| 1. |
- Ambaw, Y. A., et al.
(författare)
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Tailored polymer-based selective extraction of lipid mediators from biological samples
- 2021
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Ingår i: Metabolites. - : MDPI. - 2218-1989 .- 2218-1989. ; 11:8
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Tidskriftsartikel (refereegranskat)abstract
- Lipid mediators, small molecules involved in regulating inflammation and its resolution, are a class of lipids of wide interest as their levels in blood and tissues may be used to monitor health and disease states or the effect of new treatments. These molecules are present at low levels in biological samples, and an enrichment step is often needed for their detection. We describe a rapid and selective method that uses new low-cost molecularly imprinted (MIP) and non-imprinted (NIP) polymeric sorbents for the extraction of lipid mediators from plasma and tissue samples. The extraction process was carried out in solid-phase extraction (SPE) cartridges, manually packed with the sorbents. After extraction, lipid mediators were quantified by liquid chromatography–tandem mass spectrometry (LC–MSMS). Various parameters affecting the extraction efficiency were evaluated to achieve optimal recovery and to reduce non-specific interactions. Preliminary tests showed that MIPs, designed using the prostaglandin biosynthetic precursor arachidonic acid, could effectively enrich prostaglandins and structurally related molecules. However, for other lipid mediators, MIP and NIP displayed comparable recoveries. Under optimized conditions, the recoveries of synthetic standards ranged from 62% to 100%. This new extraction method was applied to the determination of the lipid mediators concentration in human plasma and mouse tissues and compared to other methods based on commercially available cartridges. In general, the methods showed comparable performances. In terms of structural specificity, our newly synthesized materials accomplished better retention of prostaglandins (PGs), hydroxydocosahexaenoic acid (HDoHE), HEPE, hydroxyeicosatetraenoic acids (HETE), hydroxyeicosatrienoic acid (HETrE), and PUFA compounds, while the commercially available Strata-X showed a higher recovery for dihydroxyeicosatetraenoic acid (diHETrEs). In summary, our results suggest that this new material can be successfully implemented for the extraction of lipid mediators from biological samples. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 2. |
- Azenha, Manuel, et al.
(författare)
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Vapor-phase testing of the memory-effects in benzene- and toluene-imprinted polymers conditioned at elevated temperature
- 2013
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 802, s. 40-45
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Tidskriftsartikel (refereegranskat)abstract
- The preparation of polymers imprinted with common aromatic solvents such as benzene and toluene is an under-exploited subject of research. The present study was aimed at the understanding of whether true solvent memory effects can be achieved by molecular imprinting, as well as if they are stable at elevated temperature. A set of copolymers, comprising low and high cross-linking levels, was prepared from four different combinations of functional monomer and cross-linker, namely methacrylic acid (MAA)/ethylene glycol dimethacrylate (EGDMA), methyl methacrylate (MMA)/EGDMA, MAA/divinyl benzene (DVB) and MMA/DVB. Each possible combination was prepared separately in benzene, toluene and acetonitrile. The obtained materials were applied as coatings onto nickel-titanium (Ni-Ti) alloy wires which were incorporated into solid-phase microextraction devices and finally tested for their ability to competitively adsorb vapors from the headspace of an aqueous solution containing a few volatile organic compounds. Porosity analysis showed that, regardless of the solvent used, only a high cross-linking level permitted the preparation of mesoporous copolymers (BJH radius typically in the range 13-15nm), a requirement for providing accessibility to the targeted nanoscale-imprinted cavities. A noticeable exception was, however, observed for the MMA/DVB copolymers which exhibited much diminished BJH radius. The porosity data correlated well with the extraction profiles found, which suggested the presence of benzene-imprinted sites in all the highly cross-linked copolymers prepared in benzene, except for the MMA/DVB copolymers. Concerning the effect of an elevated conditioning temperature on the memory-effects created by the imprinting process, the results were clearly indicative that the tested copolymers, including the more robust highly cross-linked ones, are not suitable for high temperature applications such as solid-phase microextraction coupled to gas chromatography.
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| 3. |
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| 4. |
- Bakkour, Rani, et al.
