The temperature measurement technology based on the fluorescence intensity ratio has garnered significant attention due to its high accuracy, rapid response, and non-contact advantages. Herein, novel double-perovskite BaSrGdSbO6: Bi3+/Mn4+ phosphors were synthesized and their luminescence properties were investigated in detail. Under 330 nm excitation, the BaSrGdSbO6: Bi3+, Mn4+ phosphors exhibited the efficient characteristic emissions of Bi3+ and Mn4+ ions simultaneously. The energy transfer from Bi3+ to Mn4+ is mainly attributed to long-range electric multipole interactions, with a possible dominant quadrupole-quadrupole contribution. Interestingly, Bi3+ exhibits an anti-thermal quenching behavior, while Mn4+ presents a strong thermal quenching behavior under 330 nm excitation. Based on the significantly different temperature sensitivities of Bi3+ and Mn4+, a ratiometric optical thermometer with a relative sensitivity of 2.02% K-1 at 473 K was designed. The study elucidates the optical properties of Bi3+ and Mn4+ ions in BaSrGdSbO6: Bi3+, Mn4+, while underscoring the promising application of these phosphors in optical temperature sensing.
Herein, we have synthesized metal-free triphenylamine-based organic D-pi-A dyes with modified pi-spacers including thiophene and thienothiophene. The photophysical and electrochemical properties of the dyes were studied, where the thienothiophene modified SP-2 dye showed a strong absorption at 483 nm corresponding to intramolecular charge transfer (ICT) transition, and a molar absorption coefficient (epsilon) of 35,336 M-1 cm(-1) was observed. Well-tuned HOMO and LUMO levels, as obtained from the optical and electrochemical data and further confirmed from theoretical DFT studies, reveal SP-2 dye to be an ideal sensitizer candidate for dye-sensitized solar cells (DSCs). DSCs were fabricated with SP-2 dye along with the conventional L0 and L1 dye molecules as the standard reference, and investigated the influence of modifying the pi-conjugation on the photovoltaic (PV) performance of the devices. The dual species [Cu(II)(dmp)(2)Cl](+)/[Cu(I)(dmp)(2)](+) electrolyte was employed as the redox mediator, and under standard 1 sun conditions (AM 1.5G), SP-2 dye-based DSC co-sensitized with XY1b delivered a PCE of 6.37%, outperforming L0 and L1 counterparts. A comprehensive study on the interfacial charge dynamics of the devices was carried out to further elucidate the origin of enhanced photovoltaic performance as a function of variation in p-spacer architecture. Importantly, under indoor lighting (1000 lx), the SP2:XY1b system delivered an outstanding efficiency of 30% and retained efficiencies above 28% across 200-2000 lx, highlighting the strong potential of these dye-sensitized devices for self-powered Internet-of-Things (IoT) applications, like smart sensors, asset tracking, and building automations.
Long-chain alkyl esters of gallic acid were investigated as potential extrinsic fluorescent probes for the fatty acid binding sites of human serum albumin (HSA). Unlike short-chain derivatives or gallic acid itself, long-chain esters such as octyl (G08) and dodecyl gallate (G12) exhibited substantial fluorescence enhancement upon complexation with HSA due to the formation of ground-state complexes. Steady-state and time-resolved fluorescence spectroscopy demonstrated that this emission is protein-induced and not due to solvent polarity effects. Displacement experiments with fatty acids (FA) and site-specific drugs confirmed that these gallates preferentially bind to the fatty acid binding pockets of HSA. Complementary molecular dynamics simulations revealed that G08 and G12 primarily occupy the FA1, FA5, and FA6 sites, stabilized by hydrophobic and van der Waals interactions, with the calculated binding affinities comparable to those of natural fatty acids. Potential of mean force (PMF) analyses indicated higher dissociation energy barriers for G08 and G12, in agreement with their stronger experimental fluorescence response. Together, spectroscopic and computational data revealed that longchain alkyl gallates act as environment-sensitive probes, mimicking the behavior of natural fatty acids and establishing them as efficient fluorescent markers capable of selectively probing the fatty acid transport sites of HSA.
The widespread occurrence of oxytetracycline (OTC) in aquatic environments necessitates the development of efficient and sustainable remediation technologies. Although AgI is a promising photocatalyst, its practical application is severely limited by the tendency to aggregate and inherent instability due to photocorrosion. In this study, an AgI/D-NH2-MIL heterojunction was successfully fabricated using a solvothermal method followed by in-situ ion precipitation. The HCl-modulated D-NH2-MIL-53(Fe) (D-NH2-MIL) provides periodically exposed Fe-O clusters that serve as ideal anchoring sites for AgI, effectively preventing nanoparticle aggregation and ensuring intimate interfacial contact. Crucially, the inherent photocorrosion of AgI is intelligently harnessed to generate in-situ metallic Ag0 nanoparticles. Herein, the "effect" mentioned in the title is explicitly defined as the synergistic combination of the surface plasmon resonance (SPR) effect, the electronic bridge effect, and the resulting photocatalytic enhancement effect. Specifically, rather than causing catalyst deactivation, the in-situ formed Ag0 acts as a highly conductive mediator to robustly facilitate the direct Z-scheme charge transfer between AgI and D-NH2-MIL, fundamentally turning the traditional material "defect" into a powerful catalytic advantage. Under simulated solar light, the degradation rate (k value) of optimized AgI/D-NH2-MIL composite for OTC is 8.8 and 4.6 times that of pristine AgI and D-NH2-MIL, respectively. Density functional theory (DFT) calculations and photoelectrochemical analysis reveal that the synergy between the internal electric field (IEF) and the SPR effect significantly narrows the bandgap, extends the light-harvesting range and accelerates charge separation. Radical quenching experiments and electron paramagnetic resonance (EPR) confirm that center dot OH and center dot O2-are the primary reactive species. Furthermore, the heterojunction demonstrates excellent recycling stability and reduced ecological toxicity for degrading OTC. This work provides a novel perspective on transforming detrimental photocorrosion into a functional advantage for designing efficient plasmonic photocatalysts in water decontamination.
Water pollution triggered by organic contaminants such as crystal violet (CV), rhodamine B (RhB), and tetracycline hydrochloride (TC) has become a pressing global environmental challenge, posing risks to aquatic ecosystems and human health. To address this issue, this study first prepared well-structured TiO2 nanotube arrays (TiO2 NTs) via an anodization method, then constructed TiO2 NTs/g-C3N4 heterojunctions using urea (U) or thiourea (T) as g-C3N4 precursors. Comprehensive characterizations revealed that the TiO2 NTs/g-C3N4 (U) heterojunction exhibited several distinct advantages: it maintained a regular one-dimensional array structure, possessed a narrowed band gap of 2.38 eV, extended visible-light absorption beyond 520 nm, and achieved high efficiency in photogenerated carrier separation. In photoelectrocatalytic tests, this heterojunction showed the highest degradation rates for CV, RhB, and TC; meanwhile, QSAR analysis combined with hydroponic experiments verified the significant toxicity reduction of CV degradation intermediates. ESR tests further verified that center dot O-2(-) and center dot OH were the key active species driving pollutant degradation, and the Z-scheme charge transfer mechanism was identified as the core reason for its excellent performance-providing a feasible strategy for the design of efficient visible-light-responsive materials for water pollution treatment.
Developing a highly sensitive and visual formaldehyde (FA) detection platform holds great importance for environmental and food monitoring. In this study, the fluorescent molecule with aggregation-induced emission (AIE) was synthesized. The density functional theory (DFT) calculations were performed and the intramolecular charge transfer (ICT) effect was demonstrated. The solvation effect of TPE-ABBA was investigated by varying the type and polarity of organic solvents, and the morphology and property of aggregates were characterized by scanning electron microscopy (SEM) and fluorescence spectra. Based on the high reactivity of TPE-ABBA, it could be used as the fluorescence probe for FA detection and the LOD could be as low as 0.0132 ppm. For the high concentration range of FA (greater than 0.04 ppm), the visual detection could be achieved according to the change of UV-Vis absorption spectroscopy and the LOD was as low as 0.073 ppm. DFT calculations, including geometric structure optimization, molecular electrostatic potential (ESP), reduced density gradient (RDG) scatter plots, and interaction region indicator (IRI) analyses, further verified the formation of stable hydrogen bonding between the probe and FA. Moreover, compared with the traditional aqueous detection, the obtained fluorescence and colorimetric dual-mode sensing system could respond to FA in organic solvent environment. At the same time, the real-time visual and quantitative detection of FA on the surface of fruits and vegetables was achieved, which holds broad application prospects in the field of environmental and food monitoring.
