Measurement of the transverse apparent elastic modulus in mammalian cardiac myocytes

Transverse mechanical properties of mammalian cardiac myocytes, was determined by using atomic force microscopy (AFM). The AFM can be used as a nano-indentation device allowing transverse stiffness measurements to be conducted on biological cells in a physiological environment. This enables real-time biomechanical and physiological processes to be monitored with nano-scale resolution. Cellular mechanical properties were determined by indenting the cell's body, and analyzing the indentation data with classical infinitesimal strain theory (CIST). This calculation was accomplished by modeling the AFM probe as a blunted cone. The blunted cone geometry fits the AFM force indentation data well and was used to calculate the apparent elastic modulus of the cardiac myocyte body. The mechanical properties of male 344 × Brown Norway F1 hybrid (F344×BN) rat cells was measured and an apparent elastic modulus of 35.1 × 0.7 kPa (n = 53) was calculated. Further studies are being conducted on myocytes isolated from aged hearts to determine whether age effects cardiac mechanical properties at the level of the single myocyte.