Spectrochimica Acta. Part A, Molecular And Biomolecular Spectroscopy[JOURNAL]
Sun
200 papers
Molecular Raman signatures of fiber types in mouse soleus muscle.
Batista AM, Pascoal DRC, Alves PKN … +4 more , Dutra LACHC, Moriscot AS, Wetter NU, Freitas AZ
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42385339 · Publisher ↗
Muscle fiber types perform distinct functions within skeletal muscle tissue, enabling a wide range of physical and motor capabilities. Although specific fiber types are well characterized by their Myosin Heavy Chain isof...
Muscle fiber types perform distinct functions within skeletal muscle tissue, enabling a wide range of physical and motor capabilities. Although specific fiber types are well characterized by their Myosin Heavy Chain isoform expression, it is highly informative to investigate these cells using further approaches. In this context, Raman spectroscopy represents a powerful tool for molecular discovery. Here, we characterized the Raman spectroscopic signatures of Type I, IIa, and IIx skeletal muscle fibers in the mouse soleus. Specific bands associated with amino acids such as tryptophan, phenylalanine, tyrosine, and the Amide I band are the main drivers of the observed variation. Interestingly, distinct spectral intensities and peak ratios particularly within the 1350 cm region and 1550-1750 cm range clearly differentiated Type I from Type IIa/IIx fibers. Principal Component Analysis further revealed that most of the observed variation is driven by changes near ∼1600 cm. Overall, the detection of these spectral patterns provides valuable insights into the biochemical characteristics of muscle fibers and highlights the potential of Raman spectroscopy to identify fiber-type-specific signatures under various physiological and pathological conditions, including atrophy, hypertrophy, and sarcopenia.
Triphenylamine-derived fluorescent probe: Synthesis and lipid droplet polarity imaging analysis.
Cui HW, Jiang ZB, Wang JW … +6 more , Cui YW, Sun SJ, Wu BX, Zhao LX, Liu YT, Zou YL
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42385338 · Publisher ↗
Lipid droplets are important parts of cells. They store lipids. They also help control cell balance. Notably, there exists a strong correlation between lipid droplet polarity and the progression of NAFLD. Accordingly, tr...
Lipid droplets are important parts of cells. They store lipids. They also help control cell balance. Notably, there exists a strong correlation between lipid droplet polarity and the progression of NAFLD. Accordingly, tracking variations in lipid droplet polarity permits the staged assessment of NAFLD. In this study, we picked triphenylamine as the electron donor. We used thiophene as the π-bridge. We also chose benzofuran as the electron acceptor. On this basis, a novel fluorescent probe (MDN) with a typical D-π-A architecture was rationally designed and synthesized for polarity detection. Specifically, the MDN probe showed special fluorescence when the environment was less polar. It had high sensitivity and good selectivity. Meanwhile, MDN had a big Stokes shift of 70 nm and its maximum fluorescence emission wavelength was over 600 nm in the test, which possess excellent optical properties Confocal imaging showed that the MDN probe matched well with intracellular structures. Also, the ClogP value of MDN was 10.876, indicating its favorable capability for lipid droplet targeting. Another study demonstrated that MDN can be used to monitor the changes of intracellular polarity. The experimental results verified that lipid droplet accumulation in liver tissues was significantly higher than that in other organs, accompanied by intense fluorescence signals. In summary, the polarity-responsive probe developed in this work possesses excellent targeting capability toward lipid droplets.
Exploring peroxidase substrates driven etching of gold nanorods towards indirect detection of amyloid beta.
Athira ET, Satija J
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42379091 · Publisher ↗
Plasmonic enzyme-linked immunosorbent assay (pELISA) leverages the localized surface plasmon resonance (LSPR) property of noble metal nanoparticles to achieve enhanced sensitivity compared to conventional immunoassays. T...
Plasmonic enzyme-linked immunosorbent assay (pELISA) leverages the localized surface plasmon resonance (LSPR) property of noble metal nanoparticles to achieve enhanced sensitivity compared to conventional immunoassays. The geometric alteration of plasmonic nanoparticles through oxidative moieties generates distinct colorimetric signals that can be employed to develop an ultrasensitive point-of-care pELISA. Advancing pELISA requires a systematic exploration of enzymatic reactions and nanomaterials, allowing for the precise detection of trace biomolecules. The study systematically investigates the etching efficiency of gold nanorods (AuNRs) using the products of five horseradish peroxidase (HRP) substrates, i.e., 3,3,5,5-tetramethylbenzidine (TMB), o-phenylene diamine dihydrochloride (OPD), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 3-amino-9-ethylcarbazol (AEC), and 3,3'diaminobenzidine (DAB). Each substrate was evaluated under controlled conditions to determine its ability to induce aspect ratio-dependent spectral shifts in AuNRs, enabling quantitative colorimetric detection. UV-Vis spectroscopy reveals that only the oxidized product of TMB (TMB) significantly etches the AuNRs, producing a notable blue shift in the LSPR peak. The optimized etching approach was applied to develop an indirect competitive pELISA for detecting amyloid beta (Aβ), a key biomarker for Alzheimer's disease. This method demonstrated a limit of detection of 0.37 pg/mL (≈83.14 fM), highlighting its potential for ultrasensitive and precise biomolecule quantification.
