TY - CHAP A1 - Gawlitza, Kornelia A1 - Wan, Wei A1 - Wagner, Sabine A1 - Rurack, Knut ED - Tiwari, Ashutosh ED - Uzun, Lokman T1 - Fluorescent Molecularly Imprinted Polymers N2 - An ideal sensor system is a combination of a selective receptor, an effective transducer, and a sensitive detector. To utilize molecularly imprinted polymers (MIPs) as responsive recognition phases in sensors, the employment of fluorescent molecules or nanoparticles (NPs) that show prominent changes in their spectroscopic properties after binding of the target molecule in the MIP’s cavity is particularly attractive. Such fluorescent MIPs (fMIPs) act through target-induced quenching, enhancement, or spectral shifts of the fluorescence. This contribution introduces different strategies of incorporation of fluorescent dyes, probes, and NPs into fMIPs. In addition, various sensing mechanisms are reviewed, and depending on the application of the sensor, the different deployable formats, their advantages, drawbacks, and impact will be presented and discussed. KW - Dyes KW - Fluorescence KW - Molecular imprinted polymers KW - Quantum dots KW - Sensors PY - 2017 SN - 978-1-119-33629-7 SP - 89 EP - 128 PB - Scrivener Publishing, WILEY CY - Beverly, MA ET - 1 AN - OPUS4-38798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - Fluorescent Sensor Particles based on Molecularly Imprinted Polymers for the Detection of Antibiotics and Herbicides in Water N2 - As the interest in rapid and sensitive detection methods is growing, molecularly imprinted polymers (MIPs) are increasingly considered as an alternative to bio-macromolecular recognition units such as antibodies or enzymes due to their facilely tailorable selectivity towards certain analytes or a group of structurally related species. The low production costs, stability, robustness and format adaptability of MIPs combined with the possibility to imprint and thus their ability to recognize a wide variety of target analytes can be potentially useful in chemical sensor applications.[1] With regard to optical sensing technologies, however, MIPs have only been used in considerably few applications, especially in fluorescence sensors. This limitation is basically due to the fact that the incorporation of a fluorescently responding moiety into a polymer matrix is a challenge. One way to overcome this limitation is to use tailor-made fluorescent indicator monomers and thin MIP-shells on silica particles.[2] Here, we present silica sensor particles with a thin MIP layer which was grown onto the silica surface via reversible addition-fragmentation chain transfer (RAFT) polymerization. The homogeneous MIP shell contains fluorescent phenoxazine-urea monomers as signal generation elements. The carboxylate salts of the antibiotic ampicillin (AMPI) and the herbicide 2,4 dichlorophenoxyacetic acid (2,4-D) were used as templates in those studies. In this case, hydrogen bonds are formed between the urea group of the fluorescent monomer and the carboxylate group of the template. To investigate the binding behavior of the MIPs and the control non-imprinted polymer (NIP) particles in terms of discrimination and imprinting factor, titration experiments with AMPI and 2,4-D salts were performed directly in organic solution. In order to study the detection possibilities in aqueous solution, a simple phase-transfer assay using fluorescence spectroscopy was investigated for both analytes. T2 - 11th Workshop on Biosensors & Bioanalytical Microtechniques in Enviromental, Food & Clinical Analysis CY - Regensburg, Germany DA - 2015-09-26 PY - 2015 AN - OPUS4-34658 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - Combining fluorescent molecularly imprinted polymer sensor particles with microfluidic devices for the detection of herbicides N2 - 2,4-Dichlorophenoxyacetic acid (2,4-D) is one important and well-known herbicide that is widely used in agriculture because of its advantages to regulate plant growth. However, the use of large quantities of the treated plants as animal feed leads to residues in meat, milk and eggs. Furthermore, the herbicide can drain away and contaminate ground and drinking water. The ingestion of 2,4-D-contaminated food and water causes damage to the inner organs of humans and animals, e.g., the kidneys and the liver. Analytical assays based on molecularly imprinted polymers (MIPs) have emerged as a valuable tool in the field of environmental analysis due to the low production costs, stability, format adaptability and the possibility to imprint and thus their ability to recognize a wide variety of target analytes. With regard to optical sensing technologies, however, MIPs have only been used in considerably few applications, especially in fluorescence sensors. This limitation is basically due to the fact that the incorporation of a fluorescently responding moiety into a polymer matrix is challenging. One way to overcome this limitation is to use tailor-made fluorescent indicator monomers for direct transfer of the binding event into an optical signal and coat the MIP via reversible addition-fragmentation chain transfer (RAFT) polymerization as a thin layer onto the surface of silica nanoparticles as primary sensing element. Here, we present the response behavior of the fluorescent MIP sensor particles in terms of sensitivity for 2,4-D detection (the so-called imprinting factor), discrimination ability against structurally similar compounds and performance in a phase-transfer assay (PTA) on chip, i.e., the