Amination of Polyurethane for Designing Infection-Resistant Surfaces

Polyurethane (PU) has emerged as a promising class of polymeric material for biomedical applications due to its outstanding physicochemical properties. However, the resulting immune response and on-site infections are unavoidable consequences of PU-based implants. Immobilizing bioactive agents and biopolymers is an excellent approach to overcome these issues. However, the inherent inertness and hydrophobicity of PU create restraint on the immobilization of bioactive agents on its surface. In this work, a PU film was subjected to aminolysis using ethylene diamine (EDA) under varied temperatures, time, and EDA concentrations. The influence of reaction parameters on the formation of free amino (-NH2) groups and the resulting changes in the physicochemical properties of PU were investigated further. The optimized amine content was similar to 0.08 mu M/cm(2) after treatment with 10% EDA for 15 min. The surface was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle measurement. Ciprofloxacin was used as a prototype drug and was immobilized by the dip-coating approach on the functionalized PU surface. The drug-immobilized PU showed excellent antibacterial and antibiofouling efficacy against both Gram-positive and Gram-negative bacteria.