Stored red blood cells retain their shape, mass, and hemoglobin content over time, but the membranes eventually become stiffer and less elastic, making them less capable of transporting oxygen through capillaries (Bhaduri B et al. Sci Rep. 2014;4:6211).
A team led by University of Illinois researchers demonstrated this with a special optical technique called spatial light interference microscopy, which uses light to noninvasively measure cell mass and topology with nanoscale accuracy.
Hampton T. Banked Blood Cells Lose Functionality Over Time. JAMA. 2014;312(17):1729. doi:10.1001/jama.2014.14318