Search

Bioimaging is a well-known process for visualizing biological substances or biological pathways in the human body at a molecular level without any intrusion. It has been used in various domains biological of chemistry, drug discovery, and disease detection, due to its potential application attributes of high resolution, high sensitivity, high selectivity, and low cost. In recent years, the transition metal-based luminescent probes or photosensitizers have a distinctive feature in optical bioimaging and photodynamic therapy, in in vivo and in vitro, as compared to other types of probes and have a strong influence on discovering biological analytes. Photodynamic therapy, a non-systemic treatment, has attracted significant attention for its ability to localize the disease. This depends on the nature of the photosensitizers, light, and reactive oxygen species (ROS), produced through electron transport or energy transfer pathways. In PDT, a photosensitizer (PS) gets activated on exposure to light of a specific wavelength and provides energy to molecular oxygen on the tissue surfaces. This generates reactive oxygen species such as superoxide, singlet oxygen, and hydroxyl radicals causing damage to cellular membranes, lipids, proteins, and DNA. Further, it also results in cell death via apoptosis and necrosis on targeted cancer cells. The current review provides a literature overview on bioimaging and PDT applications of reported ruthenium and platinum complexes acting as luminescent probes. The extensively studied ligands, in this context, are bipyridine, phenanthroline, porphyrin, BODIPY, and ferrocene. These complexes have been studied for their potential anticancer activity against different cancer cells in both light and dark conditions. In addition, these probes also possess excellent photophysical characteristics of intense emission, with significant Stokes shifts, extended lifetimes, controllable toxicity, and excellent photostability. [ABSTRACT FROM AUTHOR]

Cutaneous squamous cell carcinoma (CSCC) is common among the elderly, typically treated with surgery. However, for surgery-ineligible patients or those with non-healing wounds progressing to malignant ulcers, non-surgical local treatments are viable. This case details an 80-year-old with recurrent back CSCC and intractable malignant ulcers post-radiotherapy and chemotherapy. Treatment involved Hematoporphyrin Derivative (HpD) Photodynamic Therapy (PDT) with low-dose cindilimab immunotherapy (intravenous and intralesional). Two cycles achieved lesion remission, altering peripheral immune cell counts. HpD-PDT combined with immunotherapy is promising for treating CSCC, particularly with malignant ulcers. [ABSTRACT FROM AUTHOR]

The poor 5-year survival rate for bladder cancers is associated with the lack of efficient diagnostic and treatment techniques. Despite cystoscopy-assisted photomedicine and external radiation being promising modalities to supplement or replace surgery, they remain invasive or fail to provide real-time navigation. Here, we report non-invasive fractionated photodynamic therapy of bladder cancer with full-course real-time near-infrared-II imaging based on engineered X-ray-activated nanotransducers that contain lanthanide-doped nanoscintillators with concurrent emissions in visible and the second near-infrared regions and conjugated photosensitizers. Following intravesical instillation in mice with carcinogen-induced autochthonous bladder tumours, tumour-homing peptide-labelled nanotransducers realize enhanced tumour regression, robust recurrence inhibition, improved survival rates, and restored immune homeostasis under X-ray irradiation with accompanied near-infrared-II imaging. On-demand fractionated photodynamic therapy with customized doses is further achieved based on quantifiable near-infrared-II imaging signal-to-background ratios. Our study presents a promising non-invasive strategy to confront the current bladder cancer dilemma from diagnosis to treatment and prognosis. The poor survival rate for bladder cancers is associated with the lack of effective non-invasive theranostic techniques. Here this group reports a lanthanide-doped nanotransducer activated for real-time NIR-II imaging thereby navigates the photodynamic treatment of bladder cancer. [ABSTRACT FROM AUTHOR]

Controlling the succession of chemical processes with high specificity in complex systems is advantageous for widespread applications, from biomedical research to drug manufacturing. Despite synthetic advances in bioorthogonal and photochemical methodologies, there is a need for generic chemical approaches that can universally modulate photodynamic reactivity in organic photosensitizers. Herein we present a strategy to fine-tune the production of singlet oxygen in multiple photosensitive scaffolds under the activation of bioresponsive and bioorthogonal stimuli. We demonstrate that the photocatalytic activity of nitrobenzoselenadiazoles can be fully blocked by site-selective incorporation of electron-withdrawing carbamate moieties and restored on demand upon uncaging with a wide range of molecular triggers, including abiotic transition-metal catalysts. We also prove that this strategy can be expanded to most photosensitizers, including diverse structures and spectral properties. Finally, we show that such advanced control of singlet oxygen generation can be broadly applied to the photodynamic ablation of human cells as well as to regulate the release of singlet oxygen in the semi-synthesis of natural product drugs. Generic chemical approaches that can universally modulate photodynamic reactivity in organic photosensitizers are of high interest. Here, the authors present a strategy to fine-tune the production of singlet oxygen in multiple photosensitive scaffolds under the activation of bioresponsive and bioorthogonal stimuli. [ABSTRACT FROM AUTHOR]

The development of activatable nanoplatforms to enhance diagnostic and therapeutic performance while minimizing side effects is of great significance in treatment of chronic hepatitis B (CHB). Here, we report a novel nanomaterial composed of graphitic carbon nitride (g-C3N4) and 5-aminolevulinic acid (5-ALA), onto which our newly synthesized compound 1 is loaded, forming 5-ALA/g-C3N4@1. This nanomaterial is highly pH-sensitive and can rapidly degrade in mildly acidic environments, enabling the release of its loaded photosensitizer and compound 1, exhibiting characteristics such as fluorescence recovery and increased singlet oxygen generation. We evaluated the bioactivity of this novel composite material and explored its mechanisms of action. The effect of 5-ALA/g-C3N4@1 on the levels of HBV DNA, HBsAg and HBeAg was evaluated by treatment of HepG2.2.15 cells with the system. Our results suggest that the system can effectively inhibit HBV replication for the treatment of CHB. This work presents a novel photosensitive carrier with excellent biocompatibility and therapeutic efficacy, offering new insights into CHB research. [ABSTRACT FROM AUTHOR]

Porphyrazines (Pzs) are porphyrin derivatives that show potential application as photosensitizers for photodynamic therapy (PDT), but are still far less explored in the literature. In this work, we evaluate how the photophysics and phototoxicity of the octakis(trifluoromethylphenyl)porphyrazine (H2Pz) against tumor cells can be modulated by coordination with Mg(II), Zn(II), Cu(II) and Co(II) ions. Fluorescence and singlet oxygen quantum yields for the Pzs were measured in organic solvents and in soy phosphatidylcholine (PC) liposomes suspended in water. While H2Pz and the respective complexes with Cu(II) and Co(II) showed very low efficiency to fluoresce and to produce 1O2, the Mg(II) and Zn(II) complexes showed significantly higher quantum yields in organic solvents. The fluorescence of these two Pzs in the liposomes was sensitive to the fluidity of the membrane, showing potential use as viscosity markers. The cytotoxicity of the compounds was tested in HaCaT (normal) and A431 (tumor) cells using soy PC liposomes as drug carriers. Despite the low 1O2 quantum yields in water, the Mg(II) and Zn(II) complexes showed IC50 values against A431 cells in the nanomolar range when activated with low doses of red LED light. Their phototoxicity was ca. three times higher for the tumor cells compared to the normal ones, showing promising application as photosensitizers for PDT protocols. Considering that H2Pz and the respective Co(II) and Cu(II) complexes were practically non-phototoxic to the cells, we demonstrate the importance of the central metal ion in the modulation of the photodynamic activity of porphyrazines. [ABSTRACT FROM AUTHOR]

Nanobodies (Nbs), the smallest antigen-binding fragments with high stability and affinity derived from the variable domain of naturally occurring heavy-chain-only antibodies in camelids, have been shown as an efficient way to improve the specificity to tumors for photodynamic therapy (PDT). Nonetheless, the rapid clearance of Nbs in vivo restricts the accumulation and retention of the photosensitizer at the tumor site causing insufficient therapeutic outcome, especially in large-volume tumors. Herein, we develop photodynamic conjugates, MNB-Pyra Nbs, through site-specific conjugation between 7D12 Nbs and type I photosensitizer MNB-Pyra (morpholine-modified nile blue structure connected to pyrazolinone) in a 1:2 ratio. The photosensitizers with long-term retention can be released at the tumor site by reactive oxygen species cleavage after illumination, accompanied with fluorescence recovery for self-reporting the occurrence of PDT. Ultimately, a single dose of MNB-Pyra Nbs demonstrate highly effective tumor suppression with high biosafety in the large-volume tumor models after three rounds of PDT. This nanobody conjugate provides a paradigm for the design of precise long-time retention photosensitizers and is expected to promote the development of PDT. Cancer therapy with nanobodies (Nbs) is limited by its effective accumulation at the tumor sites. Here the authors develop a Nile blue-based photosensitizer conjugating with pyrazolone-derived Nbs thereby achieving effective retention on tumor sites and suppressing tumor progression through photodynamic therapy. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is a light-based anticancer therapy that can induce tumor necrosis and/or apoptosis. Two important factors contributing to the efficacy of PDT are the concentration of the photosensitizer in the tumor tissue and its preferential accumulation in the tumor tissue compared to that in normal tissues. In this study, we investigated the use of optical imaging for monitoring whole-body bio-distribution of the fluorescent (660 nm) photosensitizer Bremachlorin in vivo, in a murine pancreatic ductal adenocarcinoma (PDAC) model. Moreover, we non-invasively, examined the induction of tumor necrosis after PDT treatment using near-infrared fluorescent imaging of the necrosis avid cyanine dye IRDye®-800CW Carboxylate. Using whole-body fluorescence imaging, we observed that Bremachlorin preferentially accumulated in pancreatic tumors. Furthermore, in a longitudinal study we showed that 3 hours after Bremachlorin administration, the fluorescent tumor signal reached its maximum. In addition, the tumor-to-background ratio at all-time points was approximately 1.4. Ex vivo, at 6 hours after Bremachlorin administration, the tumor-to-muscle or -normal pancreas ratio exhibited a greater difference than it did at 24 hours, suggesting that, in terms of efficacy, 6 hours after Bremachlorin administration was an effective time point for PDT treatment of PDAC. In vivo administration of the near infrared fluorescence agent IRDye®-800CW Carboxylate showed that PDT, 6 hours after administration of Bremachlorin, selectively induced necrosis in the tumor tissues, which was subsequently confirmed histologically. In conclusion, by using in vivo fluorescence imaging, we could non-invasively and longitudinally monitor, the whole-body distribution of Bremachlorin. Furthermore, we successfully used IRDye®-800CW Carboxylate, a near-infrared fluorescent necrosis avid agent, to image PDT-induced necrotic cell death as a measure of therapeutic efficacy. This study showed how fluorescence can be applied for optimizing, and assessing the efficacy of, PDT. [ABSTRACT FROM AUTHOR]

The photophysical properties and efficiency of photosensitized singlet oxygen formation by meso-tetrakis(4- N-methylpyridyl)porphyrin in a complex with hydroxyapatite nanoparticles were studied. At least three types of complexes characterized by different access of oxygen to porphyrin molecules were shown to form on the surface of the hydroxyapatite nanoparticles. Rotation of the pyridyl substituents of porphyrin in the complex with hydroxyapatite nanoparticles was found to be significantly hindered, while porphyrin molecules on the surface of the nanoparticles were in a less polar environment than in water. The quantum yield of photosensitized singlet oxygen formation was observed to decrease by at least nine times for porphyrin in the complex with hydroxyapatite nanoparticles. Porphyrin was released from hydroxyapatite nanoparticles and the efficiency of singlet oxygen formation increased although it did not reach the values characteristic for free porphyrin if the pH decreased to less than 5.0 (pH < 5.0). [ABSTRACT FROM AUTHOR]

Studies of the morphological features and influence of photosensitized WS2, MoS2, and ZnS nanoparticles synthesized by laser ablation and fragmentation in liquid on human fibroblast cells are presented. Microscopy data showed that all types of nanoparticles were spherical in shape, except for WS2 nanoparticles, which were planar. Spherical nanoparticle sizes ranged from 20 to 90 nm, which meets the requirements for theranostics. Cytotoxicity studies demonstrated that MoS2 nanoparticles had high biocompatibility, while other nanoparticle types slowed cell growth, indicating future potential for use in the treatment of various diseases in living organisms. [ABSTRACT FROM AUTHOR]

The development of Type I photosensitizers (PSs) is of great importance due to the inherent hypoxic intolerance of photodynamic therapy (PDT) in the hypoxic microenvironment. Compared to Type II PSs, Type I PSs are less reported due to the absence of a general molecular design strategy. Herein, we report that the combination of typical Type II PS and natural substrate carvacrol (CA) can significantly facilitate the Type I pathway to efficiently generate superoxide radical (O2–•). Detailed mechanism study suggests that CA is activated into thymoquinone (TQ) by local singlet oxygen generated from the PS upon light irradiation. With TQ as an efficient electron transfer mediator, it promotes the conversion of O2 to O2–• by PS via electron transfer-based Type I pathway. Notably, three classical Type II PSs are employed to demonstrate the universality of the proposed approach. The Type I PDT against S. aureus has been demonstrated under hypoxic conditions in vitro. Furthermore, this coupled photodynamic agent exhibits significant bactericidal activity with an antibacterial rate of 99.6% for the bacterial-infection female mice in the in vivo experiments. Here, we show a simple, effective, and universal method to endow traditional Type II PSs with hypoxic tolerance. Developing Type I photosensitizers (PSs) is vital for tackling hypoxic intolerance of photodynamic therapy in the hypoxic microenvironment, but elusive due to the lack of a general molecular design strategy. Here the authors report a universal and simple method to covert traditional Type II PSs to Type I PSs. [ABSTRACT FROM AUTHOR]

Bacterial infections are a global health concern, particularly due to the increasing resistance of bacteria to antibiotics. Multi-drug resistance (MDR) is a considerable challenge, and novel approaches are needed to treat bacterial infections. Photodynamic inactivation (PDI) of microorganisms is increasingly recognized as an effective method to inactivate a broad spectrum of bacteria and overcome resistance mechanisms. This study presents the synthesis of a new cationic 5,15-di-imidazolyl porphyrin derivative and the impact of n-octanol/water partition coefficient (logP) values of this class of photosensitizers on PDI efficacy of Escherichia coli. The derivative with logP = –0.5, IP-H-OH2+, achieved a remarkable 3 log CFU reduction of E. coli at 100 nM with only 1.36 J/cm2 light dose at 415 nm, twice as effective as the second-best porphyrin IP-H-Me2+, of logP = –1.35. We relate the rapid uptake of IP-H-OH2+ by E. coli to improved PDI and the very low uptake of a fluorinated derivative, IP-H-CF32+, logP ≈ 1, to its poor performance. Combination of PDI with cinnamaldehyde, a major component of the cinnamon plant known to alter bacteria cell membranes, offered synergic inactivation of E. coli (7 log CFU reduction), using 50 nM of IP-H-OH2+ and just 1.36 J/cm2 light dose. The success of combining PDI with this natural compound broadens the scope of therapies for MDR infections that do not add drug resistance. In vivo studies on a mouse model of wound infection showed the potential of cationic 5,15-di-imidazolyl porphyrins to treat clinically relevant infected wounds. [ABSTRACT FROM AUTHOR]

