Spectrochimica Acta. Part A, Molecular And Biomolecular Spectroscopy[JOURNAL]
Sun
200 papers
Mesoporous silica-triggered aggregation-induced enhanced emission enables ratiometric fluorescence detection of multiple heavy metal ions in water.
Han Y, Zhang J, Fang J … +3 more , Zhu X, An J, Liu Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42322935 · Publisher ↗
Heavy metal ions pose persistent threats to aquatic environments and public health owing to their toxicity and bioaccumulative nature, highlighting the urgent need for sensitive and field-deployable detection strategies...
Heavy metal ions pose persistent threats to aquatic environments and public health owing to their toxicity and bioaccumulative nature, highlighting the urgent need for sensitive and field-deployable detection strategies in water. However, many fluorescent probes have been designed for trace analyte detection in organic media and often exhibit unsatisfactory performance in water, either because aggregation-caused quenching (ACQ) narrows their working range or because a single response pathway restricts them to single-analyte detection. In this work, mesoporous silica nanoparticles (MSN) were employed as structural triggers to induce aggregation-induced enhanced emission (AIEE) of gold nanoclusters (AuNCs) in water, thereby improving their quantum yield and optical response. Blue-emissive carbon quantum dots (BQDs) were further introduced through controlled assembly while preventing ACQ, enabling the construction of a ratiometric fluorescent probe, MSN@BQDs-AuNCs. The resulting platform enabled differential detection of Ag, Zn, and Cu, with up to a 1000-fold expansion of the linear range (maximum linear range: 0-10,000 μM) together with a 100-fold reduction in the detection limit (lowest detection limit: 0.004 μM), compared with unmodified AuNCs. To demonstrate practical applicability, a portable smartphone-assisted sensing device was fabricated via 3D printing, enabling on-site and real-time quantitative analysis based on optical signal transduction. Furthermore, principal component analysis (PCA) of smartphone-derived RGB data facilitated the discrimination of Ag-, Zn-, and Cu-induced color response patterns. Comparative investigations of the responses of AuNCs and MSN@BQDs-AuNCs toward different metal ions further revealed multiple distinct ion-recognition pathways synergistically regulated by mesoporous structures and controllable assembly.
Hyperspectral geographical origin identification of Bupleurum via spatial-spectral features based on adaptive weighted quaternion zernike moments.
Jin W, Fan S, Xu W … +5 more , Zu L, Qiu S, Zhang Y, Fu X, Zhang Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42322934 · Publisher ↗
Bupleurum, a vital herb in traditional Chinese medicine (TCM), possesses complex chemical compositions heavily dependent on variety and geographical origin. Misidentification often leads to unstable therapeutic efficacy...
Bupleurum, a vital herb in traditional Chinese medicine (TCM), possesses complex chemical compositions heavily dependent on variety and geographical origin. Misidentification often leads to unstable therapeutic efficacy and safety risks. Addressing challenges in market confusion and traceability, this study proposes a rapid, non-destructive identification framework using visible-near infrared (Vis-NIR) hyperspectral imaging. A comprehensive dataset comprising 3670 samples from 17 batches, 7 origins, and 2 varieties was established, with hyperspectral images acquired separately from the cross-sections and lateral surfaces. ROI-average spectra were extracted from both parts, while ROI spatial information was retained for AWQZM texture feature extraction. To utilize complementary information from different parts and preprocessing methods, a four-component spectral feature set was constructed from cross-section and lateral-surface preprocessed average spectra and first-derivative spectra. Adaptive Weighted Quaternion Zernike Moments (AWQZM) were introduced to extract spatial texture features from ROI images. A unified dimensionality reduction strategy and a 95% variance adaptive strategy were compared, and SVM, RF, and KNN models were optimized using Tree-structured Parzen Estimator (TPE) Bayesian optimization. The SVM model fusing SG-smoothed spectra, first-derivative spectra, and AWQZM texture features achieved the best performance, with a testing accuracy of 98.23%. These results demonstrate that fusing dual-part spectral information with spatial texture features improves Bupleurum variety and geographical origin identification, providing a feasible approach for rapid, non-destructive TCM quality traceability.
Spectroscopic and computational insights into protein interactions on silver-decorated covalent organic frameworks with antibacterial activity.
Dhama N, Panwar N, Vishwakarma VK … +2 more , Luthra PM, Masram DT
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320166 · Publisher ↗
Despite rapid progress in COF-based biomaterials, no study has yet explored the molecular-level interaction mechanism of a protein with a metal-COF hybrid. This study provides a detailed understanding of the interaction...
Despite rapid progress in COF-based biomaterials, no study has yet explored the molecular-level interaction mechanism of a protein with a metal-COF hybrid. This study provides a detailed understanding of the interaction between lysozyme and Ag@COF by integrating experimental biophysical analyses with molecular docking and DFT calculations. In this work, a silver nanoparticle-embedded covalent organic framework (Ag@COF) was prepared using a simple post-synthetic method. Structural and spectroscopic studies confirmed the framework structure, while electron microscopy showed an even distribution of silver particles within the porous framework. Interactions with lysozyme were investigated using spectroscopic methods, which indicated stable binding and only minor structural changes in the protein. Molecular docking supported these findings by identifying favorable interaction sites, with a binding energy of -214.0. Density functional theory (DFT) calculations revealed stabilizing non-covalent forces between Ag and the COF backbone. Dynamic light scattering confirmed concentration-dependent complex formation, while antibacterial tests against Escherichia coli and Enterococcus faecalis showed concentration-dependent inhibition, with a minimum inhibitory concentration (MIC) of 64 μg/mL against E. coli and 128 μg/mL against E. faecalis, supported by microscopy evidence of membrane damage, supported by microscopy evidence of membrane damage. This combined computational and experimental approach provides the first clear understanding of how proteins interact with Ag@COF surfaces, thereby guiding the future design of bioactive COF hybrid materials. Further biological studies are required to validate the broader biomedical applicability of Ag@COF.
Quantitative spectroscopic analysis of light scattering in rough granular coatings: an optimized Kubelka-Munk modeling approach.
Miao Z, Du J, Long W … +4 more , Liu H, Xue H, Wu F, Wang G
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320165 · Publisher ↗
The quantitative spectroscopic analysis of rough, granular matrices presents significant challenges due to complex non-linear light scattering and variable background absorption. To address the spectral deviations caused...
The quantitative spectroscopic analysis of rough, granular matrices presents significant challenges due to complex non-linear light scattering and variable background absorption. To address the spectral deviations caused by these optical phenomena in agricultural-grade phosphate coatings, this study proposes a physically corrected spectroscopic model based on optimizing the Kubelka-Munk (K-M) theory. A comparative analysis reveals that while empirical mathematical corrections (Quadratic model) improve the mathematical fitting of reflectance spectra, they fail to capture the underlying physical relationship between concentration and absorption, resulting in significant quantification errors (Average Relative Deviation, ARD = 2.80) for complex spectral series. In contrast, the k-corrected model, which explicitly incorporates Saunderson coefficients to account for surface refractive index and internal scattering, demonstrates superior accuracy in predicting the spectral response. Experimental validation confirms that this physically based approach significantly reduces the concentration quantification error (ARD) for the complex green series from 1.17 to 0.85 and minimizes the spectral colorimetric difference (∆E)by approximately 50% (from 2.67 to 1.35). Furthermore, for the Yellow and Coffee-brown target spectra, color differences were consistently reduced to below 1.0. These findings indicate that accounting for physical optical properties-specifically surface and internal scattering-is critical for the accurate spectroscopic modeling of granular coatings, providing a robust framework for predicting the optical behavior of complex dyed systems.
A novel imidazole derivative-based turn-on probe for rapid and sensitive detection of phosphate and carbonate in environmental samples.
Li ZY, Milaneh S, Dong FY … +1 more , Wang WL
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320164 · Publisher ↗
In this study, a novel fluorescent probe, Y, based on a thieno[2,3-b]pyrrole-dibenzimidazole scaffold, was synthesized and evaluated. Probe Y exhibited high sensitivity toward phosphate (PO) and carbonate (CO) in a DMSO:...
In this study, a novel fluorescent probe, Y, based on a thieno[2,3-b]pyrrole-dibenzimidazole scaffold, was synthesized and evaluated. Probe Y exhibited high sensitivity toward phosphate (PO) and carbonate (CO) in a DMSO: HO (9:1, v/v) medium, showing a fluorescence "turn-on" response with the emergence of an emission peak at 467 nm. Probe Y displayed strong binding affinities for both PO and CO, with detection limits of 0.67 μM and 0.26 μM, respectively. The recognition mechanisms were investigated using H NMR and Density Functional Theory (DFT) calculations. Experiments conducted using authentic water and soil matrices confirmed probe Y's high sensitivity in complex samples. Simultaneously, probe Y was effectively employed in test strips, thereby confirming its high sensitivity. This illustrates its capacity as one of the few fluorescent probes that can concurrently detect POand CO.
Intrinsic multi-component fluorescence fingerprint of bovine milk-derived exosomes for label-free biosensing.
Aray A, Morshedi A, Ramezani R … +1 more , Shokoufi N
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320163 · Publisher ↗
Bovine milk-derived exosomes are biocompatible nanovesicles with significant potential for drug delivery, yet reliable methods for their label-free identification remain limited. This study employs fluorescence spectrosc...
Bovine milk-derived exosomes are biocompatible nanovesicles with significant potential for drug delivery, yet reliable methods for their label-free identification remain limited. This study employs fluorescence spectroscopy to characterize the intrinsic optical fingerprint of BMEs. Initially, the Excitation-Emission Matrix served as an exploratory tool to map the spectral landscape. Second-derivative analysis was then applied to resolve intrinsic fluorophore hotspots obscured by background interference, followed by spectral deconvolution to separate overlapping components. This analysis revealed a distinct multi-component fluorescence signature arising from Tryptophan, NAD(P)H, AGE-related MRPs, Porphyrins, Flavins (Riboflavin/FAD), Vitamin A, and Schiff-base-type fluorophores. Moreover, all these autofluorescence spectra were recorded at pH 3, 7, and 10, revealing characteristic pH-dependent spectral changes for each component, most notably the emergence of a well-resolved 515 nm peak at pH 3 confirming riboflavin's neutral-to-anionic speciation, as well as a red-shift in porphyrin emission wavelength at pH 3 and 7. Collectively, these intrinsic optical signatures validate BMEs as self-reporting nanocarriers, providing a robust, non-invasive biosensing baseline for quality control and tracking without the structural compromise associated with external tagging.
Enhanced fluorescence of copper nanoclusters based on dual-ligand engineering for sensitive detection of vitamin B12 and diosmetin in food samples.
Huang F, Li L, Zhou Y … +3 more , Peng X, Liu R, Cheng Z
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320162 · Publisher ↗
Employing a dual-ligand surface engineering strategy, red-fluorescent copper nanoclusters (Neu5Ac@5-MTU-CuNCs) was fabricated via an eco-friendly one-pot method with 5-methyl-2-thiouracil (5-MTU) and N-acetylneuraminic a...
Employing a dual-ligand surface engineering strategy, red-fluorescent copper nanoclusters (Neu5Ac@5-MTU-CuNCs) was fabricated via an eco-friendly one-pot method with 5-methyl-2-thiouracil (5-MTU) and N-acetylneuraminic acid (Neu5Ac) as ligands. The incorporation of Neu5Ac can improve the coordination environment, restrict the vibration of 5-MTU on the CuNCs surface, and simultaneously create steric hindrance between its rigid sugar ring structure and the pyrimidine moiety of 5-MTU. Based on this, the fluorescence intensity of Neu5Ac@5-MTU-CuNCs at 680 nm was boosted, along with improved detection sensitivity for vitamin B12 (VB12) and diosmetin (Dio). Detection limits of 0.039 μM (VB12) and 0.160 μM (Dio) were received, with linear ranges of 0.10-52.25 μM and 0.50-62.25 μM. Meanwhile, synthesis conditions of Neu5Ac@5-MTU-CuNCs and corresponding quenching mechanisms were intensively studied. The CuNCs was successfully employed to monitor VB12/Dio in various foods with good recoveries, demonstrating high reliability. A compact and economical paper-based strip was formulated by leveraging Neu5Ac@5-MTU-CuNCs, enabling expeditious, equipment-free, and visual semi-quantitative determination of VB12/Dio for field deployment. Besides, the Neu5Ac@5-MTU-CuNCs also held promise for applications in multifunctional anti-forgery and dactyloscopic analysis.
Ratiometric copper nanocluster fluorescence probe coupled with deep learning for intelligent recognition of tetracycline antibiotics in food.
Xiang A, Lin X, Yang X … +4 more , Xu H, Pang J, Chen X, Yan Z
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320161 · Publisher ↗
In this study, a ratiometric fluorescence sensing strategy combined with deep learning was developed for the intelligent detection of tetracycline antibiotics (TCs) in food matrices. Blue-emitting and saffron yellow-emit...
In this study, a ratiometric fluorescence sensing strategy combined with deep learning was developed for the intelligent detection of tetracycline antibiotics (TCs) in food matrices. Blue-emitting and saffron yellow-emitting copper nanoclusters (Cu NCs) were synthesized using bovine serum albumin (BSA) and 2,3,5,6-tetrafluorothiophenol (TFTP) as ligands, respectively, and employed to construct a dual-emission ratiometric fluorescence probe (BSA/TFTP@Cu NCs). The probe exhibited distinct fluorescence response patterns toward tetracycline (TC), chlortetracycline (CTC) and doxycycline (DOX), achieving a detection limit as low as 9.26 nmol L. Under 302 nm UV illumination, visually distinguishable fluorescence color variations were observed for the three TCs. To enable intelligent analysis, a modified ResNet50 model incorporating multi-task learning and a progressive three-stage training strategy was developed. The model simultaneously achieved TCs classification and concentration prediction, attaining 100% classification accuracy and a concentration prediction accuracy exceeding 98% (R = 0.989). In the analysis of spiked milk, egg and honey samples, the recoveries of TCs ranged from 90.48% to 107.93% for the fluorescence method and 90.28% to 98.53% for the deep learning method. This study provides a novel strategy for the rapid, accurate and intelligent detection of antibiotic residues in food safety monitoring.
Compensation-alternating acquisition strategy for fluorescence residual suppression and stability enhancement in shifted-excitation Raman difference spectroscopy.
Zhao Y, Chen JW, Lin JF
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42320160 · Publisher ↗
Raman spectroscopy often encounters strong fluorescence background interference in practical applications. Although Shifted-Excitation Raman Difference Spectroscopy (SERDS) is effective for fluorescence suppression, trad...
Raman spectroscopy often encounters strong fluorescence background interference in practical applications. Although Shifted-Excitation Raman Difference Spectroscopy (SERDS) is effective for fluorescence suppression, traditional acquisition modes tend to introduce significant fluorescence residuals in direct difference spectra. These residuals arise from dynamic fluorescence decay processes such as photobleaching and thermal effects and can severely compromise the stability of reconstructed Raman spectra. Current solutions predominantly focus on algorithmic correction after the residuals have been generated, with limited strategies to suppress them at the data acquisition stage. To address this limitation, this paper proposes a novel Compensation-Alternating Acquisition Mode (CompAAM). Without extending the total exposure duration time, this method reduces background differences caused by asynchronous fluorescence attenuation by optimizing the excitation timing and implementing an exposure compensation mechanism with the dual-wavelength laser. Using highly fluorescent plastic samples, the study systematically evaluated three acquisition modes: the conventional Wavelength-Alternating Acquisition Mode (WAAM), the Count-Alternating Acquisition Mode (CAAM), and the proposed CompAAM. Experimental results demonstrate that CompAAM most effectively suppresses fluorescence residuals in difference spectra. In terms of spectral stability, the relative standard deviation (RSD) of characteristic peak intensities under this mode can be reduced to 0.97%-1.43%, significantly lower than those observed under the Wavelength-Alternating Acquisition Mode (5.85%-8.60%) and the Count-Alternating Acquisition Mode (2.10%-4.21%). This study confirms that the proposed CompAAM can substantially enhance the reconstruction quality and the stability of differential Raman spectra right from the measurement source, and provides an effective strategy for the reliable analysis of samples with strong fluorescence backgrounds.
Stable lanthanide sensor enables multicolor luminescence encoding and ratiometric detection for discriminating similar fluoroquinolone antibiotics.
Yang Y, Li L, Chen H … +3 more , Zhao D, He Y, Zhang L
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42314586 · Publisher ↗
The widespread use of fluoroquinolone antibiotics (FQs) has necessitated the development of efficient on-site detection methods. Herein, a stable Zr-based MOF UiO-67-bpydc was post-synthetically modified with Eu ions to...
The widespread use of fluoroquinolone antibiotics (FQs) has necessitated the development of efficient on-site detection methods. Herein, a stable Zr-based MOF UiO-67-bpydc was post-synthetically modified with Eu ions to create a red emissive probe Eu@UiO-67-bpydc. The antenna effect from the ligand to Eu quenches the ligand emission, eliminating spectral overlap with FQs. Upon introducing FQs, the intrinsic fluorescence of FQs enhances while the characteristic red emission of Eu at 616 nm is quenched, enabling a self-calibrating ratiometric sensing platform. This sensor achieves quantitative detection of six FQs with low limit of detection value (14.6 nM), rapid response, and high selectivity. Furthermore, a real-time colorimetric strategy was developed for the qualitative discrimination of different FQs. Recovery tests confirming the accuracy of the sensor and reliability in real water samples. This work provides a robust approach to designing an ideal optical sensor for the on-site analysis and visual identification of antibiotics in water.
Enhanced in vitro cytotoxicity of G-rich ssDNA-templated Cu nanoclusters with multienzyme-like activity and glutathione depletion capacity.
Wei C, Feng A
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42314585 · Publisher ↗
Chemodynamic therapy (CDT) has been widely explored for tumor-specific treatment. Nevertheless, glutathione (GSH)-mediated scavenging of hydroxyl radicals (·OH) and insufficient HO levels in tumor microenvironments sever...
Chemodynamic therapy (CDT) has been widely explored for tumor-specific treatment. Nevertheless, glutathione (GSH)-mediated scavenging of hydroxyl radicals (·OH) and insufficient HO levels in tumor microenvironments severely impede the clinical application of CDT. In this study, four types of DNA-templated Cu nanoclusters (DNA-CuNCs) were been fabricated using A14, G14, C14, and T14 single-stranded DNA (ssDNA) as templates. Their oxidoreductase-mimicking activities, intracellular reactive oxygen species (ROS) generation and in vitro cytotoxicity toward HeLa cells were systematically evaluated. All DNA-CuNCs presented multienzyme-like activity, including peroxidase (POD)-, oxidase (OXD)-, catalase (CAT)-, and superoxidase dismutase (SOD)-like activities, accompanied by obvious intracellular GSH depletion. Of note, G14-CuNCs, with POD-like and relatively weak CAT-like activities, could efficiently generate ·OH. Meanwhile, its OXD-like activity and GSH-depleting capability further boosted ROS production in HeLa cells. Specifically, acting as a SOD-like enzyme, G14-CuNCs could continuously self-supply HO and O, thus realizing the cyclic accumulation of massive ROS and relieving tumor hypoxia. This work suggests that G14-CuNCs hold significant potential for cancer treatment via cascade reactions and synergistic therapeutic strategies.
Easy methodology for linker-free SERS detection of vitamin D at trace levels.
Ingilala V, Tudu A, Biswas C … +3 more , Bansal C, Vadali VSSS, Ammanabrolu R
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42314584 · Publisher ↗
Vitamin D is a crucial biomarker for several human diseases. Its deficiency is overcome through pharmaceutical and food supplement interventions. Therefore, its detection at biologically relevant low concentrations or tr...
Vitamin D is a crucial biomarker for several human diseases. Its deficiency is overcome through pharmaceutical and food supplement interventions. Therefore, its detection at biologically relevant low concentrations or trace levels is crucial. SERS is a powerful analytical technique that combines the molecular specificity of Raman spectroscopy with electromagnetic field enhancement at plasmonic nanostructures, enabling single-molecule detection. However, SERS-based detection of vitamin D and its metabolites without any linker molecule is challenging and underexplored. The primary obstacle stems from its molecular structure and physicochemical properties. It is a nonpolar, lipophilic secosteroid with weak affinity for metal surfaces, leading to poor adsorption on conventional SERS substrates. This work elucidates a linker-free SERS methodology for trace-level detection of vitamin D through direct adsorption onto plasmonic silver nanoclusters. Vitamin D-like analytes possess a conjugated triene system capable of interacting with Ag nanocluster surfaces through π-metal interactions, facilitated by van der Waals forces and weak charge-transfer contributions. Upon excitation with a laser wavelength resonant with the plasmonic response of the substrate, these π-Ag interactions may enable synergistic electromagnetic and chemical enhancement of Raman-active vibrational modes associated with the conjugated triene framework. If so, the methodology can explicitly exploit the CC stretching Raman vibrational mode at ∼1599 cm (the most polarizable mode in the conjugated triene system) for quantitative analysis. In this work, using novel walnut kernel-like Ag-nanocluster-based SERS substrates, vitamin D was detected down to 1 nmol/L without the use of linker molecules, aptamers, or immunorecognition elements. The ∼1599 cm band not only enabled the detection of vitamin D at trace levels but also verified linearity in detection. This approach contrasts with conventional SERS strategies for vitamin D and 25-hydroxyvitamin D detection that rely on sophisticated aptamer- or immunosensor-based architectures, offering a simplified and cost-effective alternative while maintaining high sensitivity.
Ultrasensitive detection of alpha-fetoprotein via ZnO-mediated photo-ATRP signal amplification on chitosan-functionalized magnetic beads.
Jia J, Yao P, Tian Z … +2 more , Kong J, Zhang X
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42314571 · Publisher ↗
Alpha-fetoprotein (AFP) is a key serum biomarker for the early detection and monitoring of hepatocellular carcinoma (HCC). However, conventional methods such as enzyme-linked immunosorbent assay (ELISA) and chemiluminesc...
Alpha-fetoprotein (AFP) is a key serum biomarker for the early detection and monitoring of hepatocellular carcinoma (HCC). However, conventional methods such as enzyme-linked immunosorbent assay (ELISA) and chemiluminescence immunoassay often lack the sensitivity and practicality required for point-of-care testing, due to their complex procedures, high cost, and moderate detection limits. To overcome these limitations, we developed a highly sensitive fluorescent biosensing platform that integrates chitosan-functionalized magnetic beads with a ZnO-enhanced photoinduced atom transfer radical polymerization (photo-ATRP) signal amplification strategy. Carboxyl-modified Fe₃O₄ magnetic beads were used to immobilize anti-AFP antibodies for specific target capture. An azide-terminated AFP aptamer was conjugated via click chemistry to a phenylboronic acid functional monomer, which then selectively bound to chitosan through boronate-diol interactions. Multiple ATRP initiation sites were grafted onto chitosan using an NHS-activated bromoisobutyrate initiator. Under UV light, ZnO nanoparticles facilitated efficient electron transfer, promoting the controlled growth of fluorescent polymer brushes from the chitosan backbone. This approach enabled significant signal amplification, yielding a wide linear detection range from 10.0 fg/mL to 10.0 ng/mL and an exceptionally low detection limit of 2.3 fg/mL. The biosensor also demonstrated high selectivity, good storage stability, and reliable performance in diluted human serum. This work presents a robust, cost-effective, and sensitive platform for AFP detection, showing promising potential for AFP monitoring in complex biological matrices.
Fabrication of densely-packed nanoparticle layers@ cellulose nanofibril nanopaper via interface self-assembly and its SERS application.
Yao H, Liu X, Xue L … +3 more , Han Y, Ye Y, Zhou J
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42314570 · Publisher ↗
Cellulose-based surface-enhanced Raman spectroscopy (SERS) substrates have emerged as a prominent research focus for advancing the practical application of SERS technology. Herein, a three-phase interfacial self-assembly...
Cellulose-based surface-enhanced Raman spectroscopy (SERS) substrates have emerged as a prominent research focus for advancing the practical application of SERS technology. Herein, a three-phase interfacial self-assembly strategy was developed to deposit nanoparticle layers onto the surface of cellulose nanofibril (CNF) nanopapers. This approach enables the fabrication of large-area monolayer or multilayer metallic nanoparticles (NPs) with diverse morphologies on the CNF surface, thereby constructing versatile SERS nanopapers with tunable surface plasmonic properties. The double-layered Au NPs@CNF nanopaper showed excellent SERS performance, achieving a minimum detectable concentration (MDC) of 10 M (4-aminothiophenol, 4-ATP) and 0.1 ppm (methamphetamine, MAMP) with a wide linear range. Featuring excellent optical transparency and a well-defined porous structure, the substrate facilitates efficient extraction and enrichment of target analytes. By attaching its non-metallic side to sample surfaces, it enables SERS detection as well as food-safe, nondestructive trace analysis. As a proof of concept, these SERS nanopapers were applied to rapidly detect thiram on apple peels, with an MDC of 0.1 ng/cm, and to extract and identify dyes from textiles with minimal damage. These approaches prevent nanoparticle contamination on food surfaces and eliminate destructive sampling, providing a reliable and biosafe strategy for nondestructive in-situ SERS monitoring.
Plasmonic star-shaped gold nanoparticles for high-sensitive SERS-based detection of hepatocellular carcinoma (HCC).
Elkady A, Hagag MF, Elsaidy A … +4 more , Elzallat M, Naguib N, El-Khawaga AM, Elsaied HM
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42314569 · Publisher ↗
Surface-enhanced Raman spectroscopy (SERS) has emerged as a promising analytical tool for sensitive molecular detection in biomedical applications. In this study, star-shaped gold nanoparticles (AuNSTs) were employed as...
Surface-enhanced Raman spectroscopy (SERS) has emerged as a promising analytical tool for sensitive molecular detection in biomedical applications. In this study, star-shaped gold nanoparticles (AuNSTs) were employed as plasmonic substrates to enhance Raman signals for the analysis of hepatocellular carcinoma (HCC) directly from whole blood samples. The synthesized AuNSTs exhibited strong plasmonic resonance, enabling significant electromagnetic field localization and signal amplification. A reproducible Raman feature at ∼700 cm was consistently observed in HCC samples following nanoparticle integration, while it was not detected in healthy controls under the same experimental conditions. Although the precise biochemical origin of this feature remains to be fully elucidated, it is likely associated with alterations in biomolecular composition and nanoparticle-biomolecule interactions at plasmonic hotspots. Exosomal isolation further improved spectral clarity; however, AuNST-assisted measurements on whole blood provided sufficient spectral differentiation without the need for complex preprocessing. Chemometric analysis using principal component analysis (PCA) demonstrated clear separation between healthy and HCC samples, supporting the potential of this approach for spectral discrimination. Overall, this study presents a rapid, minimally invasive, and label-free SERS-based platform for the detection of HCC-associated spectral features in whole blood, with potential applications in clinical diagnostics and biosensing. Further studies are required to validate specificity and elucidate the molecular origin of the observed Raman signals.
