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Zwitterionic near-infrared fluorophore-conjugated epidermal growth factor for fast, real-time, and target-cell-specific cancer imaging
摘要： Epidermal growth factor receptor (EGFR) is overexpressed in many types of cancers, which is associated with metastatic potential and poor prognosis in cancer patients. Therefore, development of EGFR-targeted sensitive imaging probes has been a challenge in tumor targeting, image-guided cancer surgery, patient-selective anti-EGFR therapy, and efficient targeted therapies. Methods: We synthesized a zwitterionic near-infrared fluorophore (ATTO655)-conjugated epidermal growth factor (EGF) as a novel activatable molecular probe. Fluorescence OFF/ON property and EGFR-targeting specificity of EGF-ATTO655 as well as its utility in real-time near-infrared (NIR) fluorescence imaging of EGFR-positive cancers were evaluated using in vitro and in vivo studies. Results: When conjugated to EGF, the fluorescence of ATTO655 quenched efficiently by photo-induced electron transfer (PET) mechanism between the conjugated dyes and nearby amino acid quenchers (tryptophan/tyrosine residues), which was stably maintained at physiological pH and in the presence of serum for at least 17 h. The fluorescence of EGF-ATTO655 turned on by receptor-mediated endocytosis and subsequent disintegration of EGF in EGFR-positive A431 cancer cells, thereby enabling specific and real-time fluorescence imaging of EGFR-positive cancer cells. Consequently, EGFR-positive tumors could be clearly visualized 3 h post-injection with a significantly high tumor-to-background ratio (TBR = 6.37). Conclusion: This PET mechanism-based OFF/ON type of EGF probe showed great potential for rapid, real-time, and target-cell-specific imaging of EGFR-overexpressing cancers in vitro and in vivo.
关键词： photo-induced electron transfer,Epidermal growth factor,real-time cancer imaging,tumor-specific targeting
更新于2025-11-21 11:24:58
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Photo-Induced Phase Transition of CdZnS Based Nanocomposite at Room Temperature Under Solar Irradiation
摘要： Photo-induced phase transition (PIPT) of CdZnS based nanocomposites that was performed at the room temperature under the solar light illumination is reported here for the first time. CdZnS particles were decorated on reduced graphene oxide (RGO) with a solvothermal process and consequently RGO-CdZnS-5%Pt nanocomposites (PC) have been synthesized as zinc blende (cubic) phase of CdZnS. Zinc blende structure (cubic) of CdZnS components of PC was turned to wurtzite (hexagonal) crystal structure with PIPT during the photocatalytic hydrogen evolution reaction. The band gap of the photocatalyst decreased from 2.42 to 2.19 eV and the hydrogen evolution rate increased from 37.3 to 184.0 μ mol h?1 due to the PIPT process.
关键词： Photo-induced phase transition,Hydrogen production,Metal chalcogenides,Photocatalyst
更新于2025-09-23 15:22:29
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Effect of photo-irradiation on metal insulator transition in vanadium dioxide
摘要： We report a large transition temperature (TC) decrease in a VO2 thin film device under photo-irradiation. With the increasing photo-irradiation intensity (PIntensity) with a wavelength of 405 nm, the TC of the VO2 device decreased at a rate of (cid:2)3:2 (cid:3) 10(cid:4)2 W=cm2 and reached as low as 40.0 (cid:5)C at a PIntensity of 8:4 (cid:3) 102 W=cm2. While the change in TC is primarily due to the photothermal effect when the PIntensity is below 3:6 (cid:3) 102 W=cm2, both the photothermal and photo-induced carrier density effects contribute to the change in TC when the PIntensity is above 6:4 (cid:3) 102 W=cm2.
关键词： metal-insulator transition,vanadium dioxide,photothermal effect,photo-induced carrier density,photo-irradiation
更新于2025-09-23 15:21:21
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A Preferential Photoreaction in a Porous Crystal, Metal-Macrocycle Framework (MMF): Pd <sup>II</sup> -Mediated Olefin Migration over [2+2] Cycloaddition
摘要： A nano-sized confined space with well-defined functional surfaces has great potential to control the efficiency and selectivity of catalytic reactions. Herein we report that a 1,6-diene, which normally forms an intramolecular [2+2] cycloadduct under photo-irradiation, preferentially undergoes a photo-induced olefin migration in a porous crystal, metal–macrocycle framework (MMF), and alternatively [2+2] cycloaddition is completely inhibited in the confined space. A plausible reaction mechanism for olefin migration triggered by the photo-induced dissociation of the Pd-Cl bond is suggested based on UV-vis diffuse reflectance spectroscopy, single-crystal XRD, and MS-CASPT2 calculation. The substrate scope of the photo-induced olefin migration in MMF was also examined using substituted allylbenzene derivatives.