Background: Tooth discoloration is a common concern in antimicrobial photodynamic therapy (aPDT) using various photosensitizers (PS). Toluidine Blue (TB), Methylene Blue (MB), Phthalocyanine (Pc), and 2-mercaptopyridine-substituted zinc phthalocyanine (TM-ZnPc) are among those studied, but their relative impacts on tooth discoloration remain unclear. Aim: This study aimed to compare the effects of TB, MB, Pc, and TM-ZnPc in aPDT on tooth discoloration, utilizing a controlled experimental setup. Materials and Methods: The study comprised seventy-five single-rooted incisors with root canals. Following meticulous preparation, a standardized area on the crown surface was designated for examination, and precise measurements of the initial tooth colors were recorded. Samples were randomly divided into five groups: Negative control, MB, TM, Pc, and TM-ZnPc. Photoactivation was performed using LED light, and color measurements were taken at multiple time points up to 90 days. Data were converted to Lab* color values of the CIE Lab* color system (International Commission on Illumination, Vienna, Austria), and ΔE values were calculated. Statistical analysis was performed using Two-way ANOVA and Post-Hoc Tukey tests (p < 0.05). Results: At day 7 and 30, TM-ZnPc and Pc caused less discoloration compared to MB and TB. TM-ZnPc caused more tooth discoloration compared to Pc (p < 0.05). Compared to baseline, MB and TM-ZnPc caused more tooth discoloration at 30 days and TB caused more tooth discoloration at 90 days (p < 0.05). No significant difference was observed in terms of tooth discoloration at all periods evaluated after Pc application (p > 0.05). All photosensitizers tested in the study caused tooth coloration. Conclusion: All PS induced clinically detectable tooth discoloration, with TB and MB causing more significant discoloration compared to Pc and TM-ZnPc at certain time points. TM-ZnPc and Pc demonstrated more stable coloration levels over time, suggesting their potential reliability in aPDT applications. This study highlights the importance of selecting appropriate PS to minimize tooth discoloration in aPDT, with Pc showing promise in this regard. [ABSTRACT FROM AUTHOR]

Perylenequinones (PQs) are natural photosensitizing compounds used as photodynamic therapy, and heat stress (HS) is the main limiting factor of mycelial growth and secondary metabolism of fungi. This study aimed to unravel the impact of HS-induced Ca2+ and the calcium signaling pathway on PQ biosynthesis of Shiraia sp. Slf14(w). Meanwhile, the intricate interplay between HS-induced NO and Ca2+ and the calcium signaling pathway was investigated. The outcomes disclosed that Ca2+ and the calcium signaling pathway activated by HS could effectively enhance the production of PQs in Shiraia sp. Slf14(w). Further investigations elucidated the specific mechanism through which NO signaling molecules induced by HS act upon the Ca2+/CaM (calmodulin) signaling pathway, thus propelling PQ biosynthesis in Shiraia sp. Slf14(w). This was substantiated by decoding the downstream positioning of the CaM/CaN (calcineurin) pathway in relation to NO through comprehensive analyses encompassing transcript levels, enzyme assays, and the introduction of chemical agents. Concurrently, the engagement of Ca2+ and the calcium signaling pathway in heat shock signaling was also evidenced. The implications of our study underscore the pivotal role of HS-induced Ca2+ and the calcium signaling pathway, which not only participate in heat shock signal transduction but also play an instrumental role in promoting PQ biosynthesis. Consequently, our study not only enriches our comprehension of the mechanisms driving HS signaling transduction in fungi but also offers novel insights into the PQ synthesis paradigm within Shiraia sp. Slf14(w). Key points: • The calcium signaling pathway was proposed to participate in PQ biosynthesis under HS. • HS-induced NO was revealed to act upon the calcium signaling pathway for the first time. [ABSTRACT FROM AUTHOR]

A series of 4-carboxyphenyl/4-hydroxyphenyl meso-substituted porphyrins were synthesized, purified, and characterized. The compounds exhibited anti-HIV-1 activities, in vitro, under both non-photodynamic (non-PDT) and photodynamic (PDT) conditions. Specifically, the porphyrins inhibited HIV-1 virus entry, with c-PB2(OH)2 and PB(OH)3 showing significant anti-HIV-1 activity. All of the porphyrins inhibited HIV-1 subtype B and C virus entry under PDT conditions. Our study demonstrated that the compounds bearing combinations of 4-carboxyphenyl/4-hydroxyphenyl moieties were not toxic even at higher concentrations, as compared to the reference porphyrins 5,10,15,20-tetra-(4-carboxyphenyl)porphyrin (TCPP) and 5,10,15,20-tetra-(4-hydroxyphenyl)porphyrin (THPP), under PDT conditions. This study underscores the promising potential of these compounds as HIV entry inhibitors in both non-PDT and PDT scenarios. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cell (DSSC) is a photovoltaic device that can be produced from natural source pigments or natural dyes. The selection of natural dyes for DSSC application is currently under research. The utilization of natural dye materials that are easy to obtain, cost-effective, and non-toxic can reduce waste during DSSC fabrication. Natural dyes can be extracted from plants through extraction and chromatography methods. The suitability and viability of utilizing natural dyes as photosensitizers in DSSCs can be predicted using appropriate software simulation by varying related parameters to produce high power conversion efficiency. In this context, the purpose of the review is to highlight the evolution of performance improvement in the development of DSSCs with consideration of natural dye extraction and software simulation. This review also focuses on the results of extracting natural dyes from herbal ingredients, which are still very limited in information, and several parts of herbal plants that can be used as natural dye sources in the future of solid-state DSSCs have been identified. Based on the results of this review, the highest efficiency was obtained for the DSSC that used chlorophyll pigments as natural dyes using Peltophorum pterocarpum leaves with 6.07%, followed by anthocyanin pigments as natural dyes using raspberries (black) fruits with 1.5%, flavonoid pigments as natural dyes using Curcuma longa herbs with 0.64%, and flavonoid pigments as natural dyes using Indigofera tinctoria flowers with 0.46%. [ABSTRACT FROM AUTHOR]

The continuous and sustainable photo-activity on micro- or nano-carriers has always been a key stepping stone in the industrialization of photo-catalysis, photo-synthesis, and photo-degradation. Herein, we report a new series of positively charged hollow microspheres carrying porphyrin moieties. Such hollow spheres are formed through crosslinking of well-ordered porous thin laminates, initiated by co-assembly of regular monomers and those decorated with porphyrin moieties. On the surface of an individual sphere, densely distributed positive sites attract anionic reactants. The superficial porphyrin decomposes the accumulated reactants under 1 Sun. After degradation and release of products, the photoactive sites are thereby renewed. We demonstrate that polymer network (1:10) exhibited superior sustainable photocatalytic performance with complete degradation of methyl orange (MO) in 40 min with no observable performance deterioration after six cycles. The established close loop of adsorption–reaction–release cycle makes possible many efficient and continuous photo-catalytic processes. [ABSTRACT FROM AUTHOR]

The analysis to plan for high-efficiency with affordable molecules such as coumarin, prop-1-ene with 2-cyano-N-hydroxyacrylamide (A1), 2-cyanoprop-2-enedithioic acid (A2), 1-cyanovinylphosphonic acid (A3) and 1-cyanoethenesulfinic acid (A4) are one of the most important aspects of improving the non-linear optical (NLO) property besides dye-sensitized solar cells (DSSCs) applications. NKX-2311 has been taken as a literature molecule, it contains coumarin as a donor moiety (D), prop-1-ene as a π-spacer (π) and cyanoacrylic acid as an acceptor moiety (A). The three fragments that make up the D-π-A structure. The family of A1-A4 metal-free organic coumarin NKX-2311 dye derivatives have examined for applications involving optoelectronics in this research. Density functional theory (DFT) and time-dependent DFT (TD-DFT) techniques utilizing quantum chemical calculations, the molecular electronic structures, ultra-violet visible (UV–Vis) absorption, transition density matrix (TDM), electron–hole mobilities (reorganization energies) and photovoltaic (PV) characteristics of the A1-A4 sensitizers have been calculated. For optoelectronic devices, the effect of chemical alteration on the UV–Vis spectra about PV parameters of the NKX-2311 were illustrated. The performance of hybrid functionals such as B3LYP, CAM-B3LYP and ωB97XD was assessed to compare with the absorption wavelength of NKX-2311. The B3LYP method and NKX-2311 have had a superior fit based on the selected functionals. Consequently, the B3LYP/6-31G(d) theory has been used to study the excited state computations of A1-A4 dyes at UV–Vis wavelengths. The findings demonstrate that A2 dye has a smaller energy gap and that UV–Vis spectra were constantly redshifted. According to the computational outcomes, the A1-A4 sensitizers can respond positively to the processes of dye regeneration and electron injection based on their lowest unoccupied and highest occupied molecular orbitals (LUMOs and HOMOs), respectively. A2 dye has the greatest hole mobility due to its lowest λ + value of 0.1701 eV, while A1 dye has extreme electron mobility due to its lowest λ - value of 0.2273 eV. The NLO property of molecules A1-A4 has been calculated by two ways such as polarizability and first-order hyperpolarizability. The most promising candidate for NLO performance has been identified as the dye with computed values of A2. The results would serve as a useful resource for any upcoming demands and also more advantageous for obtaining optoelectronic applications. [ABSTRACT FROM AUTHOR]

