Blue Light Irradiation Research Articles

A carbene-stabilized diphosphorus: a triple-bonded diphosphorus (P[triple bond, length as m-dash]P) and a bis(phosphinidene) (P-P) transfer agent.

The reaction of the N,N-diisopropyl bromoiminium salt with excess sodium phosphaethynolate (NaPCO) affords a diphospha-urea 2. Under blue light irradiation (450 nm), carbon monoxide is liberated affording the bis(carbene)P2 adduct 3. Photolysis of a benzene solution of 3 at 365 nm gives rise to the carbene dimer, namely the 1,2-bis(diisopropylamino)ethylene as a cis/trans mixture, along with white and red phosphorus. Under the same experimental conditions, but in the presence of excess 2,3-dimethyl-1,3-butadiene, the classical double Diels-Alder adduct of the triple-bonded diphosphorus P[triple bond, length as m-dash]P was obtained along with the bis(phospholene) formally resulting from a double [4 + 1] reaction of the diene with the bis(phosphinidene) form of P2. A stepwise carbene-carbene exchange reaction also occurs between the monosubstituted aminocarbene of 3 and a cyclic (alkyl)(amino)carbene, possibly involving the transient formation of a diphosphorus analogue of a diazo compound.

Strong thickness dependence in thin film photocatalytic heterojunctions: the ZnO-Bi2O3 case study.

Semiconductor heterojunctions are an effective way to achieve efficient photocatalysts, as they can provide an adequate redox potential with visible light excitation. Several works have reported synergistic effects with nanoparticle semiconductor materials. The question is still open for thin film heterojunctions formed by stacked layers, as photocatalysis is considered a surface phenomenon. To investigate if the internal layer really affects or modifies the photocatalytic properties of the external material, we analyze the thin film heterojunction with ZnO and Bi2O3 semiconductors deposited by spray pyrolysis in two configurations: substrate/ZnO/Bi2O3 and substrate/Bi2O3/ZnO. Microstructural analysis was performed to verify the formation of the physical junction of the materials and discard new ternary phases. The photocatalytic activity was analyzed as a function of the thickness of the layers under blue light irradiation. We determined the conduction and valence bands positions, the carrier concentrations, mobilities, Fermi levels, etc. that allowed us to distinguish two reaction mechanisms depending on the configuration. There is a strong compromise between the order and thickness of the layers with the photocatalytic activity. The internal electric field produced in the interface defines the route of the photogenerated charges, and therefore the photocatalytic response. Thus, well-designed thin film heterojunctions can indeed improve the photocatalytic activity of the surface layer.

Transforming patterned defects into dynamic poly-regional topographies in liquid crystal oligomers.

We create high-aspect-ratio dynamic poly-regional surface topographies in a coating of a main-chain liquid crystal oligomer network (LCON). The topographies form at the topological defects in the director pattern organized in an array which are controlled by photopatterning of the alignment layer. The defect regions are activated by heat and/or light irradiation to form reversible topographic structures. Intrinsically, the LCON is rubbery and sensitive to temperature changes, resulting in shape transformations. We further advanced such system to make it light-responsive by incorporating azobenzene moieties. Actuation reduces the molecular order of the LCON coating that remains firmly adhered to the substrate which gives directional shear stresses around the topological defects. The stresses relax by deforming the surfaces by forming elevations or indents, depending on the type of defects. The formed topographies exhibit various features, including two types of protrusions, ridges and valleys. These poly-regional structures exhibit a large modulation amplitude of close to 60%, which is 6 times larger than the ones formed in liquid crystal networks (LCNs). After cooling or by blue light irradiation, the topographies are erased to the initial flat surface. A finite element method (FEM) model is adopted to simulate structures of surface topographies. These dynamic surface topographies with multilevel textures and large amplitude expand the application range, from haptics, controlled cell growth, to intelligent surfaces with adjustable adhesion and tribology.

Light-swing CO2 capture: photoirradiation-based chemical CO2 release based on photoisomerization of azobenzene-amine/guanidine derivatives

Azobenzene-amine/guanidine derivatives exhibit a light-swing method enabling CO2 release under light irradiation with photoisomerization as the driving force. This method can selectively absorb CO2 in air and release CO2 by blue-light irradiation.

