Influence of relative humidity and temperature on human whole blood drying

Abstract

The drying of human whole blood pools has been studied experimentally to improve the understanding of drops and pools of human whole blood. Here blood is assimilated to a complex fluid made of several bio-colloids. The blood pools were created inside a glove box under controlled conditions. We performed experiments at temperatures of 21${}^{°}$C, 29${}^{°}$C, and 37${}^{°}$C, and relative humidity ranging from 20% to 70%. The air inside the glove box was still, and the evaporation process was mainly purely diffusive. A human blood diffusion coefficient of $(1.08\pm 0.02)\times {10}^{-9}{\mathrm{m}}^2/\mathrm{s}$ was obtained. This value is in agreement with literature values for polymers and colloidal films. Moreover, we elaborated an updated model using Page’s model to describe the drying kinetics of human blood pools. The effect of the surface area of pools was considered using a diffusive characteristics time. These findings are of interest for biomedical and forensic applications.

Keywords:

• Human blood
• Pool and film
• Fick’s law
• Diffusion coefficient
• Drying kinetics

Acknowledgements

We would like to thank Dr. Thomas Fasquelle for donating whole blood ($500 mL$) over 5 months and the sampling nurse Magali Di Nocera, who collected the blood.

Disclosure statement

The authors have no conflict of interest to disclose.