Self-disinfecting materials that are both safe and scalable for production are increasingly in demand, particularly in healthcare settings where they can be used to combat hospital-acquired infections (HAIs). Here, we employed the natural food colorant chlorophyllin (E140ii) as a photosensitizer to prepare photodynamic antimicrobial materials through both chemical conjugation and electrospinning, resulting in chlorophyllin-grafted cotton fabric (Chl-fabric) and chlorophyllin-embedded polyacrylonitrile nanofibers (Chl-NF), respectively. The materials were characterized by a number of physical methods, as was their ability to generate singlet oxygen upon visible light illumination. The best results with Chl-fabric yielded 99.998% inactivation of vancomycin-resistant E. faecium and 99.994% of methicillin-resistant S. aureus after 60 min visible light illumination (400–700 nm, 80 ± 5 mW/cm2), whereas Chl-NF inactivated both bacteria by 99.9999%. Feline calicivirus was also photodynamically susceptible, with 99.8% inactivation by both materials. Gram-negative Klebsiella pneumoniae was not initially susceptible to photodynamic inactivation by Chl-NF, however addition of the photothermal agent MoS2 fully inactivated (99.9999%) this pathogen under NIR illumination, indicative of synergistic photothermal and photodynamic activities. These findings suggest that chlorophyllin can be used in photodynamic antimicrobial materials against drug-resistant Gram-positive bacteria, and that its efficacy can be synergistically amplified in the presence of a photothermal agent against Gram-negative pathogens. [ABSTRACT FROM AUTHOR]

Next-generation photodynamic therapy (PDT) is envisaged to be based on light-activated photosensitizers with small sizes and high performance, eradicating microbial and deadly cancer cells without harming healthy cells. Here, nitrogen-doped graphene quantum dots (N-GQDs) are hydrothermally synthesized and composited with TiO2 nanoparticles (NPs). The resulting N-GQDs/TiO2 nanocomposite is then examined as a PDT photosensitizer with an average size of 21 nm. Reactive oxygen species (ROS) production by photo-excited N-GQDs, TiO2, NPs and N-GQDs/TiO2 nanocomposite is investigated using anthracene and methylene blue as chemical probes for the identification of singlet oxygen and hydroxyl radical. The ROS-production ability of the nanocomposite is found to be considerably higher than that of N-GQDs and TiO2 NPs, achieving reduction rates of 94% and 93% in the absorption intensity of anthracene and methylene blue under UVA irradiation for 75 and 60 min, respectively. The higher ROS production is attributed to the efficient energy transfer from N-GQDs to TiO2 NPs due to the fluorescence resonance energy transfer effect as well as a reduction in the recombination of photogenerated electron–hole pairs. Furthermore, afterglow emission intensity of the nanocomposite irradiated by UVA light slightly changes after 360 s. Alternatively, no decrease is observed in the absorption intensity of the chemical probes in the presence of N-GQDs/TiO2 nanocomposite under no irradiation, indicating its lack of dark toxicity. Therefore, the proposed biocompatible TiO2-based nanocomposite with long-lived afterglow, intense photoluminescence, and high ROS production ability can be employed as a photosensitizer for cancer treatment using PDT. [ABSTRACT FROM AUTHOR]

Tomato leaf miner, Tuta absoluta (Lepidoptera: Gelechiidae), is a serious insect pest on tomato plants worldwide. Its larvae can cause up to 100% damage if not controlled. Furthermore, using of chemical pesticides is causing serious threat to environment and human health. The effect of two photosensitizers; magnesium and copper chlorophyllin (Mg-Chl and Cu-Chl) alone and two nanomaterials (GO and Ag) over their photosensitizers (Mg-Chl /Go, Mg-Chl /Ag, Cu-Chl/ Go, and Cu-Chl /Ag) on T. absoluta in tomato field at two seasons were studied. The tested concentrations of photosensitizer and nanocomposites were 10−3 (100 ml/L), 10−4 (10 ml/L) and 10–5 (1 ml/L). The effect of photosensitizer and nanocomposites on reduction % of Tuta absoluta, tomato plants growth, yield, and quality were studied. The number of tunnels was recorded, the reduction percentages for each treatment were calculated compared to control before and after 1, 5, and 7 days of spraying. Results showed that the reduction in the number of tunnels after one day of spraying with photosensitizers (Mg-Chl and Cu-Chl) at the highest concentration (10−3) was 72.79 and 70.52% in the 1st season and 77.95 and 60.08% in the 2nd season. The reduction percentage increased gradually with the number of days after spraying and reached 100% after seven days in both seasons. The reduction percentage reached 100% in plants treated with all nanomaterial concentrations after five days of spraying in the 1st season and after one day of spraying in the second season. Photosensitizer and nanocomposites treatments at all concentrations positively affected all vegetative growth parameters of tomato plants compared with insecticides and control. The highest concentration of all treatments increased yield and enhanced the storability of tomato fruits. The yield after treatment with Mg-Chl was 28.67 tons/fed, which was more than the yield of those treated with Cu-Chl (24.8 tons/fed). Loading nano silver (Ag) over Mg-Chl achieved tomato yield (35.18 tons/fed) compared with the loading of nano graphene oxide (Go) (32.95 tons/fed). Therefore, treatment with these materials can be recommended in the IPM program to control T. absoluta in tomato fields. [ABSTRACT FROM AUTHOR]

Basal cell carcinoma (BCC) is the most common skin cancer, for which there are multiple treatment options, including the gold standard Mohs micrographic surgery (MMS), surgical excision, electrodesiccation and curettage, radiation therapy, cryosurgery, and photodynamic therapy (PDT). While PDT is currently approved for treating actinic keratosis, it has been used off-label to treat BCC patients who may not tolerate surgery or other treatment modalities. We present a review of the efficacy of these modalities and describe important considerations that affect the usage of PDT and MMS. ALA-PDT and MAL-PDT are both efficacious treatment options for lower-risk BCC that can serve as non-invasive alternatives to surgical excision with favorable cosmetic outcomes in patients unsuitable to undergo surgery. In particular, PDT may be considered an adjuvant for the prevention and treatment of BCC lesions in patients with some genetic syndromes such as Gorlin syndrome, and in combination with surgical excision in lesions presenting in certain locations. Limitations to PDT include lack of margin control to prevent recurrence, pain, and cost of certain photosensitizers. Future studies should investigate the role of PDT as adjunctive therapy, standardization of protocols, and causes and ways to address recurrence following PDT treatment. [ABSTRACT FROM AUTHOR]

The study of a macromolecule derived from DPP and triphenylamine, (DPP-BisTPA) by computational chemistry, its synthesis by direct arylation, optical characterization (UV-Vis and fluorescence) and electrochemistry (cyclic voltammetry), as well as its evaluation as a generator of reactive oxygen species indirectly, through the degradation of uric acid. The results obtained by DFT using B3LYP/6-31G (d, p) and TD-DFT using CAM-B3LYP/6-31G (d, p) reveal values of energy levels of the first singlet and triplet excited state that indicate a possible intersystem crossover and the possible generation of reactive oxygen species by a type I mechanism. The compound presents an absorption region within the phototherapeutic window. The electrochemical bandgap is 1.64 eV which suggests a behavior as a semiconductor. DPP-BisTPa were processed as hemispherical nanoparticles with a size around 100 nm, and NPOs were evaluated as a photosensitizer with a ROS generation yield of 4% using a photodynamic therapy flashlight as the light source. [ABSTRACT FROM AUTHOR]

New series of cyanoaryl porphyrazines with 4-(2-propinyloxy)phenyl and 4-benzyleoxyphenyl fragments in a macrocycle framing was reported. All the compounds reported on exhibit a good potential as the effective photosensitizer for photodynamic therapy (PDT). Moreover, they demonstrate unique combination of photodynamic activity and double sensory capacity toward environmental rigidity and polarity that is the promising platform for specifically personalized medicine. [ABSTRACT FROM AUTHOR]

