A noninvasive method for measuring the oxygen binding-releasing capacity of hemoglobin-loaded polymeric nanoparticles as oxygen carrier.

Based on the strong penetration capacity of near infrared lights (NIRs) and different absorption of oxyhemoglobin and deoxyhemoglobin in NIRs region, a novel noninvasive method, with the aid of an airproof-equilibrium apparatus, was developed to determine the oxygen binding-releasing capacity, including oxygen dissociation curve (ODC) and P(50), of the hemoglobin-loaded polymeric nanoparticles (HbP) in this study. The measured ODC of the PLA-PEG HbP was very close to that of the native hemoglobin, and the corresponding P(50) (26.1 mmHg) was also near to the native precursor protein (27.3 mmHg), indicative of the validity of the method proposed. To further verify the method proposed, the oxygen binding-releasing capacity of the HbPs prepared by PCL, PCL-PEG, PLA were also investigated with human blood as control. These results indicated that the method developed here enabled accurate and noninvasive determination of the oxygen binding-releasing capacity of the biodegradable polymeric oxygen carriers.