Enhancing the electron-donating ability of dyes and broadening the spectral response range are key strategies for improving the photoelectric conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). Therefore, in this study, the effects of alkoxy substitution on the donor side and the embedding position of benzothiadiazole (BTD) as an auxiliary acceptor on the photovoltaic performance of DSSCs were systematically investigated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The geometric configurations, photoelectric properties, dye regeneration processes, and photovoltaic performance of D-it-A type dyes YYQ12 and YYQ13 were systematically simulated. The results show that the PCE of YYQ13 reaches 8.50%, which is higher than that of YYQ12 (7.78%), and shows good consistency with the experimental data. In addition, based on YYQ13 as the parent molecule, two new molecules, D-it-A-A type YYQ13-1 and D-A-it-A type YYQ13-2, were designed by introducing BTD as an auxiliary acceptor between the it-bridge and the acceptor, and between the donor and the it-bridge, respectively. Notably, YYQ13-1 exhibits a narrower band gap and a wider absorption spectrum range, with a theoretical PCE of 9.88%, significantly higher than that of YYQ13-2 (9.22%) and the experimental molecule. After the dye is adsorbed on the TiO2 surface, the band gap further narrows, which is beneficial to the electron injection process. This work furnishes a theoretical foundation for the development of high-performance sensitizers for DSSCs.
Porphyrins and their metal complexes are a uniquely versatile class of tetrapyrrolic macrocycles; their exceptional photophysical, redox, and coordination properties have placed them at the forefront of modern photo-catalysis. Their delocalized pi-conjugation, readily modifiable sites, and compatibility with visible-light excitation provide rapid single-electron and multi-electron transformations under mild and sustainable conditions; however, aggregation-induced quenching and charge recombination in homogeneous systems may limit photo-catalytic efficiency, thereby motivating the development of structurally engineered and heterogeneous porphyrin architectures. Recent advancements in beta-functionalization, heterocyclic annulation, and metalation have markedly increased structural variety, yielding porphyrins with superior light-harvesting efficiency, red-shifted absorbance, greater charge separation, and precisely adjusted redox potentials. The simultaneous incorporation of porphyrins into supramolecular, MOF, COF, and semiconductor hybrid structures has established organized catalytic environments characterized by enhanced stability, recyclability, and interfacial charge-transport efficiency. This review thoroughly delineates synthetic methodologies for the development of functional porphyrin derivatives, explains the molecular principles influencing their photoexcited-state reactivity, and discusses their catalytic roles in oxidation, reduction, C-C/C-H bond formation, and multicomponent processes. Significant attention is devoted to linking molecular structure with photocatalytic activity, encompassing the influence of metal centers, beta-annulation, substituent effects, and hybrid-framework design. Recent developments in recyclable heterogeneous porphyrin systems and applications underscore the increasing significance of these materials in green and sustainable chemistry. The review concludes by addressing current challenges and future opportunities in the development of next-generation porphyrin photocatalysts aimed at mimicking natural photosynthetic processes.
Organic pollution in aquatic environments has become a major challenge for global environmental remediation, yet traditional water treatment technologies have inherent limitations. Consequently, photocatalytic technology has emerged as a core strategy for water pollution control due to its green and sustainable nature, high catalytic efficiency, and absence of secondary pollution. In this study, AgBiS2/Bi5O7I (ABS/BIO) Z-scheme heterojunction photocatalysts were synthesized via a solvothermal in situ deposition method at temperatures of 160 degrees C, 180 degrees C and 200 degrees C. The results indicated that the reaction temperature can precisely regulate the material's crystalline phase, microstructure and interfacial electronic interactions. The ABS/BIO prepared at 180 degrees C formed a uniform, well-ordered needle-rod-like heterostructure with tight interfacial bonding and high phase purity; strong electronic coupling at the heterojunction interface efficiently drove the separation of photogenerated charges. The narrow bandgap characteristics of AgBiS2 extend the photoresponse into the near-infrared region, while the optimized band structure enables the composite material to achieve broad-spectrum light absorption with a bandgap as low as 1.11 eV. This simultaneously reduced interfacial charge transfer resistance and suppressed photogenerated carrier recombination. Furthermore, multiple reactive species, including h(+), center dot O-2(-), center dot OH and O-1(2), were generated concurrently during the photocatalytic process. Through their synergistic action, the 180 degrees C ABS/BIO composite demonstrated excellent photocatalytic degradation capabilities, achieving degradation efficiencies of 91.2% and 84.8% for rhodamine B (RhB) and tetracycline (TC), respectively, under simulated sunlight irradiation, with catalytic activity significantly superior to that of single-component materials. This temperature-controlled synthesis strategy offers new insights into the structural design and performance enhancement of high-performance bismuth-based composite photocatalysts and holds broad application prospects in the practical treatment of organic wastewater.
We report a new family of photochromic (1-(4-R-phenyl)-4,4 '-bipyridinium; R = F, Cl, Br, I), R-pbpy-Cl (R = F, Cl, Br, I) compounds, which undergo rapid and reversible light-driven transformation in both the solid state (powders and crystals) and embedded in polymer matrices. Upon UV irradiation at 365 nm, the bromine-substituted derivative (Br-pbpy-Cl) undergoes a pronounced colour change from yellow to green, attributed to the to the formation of the corresponding radical cation, as evidenced by UV-Vis and EPR spectroscopies. In polymer films, the photochromic response is strongly concentration-dependent: at low chromophore loadings, isolated radicals initially dominate and progressively convert into a second species associated with dimers, whereas higher concentrations favour radical-radical interactions that directly lead to this second species. In the presence of oxygen, both species, radicals and dimers are stabilized over extended timescales (from several hours to days), allowing detailed spectroscopic characterization. This oxygen-mediated, concentration-dependent interplay between radical recombination and dimer stabilization offers a tuneable handle over the kinetics and optical response of these photochromic materials. Altogether, these findings highlight Br-pbpy-Cl derivatives as a versatile platform for designing reversible, and fast-responsive solid-state and polymeric photochromic materials.
As lithographic resolution improves, stochastic effects during the lithography process have become increasingly significant in influencing pattern quality. Compared to polymeric resists, Single-molecule resins (SMRs), also known as molecular glasses, exhibit potential for mitigating development stochasticity due to their smaller molecular size and monodisperse nature. This study aims to investigate the relationship between the core structure of SMRs and their lithographic stochastic effects. To this end, we designed a series of bisphenol-A-like SMRs with core structures of adamantane-diyl, isopropylidene and isopropylidene, namely AD-Boc, BPA-Boc, and PH-Boc. Performance evaluations revealed the ranking in terms of LER and contrast: AD-Boc > BPA-Boc > PH-Boc. Fourier-transform infrared spectroscopy (FTIR) and X-ray reflectivity (XRR) analyses demonstrated that AD-Boc exhibits the strongest capability to suppress acid diffusion. Furthermore, calculations of the critical deprotection ratio combined with surface energy measurements confirm that AD-Boc induces the least stochasticity during development. These two effects together account for the observed differences in final lithographic performance. This work elucidates how the core structure of SMRs modulates lithographic performance by controlling acid diffusion and development stochasticity, providing valuable insights for the design of next-generation photoresists.
To enhance peracetic acid (PAA) activation under visible light for the efficient and deep removal of tetracycline (TC), a CNT@PDA@Fe3O4 (CPF) composite photocatalyst was constructed via a capillary infiltration strategy using open-ended multi-walled carbon nanotubes (CNTs), followed by thermal fixation under N2. Structural characterization confirmed that the PDA-derived carbon phase and Fe3O4 were stably anchored within/on the opened CNT channels and framework, forming an intimately coupled interface. Compared with CNT@PDA, CNT@Fe3O4, and the single-component counterparts, the optimal sample, CPF-1:2, exhibited the best performance in the visible-light/PAA system, decreasing the normalized TC concentration to about 0.08 within 60 min. Photoelectrochemical and band-structure analyses revealed that CPF possessed lower interfacial charge-transfer resistance, higher transient photocurrent response, weaker carrier recombination, and a more favorable band structure, thereby promoting visible-light harvesting, electron migration, and PAA activation through the Fe2+/ Fe3+ cycle. Scavenger tests and EPR measurements demonstrated that h+ and 1O2 were the dominant reactive species, while center dot O2- and PAA-derived reactive intermediates also contributed, whereas center dot OH played a negligible role. LC-MS analysis indicated that TC underwent sequential hydroxylation/oxygenation, de-functionalization, ring opening, and bond cleavage through three parallel pathways, eventually evolving toward low-molecularweight intermediates and deeper oxidation. Moreover, the CPF/PAA/visible-light system maintained high activity over a wide pH range (3-11), showed good applicability toward other tetracycline antibiotics (DOX, OTC, and CTC), and exhibited satisfactory matrix tolerance and cycling stability. This work provides a feasible strategy for designing carbon-confined, visible-light-assisted Fe-based catalysts for PAA activation and antibiotic abatement.
Aromatic compounds represent a large fraction of volatile organic compounds in urban atmospheres due to their use as solvents in industrial activities and their presence in gasoline used by car engines. M-xylene is one of the major aromatic species emitted in the atmosphere, impacting air quality through its reactions with atmospheric oxidants. While the fate of m-xylene in the atmosphere has been already investigated through different studies, the present work brings new information on the chemical composition of the Secondary Organic Aerosols (SOAs) formed from the m-xylene reaction with OH radicals under high NOx conditions. The SOAs were sampled from a simulation chamber on Teflon filters, extracted by water and then by dichloromethane and further analysed by Liquid Chromatography coupled to ElectroSpray Ionisation tandem Mass Spectrometry. The analyses allowed to determine the chemical composition and to identify the presence of 30 organic compounds (without counting isomers) that can be categorized into two main families: m-xylene derivatives and toluene derivatives. Four generations of oxidation products were described in a reaction mechanism, showing an additional nitro- or hydroxy- functionalization on the aromatic ring at each generation. Second- and third-generation products were dominant, suggesting high reactivity of first-generation and second-generation products, while the fourthgeneration products displayed lower concentrations. Dimers formed from the association of representatives of the two main families were also identified and their formation explained in a radical addition mechanism.
Photocatalytic hydrogen peroxide (H2O2) production offers an effective alternative to the energy-intensive Anthraquinone process (AQ) method. Covalent organic frameworks (COFs) containing electron-deficient triazine groups have attracted significant attention due to their ordered and tunable structures, which offer unique advantages in modulating the skeleton's electronic structure and constructing efficient photocatalytic active sites. However, challenges persist in photocatalytic H2O2generation, including narrow absorption spectra, facile recombination of photogenerated carriers, and difficulties in H2O2formation and desorption. We introduced tetracarboxylate cobalt phthalocyanine (CoPc(COOH)4) via a sensitization strategy to overcome these inherent limitations. Compared to TpTz-COF, the CoPc(COOH)4/TpTz-COF composite achieved a 3.21-fold increase in yield in pure water without sacrificial agents. The hydrophilic carboxyl groups not only significantly enhanced the dispersion of the material in pure water, but also served as key connection points to stabilize the composite structure through weak interactions (hydrogen bonding), with DFT calculations confirming the existence of these interactions. Mechanistic studies further revealed that the enhanced activity originated from the specific electronic modulation by the Co centers: Density of States (DOS)analysis confirmed that the Co 4d orbitals dominated the key reaction intermediates (*O2, *OOH, and *H2O2), while d-band center theory calculations indicated that this modulation optimized the adsorption strength of the reactive species, thereby accelerating the catalytic kinetics. This study provides insights for rationally designing sensitizers to address COF inherent limitations and achieve green H2O2production via photocatalysis.
Graphitic carbon nitride (g-C3N4) is a promising metal-free photocatalyst; however, its practical activity is severely limited by its low surface area, insufficient active sites, and rapid charge recombination. Herein, we report a controllable two-step, metal-free strategy that integrates NH4Cl-induced porosity engineering with post-exfoliation non-metal heteroatom modulation (S, P, B) to simultaneously optimize the surface architecture and charge dynamics in ultrathin g-C3N4 nanosheets. NH4Cl induces surface morphology, porosity, and nitrogen-rich surface functionalization, while subsequent thermal doping enables precise electronic structure tuning without disrupting the it-conjugated framework. The surface area of nitrogen-rich g-C3N4 (ENCN) is enhanced by 8.35 times compared to pure g-C3N4. Furthermore, NH4Cl integration enhances the structural properties and effectively reduces charge recombination, resulting in an excellent hydrogen evolution rate of 8.263 mmol g-1, which is 12-fold higher than that of pure g-C3N4. Among the investigated dopants, thiourea-derived sulfur doping yields the highest specific surface area (168.1 m2/g) and exhibits a markedly enhanced photocatalytic hydrogen evolution performance of 37.93 mmol g-1, approximately 37-fold higher than pure g-C3N4. Moreover, the photocatalytic performance was systematically investigated through optical and photoelectrochemical measurements, including electrochemical impedance spectroscopy, cyclic voltammetry, chronoamperometry, and electrochemically active surface area (ECSA). The band structures of all photocatalysts were examined using Mott-Schottky analysis. Vacancy defects in the doped samples were analyzed using ESR analysis.
Hydrogen peroxide (H2O2), a key member of the reactive oxygen species family, plays a crucial role in physiological and pathological processes. Abnormal fluctuations in H2O2 levels are closely associated with various diseases. Therefore, monitoring and visualizing changes in H2O2 levels play a significant role in early disease diagnosis. In this study, a near-infrared (NIR) fluorescent probe, TF-BO, was rationally designed based on a flavonoid scaffold to monitor H2O2 fluctuations in biological systems. The introduction of an electron-rich thiophene moiety enabled the modified flavonoid to exhibit fluorescence emission in the NIR region. TF-BO had high specificity, strong anti-interference capability, and a large Stokes shift (Delta lambda = 238 nm). The probe was successfully applied to image both exogenous and endogenous H2O2 in living cells and was further used to monitor H2O2 fluctuations during acetaminophen (APAP)-induced ferroptosis in hepatocytes. TF-BO was also successfully employed to visualize changes in H2O2 levels in a mouse model of APAP-induced liver injury. This work shows that the probe TF-BO is a powerful molecular tool for investigating drug-induced liver injury and ferroptosis-related processes in biological systems.
Quercetin is a bioactive compound with well-documented antioxidative properties responsible for its significant pharmacological potential. However, the employment of quercetin is severely constrained by poor water solubility and limited stability under oxidative conditions. To overcome these limitations, a green synthetic strategy was developed to conjugate quercetin to a hydrophilic natural polysaccharide, such as hyaluronic acid. The final aim was the enhancement of the bio-delivery of this natural flavonoid. Likewise, the important issue of the chemical integrity/ stability of the quercetin was thoroughly assessed, through a deep UV-vis spectroscopic analysis. Furthermore, to demonstrate that quercetin covalently bound to hyaluronic acid retains the reducing activity of its free form, an oxidative assay based on the Fe(III)/ Fe(II) redox couple was developed.
This study investigates a series of eight xanthene based molecular switches, which can be reversibly switched from a closed (spiro) to open (mero) from by induced light. This photo-induced structural change acts as a powerful functional switch, dramatically altering the electronic and optical properties of the designed systems. The ring-opening to the planar mero configuration restores it-conjugation and enhances intramolecular charge transfer. This leads to a strong amplification of the second-order nonlinear optical (NLO) response, with the first hyperpolarizability (beta HRS) increasing by over 500% for donor-substituted derivatives. Critically, the switching also fundamentally alters the symmetry of the NLO response, inducing a pronounced octupolar character. The octupolar contribution rises from 42 to 49% (static) to 51-78% at an operational wavelength of 1460 nm. This isotropic nature is confirmed by high depolarization ratios (DR = 3.74-5.34). The derivative mero-NOX-NO2 exemplifies an optimized hybrid state, exhibiting both the largest beta HRS and a highly isotropic response (DR = 4.80), suitable for electro-optical applications. These properties are purely based on electron donor and/or acceptor substituents. Strong electron-withdrawing groups (-NO2, -CN) maximize the dipole moments and NLO response but suboptimal for photovoltaics due to excessive LUMO stabilization. In contrast, electron-donating groups (-NH2,-OH) enable ideal energy level alignment for solar cell applications, yielding a record theoretical power conversion efficiency of 31.9%. This work establishes a versatile platform for adaptive molecular materials with ability to be tuned by incident to generate a state tuned, for enhanced NLO properties and for optimal solar energy conversion.
Water-soluble nanoscale systems of the hydrophobic fluorescent dye zinc tetraphenylporphyrinate (ZnTPP) were preparated by its solubilizing with amphiphilic terpolymers of N-vinylpyrrolidone with (di)methacrylates. The sizes of nanoparticles were determined in phosphate-buffered and saline solutions using dynamic light scattering. It was shown that ZnTPP nanoparticles based on terpolymers contained methacrylate acid units or residues-SC10H21 react to an increase in temperature range of 37-42 degrees C, a sharp jump in the average light scattering intensity is observed and the hydrodynamic radius of scattering centers increases. The polymer compositions demonstrated high stability in aqueous media and in the solid state after long-term storage while maintaining absorbance and fluorescence. To TEM data, the sample dried from an aqueous solution consists of amorphous particles as well as particles with ordered ("crystalline") structure. The fluorescence of developed nanoscale systems was studied in water, saline solution, and mouse brain homogenate. At first time, we studied their biodistribution in tumors and normal animal tissues in vivo and ex vivo using fluorescence imaging. The fluorescence imaging in vivo demonstrated the ability of nanoparticles based on the small-sized terpolymer to accumulate selectively in tumors. The developed systems can be used for fluorescence diagnostics and visualization for affected cells and tissues.
The modulation of excited-state behavior of fluorescent probes in organized media is of considerable interest in photochemistry. Herein, a rhodamine pseudo-azacrown probe was incorporated into sodium dodecyl sulfate (SDS) micelles to construct a highly emissive micellar system (RhoN4@SDS) and to investigate the interfacial regulation of Hg2+-induced fluorescence activation in aqueous media. Zeta potential measurements (-66.4 mV for RhoN4@SDS vs.-1.7 mV for free RhoN4) indicate strong electrostatic stabilization of the probe at the anionic micellar interface. Upon Hg2+ coordination, spirolactam ring opening of the rhodamine unit gives rise to a distinct color change and pronounced fluorescence enhancement. Among the surfactants examined, SDS provides the most effective emission amplification, which is attributed to cooperative electrostatic stabilization of the ring-opened form and hydrophobic confinement within the micellar nanoenvironment. Density functional theory (DFT) calculations further reveal that Hg2+ coordination stabilizes the ring-opened structure and markedly reduces the HOMO-LUMO energy gap, in agreement with the observed optical response. Fluorescence imaging in Peperomia pellucida additionally demonstrates in vivo visualization of Hg2+ uptake and vascular transport, with detectable emission down to 1 & times; 10-7 M. These results show that micellar interfaces can actively regulate the electronic structure and excited-state properties of rhodamine-based systems, providing photo-physical insight into environment-responsive fluorescence activation.
