Pattern formation in drying blood drops

Abstract

Patterns in dried droplets are commonly observed as rings left after spills of dirty water or coffee have evaporated. Patterns are also seen in dried blood droplets and the patterns have been shown to differ from patients afflicted with different medical conditions. This has been proposed as the basis for a new generation of low-cost blood diagnostics. Before these diagnostics can be widely used, the underlying mechanisms leading to pattern formation in these systems must be understood. We analyse the height profile and appearance of dispersions prepared with red blood cells (RBCs) from healthy donors. The red cell concentrations and diluent were varied and compared with simple polystyrene particle systems to identify the dominant mechanistic variables. Typically, a high concentration of non-volatile components suppresses ring formation. However, RBC suspensions display a greater volume of edge deposition when the red cell concentration is higher. This discrepancy is caused by the consolidation front halting during drying for most blood suspensions. This prevents the standard horizontal drying mechanism and leads to two clearly defined regions in final crack patterns and height profile. This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction’.

Drying of bio-colloidal sessile droplets: Advances, applications, and perspectives

“…Since it is not yet possible to make bio-mimetic blood like artificial urine [121], an attempt is made to compare the RBCs in PBS, BSA in PBS, and polystyrene colloidal particle model systems to identify the vital mechanistic parameters for explaining the resulting morphological patterns. The high RBC concentration does not suppress the coffee-ring effect as the high polystyrene colloidal particles do [122].…”

Optical profilometry for forensic bloodstain imaging

“…Heikkinen et al [20] used white light interferometry to identify similarities and differences between tool mark samples and further identified firing pins via impression details that could not be identified using 2D imaging. Hertaeg et al [21] used laser confocal microscopy to collect height profiles of bloodstains with varying concentrations of RBCs suspended in three different solutions: plasma, phosphate buffered saline (PBS), and bovine serum albumin (BSA). Their results corroborated previous findings that higher RBC concentrations increase the amount of RBC deposition at the edge of the bloodstain [21].…”

“…Hertaeg et al [21] used laser confocal microscopy to collect height profiles of bloodstains with varying concentrations of RBCs suspended in three different solutions: plasma, phosphate buffered saline (PBS), and bovine serum albumin (BSA). Their results corroborated previous findings that higher RBC concentrations increase the amount of RBC deposition at the edge of the bloodstain [21]. From this, we asked whether optical profilometry, using full scan and centre profiles, can also be useful in monitoring time-wise changes in degrading bloodstains.…”

Optical profilometry for forensic bloodstain imaging

“…Heikkinen et al (2011) used white light interferometry to identify similarities and differences between tool mark samples and further identified firing pins via impression details that could not be identified using 2D imaging. Hertaeg et al (2021) used laser confocal microscopy to collect height profiles of bloodstains with varying concentrations of RBCs suspended in three different solutions: plasma, phosphate buffered saline (PBS), and bovine serum albumin (BSA). Their results corroborated previous findings that higher RBC concentrations increase the amount of RBC deposition at the edge of the bloodstain (Hertaeg et al, 2021).…”