Dopamine selective molecularly imprinted polymers via post-imprinting modification

Organic precursors for tailored synthesis of sulfur- and nitrogen-doped mesoporous carbons: a molecular design approach

Insights into tailoring heteroatom-doped mesoporous carbon are provided for enhanced electrocatalytic properties. This study focuses on the design and synthesis of sulfur-doped mesoporous carbon using a sulfur-containing monomer with a chemical structure similar to dopamine. The resulting material achieves remarkable catalytic activity for the oxygen reduction reaction.

Post-imprinting modification of molecularly imprinted polymer for proteins detection: A review

Inspired by protein post-translational modification (PTM), post-imprinting modification (PIM) has been proposed and developed to prepare novel molecularly imprinted polymers (MIPs), which are similar to functionalized biosynthetic proteins. The PIM involves site-directed modifications in the imprinted cavity of the MIP, such as introducing high-affinity binding sites and introducing fluorescent signal molecules. This modification makes the MIP further functionalized and improves the shortcomings of general molecular imprinting, such as single function, low selectivity, low sensitivity, and inability to fully restore the complex function of natural antibodies. This paper describes the characteristics of PIM strategies, reviews the latest research progress in the recognition and detection of protein biomarkers such as lysozyme, prostate-specific antigen, alpha-fetoprotein, human serum albumin, and peptides, and further discusses the importance, main challenges, and development prospects of PIM. The PIM technology has the potential to develop a new generation of biomimetic recognition materials beyond natural antibodies. It can be used in bioanalysis and other multitudinous fields for its unique features in molecule recognition.

Carbon supported olivine type phosphate framework: a promising electrocatalyst for sensitive detection of dopamine

In this study, a layered olivine-type LiMnPO4/functionalized-multiwall carbon nanotube (f-MWCNTs) composite is used as an electrochemically active material for the real-time detection of dopamine. A wet-chemical ultrasonication process is used to combine LiMnPO4 with f-MWCNTs at room temperature. The composite was subjected to various structural, morphological and electrochemical studies. The blending of olivine-type LiMnPO4 into the f-MWCNTs is revealed by TEM analysis. The electrochemical activities of the LiMnPO4/f-MWCNTs composite are systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) for the real-time detection of dopamine. Furthermore, the applicability of the as prepared LiMnPO4/f-MWCNTs composite was extended for the detection of human serum (E48) and rat brain-serum (C7) samples with satisfactory recoveries for the real-time applications. All these studies revealed that the layered olivine-type LiMnPO4/f-MWCNTs composite is a potential candidate in the field of electrochemical sensing.

Beyond natural antibodies – a new generation of synthetic antibodies created by post-imprinting modification of molecularly imprinted polymers

Post-imprinting modification (PIM) is an innovative strategy for generating MIPs analogous to biosynthesising proteins to introduce new functionalities in a site-directed manner.

Oriented, molecularly imprinted cavities with dual binding sites for highly sensitive and selective recognition of cortisol

Novel, molecularly imprinted polymers (MIPs) were developed for the highly sensitive and selective recognition of the stress marker cortisol. Oriented, homogeneous cavities with two binding sites for cortisol were fabricated by surface-initiated atom transfer radical polymerization, using a cortisol motif template molecule (TM1) which consists of a polymerizable moiety attached at the 3-carbonyl group of cortisol via an oxime linkage and an adamantane carboxylate moiety coupled with the 21-hydroxyl group. TM1 was orientationally immobilized on a β-cyclodextrin (β-CD)-grafted gold-coated sensor chip by inclusion of the adamantane moiety of TM1, followed by copolymerization of a hydrophilic comonomer, 2-methacryloyloxyethyl phosphorylcholine, with or without a cross-linker, N,N'-methylenebisacrylamide. Subsequent cleavage of the oxime linkage leaves the imprinted cavities that contain dual binding sites-namely, the aminooxy group and β-CD-capable of oxime formation and hydrophobic interaction, respectively. As an application, MIP-based picomolar level detection of cortisol was demonstrated by a competitive binding assay using a fluorescent competitor. Cross-linking of the MIP imparts rigidity to the binding cavities, and improves the selectivity and sensitivity significantly, reducing the limit of detection to 4.8 pM. In addition, detection of cortisol in saliva samples was demonstrated as a feasibility study.

Multiwalled carbon nanotube supported Schiff base copper complex inorganic nanocomposite for enhanced electrochemical detection of dopamine

A MWCNT/[Cu(sal-ala)bpy] inorganic nanocomposite for the electrochemical detection of dopamine (DA).

Fluorescence signaling molecularly imprinted polymers for antibiotics prepared via site-directed post-imprinting introduction of plural fluorescent reporters within the recognition cavity

An antibiotic-imprinted cavity with two different fluorescent dyes was prepared by molecular imprinting and subsequent post-imprinting modifications (PIMs), for the readout of a specific binding event as a fluorescence signal.

Boronate affinity materials for separation and molecular recognition: structure, properties and applications

Boronate affinity materials, as unique sorbents, have emerged as important media for the selective separation and molecular recognition of cis-diol-containing compounds. With the introduction of boronic acid functionality, boronate affinity materials exhibit several significant advantages, including broad-spectrum selectivity, reversible covalent binding, pH-controlled capture/release, fast association/desorption kinetics, and good compatibility with mass spectrometry. Because cis-diol-containing biomolecules, including nucleosides, saccharides, glycans, glycoproteins and so on, are the important targets in current research frontiers such as metabolomics, glycomics and proteomics, boronate affinity materials have gained rapid development and found increasing applications in the last decade. In this review, we critically survey recent advances in boronate affinity materials. We focus on fundamental considerations as well as important progress and new boronate affinity materials reported in the last decade. We particularly discuss on the effects of the structure of boronate ligands and supporting materials on the properties of boronate affinity materials, such as binding pH, affinity, selectivity, binding capacity, tolerance for interference and so on. A variety of promising applications, including affinity separation, proteomics, metabolomics, disease diagnostics and aptamer selection, are introduced with main emphasis on how boronate affinity materials can solve the issues in the applications and what merits boronate affinity materials can provide.

Preparation of molecularly imprinted polymers for the recognition of proteins via the generation of peptide-fragment binding sites by semi-covalent imprinting and enzymatic digestion

An acryloyl protein was copolymerized with a crosslinker, followed by enzymatic digestion, yielding protein imprinted polymers bearing peptide-fragment binding sites.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Molecularly imprinted protein recognition cavities bearing exchangeable binding sites for postimprinting site-directed introduction of reporter molecules for readout of binding events

Protein-imprinted cavities bearing exchangeable domains to be used for postimprinting fluorophore introduction to transform binding events into fluorescence changes were constructed in molecularly imprinted polymer (MIPs) matrixes prepared on glass substrates. Copolymerization was performed with acrylamide, N,N'-methylenebisaclylamide, and a newly designed functional group-exchangeable monomer, ({[2-(2-methacrylamido)ethyldithio]ethylcarbamoyl}methoxy)acetic acid (MDTA), in the presence of a model basic protein, lysozyme (Lyso); MDTA can interact with Lyso and assemble close to Lyso in the resulting polymer. After removal of Lyso, followed by a disulfide reduction to cleave the (ethylcarbamoylmethoxy)acetic acid moiety from the MDTA residues, the exposed thiol groups within the imprinted cavities were modified by aminoethylpyridyldisulfide to be transformed into aminoethyl groups that function as active sites for amine-reactive fluorophores. Fluorescein isothiocyanate (FITC) was then coupled with the aminoethyl groups, yielding site specifically FITC-modified signaling imprinted cavities for Lyso binding. Because the in-cavity fluorescent labeling was achieved via a disulfide linkage, it was easy to remove, exchange, and/or replace amine-reactive fluorophores. This facilitated the screening of fluorophores to select the highest readout for binding events, replace fluorophores when photobleaching occurred, and introduce other functions. The proposed molecular imprinting process, combined with postimprinting modifications, is expected to provide an affordable route to develop multifunctional MIPs for specific detection of protein binding events.

Water-Soluble Molecularly Imprinted Nanoparticles (MINPs) with Tailored, Functionalized, Modifiable Binding Pockets

Construction of receptors with binding sites of specific size, shape, and functional groups is important to both chemistry and biology. Covalent imprinting of a photocleavable template within surface-core doubly cross-linked micelles yielded carboxylic acid-containing hydrophobic pockets within the water-soluble molecularly imprinted nanoparticles. The functionalized binding pockets were characterized by their binding of amine- and acid-functionalized guests under different pH values. The nanoparticles, on average, contained one binding site per particle and displayed highly selective binding among structural analogues. The binding sites could be modified further by covalent chemistry to modulate their binding properties.

Conjugated-protein mimics with molecularly imprinted reconstructible and transformable regions that are assembled using space-filling prosthetic groups

Conjugated-protein mimics were obtained using a new molecular imprinting strategy combined with post-imprinting modifications. An antibiotic was employed as a model template molecule, and a polymerizable template molecule was designed, which was composed of the antibiotic and two different prosthetic groups attached through a disulfide bond and Schiff base formation. After co-polymerization with a cross-linker, the template molecule was removed together with the prosthetic groups, yielding the apo-type scaffold. Through conjugation of the two different prosthetic groups at pre-determined positions within the apo-type scaffold, the apo cavity was transformed into a functionalized holo cavity, which enables the on/off switching of the molecular recognition ability, signal transduction activity for binding events, and photoresponsive activity.

A novel ion-imprinted electrode prepared by in situ polymerization for detection of platinum

A novel ion imprinted electrode with high sensitivity and specific recognition to Pt(iv) was obtained byin situpolymerization.

Enhanced chemopreventive activity of hydroxytyrosol on HL60 and HL60R cells by chemical conversion into thio derivatives

Thio derivatives of hydroxytyrosol containing thiol, thioacetate and disulfide functionalities were synthesized from natural hydroxytyrosol (3,4-DHPEA) via 3,4-dihydroxyphenethyl halides. These compounds, containing the combination of catechol moiety and divalent sulfur functions, were tested for the pro-apoptotic and anti-proliferative activities on both parental HL60 and multi-drug resistant HL60R cells. It was found that all synthesized compounds were more effective than 3,4-DHPEA in inducing apoptosis on HL60R cells, and that the hydroxytyrosol disulfide was the most active pro-apoptotic and anti-proliferative compound on both HL60 and HL60R cells. Different from 3,4-DHPEA, all thio derivatives of hydroxytyrosol induced apoptosis by a mechanism not involving the release of H(2)O(2) in the culture medium. The data on HL60R cells suggest that these compounds could be able to reverse the resistance toward the most common drugs in cancer therapy.

Effective separation of dopamine from bananas on 2-(3,4-dimethoxyphenyl)ethylamine imprinted polymer

A 2-(3,4-dimethoxyphenyl)ethylamine imprinted polymer (MIP(pt) ) was prepared via the precipitation polymerization together with a nonimprinted polymer (NIP). The morphology of particles was investigated by scanning electron microscopy and the specific surface areas were estimated by methylene blue adsorption (60.5 ± 3.5 and 36.9 ± 1.2 m(2)/g for MIP(pt) and NIP, respectively). The binding experiments were performed to determine the binding capacity of MIP(pt)/NIP particles toward dopamine. Next, the effects of solvents on loading, washing, and eluting steps were examined on solid-phase extraction (SPE). Methanol-water 85:15 v/v (loading step), methanol (washing step), and 0.04 M aqueous ammonium acetate-methanol 30:70 v/v (eluting step) were selected as the most effective systems. Described SPE protocol was successfully applied for separation of dopamine on 2-(3,4-dimethoxyphenyl)ethylamine imprinted particles. Finally, the molecularly imprinted polymer was used for determination of dopamine in spiked banana extract. The total recovery of dopamine from MIP(pt) was equal to 88.5 ± 4.6%, but from NIP was only 12.8 ± 2.3%. The developed material and method were demonstrated to be applicable for the separation of dopamine from bananas. The commercial sorbent C18 was not suitable to such application.

SPR sensing of bisphenol A using molecularly imprinted nanoparticles immobilized on slab optical waveguide with consecutive parallel Au and Ag deposition bands coexistent with bisphenol A-immobilized Au nanoparticles

A slab-type optical waveguide (s_OWG)-based microfluidic SPR measurement system for bisphenol A was developed. This s_OWG possesses consecutive parallel gold and silver deposition bands in the line of plasmon flow, allowing two individual SPR signals to be independently obtained as a result of the difference in resonant reflection spectra of these metals. As a molecular recognition element, molecularly imprinted polymer nanoparticles (MIP-Np) were employed and immobilized on the surface of each of the gold and silver deposition bands. The resonant reflection spectra were measured on the MIP-Np-immobilized consecutive parallel gold and silver deposition bands coexistent with BPA-AuNp. The Ag-based SPR spectra showed a red shift (0.7 nm) when free BPA (0.1 mM) was passed over the BPA-AuNp/immobilized MIP-Np complexes formed on the s_OWG, unlike the case for the Au deposition band, while a large excess of BPA induced a blue shift due to the competitive desorption of BPA-AuNp from the immobilized MIP-Np on the s_OWG. By using the proposed detection system, binding events of other small molecules could be monitored in conjunction with the use of MIP-Np and labeled-AuNp.

Dopamine-imprinted polymers: template-monomer interactions, analysis of template removal and application to solid phase extraction

A dopamine-imprinted polymer (MIP) was prepared in aqueous methanol solution at 60(o)C by free-radical cross-linking polymerization of methacrylic acid in the presence of ethylene glycol dimethacrylate as the cross-linker and dopamine hydrochloride as the template molecule. Its ability to isolate dopamine was evaluated as the basis of a solid phase extraction procedure and compared with that of a non-imprinted polymer(NIP). The binding of dopamine was 84.1% and 29.1% for MIP and NIP, respectively. Various reported post-polymerization treatments to reduce template bleeding were examined. In our case the lowest bleeding was achieved after applying a combined procedure: continuous extraction in a Soxhlet apparatus (CE), followed by microwave-assisted extraction (ME) to a level of 0.061 microg/mL. A simplified model of the template-monomer complexes allowed rationalization of monomer choice based on the heats of complex formation at a PM3 level of theory.