Porphyrin(2.1.2.1) organopalladium complexes as efficient singlet oxygen sensitizers.

Four new non-planar and non-aromatic porphyrin organopalladium complexes were synthesized. Conformational structures and optical and electronic properties of the obtained organopalladium complexes containing meso-substituted phenyl, p-tert-butylphenyl, or pentafluorophenyl groups were fully investigated. These complexes showed potent capacity for singlet oxygen (1O2) generation under blue-light irradiation, and the 1O2 quantum yields were in the range of 41%-56%, which were comparable to that of Ru(bpy)3Cl2 (57%), and such potency made these organopalladium complexes potential 1O2 photo sensitizers for photodynamic therapy.

Dynamic organic crystals as exceptionally efficient artificial natural light-harvesting actuators.

Dynamic organic crystal materials that can directly convert solar energy into mechanical work hold the potential to be efficient artificial actuators. However, developing dynamic organic crystals that can efficiently transform natural light energy into mechanical energy is still quite challenging. Herein, a novel dynamic organic crystal whose two polymorphs (Form I and Form II) are both capable of effectively converting natural light into work was successfully synthesized. Under the irradiation of ultraviolet (UV), blue and natural light, the on/off toggling of a photosalient effect could be triggered. Specifically, under UV light irradiation, Form I demonstrates output work densities of about 4.2-8.4 × 104 J m-3 and 1.6-4.9 × 102 J m-3 before and after disintegration, respectively. Form II exhibits output work densities of about 1.3 × 102 to 1.9 × 103 J m-3 by means of photoinduced bending, suggesting that controllable bending may be more favorable for energy harvesting than the photosalient effect. Utilizing the exceptionally high energy transduction efficiency of Form I, we developed a natural light-driven micro-actuator that can realize output work densities of 2.8-5.0 × 104 J m-3. The natural light-harvesting performance of this actuator significantly surpasses those of previously reported photomechanical crystals and could even be comparable to thermal actuators.

Anionic photochemical rearrangement of 3-hydroxypyran-4-ones bearing oxazol-2-one fragment.

The photochemical behavior of in situ generated anions of 3-hydroxypyran-4-ones containing an oxazol-2-one moiety was studied. For the first time, it was demonstrated that blue LED light irradiation (450 nm) of substituted 3-hydroxypyran-4-ones in the presence of a base leads regiospecifically to the formation of isomeric 3-hydroxypyran-2-ones. Transformation of the starting 3-hydroxypyran-4-ones into the corresponding anions is necessary for the presented photoprocess. Based on the considered visible light induced rearrangement, a general method for the synthesis of 3-hydroxypyran-2-ones with an oxazol-2-one moiety was elaborated. The structure of one of the synthesized compounds was confirmed by X-ray diffraction.

Protective and Regenerative Efficacy of a Plant Oil-Based Day and Night Cream: Investigated by a Novel Approach to Reveal the Impact of Blue Light Irradiation on Epidermal Barrier Integrity and Lipid Matrix

Protective and Regenerative Efficacy of a Plant Oil-Based Day and Night Cream: Investigated by a Novel Approach to Reveal the Impact of Blue Light Irradiation on Epidermal Barrier Integrity and Lipid Matrix

Sustainable and durable color cosmetics: riboflavin phosphate-mediated photo-crosslinked casein films with tannic acid.

The cosmetics industry is increasingly focusing on developing sustainable and environmentally friendly products while maintaining high performance. In color cosmetics, achieving long-lasting durability of water-soluble dyes remains a challenge. This study presents a sustainable approach to enhance the durability of water-soluble dyes in cosmetics using biopolymer-based films. The casein films were fabricated through riboflavin phosphate (RFP)-mediated photo-crosslinking, with tannic acid (TA) incorporated to improve mechanical properties. The fabrication process, characterization, and performance evaluation of the biopolymer-based films were investigated. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses confirmed the successful crosslinking and formation of a porous network structure. Rheological measurements revealed that the incorporation of TA significantly enhanced the mechanical strength of the films. Cytocompatibility assessment using NIH/3T3 fibroblasts demonstrated the films' excellent biocompatibility. The durability and color retention of a water-soluble red dye in the biopolymer-based films were evaluated on human skin. The films formed under blue light irradiation exhibited superior dye retention compared to non-irradiated films, with TA addition providing a minor improvement in durability. This study bridges the gap between cosmetic science and biomaterials research, providing a foundation for future investigations into bio-interactive materials for dermal applications. These findings highlight the potential of RFP-mediated photo-crosslinked casein films as a sustainable and effective solution for enhancing the durability of water-soluble dyes in color cosmetics.

Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes.

Bicyclo[1.1.0]butanes (BCBs), strained carbocycles comprising two fused cyclopropane rings, have become well-established building blocks in organic synthesis, medicinal chemistry, and chemical biology due to their diverse reactivity profile with radicals, nucleophiles, cations, and carbenes. The constraints of the bicyclic ring system confer high p-character on the interbridgehead C-C bond, leading to this broad reaction profile; however, the use of BCBs in pericyclic processes has to date been largely overlooked in favor of such stepwise, non-concerted additions. Here, we describe the use of BCBs as substrates for ene-like reactions with strained alkenes and alkynes, which give rise to cyclobutenes decorated with highly substituted cyclopropanes and arenes. The former products are obtained from highly stereoselective reactions with cyclopropenes, generated in situ from vinyl diazoacetates under blue light irradiation (440 nm). Cyclobutenes featuring a quaternary aryl-bearing carbon atom are prepared from equivalent reactions with arynes, which proceed in high yields under mild conditions. Mechanistic studies highlight the importance of electronic effects in this chemistry, while computational investigations support a concerted pathway and rationalize the excellent stereoselectivity of reactions with cyclopropenes.

Carboxymethyl chitosan modified with curcumin: A photodynamic antibacterial agent with good solubility and stability

Curcumin (CCM) is a natural photoinitiator with antioxidant, antibacterial and anti-inflammatory properties. However, hydrophobicity and low stability limit its application. In this study, CCM was coupled with carboxymethyl chitosan (CMCS) by an esterification reaction to obtain a water-soluble derivative (CMCS-CCM). A series of characterization techniques demonstrated the synthesis and aggregation properties of CMCS-CCM. The derivative exhibited good stability, antioxidant properties, and photodynamic antibacterial activity. Under the blue light irradiation of 450 nm, the minimal inhibit concentration (MIC) of CMCS-CCM against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were 128 and 512 μg/mL, respectively. Reactive oxygen species (ROS) assay and Scanning electron microscope (SEM) results indicated that the photodynamic antibacterial activity of CMCS-CCM was attributed to the disruptive effect of the generated ROS on the bacterial structure. Furthermore, the derivative did not show significant cytotoxicity and hemolytic activity. These results suggest that the derivatives can be used as a potential antibacterial agent and applied in the food industry.

Phototriggered Butenolide Formation from a Cyclobutenedione and an Acidic Nucleophile.

A phototriggered conjugation reaction of an aminocyclobutenedione and an acidic nucleophile was discovered. Upon blue light irradiation of the materials, a butenolide derivative with substituents derived from the aminocyclobutenedione and the nucleophile was produced. The reaction proceeded efficiently under organic solvent or organic solvent/aqueous buffer (1/1) conditions. This reaction would be useful for the synthesis of unique butenolide derivatives and derivatization of acidic functional groups contained in aqueous biomolecules.

Blue Light Exposure Caused Large-Scale Transcriptional Changes in the Abdomen and Reduced the Reproductive Fitness of the Fall Armyworm Spodoptera frugiperda.

In the present study, we found that blue light stress negatively affected the development periods, body weight, survival and reproduction of Spodoptera frugiperda, and it showed a dose-dependent reaction, as longer irradiation caused severer effects. Further transcriptome analysis found blue light stress induced fast and large-scale transcriptional changes in the head, thorax and, particularly, the abdomen of female S. frugiperda adults. A functional enrichment analysis indicated that shorter durations of blue light irradiation induced the upregulation of more stress response- and defense-related genes or pathways, such as abiotic stimuli detection and response, oxidative stress, ion channels and protein-kinase-based signal pathways. In the abdomen, however, different durations of blue-light-exposure treatments all induced the downregulation of a large number genes and pathways related to cellular processes, metabolism, catalysis and reproduction, which may be a trade-off between antistress defense and other processes or a strategy to escape stressful conditions. These results indicate irradiation duration- and tissue-specific blue light stress responses and consequences, as well as suggest that the stress that results in transcriptional alterations is associated with the stress that causes a fitness reduction in S. frugiperda females.

