ANALYSIS OF FORMING BLOOD ELEMENTS USING SURFACE PLASMON-POLARITON RESONANCE: MODEL OF TRANSITION LAYER

2020 ◽  
Vol 55 ◽  
pp. 136-150
Author(s):  
Yu.M. Shirshov ◽  

Despite the great practical importance, the control of blood by optical methods is enormously complicated by the strong scattering of light. This is especially true for formed blood elements (FBEs), which are a compact suspension that remains after plasma removal from blood by centrifugation. The study of the surface plasmon resonance (SPR) in Kretchman’s geometry together with measurement of the angular dependence of the light internal reflection R( φ ) at the glass/ FBEs boundary is one of the few possibilities to obtain additional information about the structure and molecular composition of this complex inhomogeneous object. Measurement of R( φ ) for contact FBEs with the glass surface allows to determine the total internal reflection (TIR) angle and the effective refractive index N of the binary of erythrocytes-blood plasma mixture. At the same time, the comparison of the angles of TIR and SPR makes it possible to establish the presence of a transition layer between gold surface and the volume of FBEs. In addition, a detailed matching of the experimental dependence R( φ ) with one of calculated curve by regression method allows minimize the objective function and allows to establish a detailed model of the transition layer. The paper shows that the value of N is 1.4003...1.4008. According to the formula of the effective Bruggeman's medium, the packing density of erythrocytes in the volume of FBEs is about 85%, which is well matched with the data known from the literature. At the same time, at least two intermediate layers were detected at the gold /FBEs interface. (1) A layer 33–38 nm thick adjacent to the hydrophobic surface of the gold film and with a refractive index of N p = 1.356–1.357. Presumably, it is a binary phase with a liquid part in the form of water, a buffer solution or blood plasma and a hard part in the form of proteins non-specifically related to gold, most likely molecules of albumin and fibrinogen. (2) A thicker, transition-to- volume FBEs layer is most likely related to the edges curvature and marginal packing of erythrocytes; the effective thickness of this layer is d m = 130-200 nm, and the effective refractive index N m = 1.356... 1.369. The details of this transition layer are currently of considerable practical interest because they can reflect the physiological state of blood cells and whole body, and the parameters d m and N m can be useful from a biological or medical point of view.

Author(s):  
Iltai (Isaac) Kim ◽  
Kenneth David Kihm

Innovative optical techniques based on nano-biophotonics such as surface plasmon resonance (SPR) imaging and R-G-B natural fringe mapping techniques are developed to characterize the transport and optical properties of nanofluids in situ, real-time, and full field manner. Recent results regarding the characterization of nanofluids are summarized and future research directions are presented. 47 nm Al2O3 nanoparticles are dispersed in water with various concentrations. Al2O3 nanofluids droplets are placed on substrates and evaporated in room temperature. In-situ visualization of evaporation-induced self-assembly is conducted to detect concentration, effective refractive index, and different self-assembled pattern including cavity with various nanofluids concentrations and surface hydrophobbicities with SPR and fringe mapping. During the evaporation, time-dependent and near-field nanoparticle concentrations are determined by correlating the SPR reflectance intensities with the effective refractive index (ERI) of the nanofluids. With increasing the concentrations of nanofluids, the existence of hidden complex cavities inside a self-assembled nanocrystalline structure or final dryout pattern is discovered in real-time. R-G-B natural fringe mapping allowed the reconstruction of the 3D cavity formation and crystallization processes quantitatively. The formation of the complex inner structure was found to be attributable to multiple cavity inceptions and their competing growth during the aquatic evaporation. Furthermore, the effect of surface hydrophobicity is examined in the formation of hidden complex cavities, taking place on three different substrates bearing different levels of hydrophobicity; namely, cover glass (CG), gold thin film (Au), and polystyrene dish (PS). These surface plamson resonance imaging and natural fringe mapping techniques are expected to provide a breakthrough in micro-nanoscale thermal fluids phenomena and nano-biochemical sensing when coupled with localized surface Plasmon and metamaterials techniques.


2013 ◽  
Vol 811 ◽  
pp. 186-191
Author(s):  
J.C. Juarez-Morales ◽  
Ma. Lourdes Granados-Marin

Associating a perturbation term for the effective refractive index which may depend ontime or position we describe the extremal features for the surface plasmon fields propagating on aroughness metal surface. This representation allows us to interpret the surface optical field as ageodesic flow which in principle enables us to associate coherence features to plasmon modes andto analyze the stability of the surface fields under small perturbations of the refractive index.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Koyo Watanabe ◽  
Koji Matsuura

Effective refractive indices detected using surface plasmon resonance techniques are calculated as a function of the tilt angle of lipid bilayers in a multilayered model. The changes in the effective refractive indices are derived from the shift of an excitation angle of surface plasmon. To obtain effective refractive index plots, we determined refractive index changes in the lipid bilayers with 3 and 5 nm thicknesses as a function of tilt angle and obtained a relationship between the effective refractive index and tilt angle. We also showed that the effective refractive index depended on the lipid bilayers thickness and anisotropic permittivities, which vary with interchain distance.


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