Laboratory 4: Laboratory of Functional Polymers

Group 4.1: Ion-sensitive matrices external stimuli responsive with sorption/release properties of bioactive species

Dr. Ecaterina Stela DRÄ‚GAN

The project aims to deepen the field of immobilization/release of bioactive ionic species such as proteins, metal ions, drugs, cells in/from porous matrix susceptible to external stimuli, and to carry out a systematic research on the synthesis, properties and specific applications of ionic porous matrices through:
(1) the generation of new porous matrices, either as thin films or as macroporous monolith, having predetermined porosities and functionalities;
(2) the study of the interaction of porous matrices with different ionic species to identify specific biomedical applications.
Both the construction of multilayer films and the synthesis of porous matrices by cryogelifiers are achieved by highly versatile and environmentally friendly techniques; therefore, they are recommended for obtaining materials with biomedical applications.

Important results

• Fast responsive macroporous interpenetrating polymer network (IPN) hydrogels were fabricated by a sequential strategy, the 1^st network consisting of poly(N,N-dimethylaminoethyl methacrylate) cross-linked with N,N’-methylenebisacrylamide (BAAm), and the 2^nd network was poly(acrylamide) cross-linked with BAAm, both networks being generated by cryogelation technique. Sorption and release upon/from the SNCs and IPN cryogels of small drugs was triggered by pH, temperature, and ionic strength.
• Synthesis and characterization of composite sorbents by impregnation and cross-linking copolymerization of acrylamide in the pores of Daisogel silica. The silica supported functional polymers were efficient in the loading/release of lysozyme as macromolecular drug.
• Novel composite sorbents consisting of chitosan (CS) and poly(vinyl amine) (PVAm), dual-cross-linked with glutaraldehyde (GA) and ethylene glycol diglycidyl ether (EGDGE), in which the microspheres of some porous strong base anion exchangers (IEx) having (vinylbenzyl diethyl 2-hydroxyethyl)ammonium chloride functional groups, and sizes in the range 90-200 mm, were evenly dispersed, were designed. Macroporous CS/PVAm/IEx composites as cryobeads or monoliths were successfully applied to the sorption of Cr(VI).
• Novel composite anion exchangers (CANEXs) were fabricated by an innovative approach consisting of using silica Daisogel as host for an anion exchanger bearing vinylbenzyl N,N-diethyl 2-hydroxyethyl ammonium moieties. CANEX microspheres were able to selectively capture Methyl Orange, in binary mixtures with either methylene blue, as cationic dye, or Chicago Sky Blue 6B as competing azo dye.