(författare)
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Molecularly Imprinted Polymers for Compound-Specific Isotope Analysis of Polar Organic Micropollutants in Aquatic Environments
- 2018
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 90:12, s. 7292-7301
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Tidskriftsartikel (refereegranskat)abstract
- Compound-specific isotope analysis (CSIA) of polar organic micropollutants in environmental waters requires a processing of large sample volumes to obtain the required analyte masses for analysis by gas chromatography/isotoperatio mass spectrometry (GC/IRMS). However, the accumulation of organic matter of unknown isotopic composition in standard enrichment procedures currently compromises the accurate determination of isotope ratios. We explored the use of molecularly imprinted polymers (MIPs) for selective analyte enrichment for C-13/C-12 and N-15/N-14 ratio measurements by GC/IRMS using 1H-benzotriazole, a typical corrosion inhibitor in dishwashing detergents, as example of a widely detected polar organic micropollutant. We developed procedures for the treatment of >10 L of water samples, in which custom-made MIPs enabled the selective cleanup of enriched analytes in organic solvents obtained through conventional solid-phase extractions. Hydrogen bonding interactions between the triazole moiety of 1H-benzotriazole, and the MIP were responsible for selective interactions through an assessment of interaction enthalpies and N-15 isotope effects. The procedure was applied successfully without causing isotope fractionation to river water samples, as well as in- and effluents of wastewater treatment plants containing mu g/L concentrations of 1H-benzotriazole and dissolved organic carbon (DOC) loads of up to 28 mg C/L. MIP-based treatments offer new perspectives for CSIA of organic micropollutants through the reduction of the DOC-to-micropollutant ratios.
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| 5. |
- Banan, Kamran, et al.
(författare)
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Nano-sized magnetic core-shell and bulk molecularly imprinted polymers for selective extraction of amiodarone from human plasma
- 2022
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Ingår i: Analytica Chimica Acta. - : Elsevier. - 0003-2670 .- 1873-4324. ; 1198
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Tidskriftsartikel (refereegranskat)abstract
- Bulk and magnetic core-shell Molecularly Imprinted Polymers (MMIPs) have been introduced and compared to extract and determine amiodarone from a complex matrix, i.e., plasma, due to the importance of Therapeutic Drug Monitoring (TDM). Polymer synthesis was confirmed by FTIR, AFM, TGA, DLS, VSM, TEM, and the adsorption studies such as capacity, isothermal models, selectivity, and regeneration were performed to evaluate and compare polymer efficiency in extraction and separation of amiodarone from sample solutions and human plasma. Both nano-sized and bulk polymers successfully extracted the target molecule at the low therapeutic ranges and the overdose concentrations (recoveries of 98.38%-102.70%). The maximum adsorption capacity of the MMIPs was 42.5 mu g/mg compared with 2.6 mu g/mg for bulk polymers. The imprinting factors of the polymers were 15.12 and 6.84 for MMIPs and bulk, respectively. MMIPs and bulk polymers presented 4.68 and 1.66 selectivity factors, respectively, towards amiodarone compared with lidocaine. LOD, LOQ and enrichment factor in human plasma were 0.09, 0.28 mu g mL(-1), and 10 respectively. Recoveries of therapeutic concentration from plasma were 91.38 and 97.33% for bulk and MMIPs, respectively. MMIPs as an adsorbent in amiodarone extraction from plasma offered reduced necessary sample amount, less adsorbent consumption, reduced pretreatment time, and reduced elution solvent waste while yielding higher extraction recovery and more specificity for the target compared with the bulk polymer. Bulk polymers have a more straightforward synthesis procedure due to fewer synthesis steps and fewer variables, and Molecularly Imprinted Polymer Solid-phase Extraction (MIP-SPE) has already been introduced commercially. MMIPs prevail on a small scale, and in the context of a simple extraction, separation, or concentration in large-scale bioanalysis, efforts towards optimization and development of MMIPs can unearth tremendous opportunities for green chemistry principles.
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| 6. |
- Bergdahl, Gizem Ertürk, et al.
(författare)
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Bisphosphonate Ligand Mediated Ultrasensitive Capacitive Protein Sensor : Complementary Match of Supramolecular and Dynamic Chemistry
- 2019
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Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry. - 1144-0546 .- 1369-9261. ; 43:2, s. 847-852
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Tidskriftsartikel (refereegranskat)abstract
- Modern healthcare demands rapid and accurate detection of proteins/enzymes at the ultratrace level. Herein we present a molecularly imprinted capacitive sensor for Trypsin, developed by microcontact imprinting. High affinity and selectivity was achieved by doping the prepolymerization mixture with a stoichiometric amount of methacrylamide-based bisphosphonate (BP) monomer. Taking advantage of the strong interaction of bisphosphonate with lysine/arginine residues on the surface of Trypsin, we have constructed a powerful polymeric sensor. The BP based sensor has the ability to recognize trypsin over other arginine-rich proteins, even in high ionic strength buffers with a sub-picomolar detection limit (pM). We believe that the combination of supramolecular chemistry, molecular imprinting and advanced instrumentation has a potential for future drug development and diagnostics that extends beyond biomolecular recognition.
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| 7. |
- Berghaus, Melanie, et al.
(författare)
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Productive encounter : molecularly imprinted nanoparticles prepared using magnetic templates
- 2014
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Ingår i: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 50:64, s. 8993-8996
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis of core-shell nanoparticles by surface initiated reversible addition fragmentation chain transfer polymerization in presence of a chiral template conjugated to magnetic nanoparticles is reported. The approach leads to imprinted nanoparticles featuring enantioselectivity and enhanced affinity compared to nanoparticles prepared using free template.
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| 8. |
- Bllaci, Loreta, et al.
(författare)
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Phosphotyrosine biased enrichment of tryptic peptides from cancer cells by combining pY-MIP and TiO2 affinity resins
- 2017
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 89:21, s. 11332-11340
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Tidskriftsartikel (refereegranskat)abstract
- Protein phosphorylation at distinct tyrosine residues (pY) is essential for fast, specific, and accurate signal transduction in cells. Enrichment of pY-containing peptides derived from phosphoproteins is commonly facilitated by use of immobilized anti-pY antibodies prior to phosphoproteomics analysis by mass spectrometry. We here report on an alternative approach for pY-peptide enrichment using inexpensive pY-imprinted polymer (pY-MIP). We assessed by mass spectrometry the performance of pY-MIP for enrichment and sequencing of phosphopeptides obtained by tryptic digestion of protein extracts from HeLa cells. The combination of pY-MIP- and TiO2-based phosphopeptide enrichment provided more than 90% selectivity for phosphopeptides. Mass spectrometry signal intensities were enhanced for most pY-phosphopeptides (approximately 70%) when using the pY-MIP-TiO2 combination as compared to TiO2 alone. pY constituted up to 8% of the pY-MIP-TiO2-enriched phosphopeptide fractions. The pY-MIP-TiO2 and the TiO2 protocols yielded comparable numbers of distinct phosphopeptides, 1693 and 1842, respectively, from microgram levels of peptide samples. Detailed analysis of physicochemical properties of pY-MIP-TiO2-enriched phosphopeptides demonstrated that this protocol retrieved phosphopeptides that tend to be smaller (<24 residues), less acidic, and almost exclusively monophosphorylated, as compared to TiO2 alone. These unique properties render the pY-MIP-based phosphopeptide enrichment technique an attractive alternative for applications in phosphoproteomics research.
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| 9. |
- Chen, Jing, et al.
(författare)
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Low-bias phosphopeptide enrichment from scarce samples using plastic antibodies
- 2015
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Phosphospecific enrichment techniques and mass spectrometry (MS) are essential tools for comprehending the cellular phosphoproteome. Here, we report a fast and simple approach for low sequence-bias phosphoserine (pS) peptide capture and enrichment that is compatible with low biological or clinical sample input. The approach exploits molecularly imprinted polymers (MIPs, "plastic antibodies") featuring tight neutral binding sites for pS or pY that are capable of cross-reacting with phosphopeptides of protein proteolytic digests. The versatility of the resulting method was demonstrated with small samples of whole-cell lysate from human embryonic kidney (HEK) 293T cells, human neuroblastoma SH-SY5Y cells, mouse brain or human cerebrospinal fluid (CSF). Following pre-fractionation of trypsinized proteins by strong cation exchange (SCX) chromatography, pS-MIP enrichment led to the identification of 924 phosphopeptides in the HEK 293T whole-cell lysate, exceeding the number identified by TiO2-based enrichment (230). Moreover, the phosphopeptides were extracted with low sequence bias and showed no evidence for the characteristic preference of TiO2 for acidic amino acids (aspartic and glutamic acid). Applying the method to human CSF led to the discovery of 47 phosphopeptides belonging to 24 proteins and revealed three previously unknown phosphorylation sites.
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| 10. |
- Chen, Jing, et al.
(författare)
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Validation of Molecularly Imprinted Polymers for side chain selective phosphopeptide enrichment
- 2016
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Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1471, s. 45-50
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Tidskriftsartikel (refereegranskat)abstract
- Selective enrichment techniques are essential for mapping of protein posttranslational modifications (PTMs). Phosphorylation is one of the PTMs which continues to be associated with significant analytical challenges. Particularly problematic are tyrosine-phosphorylated peptides (pY-peptides) resulting from tryptic digestion which commonly escape current chemo- or immuno- affinity enrichments and hence remain undetected. We here report on significant improvements in this regard using pY selective molecularly imprinted polymers (pY-MIPs). The pY-MIP was compared with titanium dioxide (TiO2) affinity based enrichment and immunoprecipitation (IP) with respect to selective enrichment from a mixture of 13 standard peptides at different sample loads. At a low sample load (1 pmol of each peptide), IP resulted in enrichment of only a triply phosphorylated peptide whereas TiO2 enriched phosphopeptides irrespective of the amino acid side chain. However, with increased sample complexity, TiO2 failed to enrich the doubly phosphorylated peptides. This contrasted with the pY-MIP showing enrichment of all four tyrosine phosphorylated peptides at 1 pmol sample load of each peptide with a few other peptides binding unselectively. At an increased sample complexity consisting of the standard peptides spiked into mouse brain digest, the MIP showed clear enrichment of all four pYpeptides.
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