Ha Anh Nguyen

Styrene is one of the most important volatile organic compounds (VOCs) used extensively in polymer and composite manufacturing, where occupational exposure occurs predominantly through inhalation of its vapor. Although surface-enhanced Raman spectroscpoy (SERS) offers exceptional sensitivity for molecular analysis, its application to vapor-phase detection remains challenging because volatile molecules are difficult to efficiently accumulate at plasmonically active sites. Consequently, conventional styrene vapor analysis generally relies on multistep workflows involving vapor sampling and analyte desorption prior to analysis. Herein, we report a flexible Cellulose/ZIF-8/Ag SERS chip combined with a simple attach-and-capture strategy for direct solvent-free detection of styrene vapor. By attaching the SERS sensing chip to the inner surface of a vial cap, vapor sampling and SERS detection were integrated into a single operation without additional sample pretreatment. The developed SERS platform achieved a detection limit of 170 mg/m3, below current occupational exposure limits for styrene, together with excellent analytical reliability (RSDs of 1.89% within a single chip and 5.29% between independently fabricated chips) and outstanding post-sampling stability, showing only a 7.3% signal decrease after seven days under ambient conditions. These findings establish the proposed attach-and-capture strategy as a practical analytical workflow for integrating vapor sampling and SERS detection into a single solvent-free operation for rapid occupational monitoring of styrene vapor.

Synthèse et caractérisation de matériaux nano-bio-hybrides à base du virus TYMV (Turnip yellow mosaic virus): La nanotechnologie est un champ multidisciplinaire regroupant la biologie, la chimie, la physique et la science des matériaux, ce qui a permis de développer des matériaux hybrides. La nano-bio-technologie s’est inspirée des architectures hautement organisées naturelles à base de sucres, lipides, acides nucléiques et protéines. Plus récemment, les capsides de virus ont été utilisées comme échafaudage grâce à leur homogénéité, taille, robustesse, faible coût et leur capacité à se désassembler et se réassembler. Les nano-objets peuvent être greffés aussi bien sur leur surface externe qu’interne. Dans ce travail, j’ai utilisé le virus de la mosaique jaune du navet (turnip yellow mosaic virus, TYMV) pour développer des nouveaux matériaux nano-bio-hybrides.Dans la première partie de ce travail, j’ai étudié la stabilité et le désassemblage de la capside dans le but d’encapsuler des nano-objects dans la cavité. TYMV est un virus robuste, sa structure est stable dans une large gamme de pH (3<pH<10), à des températures allant jusqu’à 60 °C, en présence de dénaturants (SDS 0.12 M ou urée 2.7 M), et à des forces ioniques élevées (NaCl 1.4 M ou MgCl2 3 M). En présence de DTT 1M ou de guanidine 2.5 M, la capside est dénaturée. De plus, la capside se gonfle dans une solution de MgCl2 2 M. A pH 12, TYMV relargue son ARN, et conduit à la formation de capsides vides. Ces capsides peuvent être également produites par la méthode de congélation-décongélation dans l’azote liquide. Les capsides vides obtenues par ces deux méthodes ont permis d’encapsuler des nano-objets comme la sulforhodamine B, des quantum dots de ZnS (ZnS QDs) et des nanoparticules d’Or (AuNPs). L’encapsulation a été confirmée par des expériences d’électrophorèses et de fluorescence. Ces résultats montrent la possibilité d’insérer des nano-objets dans la cavité du virus qui pourrait les protéger et les rendre moins toxiques.Dans la seconde partie, la capside de TYMV a servie d’échafaudage pour créer un réseau tridimensionnel d’objets comme des AuNPs ou ZnS QDs. Les AuNPs de taille 5, 10 et 20 nm ont été greffés sur la capside selon deux stratégies. Après purification, les matériaux AuNP-TYMV ont été caractérisés par différentes techniques : la DLS a confirmé l’augmentation du diamètre hydrodynamique du matériau après greffage (33, 50, et 68 nm pour les AuNPs de 5, 10 et 20 nm, respectivement) comparé au celui de la capside seule (28 nm). Les observations en TEM montrent que les AuNPs s’arrangent autour du virus selon une symétrie d’axe 5, en accord avec la structure icosaédrique de la capside. De plus, les spectres d’absorption UV-visible indiquent un déplacement bathochrome de 10 ou 11 nm de la bande plasmon des AuNPs lorsqu’elles étaient greffées au virus. De plus, des ZnS QD de 1-2 nm, recouverts par de la cystéamine, ont été greffés sur la surface externe du TYMV par des liaisons amides. Les matériaux obtenus avec des rapports QD :TYMV de 20 :1 et 10 :1 ont des tailles mesurées par électrophorèse ou DLS différentes (31.9 ± 3 nm et 30.7 ± 2 nm, respectivement). Avec le ratio QD :TYMV 20 :1, on observe une augmentation de l’émission de fluorescence de 22% qui pourrait être expliquée par l’augmentation locale de QDs.

Fe doping induces a synergistic enhancement of electronic conductivity and electrocatalytic activity in Gd ₂ O ₃ nanoparticles, enabling highly sensitive electrochemical detection of chloramphenicol in real pharmaceutical and milk samples.

This review frames SERS glucose sensing as an interfacial challenge, comparing boronic-acid, biomolecular, and MIP strategies to clarify how recognition, hotspot access, and signal transduction shape analytical performance.

Plasmonic nanostructures couple ultrasensitive readout with localized actuation via LSPR, enabling cancer diagnostics, therapy, and theranostics. We highlight core mechanisms, representative platforms, and translation barriers.

This review surveys surface-enhanced Raman scattering (SERS) for plant health and crop quality, relating plasmonic substrate design, sampling strategies and data analysis to sensitive, selective detection of plant stress markers and residues.

Pharmaceutical residues such as trimethoprim (TMP) and ketoprofen (KTP) are of growing environmental concern due to their persistence in wastewater and potential ecological impacts. In this study, we developed and evaluated electrochemically synthesized silver nanoparticles (e-AgNPs) immobilized on aluminum substrates as surface-enhanced Raman scattering (SERS) sensors for the detection of TMP and KTP. Structural and morphological characterization confirmed uniform, crystalline nanoparticles with an optimal size (∼50 nm) for plasmonic enhancement. Electrochemical measurements showed that TMP and KTP possess nearly identical LUMO levels, yet their SERS responses differed markedly. TMP exhibited strong and reproducible SERS bands, enabling direct quantitative detection over a wide linear range (10⁻⁴ M to 10⁻⁸ M) with a detection limit of 3.84 × 10⁻⁹ M. In contrast, KTP showed intrinsically weak signals due to unfavorable adsorption geometry. Chloride modification (10⁻⁴ M NaCl) effectively “activated” KTP detectability by displacing citrate ligands and forming Ag–Cl_x ⁻ surface states, which facilitated the adsorption and charge transfer of the substrate. Under optimized conditions, KTP was quantified over 10⁻⁴ M to 10⁻⁷ M with a detection limit of 2.69 × 10⁻⁸ M. Real-sample validation demonstrated reliable recoveries of TMP (89–96%) and KTP (88–95%) in spiked tap water and commercial pharmaceutical tablets, despite matrix interferences. These obtained results highlight the decisive role of adsorption chemistry in SERS detectability and demonstrate that interfacial modification with chloride can extend SERS applicability to weakly adsorbing pharmaceutical pollutants, offering a sensitive platform for environmental monitoring and pharmaceutical quality control.

This study presents a visible light-enhanced electrochemical sensor for detecting furazolidone (FZD), a widely used antibiotic, using a magnetoplasmonic Ag@Fe₃O₄ nanoparticle (MagPlas NPs)-modified screen-printed electrode (SPE). Under visible light irradiation, the MagPlas-based electrochemical sensor demonstrates significantly enhanced sensitivity compared to its performance in the absence of light. This enhancement is attributed to multiple synergistic mechanisms, including photosensitization of MagPlas NPs, improved electron transfer kinetics, and increased adsorption capacity. The sensor exhibits a linear response to FZD concentrations over a wide range, achieving a low limit of detection (LOD) of 0.477 μM with visible light irradiation, demonstrating the sensor's high sensitivity. It also demonstrates good repeatability and anti-interference ability, and can be successfully applied for the determination of FZD in real milk samples. This electrochemical sensor offers a promising approach for rapid, sensitive, and reliable detection of FZD in various applications.

Surface-enhanced Raman spectroscopy (SERS) is increasingly recognized as a powerful tool for analytical applications, especially in food safety, due to its ability to detect molecular fingerprints even at the single-molecule level. Developing SERS substrates that offer not only high sensitivity but also reliability and practicability is critical for transitioning SERS from a laboratory-based technique to practical field applications. In this study, we present an outstandingly sensitive, reliable, and practical Ag/CuO nanocomposite SERS substrate, fabricated through a simple green electrochemical method. The Ag/CuO substrate demonstrates remarkable sensitivity, detecting carbendazim (CBZ), a hazardous pesticide widely used in tea leaves, at an ultra-low limit of 8.85 × 10⁻¹¹ M, outperforming bare Ag substrate, which only reaches 10⁻⁶ M. The high reliability of the Ag/CuO substrate is confirmed by excellent repeatability and reproducibility, with a relative standard deviation (RSD) of less than 10%. Practicability was validated through the direct detection of CBZ in fresh tea leaves, yielding sharp recovery values of 85% to 106%. Additionally, the SERS enhancement mechanism was explored by comparing the performance of Ag, Ag/Cu₂O, and Ag/CuO substrates, revealing the critical role of metal (Ag) and semiconductor (Cu₂O, CuO) transitions in overall sensing performance. These findings underscore the potential of Ag/CuO nanocomposites for ultrasensitive pesticide detection in real-world agricultural environments and highlight the importance of metal/semiconductor transitions in designing more efficient SERS substrates. This paves the way for the development of versatile, field-ready SERS platforms applicable to a wide range of analytical and environmental monitoring needs.