Absorption Dichroism Research Articles

Aggregachromic Fluorogenic Asymmetric Cyanine Probes for Sensitive Detection of Heparin and Protamine

The precise and fast detection of heparin, the most widely used anticoagulant, remains a significant challenge for assessing its use in a clinical setting. In this work, we adapt a well-established asymmetric cyanine fluorogenic platform for the purpose of ultrasensitive heparin detection in the presence of common interferant chemical species. Three analogous fluorescence probes are synthesized in order to optimize for the number of binding moieties. Their interaction with heparin is studied using steady-state absorption, fluorescence, and circular dichroism spectroscopy. The obtained probes exhibit a highly sensitive “turn-on” fluorescence response to heparin, with a LOD in the 10–25 nM range, well within practical requirement, as well as a visible colorimetric change. The heparin–probe complex is also employed as a sensitive detection platform for protamine, both in the “turn-off” fluorescence and ratiometric detection schemes.

Physical properties of chlorophyll–quinone conjugates prepared via Friedel–Crafts reaction

Pheophytin-a derivatives possessing plastoquinone and phylloquinone analogs in the peripheral 3-substituent were prepared by Friedel–Crafts reactions of a 3-hydroxymethyl-chlorin as one of the chlorophyll-a derivatives with benzo- and naphthohydroquinones, respectively, and successive oxidation of the 1,4-dihydroxy-aryl groups in the resulting dehydration products. The 3-quinonylmethyl-chlorins exhibited ultraviolet–visible absorption and circular dichroism spectra in acetonitrile, which were composed of those of the starting 3-hydroxymethyl-chlorin and the corresponding methylated benzo- and naphthoquinones. No intramolecular interaction between the chlorin and quinone π-systems was observed in the solution owing to the methylene spacer. The first reduction potentials of the quinone moieties in the synthetic conjugates were determined by cyclic voltammetry and shifted positively from those of the reference quinones. The former quinonyl groups were reduced more readily by approximately 0.1 V than the latter quinones, which was ascribable to the stabilization of the quinonyl anion radical by the nearby macrocyclic chlorin π-chromophore. This observation implied that the reduction potentials of quinones were regulated by the close pheophytin-a derivative by through-space interaction. Considering the charge shift from pheophytin-a anion radical to plastoquinone and phylloquinone in reaction centers of photosystems II and I, respectively, the reduction potentials of these quinones as a determinant factor of the rapid electron transfer process would be dependent on the pheophytin-a in the photosynthetic reaction centers of oxygenic phototrophs as well as on the neighboring peptides.

Readily Accessible, Versatile, and Adaptive Biaxially Chiral Chromophores.

Precisely controlling quantum states is relevant in next-generation quantum computing, encryption, and sensing. Chiral organic chromophores host unique light-matter interactions, which allow them to manipulate the quantized circular polarization of photons. Axially chiral organic scaffolds, such as helicenes or twisted acenes, are powerful motifs in chiral light manipulation. However, these systems usually require complex syntheses and small-scale (10 mg) enantiomer separations, typically complicating systematic investigations of their structure-property relationships. We report here the straightforward synthesis of both enantiomers (R/S) of 10 different axially chiral chromophores. This protocol relies on a readily accessible, enantiomerically pure, and axially chiral contorting element, benzodinaptho[1,4]dioxicine-2,3-diamine (DODA), that we synthesize in two steps with high purity and good yield at gram scale. Subsequent derivation of DODA transfers the chirality from one axis to twist the dominant chromophore around a second, orthogonal axis. Using this biaxial contortion design element, we produce 10 enantiopure biaxial chromophores, without the need for chromatographic separations, and no observable compromise to chiroptical integrity. These chromophores exhibit broadband single-handed absorption without Cotton effects from 265 to 485 nm, indicating chiral excitonic character that forms between the DODA and twisted core chromophore. This platform is responsive to solvent polarity in the excited state, displaying >50 nm bathochromic shifts in the photoluminescence spectra. In addition, this scaffold intensely interacts with changes in pH, which allows us to ultimately access monosignate circular dichroism absorption over a 300 nm range.

Vibronic Coupling and Multiple Electronic States Effect in ABS and ECD Spectra: Three [7]Helicene Derivatives.

Vibronic coupling and multiple electronic states effect play a pivotal role in the molecular spectroscopy of large systems. Herein, we present a detailed theoretical study on the absorption (ABS) and electronic circular dichroism (ECD) spectra of three [7]helicene derivatives in chloroform, with a particular emphasis on the significance of vibronic coupling and the multiple electronic states effect in spectral simulations. The vertical gradient (VG) and vertical Hessian (VH) models, incorporating the Franck-Condon (FC) effect and Herzberg-Teller (HT) contribution, are considered in the vibronic calculations. The results indicate that the simulated vibrationally resolved spectra obtained by the VG model combined with the FC effect are more reliable, showing advantages in the rationality of spectral shapes, the accuracy of the relative heights of absorption peaks, and the correctness of positive and negative signals. Reliable predictions of the three [7]helicene derivatives allowed us to further explore the importance of the multiple electronic states effect in the vibrationally resolved spectra, demonstrating that the high-energy electronic excited states, particularly the fifth (S5) and sixth (S6) excited states, are essential for accurately capturing the fine structures observed in the experimental spectra. Our study predicts reliable theoretical reference spectra for the family of [7]helicene derivatives and provides a fundamental understanding of the vibronic coupling of chiral organic molecules with multiple electronic states.

RuIII-Morpholine-Derived Thiosemicarbazone-Based Metallodrugs: Lysosome-Targeted Anticancer Agents.

The idea of coordinating biologically active ligand systems to metal centers to exploit their synergistic effects has gained momentum. Therefore, in this report, three RuIII complexes 1-3 of morpholine-derived thiosemicarbazone ligands have been prepared and characterized by spectroscopy and HRMS along with the structure of 2 through a single-crystal X-ray diffraction study. The solution stability of 1-3 was tested using conventional techniques such as UV-vis and HRMS. Further, the anticancer activity of 1-3 was tested in HT-29 and HeLa cancer cell lines. To gain insight into their mechanism of action, the cytotoxicity, hydrophobicity, and the interaction of 1-3 with DNA and HSA were evaluated by different conventional methods such as absorption, fluorescence, and circular dichroism studies. Along with favorable biomolecule interaction, 1-3 revealed potent selectivity toward cancer cells, which is a prerequisite for the generation of an anticancer drug. According to cell viability results, 1 has the highest cytotoxicity among all in the group, against both cells, respectively. Additionally, the fluorescence-active ruthenium complexes selectively target lysosomes, which is evaluated by live-cell imaging. 1-3 disrupt the lysosome membrane potential by generating an excessive amount of reactive oxygen species, which results in an apoptotic mode of cell death.

In vitro studies on the metal sensing capability of annelide hemoglobin

Many studies in the literature suggest that earthworms play an important role in the use and management of soils and are considered good bioindicators of environmental contamination by presenting changes in their behavior and even death when inserted in contaminated environments. In the current study we investigated the in vitro behavior of Amynthas gracilis hemoglobin (HbAg) against copper (Cu) and cadmium (Cd) in concentrations ranging from 0 to 100 µmol L-1, at pH values 5.0 and 7.0 by optical absorption, fluorescence emission, light scattering and circular dichroism techniques. Our results sugest that the HbAg undergoes oxidation in its heme group at both pH values. As from 30 µmol L-1 of copper in pH 7.0 HbAg is oxidized, dissociates and loses part of its secondary structure. In pH 5.0, it undergoes greater oxidation, also near 30 µmol L-1 but without secondary structures loss or dissociation. Regarding the metal cadmium, no significant changes were observed. The results indicate that HbAg has a potential for studies on copper biosensing.

Computing Excited States of Very Large Systems with Range-Separated Hybrid Functionals and the Exact Integral Simplified Time-Dependent Density Functional Theory (XsTD-DFT).

Simplified quantum chemistry (sQC) methods can routinely compute excited states for very large systems in an "all-atom" fashion. They are viable alternatives to regular multiscale schemes. sQC methods have the advantage of accounting explicitly for all of the environment at a quantum mechanical (QM) level. The treatment of charge-transfer states is now improved by the native implementation of range-separated hybrid (RSH) exchange-correlation functionals into the eXact integral simplified time-dependent density functional theory (XsTD-DFT). After the RSH XsTD-DFT/TDA scheme was benchmarked, XsTD-DFT(/TDA) ultraviolet/visible absorption, circular dichroism (CD), and/or two-photon absorption (2PA) spectra were directly compared to the results of experiments for four challenging and increasingly large systems: eYFP model system, Λ-shaped multimodular D-π-A-π-D'-π-A-π-D chromophore, mixed donor/acceptor ligand Pd(II) double cage [3BF4@Pd4DmA8-m], and the photoactive yellow protein (PYP). Among the results, this study shows that an "all-atom" approach is unavoidable for reproducing absorption and CD spectra of PYP because one of the main transitions involves a local excitation on a tryptophan.

Single-step purification and characterization of Pseudomonas aeruginosa azurin.

Azurin is a small periplasmic blue copper protein found in bacterial strains such as Pseudomonas and Alcaligenes where it facilitates denitrification. Azurin is extensively studied for its ability to mediate electron-transfer processes, but it has also sparked interest of the pharmaceutical community as a potential antimicrobial or anticancer agent. Here we offer a novel approach for expression and single-step purification of azurin in Escherichia coli with high yields and optimal metalation. A fusion tag strategy using an N-terminal GST tag was employed to obtain pure protein without requiring any additional purification steps. After the on-column cleavage by HRV 3C Protease, azurin is collected and additionally incubated with copper sulphate to ensure sufficient metalation. UV-VIS absorption, mass spectroscopy, and circular dichroism analysis all validated the effective production of azurin, appropriate protein folding and the development of an active site with an associated cofactor. MD simulations verified that incorporation of the N-terminal GPLGS segment does not affect azurin structure. In addition, the biological activity of azurin was tested in HeLa cells.

Efficient purification and excitation energy transfer characterization of phycoerythrin 545 from Rhodomonas sp.

Cryptomonad phycoerythrin 545 (PE545) is an important type of phycobiliprotein in basic research and technological innovations. Herein, we report a minimalistic hydrophobic chromatography method for its purification. High purity was achieved, with a purity ratio (A545/A280) of 13.66 and a recovery ratio of 78.63 %. Following SDS-PAGE, Coomassie Brilliant Blue staining revealed three bands at 9 kDa, 10 kDa, and 20 kDa, corresponding to α1, α2 and β subunits. Multiple spectral characteristics were analyzed to ensure that optical activity was consistent with that of the natural protein. Absorption and fluorescence spectroscopies of purified PE545 displayed a strong absorption peak at 545 nm, a shoulder peak at 564 nm, and a fluorescence emission peak at 587 nm, which confirmed unchanged energy transfer properties. Furthermore, the structural and functional integrity, especially the existence of strongly coupled central chromophore pairs with excitation delocalization, was verified by circular dichroism and ultrafast absorption spectroscopy. From the studies of ultrafast absorption spectroscopy of excitation energy transfer (EET) of PE545, four decay components with lifetimes at 0.5 ps, 2.2 ps, 63 ps, and 3000 ps were obtained. In addition, the dynamics of these components confirmed the EET pathways from the central PEB chromophore pairs to the peripheral pigments and localized in the lowest state. Our work will be of considerable value for both fundamental research and applications of PE545.

Electronic Absorption and Circular Dichroism Spectra of One-Dimensional Bay-Substituted Chiral PDIs: Effects of Intermolecular Interactions, Vibronic Coupling, and Aggregate Size

Electronic Absorption and Circular Dichroism Spectra of One-Dimensional Bay-Substituted Chiral PDIs: Effects of Intermolecular Interactions, Vibronic Coupling, and Aggregate Size

Peierls Distortion Induced Giant Linear Dichroism, Second-Harmonic Generation, and In-Plane Ferroelectricity in NbOBr2.

The Peierls distortion plays an essential role in governing the in-plane ferroelectricity and nonlinear optical characteristics of anisotropic niobium oxide dihalides, such as NbOCl2 and NbOI2. Despite its significance, experimental investigation into the structural, optical, and ferroelectric properties of NbOBr2 has been lacking. Here, the successful fabrication of centimeter-sized, high-quality NbOBr2 single crystals, enabling direct observation of Peierls distortion using aberration-corrected scanning transmission electron microscopy, is reported. Notably, the magnitude of Peierls distortion in NbOBr2 falls between that observed in NbOCl2 and NbOI2. Furthermore, the existence of giant linear dichroism absorption and second-harmonic generation (SHG) phenomena associated with Peierls distortion is confirmed. Exfoliated NbOBr2 flakes exhibit single-domain ferroelectricity, with the polarization switchable by an electric field. Temperature-dependent SHG measurements reveal a Curie temperature of ≈502K for ferroelectric NbOBr2. This work demonstrates that NbOBr2 holds promise for polarized nonlinear optical devices, as well as for nonvolatile information processing and storage devices.

Asymmetric conformation of the high-spin state of iron(II)-tris(2,2-bipyridine): Time-resolved x-ray absorption and ultraviolet circular dichroism.

We analyze the structures of the low-spin (LS) ground state and the high-spin (HS) lowest excited state of the iron-(II)-tris bipyridine complex ([Fe(bpy)3]2+) using density functional theory PBE methods, modeling the solvent interactions with conductor-like polarizable continuum model. These calculations are globally benchmarked against a wide range of experimental observables that include ultraviolet-visible linear absorption and circular dichroism (CD) spectra and Fe K-edge x-ray absorption near edge spectra (XANES). The calculations confirm the already established D3 geometry of the LS state, as well as a departure from this geometry for the HS state, with the appearance of inequivalent Fe-N bond elongations. The simulated structures nicely reproduce the above-mentioned experimental observables. We also calculate the vibrational modes of the LS and HS states. For the former, they reproduce well the vibrational frequencies from published infrared and Raman data, while for the latter, they predict very well the low-frequency vibrational coherences, attributed to Fe-N stretch modes, which were reported in ultrafast spectroscopic experiments. We further present calculations of the high-frequency region, which agree with recent ultrafast transient infrared spectroscopy studies. This work offers a common basis to the structural information encoded in the excited state CD and the Fe K XANES of the HS state tying together different structural IR, UV-visible, and x-ray observables.

Magnetic circular dichroism of f-f electron transitions in Ho3+ and Nd3+ ions in antiferromagnetic crystal Ho0.75Nd0.25Fe3(BO3)4 in the region of spin-reorientation transition

Absorption and magnetic circular dichroism (MCD) spectra have been studied in the region of 5I8 → 5F2, 5S2, 5F3, and 5F5 absorption bands of the Ho3+ ion and in the region of 4I9/2→4G7/2, 2K13/2, 4S3/2, 4F7/2, 4F5/2 and 2H9/2 absorption bands of the Nd3+ ion in an antiferromagnetic trigonal crystal Ho0.75Nd0.25Fe3(BO3)4 in the temperature range from 5 to 90 K. A qualitative change in the shape of the MCD spectra of Ho3+ ion was revealed during the spin-reorientation transition at TR = 6.9 К. Below TR, in the easy-axis state of the crystal, the MCD spectrum has a shape typical for paramagnets, i.e., it consists of diamagnetic and paramagnetic parts. Just above TR, in the easy-plane state of the crystal, MCD of Ho3+ ion has a spectrum similar to the absorption spectrum, which is typical for the paramagnetic part of the MCD. It was shown, that in the easy-plane state the exchange field of iron, being perpendicular to the external field directed along the C3 axis, quenches the usual paramagnetic and diamagnetic MCD in Ho3+ ion, but creates a condition for the appearance of a large paramagnetic MCD of mixing (B-term). With temperature increasing, the MCD spectrum of Ho3+ ion gradually turns into a spectrum typical for paramagnets with the predominance of the sign-changing diamagnetic part, because the influence of the exchange field decreases. The shape of the MCD spectra of Nd3+ ions are typical for paramagnets but does not change during the reorientation transition in the rest of the crystal. This means that the magnetic moment of the Nd3+ ion does not make a reorientation transition simultaneously with the Fe3+ and Ho3+ ions of the rest of the crystal. This phenomenon is accounted for by a strong local magnetic anisotropy of the Nd3+ ion and by a weak exchange interaction Fe-Nd, which is not enough for rotation of the Nd3+ ion moment synchronously with that of the Fe3+ ion. The magneto-optical properties of neodymium are controlled by the easy-axis anisotropy of neodymium.

Origin of magnetism via cation vacancy defects in non-stoichiometric NiCo2O4 nanoparticles: A synchrotron-based x-ray absorption and x-ray magnetic circular dichroism spectroscopic study

The present study probes the effect of cation distributions in the structural, optical, electronic, and magnetic properties of mixed-valent inverse-spinel NiCo2O4 (NCO) nanoparticles (NPs). NCO NPs were prepared using the sol–gel combustion method and the grain size was obtained in the magnetic exchange length range assumed to be from single-ion anisotropy. The Raman and photoluminescence spectroscopies confirm the presence of an inverse-spinel structure with different oxidation states, and vibrating sample magnetometry clarifies the existence of ferromagnetism with the presence of magnetic anisotropy among the cations. These NPs annealed at a higher grain-growth temperature accumulate ferrimagnetic properties and produce magneto-crystalline anisotropy making NCO an assuring material for spintronic applications. A detailed x-ray absorption spectroscopy and x-ray magnetic circular dichroism studies reveal an indestructible correlation between the distribution of the present cations and the element-specific origin of ferrimagnetic behavior. Ni is found to be accountable for the magnetic moment and electronic conduction, whereas Co is associated mainly with the generation of the magnetic anisotropy even in the polycrystalline NP form. This describes the anti-ferromagnetic coupling between Co and Ni ions that is pivotal in demonstrating the exchange interaction between these cations. The above result signifies the site-dependent cation valence states for the magnetic properties, and the extent of growing conditions are related to such cation-site dysfunction. This depicts further tunability in NCO as a functional oxide material.

Thin-film fabrication of polythiophene block copolymer via friction transfer

Abstract A thin film of thiophene block copolymer composed of 3-dodecylthiophene and 3-benzenesulfonato–thiophene was fabricated by using the friction-transfer method. The benzenesulfonato moiety was transformed by heating to the corresponding sulfonic acid, which induced self-doping. The obtained friction-transfer film showed different morphology from the related cast film. It was also revealed that the film indicated anisotropy parallel/perpendicular toward the drawing direction, which induced absorption dichroism and anisotropy of electric conductivity.

In Vitro Spectroscopic Investigation of Losartan and Glipizide Competitive Binding to Glycated Albumin: A Comparative Study.

Understanding the interaction between pharmaceuticals and serum proteins is crucial for optimizing therapeutic strategies, especially in patients with coexisting chronic diseases. The primary goal of this study was to assess the potential changes in binding affinity and competition between glipizide (GLP, a second-generation sulfonylurea hypoglycemic drug) and losartan (LOS, a medication commonly prescribed for hypertension, particularly for patients with concurrent diabetes) with non-glycated (HSA) and glycated (gHSAGLC, gHSAFRC) human serum albumin using multiple spectroscopic techniques (fluorescence, UV-visible absorption, and circular dichroism spectroscopy). The results indicated that FRC is a more effective glycation agent for HSA than GLC, significantly altering the albumin structure and affecting the microenvironment around critical amino acid residues, Trp-214 and Tyr. These modifications reduce the binding affinity of LOS and GLP to gHSAGLC and gHSAFRC, compared to HSA, resulting in less stable drug-protein complexes. The study revealed that LOS and GLP interact nonspecifically with the hydrophobic regions of the albumin surface in both binary (ligand-albumin) and ternary systems (ligand-albumin-ligandconst) and specifically saturate the binding sites within the protein molecule. Furthermore, the presence of an additional drug (GLP in the LOS-albumin complex or LOS in the GLP-albumin complex) complicates the interactions, likely leading to competitive binding or displacement of the initially bound drug in both non-glycated and glycated albumins. Analysis of the CD spectra suggests mutual interactions between GLP and LOS, underscoring the importance of closely monitoring patients co-administered these drugs, to ensure optimal therapeutic efficacy and safety.

Synthesis, calf-thymus DNA interaction with trimethyl-/triphenyl-tin(IV) derivatives of ɑ-lipoic acid and their mixed ligand complexes with N-donor (1,10-phenanthroline/2,2′-bipyridyl/benzimidazole)

The mixed ligand complexes of trimethyl-/triphenyl-tin(IV) derivatives of ɑ-lipoic acid (HLA), viz. R3Sn(LA) {R = Me (1), and Ph (2)}with 1,10-phenanthroline (phen), viz. [Me3Sn(LA).phen] (3), 2,2′-bipyridyl, viz. [Ph3Sn(LA).by] (4) and benzimidazole (bz), viz. [R3Sn(LA).bz] {R = Me (5), and Ph (6)} were synthesised and satisfactorily characterized by analytical and spectroscopic techniques, especially FT-IR, NMR (1H, 13C, and 119Sn NMR) spectroscopy and ESI-MS spectrometry. The ∠C-Sn-C bond angle calculated by optimization of their gas-phase geometry revealed that complexes (1) and (2) have distorted tetrahedral geometry and complexes (3) and (4) exhibited distorted octahedral geometry while complexes (5) and (6) exhibited trigonal bipyramidal environment around the tin, which agreed with the data obtained from NMR. Spectroscopic titrations (UV–visible absorption, fluorescence titration, and circular dichroism) were performed to ascertain the binding mode of the complex with calf thymus DNA (CT-DNA). The obtained values of Kb in the order of 105 M−1 suggested partial intercalative interactions of complexes with DNA grooves/base pairs. The complexes efficiently cleaved plasmid DNA (pBR322) into supercoiled (Form I), nicked/circular (From II), and linear structure (Form III). The fascinating biophysical data suggests the potential of these complexes as anticancer agents.

Effects of rosmarinic acid covalent conjugation on the allergenicity and functional properties of egg white protein

Polyphenols can form complexes with proteins, potentially enhancing the properties of egg white protein (EWP) by altering its structure. This study aimed to explore the effect of covalent conjugating with rosmarinic acid (RA), a bioactive polyphenol found in various edible Lamiaceae herbs, on the structure, allergenicity, and functional properties of EWP. The successful preparation of EWP-RA conjugates was confirmed through RA binding equivalent analysis. Fluorescence spectroscopy, Fourier transform infrared (FTIR) spectroscopy, circular dichroism (CD), and ultraviolet (UV) absorption spectroscopy collectively indicated that the covalent conjugation with RA led to significant structural alterations in EWP. Furthermore, the conjugation of RA markedly enhanced the antioxidant capacity of EWP, as evidenced by its improved ability to scavenge DPPH and ABTS+ radicals. Enzyme-linked immunosorbent assay (ELISA) results indicated a substantial reduction in the binding capacity of EWP-RA conjugates to IgG and IgE, indicating a decrease in the allergenic potential of EWP. Moreover, the incorporation of RA was associated with an increase in the absolute zeta potential, protein flexibility, and free sulfhydryl content of EWP, alongside a reduction in surface hydrophobicity. The findings also revealed that RA enhanced the emulsifying activity, emulsion stability, foaming ability and foaming stability of EWP. Furthermore, the storage performance of EWP improved after conjugation with RA. In conclusion, the covalent conjugation of EWP with RA not only diminished its allergenic potential but also improved its functional properties through structural modification. This study posits that such an approach could be an effective strategy for enhancing the functional properties of EWP while concurrently mitigating its allergenic potential, thereby offering promising applications in the formulation of future food products.

Piperonal protects neuron-like and retinalpigment epithelial (RPE) cells from oxidative stress and apoptosis through inhibition of α-synuclein aggregation

Protein fibrillation is a crucial process in the onset of several neurodegenerative and retinal disorders due to the formation of cytotoxic species. Because of their capacity to prevent protein aggregation, small molecules have the potential to be appointed as therapeutic agents. Here, we examined the inhibitory impacts of the piperonal as a carbaldehyde-derived compound on the fibrillation process of α-synuclein and underlying cytotoxicity against neuron-like (PC12) and human retinal pigment epithelial (RPE) (ARPE-19) cells. The results showed that the values of kapp and lag time of α-synuclein were modulated with piperonal. Moreover, ANS fluorescence intensity analysis indicated that piperonal can inhibit the formation of a molten global (misfolded) state of α-synuclein, which is a necessary step in the formation of protein amyloid fibrils. Congo red absorption and circular dichroism spectroscopy also verified the inhibition of β-sheet structure formation after treatment of α-synuclein with piperonal. Furthermore, theoretical studies displayed that piperonal interacts with VAL40:HN, GLU35:O, VAL40, and LYS43 amino acid residues and forms a complex. In addition, cytotoxicity assays demonstrated that piperonal as a safe small molecule could mitigate the induced cytotoxicity by α-synuclein amyloids in PC12 and ARPE-19 cells through reduction of ROS and Bax/Bcl2 mRNA overexpression. Taken together, these outcomes showed that piperonal as a natural aldehyde compound can inhibit α-synuclein fibrillation and underlying cytotoxicity which may be developed for potential therapeutic applications in vivo.

Chiral 3D Perovskite Formation Induced by Chiral Templates.

Chiral 3D perovskites pose challenges compared to lower-dimensional variants due to limited chiral organic cation options. Here, we present a universal and controlled method for synthesizing chiral 3D lead halide perovskites using organic amines or alcohols as chiral templates. Introducing these templates to PbCl2 in N,N-dimethylformamide (DMF) under acidic conditions induces the crystallization of R/S [DMA]PbCl3 (DMA = dimethylamine). The resulting structure aligns with the templates used, stemming from the helical Pb2Cl95- chain as verified by single-crystal X-ray diffraction. Furthermore, the chiral perovskite exhibits absorption and circular dichroism (CD) signals in the high-energy band, enabling the circularly polarized light (CPL) detection in the UV spectrum. A CPL detector constructed by this chiral perovskite demonstrates excellent performance, boasting an anisotropy factor for photocurrent (gIph) of 0.296. Our work not only introduces a novel and controllable method for crafting chiral perovskites but also opens new avenues for circularly polarized light detection.