Study On Novel Ionic Crosslinked Polyampholyte Hydrogel

Eelectro-responsive hydogels have advantages such as the availability of equipment that allows precise control with regards to the magnitude of current, various manner of responsiveness, precise controlling over drug release, they might be used in the field of controlled drug delivery. Ionic crosslinked polyampholyte hydrogels containing both positive and negative charged groups, ionic crosslinkage have fromed between positive and negative charged groups. Compared with covalent bonding, ionic bonding belongs to weak interaction. Consequently, it was more sensitive to the ambient solutions. So this ionic crosslinked polyampholyte hydrogel may have dual stimulating response behavior, they might be used for electro-controlling drug delivery material. The main contents are as follows.(1) The ionic complex was formed by the proton-transfer reaction between acidic monomer (acrylic acid, AAc or 2-acrylamide-2-methyl propane sulfonic acid, AMPS) and basic monomer ((N,N-diethylamino)ethyl methacrylate, DEAEM). The FTIR spectra of the ionic complexion confirmed the proton-transfer reaction between acidic monomer and basic monomer.(2) Through the radical copolymerization of ionic complexion and acrylamide (AAm), the ionic crosslinked polyampholyte hydrogels, Two novel type of ionic crosslinked polyampholyte hydrogels (PADA, AMDA gel), were prepared in the absent of chemical crosslinker. Gels exhibited dual electro-responsiveness behavior under contact DC field: swelling and eroding. The voltage, the species and concentration of electrolyte, connect to different electrode and some other factors have great effect on the swelling/erosion behavior of gels.(3) The results showed that gels have two responsive stages (swelling stage and eroding stage) in contacted DC field. Gels swelled firstly, when the ionic crosslinkage was dissociated, gels started to occur eroding. The kinetic study on the swelling/eroding behavior demonstrated that the swelling was possibly affected by additional electric field, and the eroding followed zero-order kinetics.(4) The drug release rule of the drug loading gels was briefly researched. Concentration of the NaCl solution, pH of PBS solution and drug loading method had directly affection on the drug release behavior. Electric experiment showed that additional electric field can accelerate drug release. The affection of anode and cathode on drug delivery through the gel membrane were compared, the results showed that anode inductive drug delivery was better than cathode inducting.The total results showed that developing polyampholyte hydrogels into electro-controlling drug delivery material have great potential. But it has much work to accomplish, such as optimizing gel's property, designing the electric device, selecting condition of drug delivery, and forth and so on.