TY - CONF A1 - Bell, Jérémy T1 - Embedded sensor for the detection of TNT in surface and marine waters N2 - In 1945, the Potsdam Conference led to the decision to destroy a significant amount of ammunition from the warring parties of WWII. Dumping was considered the cheapest, quickest, and safest solution to dispose of unused ammunition. However, thin barrels or containers often leak after 50 years, allowing explosives to escape into the marine environment. As the effects of weapons chemicals on ecosystems are well-documented, it is becoming increasingly important to detect, recover and dispose of old ammunition. Physical techniques such as magnetometry and sonar are used to detect ammunition in the sea, but they do not provide chemical information. Detecting leaking organic contaminants like TNT or other explosives in water or soil requires high-end laboratory equipment like HPLC or GC-MS, making remote water testing virtually impossible. As an alternative, a miniaturized method for the selective and sensitive indication of TNT using fluorescence light-up sensing was developed. The visual identification of TNT with a nucleophile that forms a strongly absorbing charge transfer complex (CTC) is a well-known method. This CTC is formed by the attraction of an electron from the donor molecule by the electron-deficient aromatic ring. In this work, a TNT-based CTC was selectively formed by the addition of tetraoctylammonium acetate in N,N-diethylformamide and, as expected, showed strong absorption. Surprisingly, at room temperature, the CTC can be converted into a fluorescent product with an emission band centred at 577 nm. For the detection of TNT in water, a microfluidic chip made of polydimethylsiloxane (PDMS) is used for both the extraction and reaction steps. In addition to miniaturising the experimental steps, the optical system (fluorometer) has been integrated into an autonomous smartphone assembly capable of catalysing the photoreaction and analysing the fluorescence response. Taking advantage of the light-up response, TNT was still easily detectable down to 9.4 ng with the CMOS camera. Further evaluation of this analytical tool consisted of analyses of unfiltered and untreated surface water samples spiked directly with increasing concentrations of TNT to reflect different levels of contamination. LODs of 21 and 40 ng were found for samples from the Teltow Canal in Berlin (DEU) and the Baltic Sea near Greifswald (DEU). Such an analytical tool could be used to monitor water quality in the field, as the release of organic pollutants from munitions into surface and marine waters will become increasingly problematic and concentrations will continue to rise over the coming decades. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Explosives KW - Microfluidics KW - Smartphone KW - Sprengstoffe KW - Mikrofluidik KW - Sensor PY - 2025 AN - OPUS4-62767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, Yijuan A1 - Gawlitza, Kornelia A1 - Valderrey, Virginia A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors. KW - Fluorescence KW - BODIPY probe KW - Molecularly Imprinted Polymers KW - Sensor Materials KW - Dyes KW - Water analysis KW - Advanced materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629 DO - https://doi.org/10.1039/D3MA00476G SP - 1 EP - 11 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jamieson, O. D. A1 - Bell, Jérémy A1 - Hudson, A. A1 - Saczek, J. A1 - Perez-Padilla, Victor A1 - Kaiya, G. A1 - Novakovic, K. A1 - Davies, M. A1 - Foster, E. A1 - Gruber, J. A1 - Rurack, Knut A1 - Peeters, M. T1 - Design and Application of an Imprinted Polymer Sensor for the Dual Detection of Antibiotic Contaminants in Aqueous Samples and Food Matrices N2 - An innovative polymer-based dual detection microfluidic platform has been developed for the accurate and reliable sensing of trace amounts of antibiotic tetracycline in environmental and food samples. This was achieved through the production of a bespoke polymeric material formed via an imprinting technique using a fluorescent dye. Thus, this enables dual detection of tetracycline, both thermally, via analyzing the heat-transfer resistance at the solid−liquid interface, and optically, through the inner filter effect. The combination of these two methods achieved a nanomolar limit of detection for tetracycline while also providing rapid, selective, and cost-effective sensing. Additionally, this method successfully detected tetracycline levels of 0.56 μM in blank egg samples which was significantly lower than the maximum residual level of 400 μg L−1 (0.9 μM). Our work shows that this approach can be used for the efficient detection of trace antibiotics in complex environmental and food samples, offering enhanced reliability through