Integrating CO₂ laser photoacoustic spectroscopy with explainable CNNs for post-harvest quality assessment of Diospyros kaki.
Popa C, Petrus M, Bratu AM … +2 more , Gebac L, Bercu V
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42309037 · Publisher ↗
This study presents a non-invasive molecular spectroscopy approach for monitoring storage-related physiological changes in Diospyros kaki (Hachiya persimmon). CO₂ laser photoacoustic spectroscopy (CO₂LPAS) was applied to...
This study presents a non-invasive molecular spectroscopy approach for monitoring storage-related physiological changes in Diospyros kaki (Hachiya persimmon). CO₂ laser photoacoustic spectroscopy (CO₂LPAS) was applied to quantify ethylene, ethanol, and ammonia emissions from individual fruits over a six-week storage period. Early ethylene release triggered ripening processes, followed by ethanol accumulation indicative of low-oxygen metabolism and microbial activity. Progressive ammonia emissions reflected proteolytic activity and tissue degradation during late-stage spoilage. To correlate internal metabolic signatures with external phenotypic changes, visual inspection was combined with high-resolution RGB imaging and a convolutional neural network (CNN) classification into three physiological macro-states: Storage, Transition, and Spoilage. The CNN was trained using 5-fold stratified cross-validation with test-time augmentation, achieving a mean classification accuracy of 91.67 ± 3.73%. Gradient-weighted Class Activation Mapping (Grad-CAM) highlighted regions contributing to classification, showing a shift from specular highlights in early stages to tissue deformation and necrosis in later stages, confirming the link between molecular emissions and structural degradation. The combined use of CO₂LPAS-based molecular spectroscopy and image-based assessment provides a complementary framework for real-time, non-invasive evaluation of storage-related fruit quality. These results demonstrate that ethylene, ethanol, and ammonia serve as robust molecular markers of ripening, anaerobic metabolism, and spoilage, while complementary imaging captures macroscopic deterioration. This dual-method framework offers potential for predictive postharvest monitoring, quality control, and shelf-life assessment of climacteric fruits.
An AutoML framework for near-infrared spectral analysis in food quality assessment and origin traceability.
Li P, Shi L, Yan S … +4 more , Zhou D, Zhai D, Liao AM, Yang Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42309036 · Publisher ↗
Near-infrared (NIR) spectroscopy has emerged as a rapid and non-destructive analytical technique for food quality assessment; however, its predictive performance strongly depends on the appropriate combination of spectra...
Near-infrared (NIR) spectroscopy has emerged as a rapid and non-destructive analytical technique for food quality assessment; however, its predictive performance strongly depends on the appropriate combination of spectral preprocessing, wavelength selection, and modeling methods. In this study, a complexity-aware automated machine learning (AutoML) framework was developed for NIR spectral analysis to systematically construct compact and high-performing modeling pipelines. The framework integrates preprocessing optimization, wavelength subset selection, model evaluation, and complexity-aware post-selection within a unified workflow, enabling efficient exploration of candidate pipelines with varying structural complexity. Extensive experiments were conducted on multiple datasets covering both regression and classification tasks. The results demonstrate that the framework consistently identifies lightweight yet effective pipelines, achieving competitive or superior predictive performance compared with conventional manually designed approaches. Furthermore, the selected pipelines exhibit good generalization ability while maintaining relatively low computational complexity, highlighting the potential of well-optimized traditional machine learning approaches for practical NIR spectral modeling tasks. In addition, SHAP-based interpretability analysis revealed that the selected wavelengths were consistently concentrated within chemically meaningful spectral regions associated with characteristic absorption bands. Overall, this study provides a practical and interpretable AutoML-based framework for NIR spectral modeling, offering methodological and application value for rapid and non-destructive food quality evaluation.
The identification of counterfeit high-quality edible oil using EEM fluorescence spectroscopy based on GA-optimized 2D-LDA.
Cui Y, Jin Y, Li Z … +6 more , Yuan Y, Jiang H, Cui C, Wu H, Wu S, Li J
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42309035 · Publisher ↗
High-quality edible oils, characterized by their high nutritional value, are priced significantly higher than other types. However, adulteration and falsification remain a prevalent and prominent issue during production...
High-quality edible oils, characterized by their high nutritional value, are priced significantly higher than other types. However, adulteration and falsification remain a prevalent and prominent issue during production and processing. To address the authenticity identification of high-quality edible oils, this study focuses on multiple counterfeit types of sesame oil, peanut oil, and olive oil, and proposes a feature-optimized recognition method based on excitation-emission matrix (EEM) fluorescence spectroscopy fused with two-dimensional linear discriminant analysis (2D-LDA) and genetic algorithm (GA). The method employs 2D-LDA for feature extraction, followed by GA implementation where each feature is treated as a gene: initial populations are randomly generated, and iterative optimization is performed via roulette wheel selection, crossover, and mutation operations, ultimately outputting the optimal feature subset and corresponding model performance metrics. The model achieves a classification accuracy of 0.9773 for 11 types of genuine and counterfeit edible oils; after data augmentation, it still maintains a high accuracy of 0.9941, confirming its robustness. This method not only enables efficient dimensionality reduction of EEM fluorescence spectra but also reduces computational complexity, holding significant implications for the deployment and application of the algorithm.
Cell-in-water: complementary optical photothermal infrared and Raman microscopy for submicron chemical imaging of hydrated cells.
Korona W, Nowakowska AM, Pieczara A … +3 more , Orzechowska B, Unger M, Baranska M
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42309034 · Publisher ↗
Conventional Fourier transform infrared absorption spectroscopy is constrained by diffraction-limited spatial resolution and overwhelming absorption of water, typically requiring sample dehydration, which disrupts native...
Conventional Fourier transform infrared absorption spectroscopy is constrained by diffraction-limited spatial resolution and overwhelming absorption of water, typically requiring sample dehydration, which disrupts native cellular morphology. While Optical Photothermal Infrared microscopy overcomes the resolution barrier, reliable imaging of cells in their native, hydrated state remains a significant methodological challenge. In this work, an optimized Cell-in-Water protocol is presented for submicron, label-free chemical imaging of hydrated cells. The implementation of a silicone-sealed microchamber ensures a stable aqueous environment, preventing evaporation and enabling stable imaging for up to 4 h. Using a robust ratiometric data analysis framework, subcellular organelles, including nuclei and lipid droplets, are visualized with a lateral resolution of 300-500 nm. The protocol's reliability was validated through a comparative study of individual cells in both hydrated and dehydrated states, revealing critical spectral shifts and morphological distortions inherently associated with the drying process. These results provide a standardized, reproducible workflow for non-invasive, high-resolution biochemical mapping in aqueous environments, bridging the gap between conventional vibrational spectroscopy and the requirements of advanced biological imaging.
Influence of sample preparation methods on the spatial overlap between analytes and metasurfaces in metasurface-enhanced terahertz spectroscopy.
Yang Y, Yuan Y, Zhou Z … +4 more , Zhang Z, Zhao X, Zhang R, Zhang T
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42309033 · Publisher ↗
Terahertz spectroscopy, with its intrinsic molecular fingerprint characteristics, has become a powerful tool for qualitative and quantitative analysis of organic materials. Metasurfaces can significantly enhance terahert...
Terahertz spectroscopy, with its intrinsic molecular fingerprint characteristics, has become a powerful tool for qualitative and quantitative analysis of organic materials. Metasurfaces can significantly enhance terahertz signals through strong localized electromagnetic fields; however, the enhancement critically depends on the spatial overlap between the organic crystal and the metasurface resonance mode. To address the variation in coupling efficiency caused by different sample preparation conditions, this study employs absorption-induced transparency (AIT) as the characteristic enhancement mechanism and designs a terahertz metasurface for coupling-enhanced characterization of lactose thin films. Two AIT features including resonance redshift and resonance-depth reduction are used as quantitative indicators, together with uncertainty analysis, to evaluate the spatial coupling quality. Four preparation methods for forming lactose films were systematically compared: static convection heating, static conduction heating, static radiation heating, and spin-coating followed by radiation heating. Experimental analyses of film uniformity, crystal morphology, and vibration modes overlapping reveal that the spin-coating & radiation-heating method achieves the highest coupling efficiency. This method yields the strongest AIT response, with a resonance redshift of 133.9 ± 0.2 GHz and a transmission increase of 10.5 ± 0.3%, while also exhibiting the smallest uncertainties. Moreover, it requires only one-quarter of the solution amount used by the other three methods, providing the best balance between enhancement performance, reproducibility, and material utilization. This work clarifies the fundamental relationship between sample preparation and spatial coupling between metasurface and analyte, offering a reproducible experimental strategy for optimizing metasurface design and enabling highly sensitive terahertz detection of trace organic materials.
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