TY - JOUR A1 - Wan, Wei A1 - Biyikal, Mustafa A1 - Wagner, R. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Fluorescent sensorymicroparticles that 'light-up' consisting of a silica core and a molecularly imprinted polymer (MIP) shell N2 - From darkness came light: Incorporation of urea-based fluorescent dyes in an anion-imprinted thin polymer shell coated onto silica microparticles leads to a unique and highly enantioselective fluorescent 'light-up' response to analytes (see scheme, MIP molecularly imprinted polymer). KW - Core–shell particles KW - Enantioselectivity KW - Fluorescence KW - Molecularly imprinted polymers KW - Sensors PY - 2013 U6 - https://doi.org/10.1002/anie.201300322 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 52 IS - 27 SP - 7023 EP - 7027 PB - Wiley-VCH CY - Weinheim AN - OPUS4-28740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, Q. A1 - Shinde, S. A1 - Grasso, G. A1 - Caroli, A. A1 - Abouhany, R. A1 - Lanzillotta, M. A1 - Pan, G. A1 - Wan, Wei A1 - Rurack, Knut A1 - Sellergren, B. T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker. KW - Molecularly imprinted polymers KW - Phospholipids KW - Fluorescence KW - Dye monomers PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-509485 SN - 2045-2322 VL - 10 IS - 1 SP - 9924 PB - Nature Research CY - London AN - OPUS4-50948 LA - eng 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 U6 - 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 - JOUR A1 - Wan, Wei A1 - Descalzo, Ana B. A1 - Shinde, S. A1 - Weißhoff, Hardy A1 - Orellana, G. A1 - Sellergren, B. A1 - Rurack, Knut T1 - Ratiometric fluorescence detection of phosphorylated amino acids through excited-state proton transfer by using molecularly imprinted polymer (MIP) recognition nanolayers N2 - A 2,3-diaminophenazine bis-urea fluorescent probe monomer (1) was developed. It responds to phenylphosphate and phosphorylated amino acids in a ratiometric fashion with enhanced fluorescence accompanied by the development of a redshifted emission band arising from an excited-state proton transfer (ESPT) process in the hydrogen-bonded probe/analyte complex. The two urea groups of 1 form a cleft-like binding pocket (Kb>10^10 L^2 mol^-2 for 1:2 complex). Imprinting of 1 in presence of ethyl ester- and fluorenylmethyloxycarbonyl (Fmoc)-protected phosphorylated tyrosine (Fmoc-pTyr-OEt) as the template, methacrylamide as co-monomer, and ethyleneglycol dimethacrylate as crosslinker gave few-nanometer-thick molecularly imprinted polymer (MIP) shells on silica core microparticles with excellent selectivity for the template in a buffered biphasic assay. The supramolecular recognition Features were established by spectroscopic and NMR studies. Rational screening of comonomers and cross-linkers allowed to single out the best performing MIP components, giving significant imprinting factors (IF>3.5) while retaining ESPT emission and the ratiometric response in the thin polymer shell. Combination of the bead-based detection scheme with the phase-transfer assay dramatically improved the IF to 15.9, allowing sensitive determination of the analyte directly in aqueous media. KW - Core-shell particles KW - Excited-state proton transfer KW - Fluorescence KW - Molecular imprinting KW - Phosphorylated amino acids PY - 2017 U6 - https://doi.org/10.1002/chem.201703041 SN - 1521-3765 SN - 0947-6539 VL - 23 IS - 63 SP - 15974 EP - 15983 PB - Wiley-VCH CY - Weinheim AN - OPUS4-43101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burnage, Samual A1 - Bell, Jérémy A1 - Wan, Wei A1 - Kislenko, Evgeniia A1 - Rurack, Knut T1 - Combining a hybrid chip and tube microfluidic system with fluorescent molecularly imprinted polymer (MIP) core–shell particles for the derivatisation, extraction, and detection of peptides with N-terminating phosphorylated tyrosine N2 - The reliable identification and quantitation of phosphorylated amino acids, peptides and proteins is one of the key challenges in contemporary bioanalytical research, an area of particular interest when attempting to diagnose and treat diseases at an early stage. We have developed a synthetic probe for targeting phosphorylated amino acids, based on core–shell submicron-sized particles consisting of a silica core, coated with a molecularly imprinted polymer (MIP) shell. The MIP layer contains a fluorescent probe crosslinker which binds selectively to phosphorylated tyrosine (pY) moieties with a significant imprinting factor (IF) and responds with a "light-up” fluorescence signal. The bead-based ratiometric detection scheme has been successfully transferred to a microfluidic chip format and its applicability to rapid assays has been exemplarily shown by discriminating a pY-terminating oligopeptide against its nonphosphorylated counterpart. Such miniaturised devices could lead to an automated pY or pY N-terminated peptide measurement system in the future. The setup combines a modular microfluidic system for amino acid derivatisation, extraction (by micropillar co-flow) and selective adsorption and detection with the fluorescent MIP core–shell particle probes. A miniaturised optical assembly for low-light fluorescence measurements was also developed, based on miniaturised opto-electronic parts and optical fibres. The emission from the MIP particles upon binding of pY or pY N-terminated peptides could be monitored in real-time. KW - Microfluidics KW - Molecularly imprinted polymers KW - Phosphorylated peptides KW - Fluorescence KW - Core-shell particles PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-569204 SN - 1473-0197 VL - 23 IS - 3 SP - 466 EP - 474 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-56920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -