High Molar Absorptivity Research Articles

A highly sensitive and fast-response fluorescence nanoprobe for in vivo imaging of hypochlorous acid.

Fluorescent probes for in vivo hypochlorous acid (HClO) imaging often face challenges of low selectivity and high cytotoxicity, largely due to poor analyte recognition and water-insoluble aromatic skeletons. To address this, we synthesized fluorescein hydrazide by introducing a spiro-lactam unit into fluorescein, which offers high emission intensity and molar absorption. The five-membered heterocycle in fluorescein hydrazide is selectively disrupted by HClO, enhancing the conjugated system and electron delocalization of the fluorophore, resulting in highly sensitive fluorescence detection of HClO. For in vivo imaging, fluorescein hydrazide was covalently grafted onto the surface of silica nanoparticles via nucleophilic substitution reaction, avoiding complex modifications. This fluorescent nanoprobe (Si-FL) leverages the high-density fluorophores and hydroxyl groups on the silica surface to enrich low-concentrations of HClO through weak supramolecular interactions, thereby accelerating the reaction between HClO and the recognition sites. Compared to other molecular probes, Si-FL demonstrates a superior response speed (within 20 s) and a lower detection limit (72 nM), alongside excellent biocompatibility and water solubility. The nanoprobe Si-FL was successfully applied for HClO detection in living cells, zebrafish, and plants, significantly improving the stability of fluorescence imaging.

Impact of the Acceptor Group on the Properties of Triphenylamine-Donor-Acceptor Dyes: An Experimental and Computational Study.

Three triphenylamine-Indane donor-acceptor dyes with different functional groups on the acceptor were studied to investigate how substitution would affect the optical properties. The dyes studied were IndCN, containing two malononitrile groups; InO, with two ketone groups; and InOCN, which features mixed functional groups. A combination of Raman spectroscopy, UV-vis absorption and emission spectroscopy, and density functional theory (DFT) calculations were employed for characterization. The dyes exhibited intramolecular charge transfer transitions with relatively high molar absorptivity (εabs) of ∼50 mM-1 cm-1 at 491-591 nm within the visible spectrum and emissions at 690-840 nm in dichloromethane. The malononitrile-containing dyes showed lower-energy absorption and emissions due to a reduced band gap compared to ketone-containing dyes. The bulkiness of the malononitrile group led to a bent geometry, increasing nonradiative decay and reducing the fluorescence quantum yield. The dyes exhibited fluorescence quantum yields less than 0.25 and lifetimes of ∼5 ns. Resonance Raman spectra and DFT calculations showed that the longer linker group (propen-1-ylidene linker) in these systems reduced the charge-transfer character of the optical transition. The emission intensities of the three dyes were temperature-sensitive, with ketone-containing dyes showing shifts in emission bands as well. This could be due to molecular stacking and intermolecular π-interactions.

Achieving a Near-Infrared Absorption by A-DA'D-A Type Isoindigo-Based Small Molecular Acceptors for Organic Photovoltaics.

Isoindigo (IID)-based non-fullerene acceptors, known for their broad absorption spectra and high charge carrier mobilities, play a crucial role in organic photovoltaics. In this study, two A-DA'D-A type unfused ring acceptors (URAs), IDC8CP-IC and IDC6CP-IC, were designed and synthesized using cyclopentadithiophene (CPDT) and IID core units, each functionalized with different alkyl chains (2-hexyldecyl and 2-octyldodecyl), through an atom- and step-efficient direct C-H arylation (DACH) method. Both URAs, despite the absence of non-covalent conformation locking between CPDT and IID, demonstrated favorable molecular planarity, broad absorption ranges, low band gaps, and high molar absorption coefficients. Notably, IDC6CP-IC exhibited stronger intermolecular charge transfer and J-aggregation. An organic solar cell (OSC) device based on IDC6CP-IC achieved a power conversion efficiency (PCE) of 3.10%, with a broad photoresponse range extending from 400 to 900 nm. This study highlights the significant impact of alkyl chain engineering on material synthesis, photoelectric properties, and corresponding device performance. Furthermore, DACH is shown to be a promising approach for synthesizing IID-based URAs with near-infrared (NIR) absorption, making it an excellent candidate for bulk heterojunction (BHJ) OSC applications.