implementation of the assay into a microfluidic chip environment, offering a novel simple and rapid way for the detection of herbicides. T2 - 10. Interdisziplinäres Doktorandenseminar CY - Berlin, Germany DA - 28.02.2016 KW - Molecularly imprinted polymer KW - Fluorescence KW - Microfluidic devices PY - 2016 AN - OPUS4-38165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - Detection of antibiotics by combining fiber-optic array with microparticles coated with fluorescent molecularly imprinted polymers N2 - The widespread use of antibiotics in livestock farming leads to trace residues in food products and wastewater, potentially entailing antimicrobial resistance in food-borne pathogens. The determination of antibiotics in aqueous environments and foodstuff is thus of major concern. We have been developing optical sensors based on molecularly imprinted polymers (MIPs) due to the low production costs, stability, format adaptability and the possibility to imprint and thus their ability to recognize a wide variety of target analytes. As a fluorescently responding moiety in the polymer matrix a tailor-made fluorescent indicator cross-linker for direct transfer of the binding event into an optical signal was used. If such a cross-linker is integrated into a thin MIP-shell on microspheres such core/shell particles can be readily used in advanced multiplexing sensory fiber-optic microarrays. Here, we propose such a fiber-optic microarray based on fluorescent MIP microspheres for antibiotics. The binding behavior and the selectivity of a microarray using these silica core/MIP shell beads were examined and compared with a non-imprinted polymer (NIP) control, employing the target molecules and other structurally closely related antibiotics. T2 - APME2017 CY - Ghent, Belgium DA - 21.05.2017 KW - Molecularly imprinted polymers KW - Multiplexing sensory fiber-optic microarrays KW - Antibiotics PY - 2017 AN - OPUS4-40583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wagner, Sabine A1 - Bell, Jérémy A1 - Biyikal, Mustafa A1 - Gawlitza, Kornelia A1 - Rurack, Knut T1 - Integrating fluorescent molecularly imprinted polymer (MIP) sensor particles with a modular microfluidic platform for nanomolar smallmolecule detection directly in aqueous samples N2 - Fluorescent sensory MIP (molecularly imprinted polymer) particles were combined with a droplet-based 3D microfluidic system for the selective determination of a prototype small-molecule analyte of environmental concern, 2,4-dichlorophenoxyacetic acid or 2,4-D, at nanomolar concentration directly in water samples. A tailor-made fluorescent indicator cross-linker was thus designed that translates the binding event directly into an enhanced fluorescence signal. The phenoxazinone-type cross-linker was co-polymerized into a thin MIP layer grafted from the surface of silica microparticles following a RAFT (reversible addition-fragmentation chain transfer) polymerization protocol. While the indicator cross-linker outperformed its corresponding monomer twin, establishment of a phase-transfer protocol was essential to guarantee that the hydrogen bond-mediated signalling mechanism between the urea binding site on the indicator cross-linker and the carboxylate group of the analyte was still operative upon real sample analysis. 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 phasetransfer assay, extracting the analyte from aqueous sample droplets into the organic phase that contains the sensor particles. Real-time fluorescence determination of 2,4-D down to 20 nM was realized with the system and applied for the analysis of various surface water samples collected from different parts of the world. KW - Molecular imprinting KW - Microfluidics KW - Fluorescence KW - Core-shell particles KW - Droplets PY - 2018 DO - https://doi.org/10.1016/j.bios.2017.07.053 SN - 0956-5663 VL - 99 IS - 1 SP - 244 EP - 250 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-42258 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - Investigation of the Recognition Behavior of Molecularly Imprinted Polymers against Amino Acids by Using different Counter-ions T2 - Anakon 2015 CY - Graz, Österreich DA - 2015-03-23 PY - 2015 AN - OPUS4-33745 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - Fluorescent Nanosensor based on Molecularly Imprinted Polymer for the Detection of Contaminants in Water N2 - As the interest in rapid and sensitive detection methods is growing, molecularly imprinted polymers (MIPs) are increasingly considered as an alternative to bio-macromolecular recognition units such as antibodies or enzymes due to their facilely tailorable selectivity towards certain analytes or a group of structurally related species. The low production costs, stability, robustness and format adaptability of MIPs combined with the possibility to imprint and thus their ability to recognize a wide variety of target analytes can be potentially useful in chemical sensor applications.[1] With regard to optical sensing technologies, however, MIPs have only been used in considerably few applications, especially in fluorescence sensors. This limitation is basically due to the fact that the incorporation of a fluorescently responding moiety into a polymer matrix is a challenge. One way to overcome this limitation is to use tailor-made fluorescent indicator monomers and thin MIP-shells on silica particles.[2] Here, we present silica sensor particles with a thin MIP layer which was grown onto the silica surface via reversible addition-fragmentation chain transfer (RAFT) polymerization. The homogeneous MIP shell contains fluorescent phenoxazine-urea monomers as signal generation elements. The carboxylate salts of the antibiotic ampicillin (AMPI) and the herbicide 2,4 dichlorophenoxyacetic acid (2,4-D) were used as templates in those studies. In this case, hydrogen bonds are formed between the urea group of the fluorescent monomer and the carboxylate group of the template. To investigate the binding behavior of the MIPs and the control non-imprinted polymer (NIP) particles in terms of discrimination and imprinting factor, titration experiments with AMPI and 2,4-D salts were performed directly in organic solution. In order to study the detection possibilities in aqueous solution, a simple phase-transfer assay using fluorescence spectroscopy was investigated for both analytes. T2 - Adlershofer Forschungsforum 2016 CY - Berlin, Germany DA - 2015-11-11 PY - 2015 AN - OPUS4-35238 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wan, Wei A1 - Wagner, Sabine A1 - Rurack, Knut T1 - Fluorescent monomers: "bricks" that make a molecularly imprinted polymer "bright" N2 - Molecularly imprinted polymers (MIPs) are potent and established recognition phases in separation and enrichment applications. Because of their robustness, versatility and format adaptability, they also constitute very promising sensing phases, especially when the active sensing element is directly integrated into the MIP. Fluorescent MIPs incorporating fluorescent monomers are perhaps the best developed and most successful approach here. This article reviews the state of the art in this field, discussing the pros and cons of the use of fluorescent dye and probe derivatives as such monomers, the different molecular interaction forces for template complexation, signalling modes and a variety of related approaches that have been realized over the years, including Förster resonance energy transfer processes, covalent imprinting, postmodification attachment of fluorescent units and conjugated polymers as MIPs; other measurement schemes and sensing chemistries that use MIPs and fluorescence interrogation to solve analytical problems (fluorescent competitive assays, fluorescent analytes, etc.) are not covered here. Throughout the article, photophysical processes are discussed to facilitate understanding of the effects that can occur when one is planning for a fluorescence response to happen in a constrained polymer matrix. The article concludes with a concise assessment of the suitability of the different formats for sensor realization. KW - Chemical sensors KW - Fluorescence KW - Molecularly imprinted polymers KW - Dyes KW - Sol-gel PY - 2016 DO - https://doi.org/10.1007/s00216-015-9174-4 SN - 1618-2642 SN - 1618-2650 VL - 408 IS - 7 SP - 1753 EP - 1771 PB - Springer CY - Berlin AN - OPUS4-35830 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - Integrating fluorescent molecularly imprinted polymer (MIP) sensor particles with a modular microfluidic platform for the detection of the herbicide 2,4-D N2 - 2,4-Dichlorophenoxyacetic acid (2,4-D) is an important and well-known herbicide that is widely used in agriculture because of its advantages to regulate plant growth.1 However, the use of large quantities of the treated plants as animal feed leads to residues in meat, milk and eggs. Furthermore, the herbicide can drain off and contaminate ground and drinking water. The ingestion of 2,4-D-contaminated food and water can cause damage to the inner organs of humans and animals, e.g., the kidneys and the liver. Analytical assays based on molecularly imprinted polymers (MIPs) have emerged as a valuable tool in the field of environmental analysis due to the low production costs, high stability, format adaptability and the possibility to imprint—and thus their ability to recognize—a wide variety of target analytes. Regarding optical sensing technologies, however, MIPs have only been used in considerably few applications, especially in fluorescence sensors. This limitation is basically because the incorporation of a fluorescently responding moiety into a polymer matrix is challenging. One way to overcome this limitation is to use tailor-made fluorescent indicator monomers or cross-linkers for direct transfer of the binding event into an optical signal and to coat the MIP via reversible addition-fragmentation chain transfer (RAFT) polymerization as a thin layer onto the surface of silica nanoparticles as primary sensing element. Here, we present the response behaviour of fluorescent MIP sensor particles in terms of sensitivity for 2,4-D detection (the so-called imprinting factor), discrimination ability against structurally similar compounds (the discrimination factor) and performance in a phase-transfer assay (PTA) on chip, i.e., the implementation of the assay into a microfluidic chip environment, offering a novel simple and rapid way for the detection of herbicides in water. T2 - GSSMIP2017 CY - Porto, Portugal DA - 08.06.2017 KW - 2,4-Dichlorophenoxyacetic acid KW - Molecularly imprinted polymers KW - Microfluidic device PY - 2017 AN - OPUS4-40582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, Sabine T1 - On the Influence of Counter-ions on the Recognition Behavior of Molecularly Imprinted Polymers against Amino Acids T2 - Adlershofer Forschungsforum CY - Berlin Germany DA - 2014-11-11 PY - 2014 AN - OPUS4-33748 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -