TY - JOUR A1 - Bell, Jérémy A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Playing with Droplets N2 - Microfluidic devices are powerful analytical tools with appealing features such as miniaturized size, low reagent and sample consumption, rapid response and short measurement times. As society wants to be ever better, earlier and more comprehensively informed about critical factors in life, work, and the environment, the demand for powerful measurement devices for use outside of the laboratory constantly increases. KW - Microfluidics KW - Sensory particles PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459131 UR - https://www.laboratory-journal.com/ VL - 4 SP - 2 EP - 4 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim, Deutschland AN - OPUS4-45913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Johann, Sergej A1 - Mansurova, Maria A1 - Kohlhoff, Harald A1 - Gkertsos, Aris A1 - Neumann, Patrick P. A1 - Bell, Jérémy A1 - Bartholmai, Matthias T1 - Wireless Mobile Sensor Device for in-situ Measurements with Multiple Fluorescent Sensors N2 - This paper describes a wireless mobile prototype able to perform optical measurements by means of a miniatur-ized spectrometer for low light analysis, e.g. fluorescent sensors. Evaluations, calculations, calibration management and result display are performed by a computer or a standard tablet. The device was designed primarily to detect traces of oil in drinking or ground water and for the analyses of crude oils. However, it can also address a wide range of fluorescent sensors. The fast and user-friendly inspection of water quality or oil properties, as well as the adaptability and mobility, make the device attractive for a variety of users. Further application areas could be easily imple-mented by adapting the optics and the software (database, data processing and calibration plots, etc.) T2 - IEEE Sensors 2018 CY - New Delhi, India DA - 28.10.2018 KW - Wireless mobile sensor device KW - Fluorescent sensor KW - Embedded system KW - Water quality KW - Oil PY - 2018 SN - 978-1-5386-4707-3 SP - 1067 EP - 1070 PB - IEEE CY - New Delhi, India AN - OPUS4-46556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ashokkumar, Pichandi A1 - Bell, Jérémy A1 - Buurman, Merwe A1 - Rurack, Knut T1 - Analytical platform for sugar sensing in commercial beverages using a fluorescent BODIPY "light-up" probe N2 - Because of the globally increasing prevalence of diabetes, the need for accurate, efficient and at best miniaturized automated analytical systems for sugar detection in medical diagnostics and the food industry is still urgent. The development of molecular probes for sugars based on boronic acid receptors offers an excellent alternative to the kinetically slow enzyme-based sugar sensors. Moreover, by coupling such chelating units with dye scaffolds like BODIPYs (boron–dipyrromethenes), highly fluorescent sugar sensing schemes can be realized. In this work, a boronic acid-functionalized BODIPY probe was developed, which binds selectively to fructose’s adjacent diols to form cyclic boronate esters. Placement of an amino group in direct neighborhood of the boronic acid moiety allowed us to obtain a broad working range at neutral pH, which distinguishes the probe from the majority of systems working only at pH > 8, while still meeting the desired sensitivity in the micro-molar range due to a pronounced analyte-induced fluorescence increase. To enhance the applicability of the test in the sense described above, integration with a microfluidic chip was achieved. Here, fructose was selectively detected by fluorescence with similar sensitivity in real time on chip, and an assay for the straightforward detection of sugar in (colored) sodas without sample clean-up was established. KW - BODIPY dyes KW - Boronic acid KW - Fluorescence KW - Microfluidics KW - Sugars PY - 2018 DO - https://doi.org/10.1016/j.snb.2017.09.201 SN - 0925-4005 VL - 256 SP - 609 EP - 615 PB - Elsevier CY - Amsterdam AN - OPUS4-43102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abdelshafi, Nahla A. A1 - Bell, Jérémy A1 - Rurack, Knut A1 - Schneider, Rudolf T1 - Microfluidic electrochemical immunosensor for the trace analysis of cocaine in water and body fluids N2 - Quick but accurate testing and on‐the‐spot monitoring of cocaine in oral fluids and urine continues to be an important toxicological issue. In terms of drug testing, a number of devices have been introduced into the market in recent decades, notably for workplace inspection or roadside testing. However, these systems do not always fulfill the requirements in terms of reliability, especially when low cut‐off levels are required. With respect to surface water, the presence of anthropogenic small organic molecules such as prescription and over‐the‐counter pharmaceuticals as well as illicit drugs like cannabinoids, heroin, or cocaine, has become a challenge for scientists to develop new analytical tools for screening and on‐site analysis because many of them serve as markers for anthropogenic input and consumer behavior. Here, a modular approach for the detection of cocaine is presented, integrating an electrochemical enzyme‐linked immunosorbent assay (ELISA) performed on antibody‐grafted magnetic beads in a hybrid microfluidic sensor utilizing flexible tubing, static chip and screen‐printed electrode (SPE) elements for incubation, recognition, and