Xanthene-based NIR organic phototheranostics agents: design strategies and biomedical applications.

Fluorescence imaging and phototherapy in the near-infrared window (NIR, 650-1700 nm) have attracted great attention for biomedical applications due to their minimal invasiveness, ultra-low photon scattering and high spatial-temporal precision. Among NIR emitting/absorbing organic dyes, xanthene derivatives with controllable molecular structures and optical properties, excellent fluorescence quantum yields, high molar absorption coefficients and remarkable chemical stability have been extensively studied and explored in the field of biological theranostics. The present study was aimed at providing a comprehensive summary of the progress in the development and design strategies of xanthene derivative fluorophores for advanced biological phototheranostics. This study elucidated several representative controllable strategies, including electronic programming strategies, extension of conjugated backbones, and strategic establishment of activatable fluorophores, which enhance the NIR fluorescence of xanthene backbones. Subsequently, the development of xanthene nanoplatforms based on NIR fluorescence for biological applications was detailed. Overall, this work outlines future efforts and directions for improving NIR xanthene derivatives to meet evolving clinical needs. It is anticipated that this contribution could provide a viable reference for the strategic design of organic NIR fluorophores, thereby enhancing their potential clinical practice in future.

Indocarbocyanine-Indodicarbocyanine (sCy3-sCy5) Absorptive Interactions in Conjugates and DNA Duplexes.

Sulfonated indocyanines 3 and 5 (sCy3, sCy5) are widely used to label biomolecules. Their high molar absorption coefficients and lack of spectral overlap with biopolymers make them ideal as linker components for rapid assessment of bioconjugate stoichiometry. We recently found that the determination of the sCy3:sCy5 molar ratio in a conjugate from its optical absorption spectrum is not straightforward, as the sCy3:sCy5 absorbance ratio at the maxima tends to be larger than expected. In this work, we have investigated this phenomenon in detail by studying the spectral properties of a series of sCy3-sCy5 conjugates in which the dyes are separated by linkers of various lengths, including DNA duplexes. It was found that when sCy3 and sCy5 are located in close proximity, they consistently exhibit an "abnormal" absorbance ratio. However, when the two dyes are separated by long rigid DNA-based spacers, the absorbance ratio becomes consistent with their individual molar absorption coefficients. This phenomenon should be taken into account when assessing the molar ratio of the dyes by UV-Vis spectroscopy.

Novel benzophenone derivatives for low intensity visible light polymerization and multi-color 3D printing

Four novel benzophenone photoinitiators were synthesized by one-step reaction, including (4-(dimethylamino)phenyl)(10-ethyl-10H-phenothiazin-3-yl)methanone (PEPM), (4-(dimethylamino)phenyl)(10-phenyl-10H-phenothiazin-3-yl)methanone (PPPM), (10-allyl-10H-phenothiazin-3-yl)(4-(dimethylamino)phenyl)methanone (PAPM) and (4-(dimethylamino)phenyl)(10-(hex-5-en-1-yl)-10H-phenothiazin-3-yl)methanone (PHPM). Compared with benzophenone (BP), the absorption spectra of PIs are red-shifted to the visible light range, with a high molar absorption coefficient and wide absorption range from 365 nm to 475 nm. Surprisingly, under the irradiation of low intensity LED@405 nm (5 mW/cm2) and LED@440 nm (5 mW/cm2), PIs can initiate free radical polymerization and undergo rapid polymerization of PEGDA 400. Among them, the double bond conversion rate (DC) of PPPM reaches a stable value (98 %) within 20 s, which is much higher than that of BP (65 %). In addition, the curing depth of PPPM reaches 8.1 cm under the irradiation of LED@440 nm. Besides, PPPM can still perform multi-color 3D printing with 3 s/slice after adding different color (black, red, blue and yellow) dyes. At the same time, we explored the photopolymerization mechanism of the photoinitiator through photodegradation and ESR tests.

Understanding the Structural Modulations in Twisted Donor-Acceptor-Donor (D-A-D) Systems for Boosting Type I Photosensitizing Photocatalytic Activity.

