an excellent spatial resolution. The combination of optical microscopies with various spectroscopic techniques has extended the possibility of a multi-perspective investigation in photosynthesis research. Some of these spectroscopic techniques include fluorescence and absorption spectra, excitation spectra, time-resolved fluorescence measurement, Raman scattering spectroscopy, etc. These techniques can be applied to in vivo investigations of photosynthetic activity without introducing any artificial fluorophore since the photosynthetic pigments are informative probes. In particular, the technique has been effective in clarifying the dynamic physiological responses of photosynthetic organisms to variable environments. In this paper, we review the recent progress in spectral microscopy in the field of in vivo photosynthesis research. We have also introduced and discussed some distinctive spectral microscopies such as anti-Stokes fluorescence spectral microscopy, excitation spectral microscopy, cryo-microscopy, and Raman spectral microscopy.

In the past three decades, dye-sensitized solar cells (DSSCs) have gained increased recognition as a potential substitute for inexpensive photovoltaic (PV) devices, and their maximum efficiency has grown from 7% to 14.3%. Recent developments in DSSCs have attracted a plethora of research activities geared at realizing their full potential. DSSCs have seen a revival as the finest technology for specific applications with unique features such as low-cost, non-toxic, colourful, transparent, ease of fabrication, flexibility, and efficient indoor light operation. Several organic materials are being explored and employed in DSSCs to enhance their performance, robustness, and lower production costs to be viable alternatives in the solar cell markets. This review provides a concise summary of the developments in the field over the past decade, with a special focus on the incorporation of organic materials into DSSCs. It covers all elements of the DSSC technology, including practical approaches and novel materials. Finally, the emerging applications of DSSCs, and their future promise are also discussed.

Room-temperature optical manipulation of small molecules is a challenging issue in the field of material science. To increase optical force for a single molecule trapping, it has been recognized that resonant excitation of molecules should be controlled under the light illumination. Strongly interacting molecules with solid surfaces at electrified interfaces show the exotic behavior of electronic excitation by localized surface plasmon. In this review, we emphases that surface-enhanced Raman scattering can be used to evaluate the resonant excitation of target molecules at interfaces. Under such excitation, the diffusion of small molecules can be controlled by the optical force generated by the intensity gradient of a highly localized electric field.