cyclic voltammetry measurements. A linear response of the sensor vs. the logarithm of cocaine concentration was obtained with a limit of detection of 0.15 ng/L. Within an overall assay time of 25 minutes, concentrations down to 1 ng/L could be reliably determined in water, oral fluids, and urine, the system possessing a dynamic working range up to 1 mg/L. KW - ELISA KW - Kokain KW - Lab-on-chip KW - Speichel KW - Urin KW - Drogenanalytik KW - Schnelltest KW - Biosensor PY - 2018 DO - https://doi.org/10.1002/dta.2515 SN - 1942-7611 VL - 11 IS - 3 SP - 492 EP - 500 PB - Wiley-VCH CY - Hoboken, New Jersey, USA AN - OPUS4-46888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abdelshafi, Nahla A. A1 - Bell, Jérémy A1 - Rurack, Knut A1 - Schneider, Rudolf T1 - Microfluidic electrochemical immunosensor for the trace analysis of cocaine in water and body fluids N2 - Quick but accurate testing and on‐the‐spot monitoring of cocaine in oral fluids and urine continues to be an important toxicological issue. In terms of drug testing, a number of devices have been introduced into the market in recent decades, notably for workplace inspection or roadside testing. However, these systems do not always fulfill the requirements in terms of reliability, especially when low cut‐off levels are required. With respect to surface water, the presence of anthropogenic small organic molecules such as prescription and over‐the‐counter pharmaceuticals as well as illicit drugs like cannabinoids, heroin, or cocaine, has become a challenge for scientists to develop new analytical tools for screening and on‐site analysis because many of them serve as markers for anthropogenic input and consumer behavior. Here, a modular approach for the detection of cocaine is presented, integrating an electrochemical enzyme‐linked immunosorbent assay (ELISA) performed on antibody‐grafted magnetic beads in a hybrid microfluidic sensor utilizing flexible tubing, static chip and screen‐printed electrode (SPE) elements for incubation, recognition, and cyclic voltammetry measurements. A linear response of the sensor vs. the logarithm of cocaine concentration was obtained with a limit of detection of 0.15 ng/L. Within an overall assay time of 25 minutes, concentrations down to 1 ng/L could be reliably determined in water, oral fluids, and urine, the system possessing a dynamic working range up to 1 mg/L. KW - Cocaine PY - 2018 DO - https://doi.org/10.1002/dta.2515 VL - 11 SP - 492 EP - 500 PB - Wiley CY - Weinheim AN - OPUS4-48319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gotor, Raúl A1 - Tiebe, Carlo A1 - Schlischka, Jörg A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Detection of adulterated diesel using fluorescent test strips and smartphone readout N2 - The fluorescence properties of three molecular rotors, related to 4-dimethylamino-4-nitrostilbene (4-DNS), are studied versus different diesel/kerosene blends. In nonviscous solvents, these compounds can populate a twisted intramolecular charge transfer state which deactivates nonradiatively, successfully suppressing fluorescence emission. Solution experiments with diesel/kerosene blends showed a good linear correlation between the fluorescence intensity of the probe molecules and the diesel fraction of the blend. The dyes have been immobilized on paper, retaining their fluorescence behavior, i.e., negligible emission in the presence of nonviscous organic solvents and increasing fluorescence when the environment is increasingly viscous. When the impregnated paper is devised as a test strip, the latter is compatible with a newly designed smartphone reader system, which allows in-the-field measurements. The method can safely detect the presence of kerosene in diesel at ≥7%, which competes favorably with current standard methods for the detection of diesel adulteration. KW - Fuel adulteration KW - Diesel KW - Fluorescence KW - Test strip KW - Molecular rotor KW - Smartphone PY - 2017 DO - https://doi.org/10.1021/acs.energyfuels.7b01538 SN - 0887-0624 VL - 31 IS - 11 SP - 11594 EP - 11600 PB - American Chemical Society CY - Washington, D.C. AN - OPUS4-43103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Wagner, Sabine A1 - Biyikal, Mustafa A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Microfluidic platform and fluorescent sensor particles for the detection of the herbicide 2,4-D in worldwide samples N2 - Fluorescent sensory MIP (molecularly imprinted polymer) particles were combined with a droplet-based 3D microfluidic system for the sensitive and selective determination of 2,4-dichlorophenoxyacetic acid (2,4-D) in water samples. 