Fabrication of PNIPAM-chitosan/decatungstoeuropate/silica nanocomposite for thermo/pH dual-stimuli-responsive and luminescent drug delivery system.

A luminescent and dual-stimuli-responsive nanocomposite based on mesoporous silica, poly (N-isopropylacrylamide)-chitosan and decatungstoeuropate was prepared. To fabricate the nanocomposite, the mesoporous silica nanoparticles were coated with thermo/pH dual-responsive poly (N-isopropylacrylamide)-chitosan and the luminescent decatungstoeuropate particles were grafted onto copolymers. The designed nanocarrier could show exhibit good red luminescence as well as obvious thermo/pH stimuli-responsive properties, which could be employed as a drug storage reservoir for the loading and release of anticancer drug doxorubicin (DOX). The research indicated that the releases of DOX were thermo/pH dependent and high temperatures/acidic conditions were favorable for the fast release of drug. In vitro cytotoxicity tests revealed that the drug delivery carrier displayed excellent biocompatible and the composites loaded with DOX showed significant suppression effect on HeLa cells. Luminescence spectra showed that the composite containing decatungstoeuropate displayed fine red luminescence at various temperatures and pH values, which could be utilized as a potential labeling material in field of medicine.

Molecularly imprinted polymers: modulating molecular recognition by a thermal phase transition in the binding framework.

The concept used to realize the modulation of molecular recognition in a molecularly imprinted polymer is presented. Creating a thermal phase transition within the binding framework, the imprinted material was prepared using Boc-phenylalanine as the template and pNIPAM as the sensitive unit. The results indicate that such a transition causes a clear modulation in the recognition behavior of the prepared polymer which depends on the operation temperature. At a relatively low temperature, the prepared polymer acts like a traditionally imprinted one, showing a highly specific recognition for the imprint species. However, the prepared polymer does not present any notable resolution at 40 degrees C. This recognition behavior is comparable to a process that can be switched on and off, thus making modulated recognition feasible.

Rationally designing molecularly imprinted polymer towards predetermined high selectivity by using metal as assembled pivot.

This article presents an original work aiming at rationally designing a molecularly imprinted polymer (MIP) towards high selective recognition. Assembled with (S)-naproxen as a template and 4-vinylpyridine as a functional monomer, a certain amount of cobalt, as pivot, is added for the preparation of MIP. The result indicates that the use of pivot plays obviously a positive role in increasing the specificity of MIP, so as to adsorb more for the template and less for its enantiomer. Related information indicates that this, in logic, can be a result of increasing match between binding sites and the templates, which makes the polymer capable of selectively recognizing the imprint species.

A common profile for polymer-based controlled releases and its logical interpretation to general release process.

PURPOSE: The release of drug from a polymeric matrix is complicated. It often involves drug diffusion, interface movement and various interactions. It also shows a dependence on the length of polymer rod. With Lc as the 'critical length', three different phases can be distinguished from the kinetic process. Prior to reaching Lc, the interface movement plays a key role on determining the release. Otherwise, the drug diffusion can dominate the release process. Near Lc, however, both factors are involved. The rate of interface movement is closely associated with the time and position in the polymer rod. Taking these characters into account, a common model is presented in this article to be tentatively used to interpret the release process. These results provide preliminarily an insight into the understanding of controlled release process.

Establishing mathematical and physical models for the adsorption of biomacromolecules.

In this article, a series of mathematical and physical models for the adsorption of biomacromolecules are established. As shown, the adsorption of biomacromolecules is actually considerably complicated and often involves various interactions, such as electrostatic, hydrophobic, and hydrogen-bonding, etc. Considering this, these models show that if these interactions are heavily involved in the process, the plot of ln Q (or Q) vs ln C* is normally expected to be a straight-line. Otherwise, if the linearity exists between C*/Q vs C*, the adsorption would be an ideal process without the intervention of them. Meanwhile, this article also presents corresponding relationships for the adsorption in multisited binding and multilayer forms. Other aspects including ion-exchange systems are also discussed (C*, the equilibrium concentration of biomacromolecules; Q, the adsorbance).