Synthesis and characterization of molecularly imprinted polymers and their application in preconcentrators for gas phase sensors

Various of molecularly imprinted polymers were synthesized by different protocols. Piezoelectric quartz crystals coated with molecularly imprinted polymers were prepared to detect small organic vapors. Hydroquinone (HQ) and Phenol (P) have been used as non-covalent bound templates in order to generate shape-selectivity cavities in the polymer matrix. The recognition film was immobilized on the crystal surface via a pre-coated Poly(isobutylene) layer. The selective behaviors of the imprinted polymer films were studied by their steady-state response to various kinds of small organic vapors. The partition coefficients of polymers toward vapors were evaluated. The imprinted polymers exhibit high sensitivity and selectivity toward organic vapors as toluene and benzene, which are structurally related to the templates. Imprinted polymers prepared by different synthesis schemes were compared. The influence of template concentration and the polymer components was also investigated. The adsorption capacity of molecularly imprinted polymers was characterized and compared by breakthrough studies. From our results, molecularly imprinted polymer is promising for the development of selective piezoelectric sensor for organic vapor detection.;Different types of preconcentrator devices capable of pre-concentrating organic vapors at low ppm levels were fabricated and described. The target organic vapors were enriched onto a small bed of adsorbents and subsequently released by thermal desorption scheme. Solid adsorbents (Tenax GR, TA and molecularly imprinted polymers) were evaluated for possible use in a preconcentrator. Approximate preconcentration factor in the range of several thousand can be achieved by using the block polymer imprinted with hydroquinone

The Molecularly Imprinted Polymers. Influence of Monomers on The Properties of Polymers - A Review

The synthesis of MIPs for two types of templates (herbicides, and flavonoids) and their application in analytical chemistry are discussed. Particular attention has been paid the issue of bonding the template and selection of appropriate monomer in different types of compounds. This short review aims at presenting the molecular imprinting technology (MIT) which is considered as an attractive method to produce impressive receptors for application in analytical chemistry. The challenge of designing and synthesizing a molecularly imprinted polymer (MIP) can be a daunting prospect to the uninitiated practitioner, simply because of the number of experimental variables involved, e.g. the nature and levels of template, functional monomers, cross-linkers, solvents, initiators and even the method of initiation and the duration of polymerization. Indubitably, the most important place of the polymer is its quotheartquot or the cavity corresponding to the template and the waynbs

Spectroscopic and quartz crystal microbalance (QCM) characterisation of protein-based MIPs

We have studied acrylamide-based polymers of varying hydrophobicity (acrylamide, AA; N-hydroxymethylacrylamide, NHMA; N-isopropylacrylamide, NiPAm) for their capability of imprinting protein. Rebinding capacities (Q) from spectroscopic studies were highest for bovine haemoglobin (BHb) MIPs based on AA, Q = 4.8 ± 0.21 76 ± 0.5%). When applied to the QCM sensor as thin-film MIPs, NHMA MIPs were found to exhibit best discrimination between MIP and non-imprinted control polymer (NIP) in the order of NiPAm < AA < NHMA. The extent of template removal and rebinding, using both crystal impedance and frequency measurements, demonstrated that 10% (w/v):10% (v/v) sodium dodecyl sulphate:acetic acid (pH 2.8) was efficient at eluting template BHb (with 80 ± 10% removal). Selectivity studies of NHMA BHb-MIPs revealed higher adsorption and selective recognition properties to BHb (64.5 kDa) when compared to non-cognate BSA (66 kDa), myoglobin (Mb, 17.5 kDa), lysozyme (Lyz, 14.7 kDa) thaumatin (Thau, 22 kDa) and trypsin (Tryp, 22.3 kDa). The QCM gave frequency shifts of ∼1500 ± 50 Hz for template BHb rebinding in both AA and NHMA MIPs, whereas AA-based MIPs exhibited an interference signal of ∼2200 ± 50 Hz for non-cognate BSA in comparison to a ∼500 ± 50 Hz shift with NHMA MIPs. Our results show that NHMA-based hydrogel MIP are superior to AA and NIPAM

MOLECULARLY IMPRINTED POLYMERS FOR CONTROLLING DRUG RELEASE. PART 1: SYNTHESIS AND CHARACTERIZATION.