the integration of two complementary analysis techniques. This sensor has the potential to identify sources of antimicrobial resistance, which is crucial for targeted efforts to combat this pressing global health challenge. KW - Molecularly imprinted polymers KW - Antibiotics monitoring KW - Orthogonal detection KW - Sensors PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626497 DO - https://doi.org/10.1021/acsapm.4c03218 SN - 2637-6105 VL - 7 IS - 4 SP - 1 EP - 9 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-62649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, Yijuan A1 - Pérez-Padilla, Víctor A1 - Valderrey, Virginia A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Ratiometric detection of perfluoroalkyl carboxylic acids using dual fluorescent nanoparticles and a miniaturised microfluidic platform N2 - The widespread contamination of soil and water with perfluoroalkyl substances (PFAS) has caused considerable societal and scientific concern. Legislative measures and an increased need for remediation require effective on-site analytical methods for PFAS management. Here we report on the development of a green-fluorescent guanidine-BODIPY indicator monomer incorporated into a molecularly imprinted polymer (MIP) for the selective detection of perfluorooctanoic acid (PFOA). Complexation of PFOA by the indicator, which is mediated by concerted protonation-induced ion pairing-assisted hydrogen bonding, significantly enhances fluorescence in polar organic solvents. The MIP forms as a thin layer on silica nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, which provides an orange emission signal as internal reference, resulting in low measurement uncertainties. Using a liquid-liquid extraction protocol, this assay enables the direct detection of PFOA in environmental water samples and achieves a detection limit of 0.11 µM. Integration into an opto-microfluidic system enables a compact and user-friendly system for detecting PFOA in less than 15 minutes. KW - PFAS KW - Molecular imprinting KW - Microfluidics KW - Fluorescence KW - Onsite assay PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650270 DO - https://doi.org/10.1038/s41467-025-66872-9 SN - 2041-1723 VL - 16 IS - 1 SP - 1 EP - 16 PB - Springer Science and Business Media LLC AN - OPUS4-65027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-García, María Amparo A1 - Rurack, Knut A1 - Bell, Jérémy T1 - Rapid fabrication of optical elements for sensing applications using a standard SLA printer N2 - The demand for compact, high-performance optical components has driven the development of increasingly sophisticated and miniaturized optical elements, often requiring complex and costly fabrication methods. In this study, we propose a cost-effective and accessible methodology for the fabrication of lenses and free-form optics using a commercially available stereolithography (SLA) 3D printer. A systematic characterisation of six transparent photopolymer resins was conducted in terms of their spectroscopic, optical, and morphological properties, i.e., surface and dimensional properties. The evaluation encompassed parameters such as transmittance, autofluorescence, refractive index, and surface roughness. A straightforward yet resilient printing and post-treatment protocol was formulated, facilitating the fabrication of optical components with over 80% transmittance, minimal intrinsic fluorescence, and surface quality that is compatible with exacting optical applications. The fabricated components demonstrated excellent dimensional fidelity to digital designs and high reproducibility. To demonstrate the versatility of this approach, aspherical, miniaturized, and freeform lenses were designed and integrated into three fluorogenic sensing systems, including oil (strip-based) and chlorine (microfluidic-based) detection platforms, as well as a smartphone-based SARS-CoV-2 biosensor. The integration of customized 3D-printed optics has been demonstrated to enhance signal collection and readout performance, thereby highlighting the potential of this approach to democratize the rapid prototyping and deployment of miniaturized optical systems. This work represents a significant advancement in the field of additive manufacturing, particularly in relation to the development of functional photonic devices. Furthermore, it opens new prospects for sensor applications in biosensing, microfluidics, imaging, and integrated optics. KW - 3D-printing KW - Free-form KW - Prototyping KW - Optical resin KW - Surface finishing KW - Fluorescence KW - Sensor PY - 2026 DO - https://doi.org/10.37188/lam.2026.024 VL - 7 SP - 1 EP - 19 PB - Light Publishing Group CY - Changchun AN - OPUS4-65555 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -