TY - JOUR
T1 - A novel method for post-mortem interval estimation based on tissue nano-mechanics
AU - De Giorgio, Fabio
AU - Nardini, Matteo
AU - Foti, Federica
AU - Minelli, Eleonora
AU - Papi, Massimiliano
AU - D’Aloja, Ernesto
AU - Pascali, Vincenzo Lorenzo
AU - De Spirito, Marco
AU - Ciasca, Gabriele
PY - 2019
Y1 - 2019
N2 - Forensic estimation of post-mortem interval relies on different methods, most of which, however, have practical limitations or provide insufficient results, still lacking a gold standard method. In order to better understand the phenomenon of rigor mortis and its applicability to the post-mortem interval estimation, we decided to use atomic force microscopy, a tool often employed to measure mechanical properties of adherent cells. Thus, we surgically removed skeletal muscle samples of three forensic cases from 0 to 120 h post-mortem and quantitatively evaluate two parameters: the Young's modulus (E), which gives information about the sample stiffness, and the hysteresis (H), which estimates the contribution of viscous forces. Despite being a preliminary study, the obtained results show that the temporal behavior of E well correlates with the expected evolution of rigor mortis between 0 and 48 h post-mortem, and then monotonically decreases over time. Unfortunately, it is strongly affected by inter-individual variability. However, we found that H provides measurable data along a time-dependent curve back to the starting point, and these data measured on different subjects collapse onto a single master curve, getting rid of the inter-individual variability. Although a larger sampling should be performed to improve the result reliability, this finding is strongly suggestive that the evaluation of rigor mortis should involve the measure of the nanoscale dissipative behavior of muscular tissues.
AB - Forensic estimation of post-mortem interval relies on different methods, most of which, however, have practical limitations or provide insufficient results, still lacking a gold standard method. In order to better understand the phenomenon of rigor mortis and its applicability to the post-mortem interval estimation, we decided to use atomic force microscopy, a tool often employed to measure mechanical properties of adherent cells. Thus, we surgically removed skeletal muscle samples of three forensic cases from 0 to 120 h post-mortem and quantitatively evaluate two parameters: the Young's modulus (E), which gives information about the sample stiffness, and the hysteresis (H), which estimates the contribution of viscous forces. Despite being a preliminary study, the obtained results show that the temporal behavior of E well correlates with the expected evolution of rigor mortis between 0 and 48 h post-mortem, and then monotonically decreases over time. Unfortunately, it is strongly affected by inter-individual variability. However, we found that H provides measurable data along a time-dependent curve back to the starting point, and these data measured on different subjects collapse onto a single master curve, getting rid of the inter-individual variability. Although a larger sampling should be performed to improve the result reliability, this finding is strongly suggestive that the evaluation of rigor mortis should involve the measure of the nanoscale dissipative behavior of muscular tissues.
KW - Atomic force microscope
KW - Nano-mechanics
KW - Rigor mortis
KW - Time since death
KW - Atomic force microscope
KW - Nano-mechanics
KW - Rigor mortis
KW - Time since death
UR - http://hdl.handle.net/10807/133008
U2 - 10.1007/s00414-019-02034-z
DO - 10.1007/s00414-019-02034-z
M3 - Article
SN - 0937-9827
SP - 1
EP - 7
JO - International Journal of Legal Medicine
JF - International Journal of Legal Medicine
ER -