Hemoglobin (Hb) was immobilized on a glassy carbon electrode using a photo-initiated polymerization of polyethylene glycol molecules and using the 1-phenyl-2-hydroxy-2-methyl-1-propanone molecule as initiator. UV-visible absorption spectra, circular dichroism (CD) and electrochemical studies indicated native three dimensional hemoglobin structure was preserved. Thin film sensors of the same protein and polyions were also constructed using layer by layer technique and film growth was monitored using cyclic voltammetry(CV), quartz crystal microbalance (QCM). The electrochemistry from both type of sensors were compared. Reversible pairs of oxidation-reduction peaks for the two types of sensors were observed using cyclic voltammetry corresponding to the HbFeIII/HbFeII redox couples at -0.3 V vs Ag/AgCl. Catalysis of the two types of sensor assemblies is discussed