HRP-catalyzed polymerization of sugar-based phenols in aqueous organic solvents

Synthesis and chemical properties of polyphenols with oligoaniline pendant groups

Horseradish peroxidaze (HRP)- or N, N′-bis(salicylidene)ethylenediamineiron(III)-catalyzed polymerizations of 4-(4-phenylaminophenylamino)phenol (monomer-1) and 4-[4-(4-phenylaminophenylamino)phenylamino]phenol (monomer-2) caused oxidative coupling at the hydroxyphenyl group to yield polyphenols (PPs) with pendant oligoaniline (OAN) groups. UV-vis measurements suggested that the OAN pendant groups of the polymers were oxidized in air, resulting in the formation of quinoid structures, which were converted into benzonoid structures by treatment with hydrazine monohydrate. The polymers were electrochemically oxidized in solution.

Immobilized horseradish peroxidase as a reusable catalyst for emulsion polymerization

The study on the adsorption of horseradish peroxidase (HRP) onto silicon wafers was carried out by means of in situ ellipsometry, atomic force microscopy (AFM) and contact angle measurements. A smooth HRP layer adsorbed onto Si wafers. The enzymatic activity of free or adsorbed HRP was determined by the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and by the emulsion polymerization of ethylene glycol dimethacrylate (EGDMA). Upon adsorbing, HRP molecules might have undergone some conformational changes, which caused a small reduction of enzymatic activity in comparison to that observed for HRP solution. However, it was possible to reuse the same HRP-covered Si wafer as catalyst in the polymerization of EGDMA three times.

Preparation, Characterization, and Self-Assembled Properties of Biodegradable Chitosan−Poly(l-lactide) Hybrid Amphiphiles

Biodegradable chitosan-graft-poly(L-lactide) (CS-g-PLLA) hybrid amphiphiles were prepared through direct grafting of a PLLA precursor to the backbone of CS. The average number of PLLA grafts per CS could be adjusted by the feed ratio of PLLA to CS, and it varied from 1.3 to 16.8. Moreover, both the crystallization rate and degree of crystallization of PLLA grafts with these graft copolymers could be adjusted by the chain length of PLLA and the number of PLLA grafts per CS, respectively. Meanwhile, CS-g-PLLA exhibited good solubility in some nonpolar and polar organic solvents compared with the original CS. Furthermore, self-assembled nanoparticles could be generated by direct injection of these graft copolymer solutions into distilled water, and their critical aggregation concentration decreased with increasing number of PLLA grafts per CS. The average size of the nanoparticles (25-103 nm) could be adjusted through the graft copolymer composition and the graft copolymer concentration, which was very different from the observations in ordinary PLLA-b-poly(ethylene oxide) amphiphiles. Significantly, this will provide a convenient method not only to combine the bioactive functions of CS with the good mechanical properties of biodegradable polymers, but also to generate nanoparticles with adjustable sizes for targeted drug release.

Microbead analysis of cell binding to immobilized lectin: an alternative to microarrays in the development of carbohydrate drugs and diagnostic tests

Microarray technology is currently used in the development of carbohydrate drugs and diagnostic tests. Here we model an inexpensive alternative to microarrays using derivatized microbeads. In this model we examine the binding of mannose-rich yeast to microbeads derivatized with concanavalin A (Con A), a mannose-binding lectin, in the presence of 30 different sugars and 9 different pH conditions. We developed a listing of effective saccharide inhibitors of immobilized Con A based on 3901 replicates. We suggest that this is the most extensive saccharide inhibitor list ever developed for this lectin and it may be useful to use this listing to replace the less extensive lists that have been in the literature for decades. Information is also provided on pH effects on immobilized Con A binding based on 918 trials. Two assays to study binding, one which qualitatively scores more or less binding than control in thousands of replicate samples, and another that quantitatively evaluates binding by counting the number of cells bound to each bead, are also modeled here. We know of no previous studies that provide such extensive information on saccharide inhibition and pH effects on the binding of immobilized Con A. We suggest that this microbead approach, using beads derivatized with lectins or sugars, and the two simple assays presented here, can in some cases substitute for more expensive microarray technology in the development of carbohydrate drugs and diagnostic tests. If, for example, our model Saccharomyces cerevisiae was a pathogen, these studies show that it binds via cell surface mannose residues and drugs to prevent binding could be developed using the inhibitors of binding identified here. The beads could be also used in the development of diagnostic tests that identify the presence of the organism in blood samples, etc. in much the same way as microarray technology is being used today.