Using atomic force microscopy (AFM), researchers from the Biotech@ISM Lab quantitatively analyzed the variations in membrane roughness and Young’s modulus —a measure of stiffness— in human red blood cells at different aging stages (1, 7, and 12 days), both in air and in physiological buffer. The results show a progressive flattening of the cell surface, with a reduction in roughness, a phenomenon more pronounced under dehydration but still present in hydrated conditions, indicating an intrinsic change linked to cellular senescence. Concurrently, an increase in mechanical stiffness was observed, particularly during the early days of aging, associated with cytoskeletal alterations and reduced cellular deformability—crucial for capillary passage.
A key finding of the study is the lack of direct correlation between roughness and stiffness: the two parameters evolve independently, highlighting the need to analyze them separately for an accurate assessment of cellular status. The methodology employs advanced morphological corrections (7th-order polynomial fitting) and force mapping over nanoscale areas (100×100 nm² to 1×1 μm²), enabling spatially resolved and comparable analyses under different physical conditions.
The observed alterations mirror those seen in pathologies such as diabetes, sickle cell anemia, and neurodegenerative diseases, suggesting potential applications in early diagnosis through nanomechanical biomarkers. Moreover, the findings offer valuable insights for transfusion medicine by improving the assessment of stored blood quality. The study proposes a standardized protocol for the integrated analysis of cell morphology and mechanics, representing a significant contribution to cell biology and nanomedicine.