To investigate the influence of nitrogen and oxygen incorporated into N-trimethylsitylallyamine (TMSAA) plasma coating on heparin binding to the surfaces, four types of monomer combinations were utilized. Those combinations include TMSAA alone, TMSAA mixed with nitrogen (TMSAA + N-2), with air (TMSAA + air), and with oxygen (TMSAA + O-2). Fourier transform infrared (FTIR) spectroscopy was employed to study the coating of the bulk structure. The thickness and surface morphology of the coatings were measured using atomic force microscopy (AFM). Electron spectroscopy for chemical analysis (ESCA) and the contact angle were used to investigate the surface elemental composition and hydrophilicity, respectively. It was found that the incorporation of oxygen into the coating formation significantly increased the deposition rate of the TMSAA + O-2 coating, but the heparin activity was the least even though it made the coating surface more hydrophilic. This is considered to have resulted from the loss of nitrogen in the coating structure due to the oxygen replacement to nitrogen. The nitrogen incorporated into the coating had no noticeable effect on the heparin surface-binding ability. The TMSAA + air plasma grafting process exhibited the best heparin attachment to the surface, which could be largely attributed to its highest surface roughness, although the nitrogen composition was decreased to some extent compared to the pure TMSAA plasma coating. (C) 2003 Wiley Periodicals, Inc.