Estimation of postmortem interval by vitreous potassium evaluation with a novel fluorescence aptasensor

Abstract

Estimation of postmortem interval (PMI) is a central role in medico-legal identification. Analysis of vitreous potassium ions (K+) concentration is frequently used by forensic workers to estimate PMI. This paper describes interdisciplinary research to introduce fluorescence sensing techniques into forensic medicine. On the basis of silver nanoclusters (AgNCs) probe stabilized by DNA, a simple and highly sensitive fluorescence aptasensor has been proposed to selectively detect K+ ions. The linear range for K+ ions was found to be 0.1 nM-1 mM, with limit of detection of 0.06 nM. Moreover, 63 vitreous humour cases within 36 h after death were further studied to verify the utility of K+ ions in estimating the PMI. By the fluorescence aptasensor method, a new formula was built to determine the postmortem interval based on K+ ions concentration: PMI(h) = −0.55 + 1.66 × CK +(r = 0.791). And the real significance of this research was demonstrated by additional 6 cases with known PMIs. In comparison with the conventional method, the presented aptasensor strategy is cost-effective and easy in measuring vitreous K+, which may be potentially a better way for estimation of PMI in medico-legal practice.

Novel genetically encoded fluorescent probes enable real-time detection of potassium in vitro and in vivo

“…This can be done conveniently in a conventional multi-well fluorescence plate reader and has the advantage of a very small sample volume (around 5 µl) compared to common ISE instruments and most other K + indicators 15 , 16 . This could enable more repetitive sampling from small animals without sacrificing them 25 , and could also be useful in neonatal diagnostics 35 and forensic medicine 36 . We also demonstrated that an increase of [K + ] ex upon cell death is dynamically detectable in vitro and in situ with the GEPII-technology.…”

Individualised and non-contact post-mortem interval determination of human bodies using visible and thermal 3D imaging

“…These strategies generally belong to one of two groups. The first seeks to quantify thanatochemical changes such as nucleic acid degradation [2][3][4] , changes in the ocular potassium concentration [5][6][7] , as well as microbial 8 and metabolomic 9 changes. These necessitate physical sampling of human tissue or bodily fluids 10 followed by further examination in a laboratory.…”

Correlación entre Sodio, Cloro y Potasio del Cuerpo Vítreo y el Intervalo Postmortem sobre los 2.850 msnm

“…En esta investigación se corroboró que existe una correlación lineal entre el IPM y el aumento del K + descrito por autores como (Coe, 1989;Jashnani et al, 2010;Swain et al, 2015;Ding et al, 2017;Yang et al, 2018) quienes también describieron esta relación pero con dispersión creciente pasados las 20 h postmortem. En otros estudios también se encontró una relación lineal entre 12 y 100 horas postmortem, Ahi & Garg (2011) Madea et al (1989 encontraron que las concentraciones de Na + , Ca, Cly la urea fueron estables en el intervalo postmortem de 120 h.…”