A highly efficient and interpretable framework for high-precision lithological identification integrating SERS and XGBoost.
An P, Li M, Yang Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372367 · Publisher ↗
Rapid and accurate lithological identification is essential for geological exploration and deep earth engineering. However, traditional methods are often limited due to time-consuming procedures, destructive sampling, an...
Rapid and accurate lithological identification is essential for geological exploration and deep earth engineering. However, traditional methods are often limited due to time-consuming procedures, destructive sampling, and subjective experience. In this study, a high-precision lithological classification framework was proposed by integrating Surface-Enhanced Raman Scattering (SERS) technology with artificial intelligence (AI) algorithms. Silver nanoparticles (AgNPs) with an average radius of 32 nm were synthesized as substrates to enhance Raman signals and suppress fluorescence backgrounds. Finite-Difference Time-Domain (FDTD) simulations confirmed the electromagnetic enhancement mechanism, demonstrating substantial localized electric field amplification at the generated hotspots. Six AI models were evaluated using a self-constructed SERS dataset encompassing eight distinct rock types. The Extreme Gradient Boosting (XGBoost) model achieved the best performance, mitigating the high computational latency and training instability commonly observed in deep learning models. Moreover, SHapley Additive exPlanations (SHAP) was utilized to interpret the classification process. The results demonstrated that the model effectively extracts intrinsic physical features, including low-frequency lattice vibrations and SERS-activated trace signals, to accurately distinguish rocks with highly similar spectra. This study provides a reliable, interpretable, and computationally efficient approach for real-time geological monitoring in complex construction environments.
Blue to cold white tunable emission via Eu → Tb energy transfer in [Na-Tb] co-substituted Sr(PO)Br: Eu phosphors.
Liu C, He C, Zhang X … +3 more , Liu J, Wu Z, Wang X
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372366 · Publisher ↗
A series of [Na-Tb] co-doped apatite-type phosphors SrNaTb(PO)Br: 0.10Eu were synthesized via a high-temperature solid-state method, in which coupled [Na-Tb] substitution was employed to maintain charge balance and regul...
A series of [Na-Tb] co-doped apatite-type phosphors SrNaTb(PO)Br: 0.10Eu were synthesized via a high-temperature solid-state method, in which coupled [Na-Tb] substitution was employed to maintain charge balance and regulate luminescence behavior. Their phase composition, morphology, XPS spectra as well as photoluminescence properties were studied. Under near-ultraviolet (NUV) excitation, the phosphors exhibit a broadband blue emission originating from Eu (450 nm) together with characteristic green emissions of Tb (490, 545, 585 and 622 nm), enabling continuous color tuning from blue to cold white by adjusting the Tb concentration. The efficient Eu → Tb energy transfer process is verified, with a maximum efficiency of 54.20% at x = 0.50, and the transfer mechanism follows dipole-dipole interaction. Moreover, the obtained phosphors exhibit excellent thermal stability. Fabricated phosphor-converted LED devices also present acceptable luminescence performance with CRI of 61.05, CCT of 10,489 K and EQE of 15.4%. Compared with conventional fluoride-based or oxide-based apatite phosphors, the bromide-containing apatite host Sr(PO)Br provides a suitable crystal field environment for stabilizing Eu emission and facilitating effective Eu → Tb energy transfer. These results demonstrate that SrNaTb(PO)Br: 0.10Eu phosphors represent a viable blue to cold white color-tunable system with potential applicability in NUV excited phosphor-converted LEDs.
Unlocking HClO detection via an AIE "off-on-off" fluorescent switch.
Zhang Z, Wang X, Zeng X … +7 more , Zhu Y, Chen Y, Fan B, He Y, Li Y, Zhang F, Ye L
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372365 · Publisher ↗
Hypochlorous acid (HClO) is a key reactive oxygen species (ROS) involved in both normal physiology and disease pathogenesis. Imbalances in its intracellular levels are strongly associated with inflammatory disorders and...
Hypochlorous acid (HClO) is a key reactive oxygen species (ROS) involved in both normal physiology and disease pathogenesis. Imbalances in its intracellular levels are strongly associated with inflammatory disorders and cancer. In this work, we introduce TPE-ML, a novel aggregation-induced emission (AIE) probe built on a thiomorpholine scaffold. This probe features a distinctive "off-on-off" fluorescence switching behavior. It exhibits a Stokes shift of approximately 170 nm and enables sensitive detection of HClO with a limit of detection as low as 1.37 μM. Solvent-dependent assays confirm its AIE characteristics: the fluorescence intensity increases 15-fold in solvent mixtures with 99% water fraction. Upon selective oxidation by HClO, TPE-ML converts from an AIE-active aggregated state to a dispersed state, accompanied by marked fluorescence quenching. Theoretical calculations further reveal an increased dipole moment and hydrophobicity (log P) further altered electronic properties after oxidation. Using the standard addition method, TPE-ML achieved quantitative analysis of HClO in strawberries, apples, baby cabbage, and lettuce, with spiked recoveries ranging from 98.3% to 107.8%. It also permitted on site visual monitoring, as the fluorescence turned from yellow to dark under 365 nm UV illumination. Furthermore, this probe allowed real time imaging of both externally added and endogenously produced HClO in living 4 T1 cells, underscoring its biomedical promise. Collectively, this work introduces a fresh AIE based sensing mechanism for HClO, thereby enriching the methodological toolbox for ROS detection in biological specimens.
Activatable fluorescent probe for auxiliary diagnosis of atherosclerosis: from foam cells to clinical samples.
Li C, Zhang N, Yang F … +3 more , Ma Y, Shang J, Chen A
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372364 · Publisher ↗
Cardiovascular diseases remain a leading cause of morbidity and mortality worldwide, with atherosclerosis playing a central role in their pathogenesis. A fluorescent probe activatable by leucine aminopeptidase was synthe...
Cardiovascular diseases remain a leading cause of morbidity and mortality worldwide, with atherosclerosis playing a central role in their pathogenesis. A fluorescent probe activatable by leucine aminopeptidase was synthesized and designated as LAP probe. This probe was constructed using a hemicyanine scaffold conjugated with an LAP-recognizing peptide via a condensation reaction. Upon LAP activation, a bathochromic shift in absorption and a marked turn-on fluorescence response in the near-infrared region were observed, with a strong linear correlation established between fluorescence intensity and LAP concentration. The probe successfully distinguished foam cells from normal macrophages and enabled in vivo imaging of atherosclerotic plaques in high-fat diet-fed ApoE-/- mice. Serum LAP activity was found to be significantly elevated in atherosclerotic mice and in patients with arterial stenosis, particularly in those with severe stenosis exceeding 60%, as confirmed by receiver operating characteristic curve analysis. The probe exhibited low toxicity with no observable organ damage. These findings demonstrated that LAP probe holds promise for the auxiliary diagnosis and risk stratification of atherosclerosis.
Spectroscopic studies on human androglobin regulated by its heme distal Gln12 and IQ motif via interaction with calmodulin.
Ren ZH, Sun LJ, Gao SQ … +1 more , Lin YW
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372363 · Publisher ↗
Androglobin (Adgb) was discovered as the fifth mammalian globin, yet its structural and functional properties remain incompletely understood. In this study, we overexpressed the heme-binding globin domain of Adgb with st...
Androglobin (Adgb) was discovered as the fifth mammalian globin, yet its structural and functional properties remain incompletely understood. In this study, we overexpressed the heme-binding globin domain of Adgb with stabilizing mutations (C114S/C190S, denoted Adgb-SS) and investigated the role of its heme distal residue Gln12 through the generation of Q12H and Q12Y mutants. The protein structures were predicted using AlphaFold3 in combination with molecular dynamic simulations. Spectroscopic studies showed that the Q12H mutation improved protein stability under conditions of alkaline and oxidative (HO) stress, while the Q12Y substitution significantly enhanced nitrite reductase (NIR) activity. Moreover, we showed that the NIR activity of Adgb was increased by interaction with calmodulin (CaM) via its IQ motif. The structure of Adgb-CaM complex was also predicted using HDOCK. To further probe the role of the IQ motif, we generated an IQ-deletion mutant (ΔIQ-Adgb), which displayed reduced stability compared to Adgb-SS. Moreover, unlike Adgb, the turnover number (k) of ΔIQ-Adgb was not increased but rather inhibited by CaM, indicating that the IQ motif is essential for CaM-mediated activation. Collectively, these results suggest that the heme distal Gln12 regulates both the protein stability and enzymatic activity of Adgb, while the IQ motif acts as a critical structural element that governs Adgb stability and enables proper regulation by CaM. These findings enhance our understanding of the structure-function relationship of Adgb and elucidate its potential role in fertility-related and other pathologies involving CaM interactions.