Effective removing of rotifer contamination in microalgal lab-scale raceway ponds by light-induced phototaxis coupled with high-voltage pulse electroshock

Rotifer reproduction control in open microalgae cultivation systems poses a significant challenge for large-scale industries. Conventional methods, such as electric, meshing, and chemical techniques, are often expensive, ineffective, and may have adverse environmental-health impacts. This study investigated a promising control technique through light-induced phototaxis to concentrate rotifers in a specific spot, where they were electroshocked by local-limited exposure dose. The results showed that the rotifers had the most pronounced positive and negative phototropism with phototaxis rates of 66.7 % and −78.8 %, respectively, at blue-light irradiation of 30 µmol∙m−2∙s−1 and red-light irradiation of 22.5 µmol∙m−2∙s−1 for 20 min. The most effective electroshock configuration employed 1200 V/cm for 15 min with a 1-second cycle time and a 10 % duty cycle, resulting in a 75.0 % rotifer removal rate without impacting microalgae growth. The combination of the two light beams could effectively lead rotifers to designated areas where they were electrocuted successfully.

Photoredox-Catalyzed Divergent Radical Cascade Annulations of 1,6-Enynes via Pyridine N-Oxide-Promoted Vinyl Radical Generation.

The divergent organophotoredox-catalyzed radical cascade annulation reactions of 1,6-enynes were developed. A series of cyclopropane-fused hetero- and carbo-bicyclic, tricyclic, and spiro-tetracyclic compounds were facilely synthesized from a broad scope of 1,6-enynes and 2,6-lutidine N-oxide under mild and metal-free conditions with blue light-emitting diode light irradiation. The cascade annulation reaction occurs with the intermediacy of a β-oxyvinyl radical, which is produced from photocatalytically generated pyridine N-oxy radical addition to the carbon-carbon triple bond.

MscI restriction enzyme cooperating recombinase-aided isothermal amplification for the ultrasensitive and rapid detection of low-abundance EGFR mutations on microfluidic chip

The detection of low-abundance mutation genes of the epidermal growth factor receptor (EGFR) exon 21 (EGFR L858R) plays a crucial role in the diagnosis of non-small cell lung cancer (NSCLC), as it enables early cancer detection and facilitates the development of treatment strategies. A detection platform was developed by combining the MscI restriction enzyme with the recombinase-aided isothermal amplification (RAA) technique (MRE-RAA). During the RAA process, “TGG^CCA” site of the wild-type genes was cleaved by the MscI restriction enzyme, while only the low-abundance mutation genes underwent amplification. Notably, when the RAA product was combined with CRISPR-Cas system, the sensitivity of detecting the EGFR L858R mutation increased by up to 1000-fold for addition of the MscI restriction enzyme. This achievement marked the first instance of attaining an analytical sensitivity of 0.001%. Furthermore, a disk-shaped microfluidic chip was developed to automate pretreatment while concurrently analyzing four blood samples. The microfluidic features of the chip include DNA extraction, MRE-RAA, and CRISPR-based detection. The fluorescence signal is employed for detection in the microfluidic chip, which is visible to the naked eye upon exposure to blue light irradiation. Furthermore, this platform has the capability to facilitate early diagnosis for various types of cancer by enabling high-sensitivity detection of low-abundance mutation genes.

Influence of photodynamic action on pure and mixed cultures of gram-negative bacteria: related to growth mechanisms

