In Vivo Quasi-Elastic Light Scattering Eye Scanner Detects Molecular Aging in Humans and Mice

The absence of clinical tools to evaluate individual variation in the pace of aging represents a major impediment to understanding aging and maximizing health throughout life. The lens is an ideal tissue for quantitative assessment of molecular aging in vivo. Long-lived proteins in lens fiber cells are expressed during fetal life, do not undergo turnover, accumulate molecular alterations throughout life, and are optically accessible in vivo. We used quasi-elastic light scattering (QLS) to measure age-dependent signals in lenses of both healthy human subjects and wild-type C57BL/6 mice. Age-dependent QLS signal changes detected in vivo in humans and mice recapitulated time-dependent changes in hydrodynamic radius, protein polydispersity, and supramolecular order of human lens proteins during long-term incubation (~1 year) and in response to sustained oxidation (~2.5 months) in vitro. Our findings demonstrate that QLS analysis of lens proteins provides a practical technique for noninvasive assessment of molecular aging in vivo.

Comparison of Whiskbroom and Pushbroom darkfield elastic light scattering spectroscopic imaging for head and neck cancer identification in a mouse model

The early detection of head and neck cancer is a prolonged challenging task. It requires a precise and accurate identification of tissue alterations as well as a distinct discrimination of cancerous from healthy tissue areas. A novel approach for this purpose uses microspectroscopic techniques with special focus on hyperspectral imaging (HSI) methods. Our proof-of-principle study presents the implementation and application of darkfield elastic light scattering spectroscopy (DF ELSS) as a non-destructive, high-resolution, and fast imaging modality to distinguish lingual healthy from altered tissue regions in a mouse model. The main aspect of our study deals with the comparison of two varying HSI detection principles, which are a point-by-point and line scanning imaging, and whether one might be more appropriate in differentiating several tissue types. Statistical models are formed by deploying a principal component analysis (PCA) with the Bayesian discriminant analysis (DA) on the elastic light scattering (ELS) spectra. Overall accuracy, sensitivity, and precision values of 98% are achieved for both models whereas the overall specificity results in 99%. An additional classification of model-unknown ELS spectra is performed. The predictions are verified with histopathological evaluations of identical HE-stained tissue areas to prove the model’s capability of tissue distinction. In the context of our proof-of-principle study, we assess the Pushbroom PCA-DA model to be more suitable for tissue type differentiations and thus tissue classification. In addition to the HE-examination in head and neck cancer diagnosis, the usage of HSI-based statistical models might be conceivable in a daily clinical routine. Graphical abstract

Development of optical diagnostic method for colloidal solutions based on elastic light scattering

The work is devoted to colloidal solutions diagnostics by the optical method based on elastic light scattering by particles of the dispersed phase. The scheme of the developed optical electronic complex for recording the intensity of radiation scattered by colloidal particles is presented. The experimental study results of the elastic scattering of laser radiation on spherical nanometer-sized aluminum oxide particles suspended in water are represented. A method for measuring the scattering indicatrix based on the registration of radiation scattered in various directions and subsequent computer processing has been proposed. A method for reconstructing the particle size distribution function of colloidal solution dispersed phase by comparing the measured scattering indicators and their computer models has been developed. The method has been tested, as a result of which the size distribution function of aluminum oxide nanopowder particles has been restored.

The technique of optical-electrochemical microbiological testing as applied to the comparative analysis of the prebiotic and antimicrobial properties of various plant extracts

A biotesting technique is described that provides for periodic (every 2 h) recording of changes in the in-tensity of elastic light scattering, pH and electrical conductivity of a liquid nutrient medium incubated in the presence and absence of viable test microorganisms and test samples. The results of a comparative analysis using this technique of antibiotic activity against Staphylococcus aureus of different concentra-tions of whole subcritical extracts obtained using liquefied CO2 from 10 different types of plant raw mate-rials are presented. Studies have shown that among the samples studied by us, the most active prolonged antimicrobial properties were exhibited by extracts from the roots of Chelidonium majus and flowers of Calendula officinalis at their concentration in the test medium (CTE) more than 3 vol.%. And the most ac-tive prolonged prebiotic properties were exhibited by extracts from shoots of Viscum album and leaves of Juglans regia at CTE = 0.2 vol.%. In this case, the biological activity of the tested samples with respect to test microorganisms in most cases monotonically decreased with an increase in the interaction time of the mentioned microorganisms and samples. However, the exact nature of these dependencies in most cases can be established only with the help of a significant number of tests. And the latter can be conveniently carried out using the methodology presented in this work, which allows a much more rapid, objective and informative, as well as much less laborious and material-intensive, than when using standard visual mi-crobiological methods, to assess the effect on the dynamics of the vital activity of microorganisms of vari-ous tested samples.

Three dimensional tracking of nanoparticles by dual-color position retrieval in double-core microstructured optical fiber

Elastic light scattering based three-dimensional (3D) tracking of objects at the nanoscale level is essential for unlocking dynamics of individual species or interactions in fields such as biology or surface...

Three-dimensional spatiotemporal tracking of nano-objects diffusing in water-filled optofluidic microstructured fiber

Three-dimensional (3D) tracking of nano-objects represents a novel pathway for understanding dynamic nanoscale processes within bioanalytics and life science. Here we demonstrate 3D tracking of diffusing 100 nm gold nanosphere within a water-filled optofluidic fiber via elastic light scattering–based position retrieval. Specifically, the correlation between intensity and position inside a region of a fiber-integrated microchannel has been used to decode the axial position from the scattered intensity, while image processing–based tracking was used in the image plane. The 3D trajectory of a diffusing gold nanosphere has been experimentally determined, while the determined diameter analysis matches expectations. Beside key advantages such as homogenous light-line illumination, low-background scattering, long observation time, large number of frames, high temporal and spatial resolution and compatibility with standard microscope, the particular properties of operating with water defines a new bioanalytical platform that is highly relevant for medical and life science applications.