In this study, a natural dye from the flowers of Mussaenda erythrophylla extracted separately in ethanol and de-ionized water was employed as a photosensitizer in DSSCs. The quantitative phytochemical analyses were performed on both extracts. The existence of flavonoids (anthocyanin) and chlorophyll a pigments in the ethanol extract of the dye was confirmed by the UV–Visible spectroscopy. The stability study performed on the said ethanol extract confirmed that the dye extracted in ethanol was stable in the dark and did not degrade for nearly 50 days. The presence of the dye molecules and uniform adsorption of them on the P25-TiO2 surface were confirmed by fourier transform infrared spectroscopy and atomic force microscopy, respectively. Moreover, the influence of dye concentration and pH on the optical properties of the dye was also studied. The natural dye extracted in ethanol was employed in DSSCs, fabricated by utilizing the said dye sensitized P25-TiO2 photoanodes, I - / I 3 - electrolyte, and Pt counter electrode. Photovoltaic performances of the fabricated devices were determined under simulated irradiation with the intensity of 100 mWcm–2 using AM 1.5 filter. The device fabricated with the P25-TiO2 photoanode sensitized by the dye extracted in ethanol at pH = 5 exhibited the best power conversion efficiency (PCE) of 0.41% with the JSC of 0.98 mAcm–2 which could be attributed to the optimum light absorption in the visible region of solar spectrum by the chlorophyll a and anthocyanin molecules in the extracted natural dye. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic exposes our vulnerability to viruses that acquire the ability to infect our cells. Classical disinfection methods are limited by toxicity. Existing medicines performed poorly against SARS-CoV-2 because of their specificity to targets in different organisms. We address the challenge of mitigating known and prospective viral infections with a new photosensitizer for antimicrobial photodynamic therapy (aPDT). Photodynamic inactivation is based on local oxidative stress, which is particularly damaging to enveloped viruses. We synthesized a cationic imidazolyl chlorin that reduced by > 99.999% of the percentage inhibition of amplification of SARS-CoV-2 collected from patients at 0.2 µM concentration and 4 J cm–2. Similar results were obtained in the prevention of infection of human ACE2-expressing HEK293T cells by a pseudotyped lentiviral vector exhibiting the S protein of SARS-CoV-2 at its surface. No toxicity to human epidermal keratinocytes (HaCaT) cells was found under similar conditions. aPDT with this chlorin offers fast and safe broad-spectrum photodisinfection and can be repeated with low risk of resistance. [ABSTRACT FROM AUTHOR]

Infectious diseases are caused by various pathogenic microorganisms that break through the human immune barrier, then reproduce and mutate in human cells, thus causing invasive disease. Despite many recent scientific and technological advances in fields, such as genetics, chemistry, and protein engineering, and in the efficiency of drug research and development, the discovery and development of novel and potent anti-infectious disease agents have still lagged behind. It is often challenging to keep up with the emergence and mutation of new pathogenic microorganisms, which leads to the emergence of more resistant pathogenic microorganisms. The emergence of aggregation-induced emission (AIE) fluorogens with high luminescence yields and high reactive oxygen species (ROS) production rates provides scientists with a new strategy for the prevention and treatment of pathogenic microorganisms. Due to their advantages in terms of brightness, biocompatibility, photostability, and positive correlation, AIE fluorogens (AIEgens) have great potential in biological applications. This review presents a systemic overview of recent progress in AIEgen-based platforms for the photodynamic therapy (PDT) of infectious diseases, which has emerged as a promising noninvasive alternative to traditional antibiotics for combating the drug resistance of infectious diseases. This review is mainly divided into two parts according to the type of pathogenic microorganisms: a section on bacterial and fungal infections (e.g., eye, skin, oral cavity, and blood infections), and a section on viral infections. The future prospects and potential clinical applications of AIEgens are also discussed in detail. In addition to motivating further interest in this field, this review is intended to promote ideas for the further exploration of AIEgens and the development of more advanced AIEgens in a broader range of biomedical and clinical applications. [ABSTRACT FROM AUTHOR]

A series of efficient donor-π-acceptor tiny organic dyes NA1, NA6, and NA7 were developed as co-sensitizers to improve the photovoltaic performance of the black dye-based dye-sensitized solar cells (DSCs). Dye aggregation on the TiO2 surface was reduced, and improved sensitizer coverage was achieved through the introduction of a long alkoxy group in the donor part, the tuning of the anchoring parts, and the π-spacer of the co-sensitizer NA6. The spectral photoresponse was thereby dramatically improved across the spectrum from the ultraviolet to the visible range, and the recombination process was suppressed for the (black dye+NA6) co-sensitized cell compared with a single black dye. The co-sensitized black dye+NA6-based DSCs show a considerable increase in Voc (open-circuit voltage), Jsc (short-circuit current density), and FF (fill factor) to 721 mV, 21.64 mAcm−2 and 0.733, respectively. A higher efficiency of 11.43% was, consequently, achieved for the (black dye+NA6) co-sensitized cell compared to 10.56% for the DSCs based on a single black dye. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) fundamentally relies on local generation of PDT precursor states in added photosensitizers (PS), particularly triplet and photo-radical states. Monitoring these states in situ can provide important feedback but is difficult in practice. The states are strongly influenced by local oxygenation, pH and redox conditions, often varying significantly at PDT treatment sites. To overcome this problem, we followed local PDT precursor state populations of PS compounds, via their fluorescence intensity response to systematically varied excitation light modulation. Thereby, we could demonstrate local monitoring of PDT precursor states of methylene blue (MB) and IRdye700DX (IR700), and determined their transitions rates under different oxygenation, pH and redox conditions. By fiber-optics, using one fiber for both excitation and fluorescence detection, the triplet and photo-radical state kinetics of locally applied MB and IR700 could then be monitored in a tissue sample. Finally, potassium iodide and ascorbate were added as possible PDT adjuvants, enhancing intersystem crossing and photoreduction, respectively, and their effects on the PDT precursor states of MB and IR700 could be locally monitored. Taken together, the presented procedure overcomes current methodological limitations and can offer feedback, guiding both excitation and PDT adjuvant application, and thereby more efficient and targeted PDT treatments. [ABSTRACT FROM AUTHOR]

The relatively low photon-to-current conversion efficiency of dye-sensitized solar cells is their major drawback limiting widespread application. Light harvesting, followed by a series of electron transfer processes, is the critical step in photocurrent generation. An in-depth understanding and fine optimization of those processes are crucial to enhance cell performance. In this work, we synthesize two new bi-ruthenium sensitizers with extended anchoring ligands to gain insight into underlying processes determining photovoltaic action mechanisms. The structure of the compounds has been confirmed, and their properties have been thoroughly examined by various techniques such as NMR, IR, elemental analysis UV–Vis, cyclic voltammetry, and electroabsorption. The experimental characterization has been supported and developed via extensive quantum-chemical calculations, giving a broad view of the presented molecules' properties. Finally, the DSSC devices have been assembled utilizing obtained dyes. The photovoltaic and EIS measurements, combined with performed calculations and fundamental dyes characterization, unraveled an intramolecular electron transfer as an initial step of the electron injection process at the dye/semiconductor interface. The overall photovoltaic action mechanism has been discussed. Our study demonstrates the significance of the anchoring group architecture in the molecular design of new sensitizers for DSSC applications. [ABSTRACT FROM AUTHOR]

