Dual temperature/pH-sensitive polyampholyte gels were developed for use as adsorbents and carriers that deal with organic electrolytes such as proteins. NIPA-co-DMAPAA-co-AA gels were prepared by copolymerizing N-isopropylacrylamide (NIPA) as a thermosensitive component with N,N-dimethylaminopropylacrylamide (DMAPAA) as a weakly-basic cation-comonomer, acrylic acid (AA) as a weakly-acidic anion-comonomer, and N,N'-methylenebisacrylamide (MBAA) as a cross-linker, and their thermosensitive and pH-sensitive swelling properties and protein adsorption properties were investigated. The gel adsorbed bovine serum albumin (BSA) applied as a model protein at pH values in the range of 4.5-10 and 25 degrees C as a result of the electrostatic interactions. In addition, the pre-adsorbed BSA was well desorbed from the gel at pH values less than 4 or greater than 11. The pH-sensitivity of the adsorption is found to be based on the protonation of amino groups in DMAPAA and dissociation of carboxyl groups of AA. The BSA adsorption was investigated as a function of MBAA concentration and temperature, and was discussed in terms of the difference in the sizes of the BSA molecule and gel network. (C) 2012 Elsevier B.V. All rights reserved.