Spatiotemporal tracking of cysteine fluctuations during organelle interactions with a lysosome-targeted fluorescent probe.
Liu X, Zhang J, Liu M … +3 more , Li Y, Yan H, Zhou Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372326 · Publisher ↗
Cysteine (Cys) is a crucial amino acid and plays a protective role for cells by eliminating superfluous endogenous reactive oxygen species (ROS). Organelle interactions are consistently carried out during cellular physio...
Cysteine (Cys) is a crucial amino acid and plays a protective role for cells by eliminating superfluous endogenous reactive oxygen species (ROS). Organelle interactions are consistently carried out during cellular physiological and pathological activities, and Cys levels change concomitantly with cell viability. Nevertheless, the dynamic fluctuations of Cys during organelle interactions remain largely unexplored to date. To address this issue, we developed a lysosome-targeted fluorescent probe, CSDC, by conjugating a 2,4-dinitrobenzenesulfonyl (DNBS) group onto a coumarin fluorophore, thereby achieving real-time imaging of Cys dynamics during mitochondrial and lysosomal fusion. The fluorescence of CSDC can be lightened by inhibiting the photoinduced electron transfer (PET) effect, and high sensitivity of 19 nM was achieved for CSDC. Leveraging the excellent fluorescence performance of CSDC, endogenous Cys under different cellular state was sensitively imaged. Furthermore, fluorescence imaging results exhibited that the content of Cys increased distinctly at the initial stage of mitophagy because of the cytoprotective effect, then gradually reduced to equilibrium during the following organelle interaction. This work not only provide a practically useful tool for sensing Cys, but also offered a direction in revealing the dynamic change of active molecule during organelle interaction with fluorescent probe.
Fluorine and nitrogen co-doped carbon dots (F, N-CDs) for enhanced luminol chemiluminescence and sensitive detection of levetiracetam.
Xue H, Ma T, Zheng H … +2 more , Zhang L, Cheng K
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372325 · Publisher ↗
Biomass-derived fluorine and nitrogen co-doped carbon dots (F, N-CDs) were synthesized via a one-step hydrothermal method using Rhododendron simsii flowers as the precursor. The prepared F, N-CDs exhibited favorable opti...
Biomass-derived fluorine and nitrogen co-doped carbon dots (F, N-CDs) were synthesized via a one-step hydrothermal method using Rhododendron simsii flowers as the precursor. The prepared F, N-CDs exhibited favorable optical properties, good water solubility, and a pronounced enhancement effect on the chemiluminescence (CL) of the Luminol-KSO-NaOH system. The optical characteristics were systematically investigated by UV-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence lifetime analysis. The possible CL enhancement mechanism was further investigated through reactive oxygen species scavenging experiments and singlet oxygen probe experiments. On this basis, an enhanced flow-injection chemiluminescence (FI-CL) method was developed for the determination of levetiracetam (LEV). Under the optimized conditions, the relative CL intensity exhibited a satisfactory linear relationship with LEV concentration over the range of 0.10-10.00 mM, with a limit of detection (LOD) of 2.02 × 10 mM and a limit of quantification (LOQ) of 6.71 × 10 mM. The proposed method was successfully applied to the commercial LEV pharmaceutical formulations, giving recoveries of 94.8-103.1% and relative standard deviations (RSDs) below 4.68%. These results demonstrate the potential of biomass-derived carbon dots for spectroscopic and characterization and chemiluminescence-based analytical applications.
Interference effects in HO quantification: A comparative study of three common methods in photocatalytic systems.
Zhang P, Liu S, Wang J … +2 more , Yu Y, Zhang G
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372324 · Publisher ↗
Precise measurement of the production of HO during the photocatalytic process is important for the performance assessment of photocatalysts. N,N-diethyl-1,4-phenylenediamine (DPD) method, iodometry method and cerium sulf...
Precise measurement of the production of HO during the photocatalytic process is important for the performance assessment of photocatalysts. N,N-diethyl-1,4-phenylenediamine (DPD) method, iodometry method and cerium sulfate Ce(SO) titration method are currently the most widely employed in relevant research. However, the effectiveness and reliability of these methods have rarely been systematically investigated. In this study, using g-CN, TiO, ZnSe and resorcinol formaldehyde (RF) as model photocatalysts, a comparative analysis of these three methods was conducted. The results demonstrate that certain byproducts are formed during the production of HO, and they act as interferents that compromise the accuracy of the measurement. Although Ce(SO) titration method is accurate for standard HO solutions, it usually overestimates the production of HO in the photocatalytic process. Nitrogen species, particularly NO, are key interferents influencing the measurement. Moreover, the iodometric method is highly susceptible, as NO amplifies the formation of through a catalytic cycle, which induces a significant and time-dependent overestimation. Among the methods, the DPD method demonstrates excellent anti-interference capability.
AI-assisted Python automation of mean-centering spectrophotometric methods with comprehensive sustainability assessment.
Badrawy M, Nour IM
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372323 · Publisher ↗
The simultaneous spectrophotometric determination of drugs with overlapping spectra remains a challenging analytical task. In this study, a hybrid analytical strategy combining classical UV-Vis spectrophotometry with art...
The simultaneous spectrophotometric determination of drugs with overlapping spectra remains a challenging analytical task. In this study, a hybrid analytical strategy combining classical UV-Vis spectrophotometry with artificial intelligence (AI)-assisted Python automation is proposed for the simultaneous determination of amlodipine besylate (AMT) and hydrochlorothiazide (HYCD) in their combined dosage form. AMT was quantified using a zero-crossing method at 366 nm, while HYCD was determined using the mean-centering of ratio spectra (MCR) approach AI-assisted Python scripting was employed to automate spectral preprocessing, divisor selection, calibration, and validation, enabling systematic and reproducible evaluation of multiple divisor scenarios. The optimized mean spectrum divisor provided improved analytical performance, with strong linearity (R ≥ 0.9998), low detection limits (LOD = 0.25 μg/mL for HYCD and 0.83 μg/mL for AMT), acceptable accuracy (mean recoveries of 99.8-100.1%), and good precision (RSD < 1.2%). The method was further evaluated using multiple sustainability assessment tools, including GAPI, WAC, Blueness, and AGREE, demonstrating favorable environmental performance. Compared to conventional chromatographic techniques, the proposed approach offers a simple, cost-effective, and reproducible alternative for routine pharmaceutical quality control. The results highlight the role of AI-assisted automation in enhancing workflow efficiency and reproducibility without altering the underlying analytical principles.
New lanthanide complexes containing maltol and bipyridine ligands: Synthesis, solid state characterization, experimental and computational spectroscopic studies and their cytotoxic activities.
Camargo MA, da Cunha DSC, Resende AA … +10 more , Rodrigues FS, da Luz LL, da Silva JAB, de Souza JIR, Bortoluzzi AJ, Cuin A, D'Oliveira KA, Nassar EJ, da Silva JR, Azevedo RB
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372322 · Publisher ↗
Three new lanthanide complexes [Ln(maH)(ma)(bipy)(NO)](Ln = Gd, Eu or Tb; maH = maltol, ma = maltolate, bipy = 2,2'-bipyridine) were synthesized and characterized by infrared spectroscopy, powder and single-crystal X-ray...
Three new lanthanide complexes [Ln(maH)(ma)(bipy)(NO)](Ln = Gd, Eu or Tb; maH = maltol, ma = maltolate, bipy = 2,2'-bipyridine) were synthesized and characterized by infrared spectroscopy, powder and single-crystal X-ray diffraction, and thermogravimetric analysis. The complexes crystallize in the monoclinic system, with the Europium complex belonging to space group P21/n, and the Gadolinium and Terbium complexes to P21/c. Each lanthanide center adopts a nine-coordinate geometry, chelated by one bidentate bipyridine, two bidentate nitrate anions, one bidentate maltolate, and one monodentate maltol ligand. The Europium complex was studied from molecular modeling. The WB97XD model was considered suitable for describing both structural and photophysical properties of the complexes. Excited singlet (S₁) and triplet (T₁) ligand states were investigated by time-dependent DFT calculations, and LC-WPBE functional showed good agreement with experimental data. Photoluminescence measurements, including lifetimes and quantum yields, revealed distinct intramolecular energy transfer pathways for the Europium and Terbium complexes. Experimental and theoretical Judd-Ofelt intensity parameters, combined with a proposed Jablonski-type energy diagram, were employed to describe the luminescence properties of the Europium complex. The low emission quantum efficiency of the D₀ emitting level was attributed to the presence of the ligand-to-metal charge transfer state (LMCT), supported by experimental and theoretical analyses. The proposed kinetic model showed excellent agreement with experimental results. Additionally, the complexes exhibited higher cytotoxic activity against human breast cancer cells (MDA-MB-231) compared with normal human fibroblast cells (NIH-3 T3).
Deciphering the ESIPT mechanism and AIE behavior of HNBT under controlled polarity gradients: A theoretical study.
Liu Z, Wang X, Liang J … +2 more , Jin Y, Li H
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372321 · Publisher ↗
Combining excited-state intramolecular proton transfer (ESIPT) with aggregation-induced emission (AIE) is an effective strategy for designing fluorescent probes with high selectivity and strong anti-interference capabili...
Combining excited-state intramolecular proton transfer (ESIPT) with aggregation-induced emission (AIE) is an effective strategy for designing fluorescent probes with high selectivity and strong anti-interference capability. Herein, we uncover a polarity and aggregation-regulated ESIPT-TICT-AIE interplay in 2-hydroxynaphthylbenzothiazole (HNBT) using density functional theory (DFT) and time-dependent DFT calculations. Solvent-dependent geometrical and electronic analyses reveal that photoexcitation strengthens intramolecular hydrogen bonding and induces pronounced intramolecular charge transfer, as evidenced by frontier molecular orbital (FMO) and density of states (DOS) analyses. Electrostatic potential (ESP) and dipole moment calculations further demonstrate enhanced charge separation and excited-state polarization in polar solvents, providing a driving force for proton transfer. These effects collectively lower the ESIPT barrier, as confirmed by potential energy curves (PECs), infrared spectra, charge variation balance (CVB), and natural bond orbital (NBO) analyses, while simultaneously promoting twisted intramolecular charge transfer (TICT) characteristics. In water/ACN mixtures, increasing water fraction further strengthens hydrogen bonding and reduces the HOMO-LUMO gap, which modulates the excited-state properties of HNBT. However, aggregation suppresses TICT-related nonradiative decay while enhancing radiative transitions, leading to pronounced AIE emission. Spectral simulations confirm exclusive enol* emission with quenched keto* emission due to the ESIPT-TICT competition. Overall, the emission of HNBT is governed by a dynamic balance between ESIPT-driven proton transfer, TICT-mediated nonradiative decay, and aggregation-induced restriction of intramolecular motion. Solvent polarity stabilizes charge separation and facilitates ESIPT, while aggregation shifts the balance toward radiative decay, enabling strong AIE emission. These findings clarify the subtle solvent-regulated excited-state dynamics of HNBT and provide theoretical guidance for designing highly sensitive, environment-responsive AIE-ESIPT fluorescent probes.
A lipid droplet-targeted viscosity-sensitive fluorescent probe for visualization of tumor and NAFLD imaging.
Zhao Y, Li J, Wan L … +7 more , Zhao X, Huang C, Liu K, Feng Z, Wu Y, Hu L, Wang H
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42372320 · Publisher ↗
Non-alcoholic fatty liver disease (NAFLD) and tumors remain major clinical challenges, characterized by aberrant lipid droplets (LDs) accumulation and elevated microenvironmental viscosity as key pathological features. I...
Non-alcoholic fatty liver disease (NAFLD) and tumors remain major clinical challenges, characterized by aberrant lipid droplets (LDs) accumulation and elevated microenvironmental viscosity as key pathological features. In this study, we developed a series of carbazole-based fluorescent probes, LJL1-LJL6. Through systematic screening of their photophysical properties and bioimaging performance, LJL1 was identified as the optimal candidate due to its superior viscosity sensitivity and LDs-targeting specificity. Specifically, LJL1, featuring a carbazole-thiophene electron-donating unit and a pyridine-based electron acceptor, exhibited an approximately 29-fold fluorescence enhancement in pure glycerol compared to water, with a robust linear correlation between fluorescence intensity and viscosity. Moreover, probe LJL1 demonstrated excellent photostability, low cytotoxicity, and exceptional LDs-targeting specificity. In biological applications, leveraging its wash-free imaging advantage, LJL1 successfully enabled real-time monitoring of dynamic LDs viscosity fluctuations under various physiological and pathological conditions, including oleic acid (OA) stimulation, starvation, pharmacological interventions, inflammatory responses, and ferroptosis. Furthermore, probe LJL1 exhibited outstanding spatiotemporal dynamic tracking capability for the lipophagy process. Mouse imaging studies revealed that LJL1 not only allowed imaging of 4 T1 tumor models but also sensitively monitored increased viscosity in liver tissues of NAFLD models, significantly distinguishing diseased livers from healthy ones. Collectively, this study establishes LJL1 as a high-performance LDs-targeted viscosity probe with substantial potential for mechanistic research of metabolic diseases.
Ultrasensitive quantification of Hg in real samples using colorimetric, fluorimetric and smartphone-based triple-mode system integrated with a new indoline-fused chromenylium-cyanine chemodosimeter.
Ozdemir E, Alcay Y, Gunduz MI … +6 more , Yavuz O, Kura B, Tuzun NŞ, Çil C, Kılıç A, Yilmaz I
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42365704 · Publisher ↗
Mercury is one of the most toxic heavy metal, posing severe threats to environmental safety and human health due to its persistence, bioaccumulation, and detrimental neurological and systemic effects. Therefore, the deve...
Mercury is one of the most toxic heavy metal, posing severe threats to environmental safety and human health due to its persistence, bioaccumulation, and detrimental neurological and systemic effects. Therefore, the development of fast, sensitive, selective, and on-site detection methods for Hg remains an urgent priority. Herein, we present a phenylthiourea-derived indoline-fused chromenylium-cyanine chemodosimeter (INIR2), engineered as a "turn-on" near-infrared (NIR) fluorescent and colorimetric probe for Hg recognition. Upon coordination with Hg, INIR2 undergoes a specific chemical transformation that results in a distinct color change and a remarkable fluorescence enhancement in the NIR region (λ = 766 nm) within 10 s. The probe exhibited ultralow detection limits (UV-Vis: 1.13 × 10 M (2.27 ng/mL); fluorescence: 1.83 × 10 M (3.67 ng/mL)) and outstanding selectivity among a wide range of competing metal ions. INIR2 also demonstrated robust performance across diverse matrices, including environmental waters (tap, drinking and lake) and food samples (corn and rice), achieving near-quantitative recoveries. Most importantly, the analysis of Hg from micromolar to nanomolar levels (LOD: 2.10 × 10 M) was performed using a smartphone-based RGB application among molecular turn-on probes. This method has significant potential for cost-effective and real-time monitoring of Hg in the field, even at ultra-trace levels. Cellular studies confirmed low cytotoxicity and selective fluorescence activation in Hg-treated cells, further highlighting its bioimaging capability. These findings demonstrate that INIR2 is a highly sensitive and versatile tool for instantaneous and on-site mercury detection, with promising applications in environmental monitoring, food safety and biomedical research.
Exploring spin-phonon coupling, barocaloric, and polar phonon features in the multiferroic [(CH)NH][Mn(N)] hybrid perovskite.
Hora RR, Silva RX, Nonato A … +9 more , Silva JAS, Gómez MAP, Gómez-Aguirre LC, Vidal LMT, Ayala AP, Freire PTC, Corrêa MA, Silva RB, Paschoal CWA
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42365703 · Publisher ↗
We report a temperature-dependent Raman scattering study of the hybrid organic-inorganic azide perovskite of formula [(CH)NH][Mn(N)]([DMA][Mn(N)]). The Raman spectra reveal distinct shifts in phonon frequencies, particul...
We report a temperature-dependent Raman scattering study of the hybrid organic-inorganic azide perovskite of formula [(CH)NH][Mn(N)]([DMA][Mn(N)]). The Raman spectra reveal distinct shifts in phonon frequencies, particularly in the νCNC and ν(ν)N modes, demonstrating that spin-phonon interactions play a critical role in their thermal and magnetic responses. Differential scanning calorimetry confirmed a first-order structural phase transition, from an orthorhombic high-temperature HT(α) phase, belonging to the Cmca space group, to a monoclinic low-temperature LT(β) phase, with P2 symmetry. The associated entropy change was found to be |∆S| ∼ 8.45 J mol K (37.2 J kg K), and the barocaloric (BC) coefficient (|δTt/δP|) was ∼2.94 K kbar, estimated by using the Clausius-Clapeyron method. Room-temperature FTIR reflectivity spectra revealed the polar phonon modes and their corresponding damping coefficients, showing minimal contributions from the DMA cation to the intrinsic dielectric constant (∼4.3). These results provide new insights into the coupling between lattice dynamics, spin interactions, and barocaloric behavior in azide-based hybrid perovskites.
Nitrogen and sulfur-doped Carbon Quantum Dots as fluorescent probe for inorganic arsenic sensing in water and seaweed samples.
Lima FEH, Oliveira CMP, Ferreira AA … +12 more , de Carvalho EF, Moura TA, Paschoal AR, Antunes RA, Neto MLA, César CL, de Carvalho HF, Freire RM, Fechine PBA, da Silva FLF, Carneiro SV, Matos WO
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42364483 · Publisher ↗
The inorganic arsenic species (iAs), As (III) and As (V), are the most toxic arsenic (As) chemical forms, being considered carcinogenic. The main sources of As exposure for humans are water and food. Thus, it is crucial...
The inorganic arsenic species (iAs), As (III) and As (V), are the most toxic arsenic (As) chemical forms, being considered carcinogenic. The main sources of As exposure for humans are water and food. Thus, it is crucial monitoring iAs in these matrices. In general, these As species are analyzed by high-performance liquid chromatography hyphenated with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). In this work, a non-chromatographic alternative method based on Carbon Quantum Dots (CQDs) using fluorescence as detector for iAs analysis was developed. Nitrogen- and sulfur-doped carbon quantum dots (N,S-CQDs) with a high quantum yield (QY) of 32.22% ± 1.27 were employed as turn-off sensors. This work describes the optimization of the synthesis of N,S-CQDs derived from citric acid, ethylenediamine, and mercaptosuccinic acid via the hydrothermal method. The N,S-CQDs were characterized and applied to iAs sensing in well water and seaweed samples, showing detection limits (LOD) below 0.92 μg L. The accuracy of iAs quantification in seaweed sample was verified comparing the result with inductively coupled plasma optical emission spectrometry (ICP-OES) analysis after magnetic solid phase extraction using FeO@DTPMP nanoparticles (101% recovery), while for well water samples addition and recovery test was applied (95% to 104% recovery). The iAs mass fraction value found in seaweed sample was 2.55 ± 0.02 mg L, and the values in well water samples were below LOD. The proposed method reveled greater environmental friendliness compared to the traditional techniques according to greenness assessment.
A portable sensing platform enabled by permanganate-peroxide coupling for time-resolved analysis of xanthine oxidase activity in circulating tumor cells.
Zhao X, Chen S, Chen J … +6 more , Fang H, Yao J, Guo Z, Hu Y, Wu L, Qing Z
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42364482 · Publisher ↗
Early cancer diagnosis demands rapid, sensitive and portable approaches for detecting cellular metabolic activities. Herein, we construct a portable time-resolved biosensing platform for visual and quantitative detection...
Early cancer diagnosis demands rapid, sensitive and portable approaches for detecting cellular metabolic activities. Herein, we construct a portable time-resolved biosensing platform for visual and quantitative detection of xanthine oxidase (XOD) activity in circulating tumor cells (CTCs) based on a permanganate-peroxide coupling mechanism. In this strategy, XOD catalyzes the oxidation of xanthine to uric acid, accompanied by the generation of hydrogen peroxide (HO). The as-produced HO subsequently reduces potassium permanganate (KMnO) under mildly acidic conditions, resulting in a rapid decrease in the characteristic absorption of Mn(VII) species and a visually distinguishable color transition from purplish red to light yellow within 60 s. Since the yield of HO generated is directly related to enzymatic turnover, XOD activity can be quantitatively translated into optical and digital colorimetric signals. The reaction can be monitored spectroscopically through absorbance changes at 526 nm or analyzed using smartphone-based RGB extraction for instrument-free quantification. Under optimized conditions, the optical response shows a good linear correlation with the logarithm of XOD activity with a detection limit of 0.0039 U/L (S/N = 3). Cellular studies revealed elevated XOD activity in cancer-derived CTCs compared with normal cells, as well as significant responses to XOD inhibition and oxidative stress. This platform provides a simple and portable tool for cellular enzyme profiling and point-of-care cancer diagnostics.
Inhibitory effect and mechanism of NbC nanochaperone on bovine serum albumin unfolding.
Li N, Ye Y, Zhou T … +4 more , Ma C, Li N, Liu Y, Chen H
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42364481 · Publisher ↗
Bovine serum albumin (BSA) was used as a model protein to investigate the mechanism of guanidine hydrochloride (GdnHCl) induced unfolding and the protective effect of NbC nanosheets. Spectroscopic and structural analyses...
Bovine serum albumin (BSA) was used as a model protein to investigate the mechanism of guanidine hydrochloride (GdnHCl) induced unfolding and the protective effect of NbC nanosheets. Spectroscopic and structural analyses showed that GdnHCl induced concentration-dependent unfolding of BSA through a native to intermediate to unfolded transition, accompanied by fluorescence quenching, emission red shift, secondary structure rearrangement, and decreased thermal stability. Mechanistic studies indicated that this process was closely associated with disruption of the water hydrogen-bond network rather than simple direct denaturant protein binding. Raman analysis showed that GdnHCl decreased strong hydrogen bonds while increasing weak hydrogen bonds, and the resulting water-structure reorganization was highly correlated with the unfolding degree of BSA, with a Pearson correlation coefficient of 0.978. NbC nanosheets effectively suppressed GdnHCl-induced unfolding, increasing the unfolding midpoint concentration from 3.66 to 4.71 mol/L in the presence of 50 μg/mL NbC. NbC also alleviated the loss of ordered secondary structure and improved the thermal stability of unfolded BSA, increasing the melting temperature from 43.9 to 61.0 °C. Fluorescence quenching and isothermal titration calorimetry demonstrated that NbC interacted spontaneously with BSA mainly through hydrogen-bond-dominated interfacial interactions. This work provides a solvent centered perspective on chemical denaturation and identifies NbC as a promising nanochaperone for protein conformational protection.
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