MOLECULARLY IMPRINTED POLYMERS FOR CONTROLLING DRUG RELEASE. PART 1: SYNTHESIS AND CHARACTERIZATION. Molecularly imprinted polymers (MIPs) consist of synthetic macromolecular matrix, obtained through molecular imprinting-based methods that show ability to selectively recognize important biological molecules and its application in the drug delivery field is under development. In the present review the main aspects related to the synthesis and characterization of MIPs are studied. The fundamental variables participating in the synthesis process. Such as template molecule, functional monomers. cross-linking agents, solvents, and imprinting approaches are discussed, Moreover. the main available methods for MIPs chemical and morphological characterization are presented and the importance of the obtained information is discussed

Selective extraction of proteins and other macromolecules from biological samples using molecular imprinted polymers

The accurate determination of intact macromolecules in biological samples, such as blood, plasma, serum, urine, tissue and feces is a challenging problem. The increased interest in macromolecules both as candidate drugs and as biomarkers for diagnostic purposes means that new method development approaches are needed. This review charts developments in the use of molecularly imprinted polymers first for small-molecular-mass compounds then for proteins and other macromolecules. Examples of the development of molecularly imprinted polymers for macromolecules are highlighted. The two main application areas to date are sensors and separation science, particularly SPE. Examples include peptides and polypeptides, lysozyme, hemoglobin, ovalbumin, bovine serum albumin and viruses

Electrochemical probing of selective haemoglobin binding in hydrogel-based molecularly imprinted polymers

An electrochemical method has been developed for the probing of hydrogel-based molecularly imprinted polymers (HydroMIPs) on the surface of a glassy carbon electrode. HydroMIPs designed for bovine haemoglobin selectivity were electrochemically characterised and their rebinding properties were monitored using cyclic voltammetry. The electrochemical reduction of bovine oxyhaemoglobin (BHb) in solution was observed to occur at ?0.460 V vs (Ag/AgCl) in 150 mM phosphate buffer solution (PBS). When the protein was selectively bound to the MIP, the electrochemical reduction of oxyhaemoglobin could be observed at a similar peak potential of ?0.480 V vs (Ag/AgCl). When analysing the non-imprinted control polymer (NIP) interfaced at the electrode, which contained no protein, the peak reduction potential corresponded to that observed for dissolved oxygen in solution (?0.65 V vs (Ag/AgCl)). MIP and NIP (in the absence of protein) were interfaced at the electrode and protein allowed to diffuse through the polymers from the bulk solution end to the electrode. It was observed that whereas NIP exhibited a protein response within 10 min of protein exposure, up to 45 min of exposure time was required in the case of the MIP before a protein response could be obtained. Our results suggest that due to the selective nature of the MIP, BHb arrival at the electrode via diffusion is delayed by the MIP due to attractive selective interactions with exposed cavities, but not the NIP which is devoid of selective cavities

MOLECULARLY IMPRINTED POLYMERS

The present invention refers to new classes of polymerisable monomers targeting biotin, a biotin derivative, a biotin analogue or a biotinylated molecule and related structures, as well as molecularly imprinted polymers obtainable by polymerisation of at least one of these monomers and at least one cross-linking monomer in the presence of a suitable template molecule. The obtained polymers may be used for separation of biotin and related small molecules, together with larger biotinylated molecules of biological origin, e.g. proteins, from complex mixtures

Substitution of antibodies and receptors with molecularly imprinted polymers in enzyme-linked and fluorescent assays

A new technique for coating microtitre plates with molecularly imprinted polymers (MIP), specific for low-molecular weight analytes (epinephrine, atrazine) and proteins is presented. Oxidative polymerization was performed in the presence of template; monomers: 3-aminophenylboronic acid, 3- thiopheneboronic acid and aniline were polymerized in water and the polymers were grafted onto the polystyrene surface of the microplates. It was found that this process results in the creation of synthetic materials with antibody-like binding properties. It was shown that the MIP-coated microplates are particularly useful for assay development. The high stability of the polymers and good reproducibility of the measurements make MIP coating an attractive alternative to conventional antibodies or receptors used in ELISA

Nanoparticles as a biorecognition platform in combination with LA-ICP-MS

Metal nanoparticles proved to be effective signaling tags in combination with laser ablation followed by inductively coupled plasma mass spectrometric detection. The surface may be suitably modified by various biorecognition elements such as antibodies or aptamers. Moreover, molecularly imprinted polymers can be prepared on their surface. In this study, the biorecognition capabilities of nanoparticles functionalized by antibodies and molecularly imprinted polymers were compared

The importance of size and shape in imprinted polymers

The existence of shape selectivity in non-covalent molecularly imprinted polymers has been proven using molecular probes. A series of amines varying with different structural motifs and secondary amines with different sized side chains were imprinted, and binding evaluated by HPLC for each amine on polymers imprinted with similar amines. Trends in the binding relationships revealed two major contributions of cavity structure on selectivity afforded by molecularly imprinted polymers (MIPs). First, sterics play a dominant role in cases where a molecules structure is too big too fit into an imprinted site formed from a smaller template molecule. Second, molecular structures that are equal to or smaller than those of the template molecule are selected by maximizing Van der Waals interactions within the MIP binding site