A DFT and TDDFT study has been carried out on Red Nile dye (RN) and on two chalcogens-derivatives in which the carbonyl-oxygen was replaced by Sulfur-(SNR) and Selenium-(SeNR) in order to evaluate the effect of such substitution on their photophysical properties. Inspection of Type I and Type II photoreactions have been achieved exploring the absorption properties, computing spin–orbit coupling, proposing the most plausible deactivation channels leading to the population of excited triplet states and through the analysis of vertical electron affinities and ionization potentials. Our data show a useful bathochromic shift of the lowest energy 1ππ* absorption band as the size of the substituted atom increases combined with an enhancement of the SOC values for the main nπ* → ππ* S1 → T1 deactivation pathways, suggesting a more efficient ISC mechanism for the thio- and seleno-dye. Moreover, the introduction of selenium in the NR dye has the intriguing effect to promote also the electron transfer reaction producing the O2(−)• species through the TypeI mechanism, allowing us to propose that designed dye as a dual TypeI/II PS. Our study supports the strategy to afford heavy-atom effect by using chalcogens showing as it could be successfully exploited to achieve metal-free PSs with desirable properties. [ABSTRACT FROM AUTHOR]

To improve bacterial photodynamic inactivation (PDI), this work analyzes the photodynamic effect caused by the combination of photosensitizers (PSs) on two bacterial models and different growth mode. Simultaneous administration of PSs from different families, zinc(II) 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]phthalocyanine (ZnPPc4+), 5,10,15,20-tetra(4-N,N,N-trimethylammonium phenyl)porphyrin (TMAP4+), meso-tetrakis(9-ethyl-9-methyl-3-carbazoyl)chlorin (TEMCC4+) and 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl] chlorin (TAPC) was investigated against Staphylococcus aureus and Escherichia coli, in planktonic form, biofilm and growth curve. Various PSs combinations showed greater inactivation compared to when used separately under the same conditions but at twice the concentration. However, differences were found in the effectiveness of the PSs combinations on Gram positive and negative bacteria, as well as in planktonic or biofilm form. Likewise, the combination of three PSs completely stopped E. coli growth under optimal nutritional conditions. PSs combination allows extending the range of light absorption by agents that absorb in different areas of the visible spectrum. Therefore, PDI with combined PSs increases its antimicrobial capacity using agents' concentrations and light fluences lower than those necessary to cause the same effect as single PS. These advances represent a starting point for future research on the potentiation of PDI promoted by the combined use of PSs. [ABSTRACT FROM AUTHOR]

Applications of lasers in phototherapy have been the trend for the last few decades. The photodynamic therapy process normally depends on photosensitizers and laser beams. Through this study, indocyanine green has been used as a photosensitizer, which is normally activated using laser lines between 750 and 805 nm. The activity of the indocyanine green to do fluorescence by other pulsed laser sources has been tested by fluorescence technique, and it has been proven that the laser lines at 810, 940, and 980nm are able to excite the indocyanine green with different extents. The indocyanine green activation has been tested by several laser lines (810, 940, and 980 nm) commonly used as surgical lasers. The generated oxygen has been measured after irradiating the indocyanine green with the different laser lines. A comparison has been made between laser irradiation as a pinpoint and a broad beam. It is found that the wide beam is more effective in activating oxygen production. In the end, it is concluded that lines 810 and 940nm were effective in activating the used dye, while the 980nm activity did not show enough efficiency. [ABSTRACT FROM AUTHOR]

In this study, Schiff base substituted phthalocyanine complexes (Zn1c, Zn2c) and their quaternized derivatives (Q-Zn1c, Q-Zn2c) were synthesized for the first time. Their structures have been characterized by FT-IR, 1H-NMR, UV–Vis, mass spectrometry and elemental analysis as well as. The photophysicochemical properties (fluorescence, singlet oxygen and photodegradation quantum yield) of these novel complexes were investigated in dimethylsulfoxide (DMSO) for both non-ionic and quaternized cationic phthalocyanine complexes and in aqueous solution for quaternized cationic phthalocyanine complexes. Water soluble cationic phthalocyanine compounds gave good singlet oxygen quantum yield (0.65 for Q-Zn1c, 0.66 for Q-Zn2c in DMSO; 0.65 for Q-Zn2c in aqueous solution). The binding of Q-Zn1c and Q-Zn2c to BSA/DNA was studied by using UV–Vis and fluorescence spectroscopy and these. Studies indicate that the mechanism of BSA quenching by quaternized zinc(II) phthalocyanines was static quenching. Quaternized zinc(II) phthalocyanines interacted with ct-DNA by intercalation. Quaternized zinc(II) phthalocyanines caused a decrease in cell viability and triggered apoptotic cell death after PDT was applied at a concentration that did not have a toxic effect on their own. Q-Zn1c and Q-Zn2c mediated PDT reduced the activity of SOD, CAT, GSH while increased MDA level in the prostate cancer cells. Furthermore, expression of apoptotic proteins after PDT was examined. The results revealed that the synthesized water soluble quaternized zinc(II) phthalocyanine complexes (Q-Zn1c and Q-Zn2c) are promising potential photosensitizers for PDT. [ABSTRACT FROM AUTHOR]

Opinion Statement : Photodynamic therapy (PDT) has garnered increasing attention in cancer treatment because of its advantages such as minimal invasiveness and selective destruction. With the development of PDT, impressive progress has been made in the preparation of photosensitizers, particularly porphyrin photosensitizers. However, the limited tissue penetration of the activating light wavelengths and relatively low light energy capture efficiency of porphyrin photosensitizers are two major disadvantages in conventional photosensitizers. Therefore, tissue penetration needs to be enhanced and the light energy capture efficiency of porphyrin photosensitizers improved through structural modifications. The indirect excitation of porphyrin photosensitizers using fluorescent donors (fluorescence resonance energy transfer) has been successfully used to address these issues. In this review, the enhancement of the light energy capture efficiency of porphyrins is discussed. [ABSTRACT FROM AUTHOR]

Metallo-phthalocyanines (MPc) are common photosensitizers with ideal photophysical and photochemical properties. Also, these molecules have shown to interact with non-canonical nucleic acid structures, such as G-quadruplexes, and modulate oncogenic expression in cancer cells. Herein, we report the synthesis and characterisation of two metallo-phthalocyanines containing either zinc (ZnPc) or nickel (NiPc) in the central aromatic core and four alkyl ammonium lateral chains. The interaction of both molecules with G-quadruplex DNA was assessed by UV–Vis, fluorescence and FRET melting experiments. Both molecules bind strongly to G-quadruplexes and stabilise these structures, being NiPc the most notable G-quadruplex stabiliser. In addition, the photosensitizing ability of both metal complexes was explored by the evaluation of the singlet oxygen generation and their photoactivation in cells. Only ZnPc showed a high singlet oxygen generation either by direct observation or by indirect evaluation using a DPBF dye. The cellular evaluation showed mainly cytoplasmic localization of ZnPc and a decrease of the IC50 values of the cell viability of ZnPc upon light activation of two orders of magnitude. [ABSTRACT FROM AUTHOR]

Background: A family of BF2-chelated tetraaryl-azadipyrromethenes was developed as non-porphyrin photosensitizers for photodynamic therapy. Among the developed photosensitizers, ADPM06 exhibited excellent photochemical and photophysical properties. Molecular imaging is a useful tool for photodynamic therapy planning and monitoring. Radiolabeled photosensitizers can efficiently address photosensitizer biodistribution, providing helpful information for photodynamic therapy planning. To evaluate the biodistribution of ADPM06 and predict its pharmacokinetics on photodynamic therapy with light irradiation immediately after administration, we synthesized [18F]ADPM06 and evaluated its in vivo properties. Results: [18F]ADPM06 was automatically synthesized by Lewis acid-assisted isotopic 18F-19F exchange using ADPM06 and tin (IV) chloride at room temperature for 10 min. Radiolabeling was carried out using 0.4 μmol of ADPM06 and 200 μmol of tin (IV) chloride. The radiosynthesis time was approximately 60 min, and the radiochemical purity was > 95% at the end of the synthesis. The decay-corrected radiochemical yield from [18F]F− at the start of synthesis was 13 ± 2.7% (n = 5). In the biodistribution study of male ddY mice, radioactivity levels in the heart, lungs, liver, pancreas, spleen, kidney, small intestine, muscle, and brain gradually decreased over 120 min after the initial uptake. The mean radioactivity level in the thighbone was the highest among all organs investigated and increased for 120 min after injection. Upon co-injection with ADPM06, the radioactivity levels in the blood and brain significantly increased, whereas those in the heart, lung, liver, pancreas, kidney, small intestine, muscle, and thighbone of male ddY mice were not affected. In the metabolite analysis of the plasma at 30 min post-injection in female BALB/c-nu/nu mice, the percentage of radioactivity corresponding to [18F]ADPM06 was 76.3 ± 1.6% (n = 3). In a positron emission tomography study using MDA-MB-231-HTB-26 tumor-bearing mice (female BALB/c-nu/nu), radioactivity accumulated in the bone at a relatively high level and in the tumor at a moderate level for 60 min after injection. Conclusions: We synthesized [18F]ADPM06 using an automated 18F-labeling synthesizer and evaluated the initial uptake and pharmacokinetics of ADPM06 using biodistribution of [18F]ADPM06 in mice to guide photodynamic therapy with light irradiation. [ABSTRACT FROM AUTHOR]

During the Covid-19 pandemic, health agencies worldwide have recommended frequent handwashing and sanitizing. A variety of hand gel products were made available on the market, often with fragrances added to curtail the strong smell of alcohol. Commonly used Citrus fragrances contain volatile aroma constituents and non-volatile oxygen heterocyclic compounds (OHCs), consisting mostly of polymethoxyflavones, coumarins, and furocoumarins. The latter have long been investigated for their phototoxic properties, and their safety as cosmetic product ingredients has been debated recurrently. To this concern, twelve commercial Citrus-scented products were investigated in this study. An extraction method was optimized for thirty-seven OHC compounds, obtaining absolute mean recovery values in the 73.5–116% range with only few milliliters of solvent consumption. Analysis by ultra-high-pressure liquid chromatography with tandem mass spectrometry detection evidenced that three samples did not conform to the labeling requirements for fragrance allergens (coumarin) laid down by the European Union Regulation on Cosmetic Products. The total furocoumarin (FC) content of the samples investigated was in the 0.003–3.7ppm range, with some noteworthy exceptions. Specifically, in two samples, the total FCs were quantified as 89 and 219 ppm, thus exceeding the safe limits recommended up to a factor of 15. Finally, the consistency of the volatile fingerprint attained by gas chromatography allowed drawing conclusions on the authenticity of the Citrus fragrances labeled, and several products did not conform to the information reported on the label concerning the presence of essential oils. Besides the issue of product authenticity, analytical tools and regulatory actions for widespread testing of hand hygiene products are urgent, to protect consumers' health and safety. [ABSTRACT FROM AUTHOR]

Aggregation studies of a photosensitizer (PS), tricationic chlorin (H2Chl3+), and its interaction with passive delivery vehicles Tween 80 and polyvinylpyrrolidone (PVP) in aqueous solutions have been carried out using 1D and 2D NMR spectroscopy, which has been shown to be a powerful tool for detecting both nanoaggregates at about 10–3 mole/kg and associates formed in solutions of H2Chl3+ at PS concentration lower by two orders of magnitude. NMR spectroscopy also can be used to identify molecular fragments of PS responsible for aggregation. The addition of solubilizers Tween 80 and PVP leads to the destruction of the PS nanoaggregates and formation of stable complexes with potential carriers, while the associated forms of the macrocycle may be retained in the solution. These results are consistent with the adsorption, fluorescence, and dynamic light scattering data. The molecular complex of water-soluble H2Chl3+ ions with the PVP macromolecule in aqueous solution is additionally stabilized by hydrogen bonding of the amide NH proton of the photosensitizer and oxygen atom of the polymer carbonyl group. [ABSTRACT FROM AUTHOR]

The review covers literature data on the synthesis of porphyrins, including amphiphilic star-shaped porphyrins which attract increasing attention from synthetic chemists. The potential of various porphyrins, metalloporphyrins, and their derivatives as photosensitizers for photodynamic therapy of cancer has been dis-cussed. The relation between the structure of porphyrins and their antimicrobial activity has been demonstrated. Polymer–porphyrin systems based on biodegradable polyesters and tetraphenylporphyrins immobilized thereon have been considered to be promising composite materials with bactericidal properties. [ABSTRACT FROM AUTHOR]

Luminescent lanthanide complexes containing effective photosensitizers are promising materials for use in displays and sensors. The photosensitizer design strategy has been studied for developing the lanthanide-based luminophores. Herein, we demonstrate a photosensitizer design using dinuclear luminescent lanthanide complex, which exhibits thermally-assisted photosensitized emission. The lanthanide complex comprised Tb(III) ions, six tetramethylheptanedionates, and phosphine oxide bridge containing a phenanthrene frameworks. The phenanthrene ligand and Tb(III) ions are the energy donor (photosensitizer) and acceptor (emission center) parts, respectively. The energy-donating level of the ligand (lowest excited triplet (T1) level = 19,850 cm−1) is lower than the emitting level of the Tb(III) ion (5D4 level = 20,500 cm−1). The long-lived T1 state of the energy-donating ligands promoted an efficient thermally-assisted photosensitized emission of the Tb(III) acceptor (5D4 level), resulting in a pure-green colored emission with a high photosensitized emission quantum yield (73%). Luminescent lanthanide complexes are promising materials for use in displays and sensors, however, these materials often undergo thermal quenching. Here, the authors synthesize and characterize a terbium dinuclear phosphine oxide-bridged phenanthrene complex, which exhibits thermally-enhanced emission. [ABSTRACT FROM AUTHOR]

The adsorptive properties onto TiO2 film, and the solubility behaviors of eighteen porphyrin derivatives in acetonitrile (AcCN), dichloromethane (DCM), dimethyl sulphoxide (DMSO), and ethanol (EtOH) have been predicted using thermodynamic data obtained from density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The computed photovoltaic (PV) properties were found to be enhanced with -CO2H group as the substituent of the parent porphyrin, and AcCN or DCM as solvent. The adsorption properties of the porphyrins on the TiO2 surface as predicted, were just about 22% similar to the computed solubility properties in the selected solvents. The poor correlation observed between the two parameters is a result of the porphyrin-solvent-TiO2 interaction which is present for adsorption, but absent for solubility. The described method could be employed for the design of efficient porphyrin-solvent systems for DSSC application. [ABSTRACT FROM AUTHOR]

Here, we synthesized metal-free organic dye (CCPICPB) with two carbazole donor groups and two anchoring groups that exhibit a panchromatic absorption in the near-infrared range of up to 750 nm. To study the photophysical properties of synthesized CCPICPB dye, the UV–Vis and cyclic voltammetric experiments were studied and the obtained results were validated with theoretical simulation studies. After that, the solvothermal approach is used to synthesize pristine anatase and calcium (Ca)-doped TiO2 microspheres with a smooth morphology. These microstructures are examined in depth using XRD, electron microscopy and electrochemical analysis methods. On TiO2 and Ca-doped TiO2 photoanode materials, we first evaluated the performance of CCPICPB dye. Upon our optimized experimental condition, the 3% Ca-TiO2 photoanode-based device exhibits an efficiency of 4.04%, which is greater than that of the pristine TiO2 photoanode-based device (2.93%). Because of the quicker electron transport in the Ca-TiO2 film, the short-circuit current density and efficiency of DSSCs were improved. Moreover, when the CCPICPB dye was used as a co-sensitizer with the common Ru(II) dye (Z907), interestingly it showed the highest efficiency (6.11%) when compared with Z907 alone (5.12%). This improved efficiency of the co-sensitized device resulted from greater VOC conjugated with improved JSC. The JSC was improved because CCPICB dye could compensate for the photocurrent loss caused by redox electrolyte while the VOC was improved because electron recombination was inhibited under the co-sensitization conditions. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) plays a pivotal role in advanced electrochemical energy conversion devices. However, the ORR conversion efficiency is extremely limited. The major obstacles originate from the adsorption and activation of O2 on the electrode surface. A novel nanocomposite catalyst, photosensitizers (PS) meso-tetraphenylporphyrin iron(III) chloride (FePcCl)/NiCoFe-layered double hydroxides (NiCoFe-LDHs) is designed in this study. Herein, owing to excellent oxygen molecules activation ability and remarkable illumination absorption feature, FePcCl/NiCoFe-LDHs is employed to uncover the relationship between the intrinsic ORR activity and PS behaviour. Interestingly, the reaction mechanism of singlet 1O2 is proposed owing to the combination of electrochemical ORR catalysed via LDHs and PS. The boosted cathodic ORR properties exhibit singlet 1O2 dependent response arising from the synergistic effect to selectively produce active intermediates in alkaline medium. This work imparts the promising new mechanism about the high 4-electron ORR selectivity via material design, which will guide the development of photo-assisted energy conversion devices. [ABSTRACT FROM AUTHOR]

Engineering excitation wavelength of photosensitizers (PSs) for enhanced reactive oxygen species (ROS) generation has inspired new windows for opportunities, enabling investigation of previously impracticable biomedical and photocatalytic applications. However, controlling the wavelength corresponding to operating conditions remains challenging while maintaining high ROS generation. To address this challenge, we implement a wavelength-engineerable imidazolium-based porous organic photocatalytic ROS generation system (KUP system) via a cost-effective one-pot reaction. Remarkably, the optimal wavelength for maximum performance can be tuned by modifying the linker, generating ROS despite the absence of metal ions and covalently attached heavy atoms. We demonstrate that protonated polymerization exclusively enables photosensitization and closely interacts with oxygen related to the efficiency of photosensitizing. Furthermore, superior tumor eradication and biocompatibility of the KUP system were confirmed through bioassays. Overall, the results document an unprecedented polymerization method capable of engineering wavelength, providing a potential basis for designing nanoscale photosensitizers in various ROS-utilizing applications. Engineering excitation wavelength of photosensitizers allows to enhanced reactive oxygen species but controlling the wavelength corresponding to operating conditions remains challenging. Here, the authors implement a wavelength-engineerable imidazolium-based porous organic polymer and demonstrate tuning of the optimal wavelength for maximum performance by modifying the linker system. [ABSTRACT FROM AUTHOR]

In this work, dye extracts of carrisa spinuram, iresine herbstii and ipomoea purpurea (morning glory), were used as natural dyes in titanium (II) oxide (TiO2) nanoparticles-based dye sensitized solar cells (DSSCs). Fourier Transform Infrared (FTIR), Ultraviolet-Visible (UV-Vis), Photoluminescence (PL), and electrochemical impedance spectroscopy were utilized to study the functional groups, optical response, and redox-oxidation potentials of these extracted dyes respectively. The energy bands like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of these dyes were determined by employing cyclic-voltammetry (CV) and as well as optical absorption techniques. The FTIR data of under study dyes show various function groups. The associated groups corresponding to electron transferring entity are also observed in them. These dyes were excited with 530 nm wavelength and in reverse they emitted in yellow and red regions of the electromagnetic spectrum. Based on these emitted photons, they can potentially be used as chromophores and can lead a good efficiency in the DSCCs. The different photovoltaic parameters of these dyes (as photosensitizer) in the prepared DSSCs were estimated from current–voltage (I-V) data. The life time of minority carriers and the external quantum efficiency (EQE) were obtained from open circuit voltage decay (OCVD) method and incident photon to current efficiency (IPCE) technique respectively. The carrisa spinuram dye based solar cell (SC) showed highest photovoltaic response of around 424mV open circuit voltage (VOC) and 5.2mA/cm2 short circuit current density (JSC) with an SC efficiency (ɳ%) of 1.1952% and efficiency in ipomoea purporea and iresine herbstii dye-based cells was recorded around 0.87927% and 0.55976% respectively. The same photovoltaic parameters in red, green, blue light were also investigated. The present work demonstrates the potential of these dyes in TiO2 based DSSCs. [ABSTRACT FROM AUTHOR]

Cationic amphipathic structures are often utilized in natural membrane-active host-defense peptides. Negatively charged surface membranes of rapidly proliferating bacterial and cancer cells have been targeted by various synthetic peptides and peptidomimetics adopting the structural motif. Herein, we synthesized a set of conjugates composed of cationic amphipathic peptoids (i.e., oligo-N-substituted glycines) and a chlorin photosensitizer, named chlorin e6 (Ce6)-peptoid conjugates (CPCs). Among the nine CPCs, CPC 7, composed of Ce6, a PEG linker, and guanidine-rich helical amphipathic peptoids, exhibited a distinct photoresponsive inactivation of Gram-positive and Gram-negative bacteria. Subsequent studies showed that CPC 7 effectively killed various cancer cells after irradiation with red light (655 nm), suggesting the potential of CPC 7 as a dual antimicrobial and anticancer agent. Confocal laser scanning microscopy and flow cytometry data suggested that CPC 7 could induce apoptotic cell death. Our results show the potential of peptoid-based photosensitizer conjugates as a versatile platform for antimicrobial and anticancer photodynamic therapy agents and peptoid therapeutics. [ABSTRACT FROM AUTHOR]

Photodynamic therapy is a minimally invasive treatment of tumors using photosensitizers, light, and reactive oxygen species, which can destroy cellular structures. With the development of photodynamic therapy, significant efforts have been made to create new efficient photosensitizers with improved delivery to cells, stability, and selectivity against cancer tissues. Naturally occurring tetrapyrrolic macrocycles, such as porphyrins and chlorins, are very attractive as photosensitizers, and their structural modification and conjugation with other biologically active molecules are promising approaches for creating new photosensitizers specifically targeting cancer cells. The present review aims to highlight recent developments in the design, preparation, and investigation of complex conjugates of tetrapyrrolic macrocycles, which can potentially be used as sensitizers for target-oriented photodynamic therapy of cancer. In this review, we discuss the structure, photodynamic effect, and anticancer activity of the following conjugates of tetrapyrrolic macrocycles: (1) conjugates obtained by modifying peripheral substituents in porphyrins and chlorins; (2) conjugates of porphyrins and chlorins with lipids, carbohydrates, steroids, and peptides; (3) conjugates of porphyrins and chlorins with anticancer drugs and some other biologically active molecules; (4) metal-containing conjugates. The question of how the conjugate structure affects its specificity, internalization, localization, and photoinduced toxicity within cancer cells is the focus of this review. [ABSTRACT FROM AUTHOR]

The storage and controlled release of singlet oxygen (1O2) have attracted increasing attention due to the wide application and microsecond lifetime of 1O2 in water. Herein we provide an integrated nanoplatform consisting of a diphenylanthracene derivative, a water-soluble pillar[5]arene and a photosensitizer tetrakis(4-hydroxyphenyl)porphyrin (TPP), that may provide the controlled generation, storage and release of singlet oxygen. We design a new diphenylanthracene derivative with two trimethylammonium bromide groups on both ends that can be well recognized by the pillar[5]arene. The formed nanocarriers can be used to load TPP through their supramolecular self-assembly. The resulting nanoparticles show good water-solubility and uniform spherical morphology. After laser irradiation (660 nm), the nanoparticles exhibit excellent ability for the generation and storage of 1O2. When the irradiated nanoparticles are heated above 80 °C, 1O2 can be released from the system. Therefore, in this paper we pioneer the use of noncovalent interaction to integrate the diphenylanthracene derivatives and photosensitizers into one functional system, which provides a new strategy for the controlled generation, storage and release of singlet oxygen. We believe this groundbreaking strategy will have a great potential in providing necessary amounts of 1O2 for the photodynamic therapy of tumors in dark. [ABSTRACT FROM AUTHOR]

Two novel metal-free organic dyes, TM-a and TM-b derived from triphenylamine have been successfully synthesized and characterized. These D-π-A sensitizers feature triphenylamine as an electron donor, fluorene and thiophene as π-bridges, and 2-cyanoacrylic acid as both an acceptor and an anchor. This architecture allows a deeper insight into the effect of modification of the properties of D-π-A sensitizers, which is beneficial to improve their performance of in dye-sensitized solar cells (DSSCs). Both the TM-a and TM-b dyes displayed maximum absorption in the visible region at 457 and 454 nm, respectively. The DSSCs based on TM-a exhibited a superior photoelectric conversion efficiency, along with higher open-circuit voltage and short-circuit current (η 2.91%, VOC 657 mV, JSC 6.81 mA cm–2, and FF 0.65). These results indicate that the dye, with triphenylamine as an electron donor and fluorene as a π-linker, is a highly promising candidate for efficient DSSC applications. [ABSTRACT FROM AUTHOR]