Gram-negative bacteria present a significant challenge to conventional treatments due to their structurally complex cell walls, setting them apart from their gram-positive counterparts. These structural distinctions, coupled with various antimicrobial resistance mechanisms, make them highly resilient. Photodynamic inactivation (PDI) has emerged as a promising technique to address this challenge, capitalizing on oxidative stress induced by the synergy of light and a photosensitizer (PS). In this study, we delved into the application of PDI and its repercussions on both Klebsiella pneumoniae and Escherichia coli bacteria, in both pure cultures and mixed populations. Our investigation encompassed an analysis of changes in growth curves when influenced by photodynamic and the response to the susceptibility to gentamicin. Methods: Various concentrations (50 μM, 100 μM, and 150 μM) of synthetic curcumin solutions served as PS in treatment groups. Additionally, solvents such as dimethyl sulfoxide and 0.1% sodium dodecyl sulfate (SDS) were evaluated to enhance PS mobility and absorption. Growth curves for pure and mixed cultures were established, both pre- and post-PDI, and in the presence of 0.1% SDS. Blue light irradiation at 30 J cm−2 and 450 nm was employed. The minimum inhibitory concentration (MIC) of the antibiotic was determined with and without PDI + SDS. Results: While PDI did not achieve optimal bacterial reduction for these strains, it did introduce oxidative damage that has the potential to affect other critical aspects of the temporal progression of cultures and their responses to antibiotics. Conclusion: This study shows that even with the minimal impact of PDI in the presence of 0.1% SDS, observable alterations in bacterial growth profiles and MIC values occur and can be used in favor of treatment involving such infections.

Crystallization engineering in PVDF enables ultrastable and highly efficient CsPbBr3 quantum dots film for wide color gamut Mini-LED backlight

The polymeric composite films incorporating inorganic lead halide perovskite quantum dots (CsPbX3 QDs, X = Cl, Br or I) are promising color conversion layers for wide gamut display devices such as Mini-LED backlight-based televisions. However, the relatively low emission efficiency and poor stability of these composite films present significant challenges for practical applications. In this study, we present a novel low-temperature in-situ crystallization strategy to prepare CsPbBr3/PVDF composite film through a rational designed of precursor, solvent and polymer structure. The strong interaction between PVDF and perovskite QDs via Lewis acid-base interaction allows for precise control over the crystallization and passivation of perovskite QDs. The optimized CsPbBr3/PVDF film exhibits bright emission with a photoluminescence quantum yield (PLQY) of up to 70 %, surpassing those of other CsPbBr3/polymers counterparts. Furthermore, the films demonstrate remarkable stability, retaining over 90 % of their original PLQY even after 50 days of aging under various environmental conditions such as exposure to air, immersion in water and blue light irradiation. By integrating the green and red emissive CsPbX3/PVDF films with blue Mini-LEDs, we successfully fabricate a prototype liquid crystal display (LCD) with an outstanding wide color gamut (128 % of NTSC 1931). These performances outperform that of commercial white-LED-based LCDs, highlighting the immense potential of CsPbX3/PVDF for high-definition display applications in the future.

Electron Donor-Acceptor Complex Enabled Radical Cyclization of α-Diazodifluoroethyl Sulfonium Salt with Unactivated Alkynes.

An α-diazodifluoroethane sulfonium reagent was developed in this study to undergo [3 + 2] radical cyclization with unactivated alkynes to give the corresponding 3-difluoromethyl pyrazoles under blue light irradiation conditions. The key to the success of this transformation lies in the formation of an electron donor-acceptor (EDA) complex between an electron-deficient α-diazo sulfonium salt and an electron-rich triaryl amine. This study circumvents a major substrate scope limitation in polar cycloaddition reactions of existent diazodifluoroethane reagents.

Integrated municipal wastewater treatment and lipid accumulation by a self-flocculating/floating microalga Limnothrix sp.

The present study evaluated the growth, self-flocculation, lipid content, and pollutants removal by Limnothrix sp. BASMWW-9 isolated from municipal wastewater treatment system and cultivated in municipal wastewater. The biomass yield and lipid content after 6 days of cultivation were 1.07 g dw/L and 27.34 %dw, respectively. In addition, its self-flocculating ability reached up to 90 % after harvesting time of 180 min. Moreover, COD,NH3-N, TN, and TP removalefficiencies were 71.65 %, 81.89 %, 74.64 %, and 80.16 %, respectively. The self-flocculation performance of Limnothrix sp. was greatly associated to its morphology and production of extracellular polymeric substances (EPS), with significant positive impact of the high calcium and magnesium content in municipal wastewater. Interestingly, blue light irradiation during harvest enhanced the aggregation and floc formation as a floating biomat, which was attributed to enhanced polysaccharides production. This study provides innovative harvest method for Limnothrix sp. BASMWW-9 cultivated in wastewater using blue light for enhanced lipid recovery.