Effect of Vortex-Induced Physical Stress on Fluorescent Properties of Dye-Containing Poly(Ethylene Glycol)-Block-Poly(Lactic Acid) Micelles

The effect of vortex-induced mechanical stresses on the fluorescent properties of dye-containing poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) block copolymer micelles has been investigated. PEG-b-PLA block copolymer micelles containing fluorescent dyes, 3,3′-dioctadecyloxacarbocyanine perchlorate (DiO) and/or 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI), are prepared by a simple one-step procedure that involves the self-assembly of block copolymers and spontaneous incorporation of hydrophobic dyes into the core of the micelles. Upon vortexing, the micelle dispersion samples showed a decrease in fluorescence intensity in a rotational speed- and time-dependent manner. The results demonstrated that the vortexing can alter the fluorescent properties of the dye-containing PEG-b-PLA block copolymer micelle dispersion samples, suggesting the potential utility of block copolymer micelles as a mechanical stress-responsive nanomaterial

Nano- and Micro-sized Molecularly Imprinted Polymer Materials for Analytical Application

Specific molecular recognition materials are important in analytical applications. It has been a longstanding dream for scientific explorers to realise a versatile method to generate materials that can recognize biological and chemical substance of interests. Toward this goal, developing synthetic polymer materials, molecularly imprinted polymers (MIPs) is one of the most promising approaches. Especially development of nano- and micro-sized MIP material is expected to open up a wide range of application opportunity. New strategies related with preparation of nano- and micro-sized MIP and also their potential in analytical application are described in this thesis. First, methods for preparing uniformly sized MIP microspheres and nanoparticles which are selective to the drug compound, propranolol and the neouropeptide, Leu-enkephalin are described, and the binding properties of the MIPs are investigated. Second, strategies to prepare nano- and micro-sized MIP thin-film and nanofiber composite materials are described. Finally, the obtained nano- and micro-sized MIP materials are applied in competitive binding assay, sample preparation for preconcentrating the analyte and for constructing a QCM-based chemical sensor. The applicability in real sample analyses has been demonstrated in two examples. Preconcentration with the MIP allowed a trace amount of propranolol (3.4 nM) in tap water to be detected by LC/MS/MS, whereas the same drug compound in urine (1 μΜ) could be detected by a rapid non-separation assay based on new scintillation MIP nanofibers

Characterization of molecularly imprinted polymer nanoparticles by photon correlation spectroscopy

We follow template‐binding induced aggregation of nanoparticles enantioselectively imprinted against (S)‐propranolol, and the non‐imprinted ones, using photon correlation spectroscopy (dynamic light scattering). The method requires no separation steps. We have characterized binding of (R,S)‐propranolol to the imprinted polymers and determined the degree of non‐specificity by comparing the specific binding with the results obtained using non‐imprinted nanoparticles. Using (S)‐propranolol as a template for binding to (S)‐imprinted nanoparticle, and (R)‐propranolol as a non‐specific control, we have determined range of concentrations where chiral recognition can be observed. By studying aggregation induced by three analytes related to propranolol, atenolol, betaxolol, and 1‐amino‐3‐(naphthalen‐1‐yloxy)propan‐2‐ol, we were able to determine which parts of the template are involved in the specific binding, discuss several details of specific adsorption, and the structure of the imprinted site. Copyright © 2014 John Wiley & Sons, Ltd

A simple method for preparation of molecularly imprinted nanofiber materials with signal transduction ability

A simple electrospinning method is developed to introduce signal transduction ability into molecularly imprinted nanofibers

Selective molecular adsorption using electrospun nanofiber affinity membranes.

Molecularly imprinted nanoparticles were encapsulated into polymer nanofibers with a simple electrospinning method. The composite nanofibers form non-woven mats that can be used as affinity membrane to greatly simplify solid phase extraction of drug residues in analytical samples. Upward 100% of propranolol-imprinted nanoparticles can be easily encapsulated into poly(ethylene terephthalate) nanofibers, ensuring the composite materials to have a high specific binding capacity. As confirmed by radioligand binding analysis, the specific binding sites in the composite materials remain easily accessible and are chiral-selective. Using the new composite nanofiber mats as solid phase extraction materials, trace amount of propranolol (1ngmL(-1)) in tap water can be easily detected after a simple sample preparation. As validated in this study, there is no problem of template leakage from the composite nanofibers. Without the solid phase extraction, the existence of propranolol residues in water cannot be confirmed with even tandem HPLC-MS/MS analysis

Peptide-imprinted polymer microspheres prepared by precipitation polymerization using a single bi-functional monomer.

A single bi-functional monomer, N,O-bismethacryloyl ethanolamine (NOBE), was used in precipitation polymerization system to synthesize molecularly imprinted polymer (MIP) microspheres. Highly specific binding sites were obtained for N-terminal protected neuropeptides, Boc-Leu-enkephalin and Pyr-Leu-enkephalin. The use of NOBE allowed binding sites to be formed in polymer microspheres that are able to recognize target peptides through the consensus C-terminal sequence. The interesting molecular binding results suggest a new approach for peptide analysis combining in situ chemical modification with MIP recognition under non-aqueous conditions

Influence of template/functional monomer/cross‐linking monomer ratio on particle size and binding properties of molecularly imprinted nanoparticles

A series of molecularly imprinted polymer nanoparticles have been synthesized employing various template/functional monomer/crosslinking monomer ratio and characterized in detail to elucidate the correlation between the synthetic conditions used and the properties (e.g., particle size and template binding properties) of the obtained nanoparticles. In brief, the presence of propranolol (template) in the polymerization mixture turned out to be a critical factor on determination of the size as well as the binding properties of the imprinted nanoparticles. The functional monomer/crosslinking monomer ratio significantly affects the binding capability of the imprinted nanoparticles, but its influence on the size of the nanoparticles was found to be rather limited. The results obtained provide valuable clues for designing molecularly imprinted nanoparticle preparation in future studies, where fine tuning of particle size and binding properties are required to fit practical applications. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 201

"Clickable" affinity ligands for effective separation of glycoproteins.

In this paper, we present a new modular approach to immobilize boronic acid ligands that can offer effective separation of glycoproteins. A new "clickable" boronic acid ligand was synthesized by introducing a terminal acetylene group into commercially available 3-aminophenyl boronic acid. The clickable ligand, 3-(prop-2-ynyloxycarbonylamino)phenylboronic acid (2) could be easily coupled to azide-functionalized hydrophilic Sepharose using Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction under mild condition. Compared to other boronic acid affinity gels, the new affinity gel displayed superior effectiveness in separating model glycoproteins (ovalbumin and RNase B) from closely related bovine serum albumin and RNase A in the presence of crude Escherichia coli proteins. Because of the simplicity of the immobilization through "click chemistry", the new ligand 2 is expected to not only offer improved glycoprotein separation in other formats, but also act as a useful building block to develop new chemical sensors for analysis of other glycan compounds