"Smart" polymers and gels, which can respond with dramatic property changes to small modifications in their environment (pH, temperature, ionic strength, magnetic or electric field, etc.) represent a very interesting class of materials due to their applications in drug delivery and sensor development. The present project focused on thermo- and/or-pH-sensitive materials in which the widely studied thermosensitive polymer, poly(N-isopropylacrylamide), is replaced with the more biocompatible poly(N-vinylcaprolactam), and the pH-sensitivity is given by maleic acid. The presence of two adjacent carboxylic groups in maleic acid copolymers determines the dissociation in two steps that offer special pH-sensitivity. The project proposed to develop new pH- and/or thermo-sensitive hydrogels based on maleic copolymers cross-linked by chemical and by physical bonds and to obtain "smart" micro/nano-particles for controlled drug delivery.