Patterns in quench-frozen, freeze-dried, blood proteins

Scanning electron micrographs of whole blood prepared with cryotechnics demonstrated patterns assumed to be artifacts of the freezing process. A SEM investigation of the effects of freezing and freeze-drying on columns of purified blood proteins has been carried out using quench-freezing and cryo-fracturing followed by freeze-drying. Correlative studies with a light microscope and a transmission electron microscope are included. The resulting patterns depended on the type and concentration of protein as well as on the position within the sample and the orientation of the fracture plane relative to the column axis.