Colloidal systems are used in different fields of science and industry. At present, colloidal systems and their properties are being actively studied. The stability of colloidal systems is the main characteristic. For example, stability is hindered by aggregation and sedimentation phenomena, which are driven by the colloid's tendency to reduce surface energy. The technique of electrophoretic light scattering allows us to measure zeta - potential of colloidal systems related to stability of systems. As compared with other methods (Doppler velocimetry, electrophoresis, optical microscopy, Raman spectroscopy), this technique has a short time for analyses, a small volume of the objects to be investigated and cheap equipment. Zeta-potential is used to characterize particle surface charge and to obtain information about their stability and surface interaction with other molecules. In this review, we focus on nanoparticle characterization. In our study, the new techniques for measurement of zeta-potential of colloidal system is realized on the basis of a total internal reflection prism where the free electrophoresis regime is set. The purpose of our work is to compare two types of sample cells and different techniques of measuring electrophoretic mobility and zeta-potential of colloidal systems. The silicon oxide spheres suspended in deionized water with a concentration of 25% and a diameter of 320 nm were used as a test sample. The results obtained in our study demonstrated the applicability of the method for the investigation of liquid solutions, including biological fluids, and a higher sensitivity as compared with standard measurements techniques in bulk measurements.
A new approach to measure changes of polarization state of the light scattered from a biological object using crosspolarization and polarimetry imagining technique is considered. The method is based on the calculation of the coefficient of residual polarization. Two experimental setups based on incoherent white light source and infrared light source for imaging of the skin pathology with polarimetric detection and processing are developed. The results of two experimental setups are compared and analyzed. The experimental setup based on infrared light source allows one to get better results than the experimental setup based on white light source, because the depth of penetration of infrared radiation is ten times greater than the depth of penetration of visible light.
The latest tendencies in individual diagnostics show high interest in development of optical methods. We have used a dynamic light scattering technique to study the size composition of proteins in blood serum of donors with different diseases. In this work, we focused our attention on demonstration of differences between size compositions of blood serum of donors with different types of diseases. It had been found that the proteins' size composition for sick donors differs in a certain way from the size map of healthy donors. Specifically, the relative concentrations of albumins, globulins and circulating immune complex can be used as a diagnostic parameter as it changes significantly on the disease. This result shows the possibilities of application of dynamic light scattering technique to analyze progress and stage of different diseases, in particular, immune diseases and oncology. We declare that the proposed dynamic light scattering technique can be used in medical practice for early fast and simple diagnostics.
Immune diseases are associated with the activity of cellular and humoral immunity. The humoral (molecular) immunity plays the role in mechanisms of immunological tolerance and pathogenesis of many diseases, including cancerous. The opportunities as well as the challenges facing the humoral immunity analysis are formidable. The study of molecular composition and functionality of humoral immunity is capable to reveal effective strategies for early diagnosis and treatment. The optical techniques were selected for this research due to the noninvasiveness and simplicity of in vivo imaging, allowing real-time observations of the immune activation process. The laser correlation spectroscopic technique allows one to determine sizes of nanoparticles, in particular molecules and molecular agglomerates. In this work, the original scheme of the device based on laser correlation spectroscopic technique is suggested. In the presented work, the molecular compounds were investigated in blood serum. We measured the size distribution of protein molecules in blood of several donors. We observed both single proteins and the protein agglomerates demonstrating normal course of metabolic process in an organism. Then we initiated the immune reactions by the addition of the vaccines to the blood serum. After that, the noticeable aggregation of proteins was observed. To separate specific and nonspecific immune reactions a blood serum with inactivated complement system was also studied. It showed a significantly different outcome. So the laser correlation spectroscopic technique can be successfully used for analysis of the immune activation processes and further diagnostics.
In this article the interaction between ionically stabilized magnetic nanoparticles and blood serum albumin proteins in liquid medium are discussed. Some distributions of nanoparticles’ agglomerate sizes in solutions of albumin molecules, magnetic nanoparticles and their mixtures both under the influence of magnetic field and free from it are presented. It is shown that magnetic nanoparticles interact with albumin molecules, forming agglomerates. It is also shown that at the influence of magnetic field sizes of agglomerates increase proportionally to the magnetic field density.
At present, saliva and its properties are being actively studied. Human saliva is a unique biological material that has potential in clinical practice. A detailed analysis of the characteristics and properties of saliva is relevant for diagnostic purposes. In this paper, the properties and characteristics of saliva are studied using optoelectronic methods: dynamic light scattering, electrophoretic light scattering and optical microscopy. Mixed saliva from a healthy patient and patient with diabetes mellitus type 2 was used as an object of the study. The dynamics of the behavior of a healthy and patient with diabetes mellitus type 2 is visible according to the results obtained. All three methods confirm hypothesis of structural changes in mixed saliva in the disease of diabetes mellitus type 2.
Investigation of fullerenol solutions with metal salts (magnesium sulfate and calcium chloride) by the laser correlation spectroscopy is presented. The results of the experimental study are discussed. Some peculiarities of interaction between fullerenol and different metal salts were observed. The results of the experiments revealed that fullerenol can be the chelate ligand that may be useful for medical applications.