EXPLORATORY RESEARCH PROJECTS
Cod: PN-II-ID-PCE-2011-3-0300
Contract number: 140/25.10.2011
Project Director: CS I Dr. Ecaterina Stela Dragan
Contract Authority: Executive Unit for Financing Higher Education, Research Development and Innovation (UEFISCDI)
Contractor: "Petru Poni" Institute of Macromolecular Chemistry, Iasi
Project duration: 2012 - 2016
Budget: 1350000 lei
2012: 375000.00 lei
2013: 220101.79 lei
2014: 243750.00 lei
2015: 404024 lei
2016: 107124.21 lei
Project description:
Entrapping/immobilization of the bioactive substances in an appropriate material follow to improve its performance, to protect it, or to control its delivery. In general, immobilization is focused on the enzymes as biocatalysts, proteins, cell proliferation, controlled drug release, agricultural applications, in protection of seeds, etc. So far, as matrices for (bio)immobilization have been used ion exchangers as beads, polyacrylamide and poly(vinyl alcohol) gels. This project is focused on the preparation and characterization of novel porous ionic matrices as: (i) porous ionic thin films, and (ii) superporous matrices as monoliths with architecture and stimuli responsiveness controlled by the polymer structure and synthesis conditions, endowed with capacity to host and to release bioactive compounds.
(i) The most versatile and utilized strategy in the preparation of ionic thin films is the layer-by-layer (LbL) deposition of strong or weak polyelectrolytes on different substrates. Weak polyelectrolytes are lately preferred because, by their sensitivity at the medium pH, they give the possibility to tailor the film properties. A less investigated aspect of the LbL thin films is the generation of porous LbL thin films. Identification and manipulation of the specific interactions between the porous ionic LbL thin films and the bioactive objects, as well as their potential applications are the central tasks of this project.
(ii) Among the porous ionic materials, much attention has been lately addressed to cryogels, which are gel-based matrices formed as a result of cross-linking under freezing conditions of monomers or linear polymers dissolved most often in water, the most studied being poly(acrylamide), and poly(vinyl alcohol). During the cryogelation, most of the water forms ice crystals, whereas bound water and soluble substances accumulate in a non-frozen liquid micro-phase, where the gel is formed. Supermacroporous cryogels, by their unique heterogeneous open porous structure, allow unhindered diffusion of solutes, nano-particles and even micro-particles. Supermacroporous cryogels have already demonstrated a high efficiency in processing cells and virus suspensions, as well as in cells proliferation. Less investigations have been addressed to the multicomponent networks prepared under freezing conditions. Multicomponent ionic interpenetrated networks (IPN) cryogels, which bring further functionalities and open novel directions for fundamental research, separation science, and biomedical applications, will be prepared for the first time in the frame of this project. Therefore, ionic polymers, either trapped in a matrix or synthesized as an ionic matrix around a preformed nonionic or ionic polymer, will be used to generate new multi-component porous ionic matrices (PIM) by cryogelation technique.
The presence of polyelectrolytes either trapped or as a matrix in these porous materials will make them also multi-functional. Ionic natural or synthetic polymers will be used in the synthesis of the novel PIM. Ionic functionalities and the presence of pores make these materials suitable for biomedical applications, drugs and protein release, chromatrographic separations, removal of metal ions and dyes, etc. On the other side, among the polymeric hydrogels, those based on the so-called “smart” polymers occupy a special place. Such hydrogels undergo significant changes of their swelling properties (shape/volume) at small changes in the environmental conditions near the critical value of a certain parameter (temperature, pH, ionic strength, electric or magnetic field, etc.). “Smart” macroporous cryogels have attracted much interest last years due to their numerous advantages, one of them being the hydration/dehydration behavior, which is much more rapid compared to the corresponding conventional hydrogels. Novel multiple responsive cryogels having a high biocompatibility will be prepared in the frame of the project. The facile synthesis combined with low production cost and benign processing conditions (preparation of LbL thin films and cryogels is usually performed from aqueous solutions) make the novel porous ionic materials very attractive for biomedical applications as well as for separation/sorption processes.
Cod: PN-II-ID-PCE-2011-3-0300
Contract number: 140/25.10.2011
Project Director: CS I Dr. Ecaterina Stela Dragan
Contract Authority: Executive Unit for Financing Higher Education, Research Development and Innovation (UEFISCDI)
Contractor: "Petru Poni" Institute of Macromolecular Chemistry, Iasi
Project duration: 2012 - 2016
Budget: 1350000 lei
2012: 375000.00 lei
2013: 220101.79 lei
2014: 243750.00 lei
2015: 404024 lei
2016: 107124.21 lei
Project description:
Entrapping/immobilization of the bioactive substances in an appropriate material follow to improve its performance, to protect it, or to control its delivery. In general, immobilization is focused on the enzymes as biocatalysts, proteins, cell proliferation, controlled drug release, agricultural applications, in protection of seeds, etc. So far, as matrices for (bio)immobilization have been used ion exchangers as beads, polyacrylamide and poly(vinyl alcohol) gels. This project is focused on the preparation and characterization of novel porous ionic matrices as: (i) porous ionic thin films, and (ii) superporous matrices as monoliths with architecture and stimuli responsiveness controlled by the polymer structure and synthesis conditions, endowed with capacity to host and to release bioactive compounds.
(i) The most versatile and utilized strategy in the preparation of ionic thin films is the layer-by-layer (LbL) deposition of strong or weak polyelectrolytes on different substrates. Weak polyelectrolytes are lately preferred because, by their sensitivity at the medium pH, they give the possibility to tailor the film properties. A less investigated aspect of the LbL thin films is the generation of porous LbL thin films. Identification and manipulation of the specific interactions between the porous ionic LbL thin films and the bioactive objects, as well as their potential applications are the central tasks of this project.
(ii) Among the porous ionic materials, much attention has been lately addressed to cryogels, which are gel-based matrices formed as a result of cross-linking under freezing conditions of monomers or linear polymers dissolved most often in water, the most studied being poly(acrylamide), and poly(vinyl alcohol). During the cryogelation, most of the water forms ice crystals, whereas bound water and soluble substances accumulate in a non-frozen liquid micro-phase, where the gel is formed. Supermacroporous cryogels, by their unique heterogeneous open porous structure, allow unhindered diffusion of solutes, nano-particles and even micro-particles. Supermacroporous cryogels have already demonstrated a high efficiency in processing cells and virus suspensions, as well as in cells proliferation. Less investigations have been addressed to the multicomponent networks prepared under freezing conditions. Multicomponent ionic interpenetrated networks (IPN) cryogels, which bring further functionalities and open novel directions for fundamental research, separation science, and biomedical applications, will be prepared for the first time in the frame of this project. Therefore, ionic polymers, either trapped in a matrix or synthesized as an ionic matrix around a preformed nonionic or ionic polymer, will be used to generate new multi-component porous ionic matrices (PIM) by cryogelation technique.
The presence of polyelectrolytes either trapped or as a matrix in these porous materials will make them also multi-functional. Ionic natural or synthetic polymers will be used in the synthesis of the novel PIM. Ionic functionalities and the presence of pores make these materials suitable for biomedical applications, drugs and protein release, chromatrographic separations, removal of metal ions and dyes, etc. On the other side, among the polymeric hydrogels, those based on the so-called “smart” polymers occupy a special place. Such hydrogels undergo significant changes of their swelling properties (shape/volume) at small changes in the environmental conditions near the critical value of a certain parameter (temperature, pH, ionic strength, electric or magnetic field, etc.). “Smart” macroporous cryogels have attracted much interest last years due to their numerous advantages, one of them being the hydration/dehydration behavior, which is much more rapid compared to the corresponding conventional hydrogels. Novel multiple responsive cryogels having a high biocompatibility will be prepared in the frame of the project. The facile synthesis combined with low production cost and benign processing conditions (preparation of LbL thin films and cryogels is usually performed from aqueous solutions) make the novel porous ionic materials very attractive for biomedical applications as well as for separation/sorption processes.