关键词： photo-induced olefin migration,metal–macrocycle framework,Pd-Cl bond dissociation,nano-sized confined space,[2+2] cycloaddition
更新于2025-09-23 15:21:21
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Unraveling the impact of hole transport materials on photostability of perovskite films and p-i-n solar cells
摘要： We investigated the impact of a series of hole transport layer materials (HTLs) such as PEDOT:PSS, NiOx, PTAA, and PTA on photostability of thin films and solar cells based on MAPbI3, Cs0.15FA0.85PbI3, Cs0.1MA0.15FA0.75PbI3, Cs0.1MA0.15FA0.75Pb(Br0.15I0.85)3, and Cs0.15FA0.85Pb(Br0.15I0.85)3 complex lead halides. Mixed halide perovskites showed reduced photostability in comparison with similar iodide-only compositions. In particular, we observed light-induced recrystallization of all perovskite films except MAPbI3 with the strongest effects revealed for Br-containing systems. Moreover, halide and β FAPbI3 phase segregations were also observed mostly in mixed-halide systems. Interestingly, coating perovskite films with PCBM layer spectacularly suppressed light-induced growth of crystalline domains as well as segregation of Br-rich and I-rich phases or β FAPbI3. We strongly believe that all three effects are promoted by the light-induced formation of surface defects, which are healed by adjacent PCBM coating. While comparing different hole-transport materials, we found that NiOx and PEDOT:PSS are the least suitable HTLs due to their interfacial (photo)chemical interactions with perovskite absorbers. On the contrary, polyarylamine-type HTLs PTA and PTAA form rather stable interfaces, which makes them the best candidates for durable p-i-n perovskite solar cells. Indeed, multilayered ITO/PTA(A)/MAPbI3/PCBM stacks revealed no aging effects within 1000 h of continuous light soaking and delivered stable and high power conversion efficiencies in solar cells. The obtained results suggest that using polyarylamine-type HTLs and simple single-phase perovskite compositions paves a way for designing stable and efficient perovskite solar cells.
关键词： stable HTL/perovskite interface,interface-induced degradation,light-induced perovskite crystallization,photo-induced degradation,p-i-n perovskite solar cells
更新于2025-09-23 15:21:01
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Theory of photoinduced ultrafast switching to a spin-orbital ordered hidden phase
摘要： Photo-induced hidden phases are often observed in materials with intertwined orders. Understanding the formation of these non-thermal phases is challenging and requires a resolution of the cooperative interplay between different orders on the ultra-short timescale. In this work, we demonstrate that non-equilibrium photo-excitations can induce a state with spin-orbital orders entirely different from the equilibrium state in the three-quarter-filled two-band Hubbard model. We identify a general mechanism governing the transition to the hidden state, which relies on a non-thermal partial melting of the intertwined orders mediated by photoinduced charge excitations in the presence of strong spin-orbital exchange interactions. Our study theoretically confirms the crucial role played by orbital degrees of freedom in the light-induced dynamics of strongly correlated materials and it shows that the switching to hidden states can be controlled already on the fs timescale of the electron dynamics.
关键词： spin-orbital orders,photo-induced hidden phases,non-equilibrium photo-excitations,two-band Hubbard model,ultrafast switching
更新于2025-09-23 15:21:01
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Zn2+ leakage and photo-induced reactive oxidative species do not explain the full toxicity of ZnO core Quantum Dots
摘要： Metal oxide nanoparticles (NPs), and among them metal oxides Quantum Dots (QDs), exhibit a multifactorial toxicity combining metal leaching, oxidative stress and possibly direct deleterious interactions, the relative contribution of each varying according to the NP composition and surface chemistry. Their wide use in public and industrial domains requires a good understanding and even a good control of their toxicity. To address this question, we engineered ZnO QDs with di?erent surface chemistries, expecting that they would exhibit di?erent photo-induced reactivities and possibly di?erent levels of interaction with biological materials. No photo-induced toxicity could be detected on whole bacterial cell toxicity assays, indicating that ROS-dependent damages, albeit real, are hidden behind a stronger source of toxicity, which was comforted by the fact that the di?erent ZnO QDs displayed the same level of cell toxicity. However, using in vitro DNA damage assays based on quantitative PCR, signi?cant photo-induced reactivity could be measured precisely, showing that di?erent NPs exhibiting similar inhibitory e?ects on whole bacteria could di?er dramatically in terms of ROS-generated damages on biomolecules. We propose that direct interactions between NPs and bacterial cell surfaces prime over any kind of intracellular damages to explain the ZnO QDs toxicity on whole bacterial cells.
关键词： Cell surface damages,Nanotoxicity,ZnO Quantum Dots,Photo-induced reactive oxygen species,Metal oxide nanoparticles
更新于2025-09-23 15:21:01
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Laser-Induced Dissociation of the Monolayer of Adsorbed Methanol Molecules
摘要： Astronomical observations indicate a high abundance of methanol molecules in the gas phase of molecular-cloud dense cores, which cannot be explained by gas-phase chemical reactions only. A significant contribution to the methanol abundance should be provided by chemical reactions on the dust particle surface with subsequent desorption of the produced molecules into the gas phase. For the development and refinement of models involving these processes, laboratory studies of photo-induced processes occurring in the adsorbed material are necessary. In this paper, the experiment results of adsorbed methanol molecules are presented. A methanol molecule monolayer, physically adsorbed on fused silica surface cooled by liquid nitrogen (Т ～ 100 K), was irradiated in high vacuum by nanosecond pulses of an excimer KrF laser with a fixed wavelength λ = 248 nm. The photodissociation products of three-photon laser excitation were recorded by a quadrupole mass spectrometer. Relative yields of photofragments H, OH, and CH3 were determined. Photolysis of partially deuterated CH3OH molecules has shown that hydrogen atoms can be ejected both from hydroxyl and methyl groups. In contrast to the isolated molecule photolysis in the gas phase and dissociation of the multilayer molecular coatings, photoexcitation of adsorbed methanol monolayer even in the energy region of 10 eV does not cause noticeable chemical transformations and does not lead to the formation of molecular components H2 and CH4. Due to existing astrochemical modeling problems, possible application methods of the obtained laboratory results are considered.
关键词： chemical reactions,astronomical observations,adsorbed monolayer,mass spectrometry,photo-induced processes,gas phase,dust particle surface,KrF laser,photodissociation,methanol
更新于2025-09-23 15:21:01
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Laser-Assisted Fabrication for Metal Halide Perovskite-2D Nanoconjugates: Control on the Nanocrystal Density and Morphology
摘要： We report on a facile and rapid photo-induced process to conjugate graphene-based materials with metal-halide perovskite nanocrystals. We show that a small number of laser pulses is sufficient to decorate the 2-dimensional (2D) flakes with metal-halide nanocrystals without affecting their primary morphology. At the same time, the density of anchored nanocrystals could be finely tuned by the number of irradiation pulses. This facile and rapid room temperature method provides unique opportunities for the design and development of perovskite-2D nanoconjugates, exhibiting synergetic functionality by combining nanocrystals of different morphologies and chemical phases with various 2D materials.
关键词： graphene oxide,2D materials,photo-induced processes,laser-induced synthesis,nanoparticles,anion exchange,synergistic effects
更新于2025-09-23 15:19:57
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Photo-induced meta-stable polar conformations in polystyrene microspheres revealed by time-resolved SHG microscopy
摘要： Photo-induced second harmonic generation (SHG) was observed in centrosymmetric polystyrene (PS) microspheres using 1064 nm, sub-nanosecond laser-pulse irradiation. The SHG signal gradually increased upon stationary laser-pulse irradiation. After stopping the irradiation, the increased SHG signal disappeared in approximately 30 min. When the PS bead was irradiated by laser pulses again, the SHG signal reappeared with similar temporal behavior, which was attributed to the probable growth and contraction of meta-stable polar conformations of PS chain segments under periodic photo-thermal stimuli.
关键词： second harmonic generation,photo-induced,polystyrene microspheres,time-resolved SHG microscopy
更新于2025-09-23 15:19:57