Supramolecular assemblies based on the twisted donor-acceptor-donor (D-A-D) building block Qx-Ind have been developed, which interestingly, due to the balanced angle of twist (38.28°), high intermolecular charge transfer, and crystallization induced emission (CIE) characteristics, exhibit high molar absorptivity and a long-lived "lighted" excited state at the supramolecular level. The validity of the design concept was examined by preparing CIE active D-A-D system Qx-Indaz (weak donor, low angle of twist: 35.45°), in which, due to the insertion of an additional binding site for noncovalent interactions, a drastic change in the photophysical behavior is observed. The combined spectroscopic studies of all the compounds unveil the strong impact of modulation of the angle of twist and intermolecular charge transfer upon photophysical behavior in the aggregated state. Due to the favorable photophysical behavior, the supramolecular assemblies of Qx-Ind exhibit high type I photosensitizing activity in comparison to Qx-Indaz. The superior type I photosensitizing activity of Qx-Ind assemblies is manifested in their ability to efficiently catalyze the aerobic oxidative synthesis of quinazolin-4(3H)-ones (via type I ROS) from 2-aminobenzamide and aromatic aldehydes in the absence of additional additives (base/oxidant). Unlike photocatalytic nanoassemblies reported in the literature, due to the CIE characteristics, Qx-Ind does not require preliminary preparation and could be directly introduced in the solid state to reaction media. Thus, the present work demonstrates a simple strategy of upgrading type I photosensitizing activity by improving the ground/excited state behavior of a twisted D-A-D system through modulation of the angle of twist and charge transfer characteristics.

Novel benzophenone derivatives photoinitiators based on carbazole group for deep curing and fast 3D printing

With the development of photopolymerization in thick film curing, the design and synthesis of effective photoinitiators are becoming increasingly critical. A series of photoinitiators (4-(dimethylamino)phenyl)(9-ethyl-9H-carbazol-3-yl)methanone (PECM), (4-(dimethylamino)phenyl)(9-phenyl-9H-carbazol-3-yl)methanone (PPCM), (9-allyl-9H-carbazol-3-yl)(4-(dimethylamino)phenyl)methanone (PACM), and (4-(dimethylamino)phenyl)(9-(hex-5-en-1-yl)-9H-carbazol-3-yl)methanone (PHCM) based on carbazole group were synthesized for thick film curing. These photoinitiators exhibited the maximum absorption wavelength red-shifted to 353 nm compared to BP and had high molar absorption coefficients (over 27,000 L·mol−1·cm−1). Under the irradiation of LED, the three-component system composed of photoinitiator, diphenyliodonium hexafluorophosphate, and triethanolamine could initiate the rapid photopolymerization of polyethylene glycol diacrylate (PEGDA 400). Under low intensity LED@405 nm (5 mW/cm2) irradiation, PHCM achieved a final double bond conversion (DC) of 98 % within 20 s, significantly higher than BP (65 %). Under the irradiation of LED@365 nm (5 mW/cm2), PHCM reached 99 % DC within 8 s, while BP reached 97 % within 20 s. This performance was attributed to the fact that the molar absorption coefficients of PHCM at 365 nm (30010 L·mol−1·cm−1) and 405 nm (746 L·mol−1·cm−1) were much higher than those of BP (71 L·mol−1·cm−1, 46 L·mol−1·cm−1). Additionally, curing depth of PHCM reached 8.4 cm after 100 s irradiation under LED@405 nm. PHCM also demonstrated excellent cell compatibility and migration ratio as low as 1.8 %, which was 1/5 of that of BP (9.5 %). Furthermore, PHCM was suitable for 3D printers with 4 s/layer. In addition, the initiation mechanism of the photoinitiator was studied by photodegradation and ESR tests.

Based on thiophene-containing Zn(II) and Co(II) complexes: Synthesis, characterization, and application to dye-sensitized solar cells

Dye-sensitized solar Cells have attracted great attention recently due to their excellent advantages. This study introduces the cobalt and zinc metal complexes as a new class of sensitizers for evaluation. We report the synthesis and characterization of zinc and cobalt complexes of organic dyes and applications of Dye-Sensitive TiO2 Solar Cells. In this study, the reason we prefer cobalt and zinc complexes is that they provide a wide absorption spectrum and high molar absorption. The fact that these complexes have good energy level adaptations helps in efficient electron transfer. In the designed complexes, 4,5-diazafluoren metal complexes bonded with thiophene and carbonyl as electron donors and as electron-with drawing groups were synthesized. Structural characterization was achieved with FTIR, UV-Vis, and Maldi-MS. The metal complex binder dye has demonstrated promising DSSC properties such as short-circuit current, open-circuit voltage, and fill factor, indicating efficient charge generation and injection. The bathochromic shift seen in the UV-Vis spectra of the dyes was promising for good efficiency. Notably, the highest efficiency was obtained from ZnS2 with 0.61%, while the lowest was from CoS1 with 0.17%. The power conversion efficiencies (η) produced by CoS1, CoS2, ZnS1, and ZnS2 dyes exhibit device performance ZnS2 > ZnS1 > CoS2 > CoS1 respectively. With these results, the development of DSSCs is promising.

Enhanced Singlet Oxygen Generation in Aggregates of Naphthalene-Fused BODIPY and Its Application in Photodynamic Therapy.

Several reports are available on aggregation-induced emission and its applications in biomedical imaging and other material sciences. However, enhancement of singlet oxygen generation in nanoaggregates is rarely reported. Here, we report the synthesis of Naph-BODIPY Br2, which absorbs at 661 nm (monomer) with a high molar absorption coefficient. The presence of bromine promotes intersystem crossing, thereby enhancing the singlet oxygen quantum yield (ΦΔ ∼ 0.50 in methanol). In order to increase hydrophilicity, we developed Naph-BODIPY Br2 nanoaggregates (∼100 nm), which demonstrated aggregation-induced properties and exhibited a bathochromic shift with an absorption maximum at 757 nm. The bathochromic shift in the UV-vis spectra due to aggregation is corroborated by TD-DFT analysis. The computational data also confirm the presence of a low-lying triplet state, which enhances the generation of singlet oxygen, making it effective for photodynamic therapy. These aggregates showed excellent singlet oxygen generation in aqueous media, compared to their monomeric form and standard methylene blue. Their hydrophilic nature and high singlet oxygen generation enabled significant phototoxicity against human carcinoma cells with IC50 values of 4.06 ± 0.01 and 4.09 ± 0.1 μM, respectively, for MCF-7 and A549 cells upon 5 min exposure to light. Moreover, their phototoxicity further increases with an increasing exposure time of light for both cell lines. Notably, Naph-BODIPY Br2 nanoaggregates exhibited nearly zero dark cell toxicity and effectively induced apoptosis in cancer cells upon light activation, highlighting their potential as powerful photosensitizers for photodynamic cancer therapy.

LC enantioseparation of active pharmaceutical ingredients using rationally synthesized CDRs and chiral molecules with high molar absorptivity.

The synthesis of optically active compounds requires determination of ee, er, and enantiomeric purity. The aim of the present paper is to review the synthesis of several chiral derivatizing reagents (CDRs) in a rational manner, which were successful for the separation and isolation of enantiomers of a variety of active pharmaceutical ingredients and other important and useful racemates. Besides, the application of (i) certain enantiomerically pure amines, either directly or by incorporating each of them as chiral auxiliary in difluorodinitrobenzene or cyanuric chloride moieties to construct the CDR, (ii) (S)-ketoprofen and (S)-levofloxacin as chiral platforms, and (iii) a few isothiocyanates, have been suitably included. Attention is drawn to the use of water micellar mobile phase as the "green" RP-HPLC method and the use of simple achiral derivatization with ninhydrin, particularly. Synthesis of CDRs and their application for enantioseparation of racemates and detagging of certain chromophoric reagent components for obtaining native enantiomers are other interesting features included herein. The methods can be easily used to determine and control enantiomeric purity with advantages over a variety of commercial chiral phases. This comprehensive review not only highlights innovative methodologies for enantioseparation but also underscores their practical applications in controlling and ensuring the enantiomeric purity of pharmaceutical compounds.

RNA-Activatable Near-Infrared Photosensitizer for Cancer Therapy.

Photodynamic therapy (PDT) has recently come to the forefront as an exceptionally powerful and promising method for the treatment of cancer. Existing photosensitizers are predominantly engineered to target diverse biomolecules, including proteins, DNA, lipids, and carbohydrates, and have proven to greatly enhance the efficacy or specificity of PDT. However, it is noteworthy that there exists a conspicuous scarcity of photosensitizers specifically designed to target RNAs. Recognizing the crucial and multifaceted roles played by RNAs in various cellular processes and disease states, we have ventured into the development of a novel RNA-targeting photosensitizer, named Se-718, designed specifically for PDT-based cancer therapy. Se-718 has been engineered to exhibit a high molar absorption coefficient in the NIR region, which is crucial for effective PDT. More importantly, Se-718 has demonstrated a distinct RNA-targeting capability, as evidenced through rigorous testing in both circular dichroism and fluorescence experiments. Furthermore, Se-718 has been shown to display both type I and type II photodynamic properties. This unique characteristic enables the efficient killing of cancer cells under a wide range of oxygen conditions, both normoxic (21% O2) and hypoxic (2% O2). The IC50 of Se-718 can be as low as 100 nM, and its light-to-dark toxicity ratio is an impressive 215 times higher, outperforming most photosensitizers currently available. Moreover, in vivo studies conducted with tumor-bearing mice have demonstrated the excellent antitumor effects and high safety profile of Se-718. Considering the outstanding PDT efficacy of Se-718, we are optimistic that the development of RNA-targeting photosensitizers may provide an innovative and highly effective option for cancer therapeutics in the near future.

Photocytotoxic and cellular metabolism studies of curcuminoid-BF2 nanoaggregates in human carcinoma cells

Heavy atom-free photosensitizers represent a paradigm shift in the field of photodynamic therapy (PDT), offering a safer and more versatile alternative to traditional photosensitizers. As research progresses, the development of novel heavy-atom free compounds holds the potential to enhance the effectiveness and broaden the application of PDT, enabling the way for more targeted and less toxic cancer treatments. In this article, we report the application of heavy atom free curcuminoid BF2 (Diethylamine-CUR-BF2) containing acid sensitive amine group. Diethylamine-CUR-BF2 absorbs in deep red region at ∼618 nm and has high molar absorption coefficient. Nanoaggregates of Diethylamine-CUR-BF2 dispersed in aqueous medium showed high singlet oxygen production efficiency. The release kinetics of Diethylamine-CUR-BF2 showed efficient release of photosensitizer in slight acidic medium (at pH=5.0). Further, applications of Diethylamine-CUR-BF2 nanoaggregates in photocytotoxic studies using MCF-7 and A549 cells showed IC50 values 5.15 ± 1.4 μM and 8.05 ± 0.4 μM respectively. Cell death mechanism explored for photocytotoxicity studies utilizing Diethylamine-CUR-BF2 nanoaggregates is found to be apoptosis which is considered as normal programmed cell death pathway. Additionally, NADH FLIM studies revealed that the compound had an impact on cellular metabolism, prompting a shift from OXPHOS to glycolysis.

Efficacy of 222 nm radiation on degradation of organic micropollutants in water

In this work, a dielectric barrier discharge (DBD) based exciplex lamp emitting radiation at far UV-C wavelength 222 nm has been reported. The developed UV source has been used for the degradation of organic micropollutants (OMPs), i.e., brilliant red 5B (BR-5B) and sulfamethoxazole (SMX) in a batch-scale reactor. The degradation of OMPs has been performed using an advanced oxidation process by loading hydrogen peroxide (H2O2) as a radical promotor. The degradation efficiency and energy yield in the case of BR-5B have been found twofold as compared to SMX at similar experimental conditions, because of its high molar absorption coefficient at 222 nm radiation.

The effect of photoinitiator type and filler load on physicochemical and mechanical properties of experimental light-cured resin cements through lithium disilicate ceramics of different shades and thicknesses

ObjectiveThis study investigated the influence of photoinitiator types on degree of conversion (DC), rate of polymerization (RP), flexural strength (FS), flexural modulus (FM), and light transmittance (LT) of filled and unfilled light-curable resin cements through different thicknesses and shades of lithium disilicate ceramics. MethodsLithium disilicate ceramic discs (IPS Emax Press, background [0.0], 0.5, 1.0, 2.0, 3.0, and 4.0 mm, shades A1 and BL3) were prepared. Experimental resin-based cements [TEGDMA/BisGMA (50/50 mass%)] were prepared using either camphorquinone (CQ)/amine (0.44/1.85 mol%) or TPO (0.44 mol%)], and a micro and nanofiller loads of nil (unfilled); 40/10 mass%; and 50/10 mass%). Resin cements (0.2 mm thick) were placed on the lower surface of the ceramic specimens and light-activated for 30 s from the upper surface using a Bluephase Style curing light (exitance at tip: 1236 mW/cm2 ± 1.20). LT and distribution of irradiance through the ceramics were measured using a UV–vis spectrometer and a beam profile camera, respectively (n = 3). The DC and RP were measured in real-time using mid infrared spectroscopy in attenuated total reflectance (ATR) mode (n = 3). FS and FM were measured using a universal testing machine (n = 5). Statistical analyses were performed on LT, DC, RP, FS, and FM data using a general linear model, and supplementary ANOVA and post hoc Tukey multiple comparison test were also performed (α = .05). ResultsThicknesses, shades, photoinitiator type, and fillers load significantly influenced the optical and mechanical characteristics of the resin-based materials (p < 0.05). The BL3 shade ceramic provided higher values of DC, RP, FS, FM, and LT compared with the A1 shade (p < 0.05). Increasing ceramic thickness decreased the properties of the resin-based materials (p < 0.05). Generally, TPO improved mechanical properties of the resin cement compared with CQ (p < 0.05). SignificanceThe luting process of indirect restorations may be improved by using high molar absorptivity, more reactive, and more efficient photoinitiators such as TPO, as opposed to conventional CQ. The use of such initiator may allow the placement of thicker and more opaque indirect restorations.

Matching periodate peak absorbance by far UVC at 222 nm promotes the degradation of micropollutants and energy efficiency

Periodate (PI)-based advanced oxidation processes have gained increasing interest. This study for the first time elevates the light-activation capacity of PI by using far UVC at 222 nm (UV222/PI) without extra chemical inputs. The effectiveness and the underlying mechanisms of UV222/PI for the remediation of micropollutants were studied by selecting atenolol (ATL) as a representative. PI possessed a high molar absorption coefficient of 9480–6120 M−1 cm−1 at 222 nm in the pH range of 5.0–9.0, and it was rapidly decomposed by UV222 with first-order rate constants of 0.0055 to 0.002 s−1. ATL and the six other organic compounds were effectively degraded by the UV222/PI process under different conditions with the fluence-based rate constants generally two to hundred times higher than by UVA photolysis. Hydroxyl radical and ozone were confirmed as the major contributors to ATL degradation, while direct photolysis also played a role at higher pH or lower PI dosages. Degradation pathways of ATL were proposed including hydroxylation, demethylation, and oxidation. The high energy efficiency of the UV222/PI process was also confirmed. This study provides a cost-effective and convenient approach to enhance PI light-response activity for the treatment of micropollutants.

Triphenylamine based oxime ester photoinitiator for LED-induced free radical photopolymerization and 3D printing

With the development of light-emitting diode (LED), it is increasingly important to design and prepare photoinitiators that can be used for LED excitation. We designed and synthesized four new LED oxime ester photoinitiators (TOXEs) based on the triphenylamine group. Among them, the maximum absorption wavelengths of TOXE-3 and TOXE-4 are red-shifted to 402 nm and 397 nm, and have high molar absorption coefficients (ε) of 24315 M-1cm−1 and 29915 M-1cm−1, respectively, which are higher than that of ethenone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl] ethanone 1-(O-acetyloxime) (OXE02, 342 nm, 21836 M-1cm−1), indicating that it can be used in LED polymerization. Investigating the photopolymerization properties of the TOXEs/α, ω-diacryloyl poly(ethylene glycol) (PEGDA) system, under LED@365 nm irradiation, the double bond conversion rate (DC) of TOXE-1 and TOXE-2 were 83 % and 92 %, which were higher than OXE02 (80 %). Under LED@405 nm irradiation, the DC of TOXE-3 and TOXE-4 are 80 % and 78 % respectively, which is higher than that of OXE02 (52 %). To improve the photoinitiation ability of TOXEs, a two-component photoinitiation system using bis(4-tert-butylphenyl) iodonium (Iod) as an additive was tested. The DC of TOXEs has been improved under different light sources. Under LED@480 nm irradiation, the final DC of TOXE-4/Iod/PEGDA is 83 %. In addition, TOXE-3 and TOXE-4 can be applied to the laser cladding deposition (LCD) 3D printers. At the same time, we conduct research and verification on the polymerization mechanism of TOXEs through steady-state photolysis and electron spin resonance spin trapping experiments (ESR-ST). In addition, cytotoxicity assay and thermal stability testing showed that TOXEs exhibited excellent biocompatibility and thermal stability.

Near-Infrared Absorbing Aza-BODIPY Dyes for Optoelectronic Applications.

Organic dyes that absorb light in the visible to near-infrared region have garnered significant interest, owing to their extensive utility in organic photovoltaics and various biomedical applications. Aza-boron-dipyrromethene (Aza-BODIPY) dyes are a class of chromophores with impressive photophysical properties such as tunable absorption from the visible region towards near infrared (NIR) region, high molar absorptivity, and fluorescence quantum yield. In this review, we discuss the developments in the aza-BODIPYs, related to their synthetic routes, photophysical properties and their applications. Their design strategies, modifications in chemical structures, mode/position of attachment, and their impact on photo-physical properties are reviewed. The potential applications of aza-BODIPY derivatives such as organic solar cells, photodynamic therapy, boron-neutron capture therapy, fluorescence sensors, photo-redox catalysis, photoacoustic probes and optoelectronic devices are explained.

Plasma membrane-anchored fluorescent tracker based on boron-dipyrromethene

The construction of a stable membrane tracker has significant implications for the visualization of the membrane in live cells. However, most current plasma trackers are not suitable for tracking plasma membranes for a long time due to their limited retention time. Herein, Mem580-F-Sulfo is designed to target and anchor cell membranes, and therefore track cell membranes for a longer time. This tracker is composed of a lipophilic BODIPY derivative and a hydrophilic zwitterion to form an amphiphilic structure, which enables its targeting ability toward cell membranes. Moreover, a reactive ester group is included to bind with proteins through covalent bonds in cell membranes non-specifically, which extends retention time in cell membranes. Mem580-F-Sulfo shows intense brightness (94600) with a high molar absorption coefficient of up to about 100000 L·mol-1·cm-1 and a fluorescence quantum yield of up to 0.97. It shows fast cell membrane targeting ability and long retention up to 90 min. In brief, this work has not only developed a tracker with good cell membrane targetability but also provided a new strategy for improving the targeting stability of cell membranes.

Towards sustainable solar cells: unveiling the latest developments in bio-nano materials for enhanced DSSC efficiency

Abstract Fossil fuels—instrumental in powering the nineteenth-century Industrial Revolution—are now under heightened scrutiny due to environmental concerns and carbon emissions. Consequently, there is a global impetus towards achieving carbon-neutral energy production, with solar energy emerging as a cornerstone in this transition. Over the past three decades, dye-sensitized solar cells (DSSCs) have gained increasing prominence due to their unique advantages. This review elucidates several crucial elements essential to DSSC construction, notably bio-nano materials, prized for their structural flexibility, cost-effectiveness and high molar absorption coefficient. It delves into the intricate relationship between molecular structure and DSSC performance, showcasing significant advancements with light-to-power conversion efficiencies reaching 11%. A comprehensive analysis of the photovoltaic performance of DSSCs utilizing bio-nano-based dyes offers invaluable insights into the state of this rapidly evolving industry. Key components under scrutiny include transparent conductive oxide (TCO) layers, physical techniques for metal oxide deposition onto TCO thin films, diverse dye variants and foundational knowledge of components ripe for growth and enhancement. Moreover, the review outlines the latest breakthroughs in the field, providing glimpses into the current status of prototype DSSCs.