Drop Drying on the Sensor: One More Way for Comparative Analysis of Liquid Media

It is known that the processes of self-organization of the components of drying a liquid drop on a solid substrate are well reproduced under the same external conditions and are determined only by the composition and dispersion of the liquid. If the drop dries on the surface of the sensor device, these processes can be recorded and used as a passport characteristic of the liquid. The first half of the article is devoted to the description of the principles of the method and the proof of the validity of our assumptions. The second half of the article is devoted to the development of a user-friendly version of the device, where the change in the real and imaginary parts of the electrical impedance of the resonator was used as an informative parameter. The measure of the closeness of the relative positions of the hodographs of the compared samples on the complex plane is used as a criterion for the similarity-/-difference of various liquids. The design of a new sensor device and the results of its tests for distinguishing between different brands of alcoholic beverages and reconstituted milk of different concentrations are presented.

Interfacial energy driven distinctive pattern formation during the drying of blood droplets

HYPOTHESIS

Dried blood droplet morphology may potentially serve as an alternative biomarker for several patho-physiological conditions. The deviant properties of the red blood cells and the abnormal composition of diseased samples are hypothesized to manifest through unique cell-cell and cell-substrate interactions leading to different morphological patterns. Identifying distinctive morphological trait from a large sample size and proposing confirmatory explanations are necessary to establish the signatory pattern as a potential biomarker to differentiate healthy and diseased samples.

EXPERIMENTS

Comprehensive experimental investigation was undertaken to identify the signatory dried blood droplet patterns. The corresponding image based analysis was in turn used to differentiate the blood samples with a specific haematological disorder "Thalassaemia" from healthy ones. Relevant theoretical analysis explored the role of cell-surface and cell-cell interactions pertinent to the formation of the distinct dried patterns.

FINDINGS

The differences observed in the dried blood patterns, specifically the radial crack lengths, were found to eventuate from the differences in the overall interaction energies of the system. A first-generation theoretical analysis, with the mean field approximation, also confirmed similar outcome and justified the role of the different physico-chemical properties of red blood cells in diseased samples resulting in shorter radial cracks.

Morphology of Dried Drop Patterns of Saliva from a Healthy Individual Depending on the Dynamics of Its Surface Tension

Background: The study of processes in the drying drops of biological fluids (dried drop patterns) and the method of dynamic surface tensiometry can be attributed to integral methods of assessing the state of the organism. Research objective: to establish the relationship between the type of crystallization patterns and the surface tension of human saliva in normal conditions. Methods: 100 volunteers (40 males, 60 females) that were aged 30–59 participated in the study. In all saliva samples, the parameters of dynamic tensiometry, types of crystallization patterns and 11 biochemical parameters were determined. Results: No statistically significant differences in the saliva crystallization patterns were observed, depending on the age and gender characteristics of the volunteers. A negative correlation of the area of the crystallization zone and the surface tension of saliva is shown. When considering the crystallization patterns, their considerable variability was noted; on this basis, the entire studied sample was divided into four clusters by surface tension. Conclusion: In general, the crystallization patterns that are inside the selected groups remain quite heterogeneous. This increases the likelihood of making an incorrect diagnosis when using visual methods to evaluate the crystallization patterns, which significantly limits the use of such diagnostic methods in clinical practice.