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- 摘要
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- 实验方案
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Optical Control of Biomimetic Nanoparticle Catalysts Based Upon the Metal Component
摘要： Nanoparticle catalysts provide an intriguing route to achieving sustainable reactivity. Recent evidence has suggested that both the underlying metallic core and the passivating ligand layer can be exploited to control reactivity. The intimate interactions between the core metal and structure of the ligand layer can change based upon the metal used to generate the catalytic particle. Through judicious selection of both components, nanoparticle catalytic systems can be designed to be stimuli responsive for controlled reactivity. Herein we demonstrate the effects of the underlying metal on the optically modulated catalytic activity of peptide-capped noble metal nanoparticles. For this, a photoswitch was incorporated into the peptide that enables reversible reconfiguration of the bioligand overlayer structure between two conformations based upon the isomerization state of the photoswitch. These changes in activity are dependent upon the inorganic metal of the particle core, and we exploit this dependence to demonstrate changes in the activity. The materials were fully characterized via spectroscopic methods and microscopy to correlate the observed reactivity to the material composition. The results provide new pathways to achieve remotely responsive catalysts that could be important for controlled multistep reactions or be exploited for other applications including biosensing and plasmonic devices.
关键词： optically modulated catalytic activity,peptide-capped noble metal nanoparticles,biosensing,Nanoparticle catalysts,photoswitch,plasmonic devices
更新于2025-09-23 15:21:21
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Photoinduced reversible solid-to-liquid transitions using photoswitchable materials
摘要： Heating and cooling can induce reversible solid-to-liquid transitions of matter. In contrast, athermal photochemical processes can induce reversible solid-to-liquid transitions of some newly developed azobenzene compounds. Azobenzene is photoswitchable. UV light induces trans-to-cis isomerization; visible light or heat induces cis-to-trans isomerization. Trans and cis isomers usually have different melting points (Tms) or glass transition temperatures (Tgs). If Tms or Tgs of an azobenzene compound in trans and cis forms are above and below room temperature, respectively, light may induce reversible solid-to-liquid transitions. In this review, we introduce azobenzene compounds that exhibit photoinduced reversible solid-to-liquid transitions, discuss the mechanisms and design principles, and show their potential applications in healable coatings, adhesives, transfer printing, lithography, actuators, fuels, and gas separation. Finally, we discuss remaining challenges in this field.
关键词： photoswitch,isomerization,azobenzene,solid-to-liquid transition,photochemistry
更新于2025-09-19 17:15:36
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Photo-controlled reversible binding between the protein A-derived Z domain and immunoglobulin G
摘要： Photoisomerization of the trans and cis isomers of azobenzene derivatives has been used to control the function of biomolecules in a reversible and non-destructive manner. In this study affibody molecules, representing a class of small, helical proteins that can be engineered for binding to a wide range of target proteins, have been investigated by the incorporation of a photoswitchable azobenzene derivative in the molecule. Three different Z domain variants were produced by solid phase peptide synthesis and conjugated by thiol-directed chemistry to an azobenzene-based photoswitch. The proteins were screened for binding to and light elution from an IgG-sepharose affinity column. One of tested Z variants, ZC3, showed efficient binding to the column and could be eluted by irradiation with light at 400 nm. In a reverse affinity chromatography assay, where the ZC3 variant was coupled to sepharose, human IgG1 could be captured to the column and partially eluted by light. Further studies of the azobenzene-conjugated ZC3 domain by surface plasmon resonance (SPR) confirmed the high affinity binding to IgG, and circular dichroism (CD) spectroscopy showed that the protein has a high alpha-helical secondary structure content.
关键词： immunoglobulin G,affibody molecule,photoswitch,Z domain,affinity chromatography,azobenzene
更新于2025-09-19 17:13:59
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Thiophenylazobenzene - an alternative photoisomerization controlled by lone pair???π interaction
摘要： Azoheteroarene photoswitches have attracted attention due to their unique properties. We present here the stationary photochromism and the ultrafast photoisomerization mechanism of thiophenylazobenzene (TphAB) – an alternative sulfur-based azoheteroarene design. TphAB demonstrates impressive fatigue resistance and photoisomerization efficiency, and shows favorably separated (E)- and (Z)-isomer absorption bands, allowing for highly selective photoconversion. The (Z)-isomer of TphAB adopts an unusual orthogonal geometry where the plane of the thiophene is perfectly perpendicular to that of the benzene. This geometry is stabilized by a rare lone pair???π interaction between the S-atom and the benzene. The photoisomerization of TphAB occurs on the sub-ps to ps timescale and is governed by the lone pair???π interaction. Therefore, the adoption and disruption of the orthogonal geometry requires significant movement along the inversion reaction coordinates (CNN and NNC angles). Our results establish TphAB as an excellent photoswitch with versatile properties that expand the application possibilities of AB derivatives.
关键词： time-resolved spectroscopy,photochromism,photoswitch,thiophenylazobenzene,isomerization mechanism
更新于2025-09-19 17:13:59
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Thiophenylazobenzene – an alternative photoisomerization controlled by lone pair???π interaction
摘要： Azoheteroarene photoswitches have attracted attention due to their unique properties. We present here the stationary photochromism and the ultrafast photoisomerization mechanism of thiophenylazobenzene (TphAB) – an alternative sulfur-based azoheteroarene design. TphAB demonstrates impressive fatigue resistance and photoisomerization efficiency, and shows favorably separated (E)- and (Z)-isomer absorption bands, allowing for highly selective photoconversion. The (Z)-isomer of TphAB adopts an unusual orthogonal geometry where the plane of the thiophene is perfectly perpendicular to that of the benzene. This geometry is stabilized by a rare lone pair???π interaction between the S-atom and the benzene. The photoisomerization of TphAB occurs on the sub-ps to ps timescale and is governed by the lone pair???π interaction. Therefore, the adoption and disruption of the orthogonal geometry requires significant movement along the inversion reaction coordinates (CNN and NNC angles). Our results establish TphAB as an excellent photoswitch with versatile properties that expand the application possibilities of AB derivatives.
关键词： photochromism,time-resolved spectroscopy,thiophenylazobenzene,isomerization mechanism,photoswitch
更新于2025-09-11 14:15:04