2,4-D being an important and widely used herbicide to regulate plant growth, its extensive use leads to food or ground water contamination. Analytical assays based on MIP have emerged as a valuable tool in the field of environmental analysis thanks to low production costs, stability, format adaptability and their ability to recognize a wide variety of targets, such as the critical neutral organic molecules present in water: herbicides, pesticides, antibiotics, etc. To accomplish this, a tailor-made fluorescent indicator cross-linker was designed that translates directly the binding event into an enhanced fluorescence signal. This phenoxazinone-type cross-linker was co-polymerized into a thin MIP layer grafted from the surface of silica microparticles. The latter was achieved by integration of the fluorescent core-shell MIP sensor particles into a modular microfluidic platform that allows for an in-line phase-transfer assay, extracting the analyte from aqueous sample droplets into organic phase droplets that contain the sensor particles. This tool offering a novel simple and rapid way for the detection of herbicides, real-time fluorescence determination of 2,4-D down to 20 nM was realized with the system and applied for the analysis of worlwide surface water samples. T2 - INTERNATIONAL CONFERENCE ON CHEMISTRY AND THE ENVIRONMENT - ICCE 2017 CY - Oslo, Norway DA - 18.06.2017 KW - Microfluidics KW - MIP KW - Fluorescence KW - Pesticide PY - 2017 AN - OPUS4-42454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Wan, Wei A1 - Rurack, Knut T1 - Phosphorylated amino acids detection and extraction combining fluorogenic MIP core-shell particles and microfluidics N2 - The identification and quantification of phosphorylated amino acids, peptides and proteins is one of the key challenges in contemporary bioanalytical research, noteworthy to diagnose and treat diseases at an early stage. Small sensing devices like microfluidic chips combined with “smart” detection chemistry and simple data assessment, processing and presentation are attractive in this regard. We developed novel synthetic probes, targeting phosphorylated amino acids, based on core-shell microparticles consisting of a silica core coated with a molecularly imprinted polymer shell (MIP). These “plastic antibodies” which are extremely robust, resist denaturing solvents and high temperatures, can be reproducibly produced at low cost, can potentially overcome many of the problems in the current detection strategies. The MIP layer, containing a fluorescent probe monomer, responds to phosphorylated amino acids such as phosphorylated tyrosine (pTyr) with a significant imprinting factor, i.e. selectivity, higher than 3.5, and a “lighting-up” of its fluorescence accompanied by the development of a strongly red-shifted emission band. The bead-based ratiometric detection scheme has also been successfully transferred to a microfluidic chip format to demonstrate its applicability to rapid assays. Such a device could yield an automated pTyr measurement system in the future. The setup was built by coupling a PDMS/Teflon/glass microfluidic chip with an optical setup for fluorescence measurements able to extract and monitor pTyr concentration from 0.5–200 μM. T2 - International Conference on "Instrumental Methods of Analysis: Modern Trends and Applications", IMA 2017 CY - Heraklion, Greece DA - 17.09.2017 KW - Microfluidics KW - MIP KW - Fluorescence KW - Amino acids PY - 2017 AN - OPUS4-42456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bell, Jérémy A1 - Climent Terol, Estela A1 - Hecht, Mandy A1 - Buurman, Merwe A1 - Rurack, Knut T1 - Combining a droplet-based microfluidic tubing system with gated indicator releasing nanoparticles for mercury trace detection N2 - A droplet-based microfluidic sensor was developed for the detection of Hg2+ traces in water. The approach uses gated mesoporous nanoparticles loaded with a fluorescent BODIPY dye. The squaraine-based gating mechanism is highly selective for Hg2+ and the indicator release mechanism ensures sensitive detection. The microfluidic system is modular and was assembled from simple PTFE/PFA tubes, while detection was realized with standard optomechanic, optic, and electronic parts. The sensor shows a stable response without memory effects and allows the detection of Hg2+ in water down to 20 ppt. KW - Microfluidic sensor KW - Gated delivery system KW - Fluorescence KW - Mercury KW - Hybrid nanoparticles PY - 2016 DO - https://doi.org/10.1021/acssensors.5b00303 SN - 2379-3694 VL - 1 IS - 4 SP - 334 EP - 338 PB - American Chemical Society CY - Washington, DC AN - OPUS4-35831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bell, Jérémy A1 - Climent Terol, Estela A1 - Buurman, Merwe A1 - Rurack, Knut T1 - Microfluidic tubing system for mercury detection utilizing fluorescent sensor nanoparticles N2 - Currently, the development of portable devices to detect traces of chemical species by real time monitoring is a highly topical research area in the chemical sciences. Indeed, the lowering of standards for pollutants in drinking water requires the development of new technologies and devices. In this context, gated sensory nanoparticle systems for selective and sensitive recognition of targets such as heavy metal ions, small molecules or oligonucleotides are excellent candidates[1,2]. Provided that such sensory delivery systems are highly porous nanoparticles loaded with indicator dyes and capped with bulky stoppers that can be uncapped only by the designated analyte, an integration with a microfluidic tubing system designed for droplet-assisted liquid-liquid extraction enable separation of released from still particle-confined dye by phase-transfer extraction and subsequent selective detection by fluorescence. The incorporation in a simple microfluidic tubing system is an innovative way towards the realization of a sensor for trace analysis of target molecules in real time. T2 - 9th International Conference on "Instrumental Methods of Analysis-Modern Trends and Applications" (IMA 2015) CY - Kalamata, Grece DA - 2015-09-20 PY - 2015 AN - OPUS4-34774 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -