Absorption spectra from average of four optically trapped chicken RBCs. Peaks at the straight lines indicate oxygenated state, at the dotted line indicates deoxygenated state. At time (t = 0 s) we see the oxygenated state(spectra No. 1). After 289 s of flow with buffer EC deoxygenated solution (0% O 2) the deoxygenated state was reached(spectra No. 10). After that the flow of (0% O 2) was stopped to see whether oxygen could diffuse into the LOC. After 5400s the deoxygenated state was still shown (Spectra No. 11) and latterly, a flow of oxygenated EC buffer solution (18% O 2) was started. After 428 s the oxygenated state was reached again (Spectra No. 12).