Capabilities of Double-Resonance LPG and SPR Methods for Hypersensitive Detection of SARS-CoV-2 Structural Proteins: A Comparative Study

Eftimov, Tinko; Genova-Kalоu, Petia; Dyankov, Georgi; Bock, Wojtek J.; Mankov, V.; Ghaffari, Sanaz Shoar; Veselinov, Petar; Arapova, А. V.; Makouei, Somayeh

doi:10.3390/bios13030318

Cited by 8 publications

(9 citation statements)

References 47 publications

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“…Some of them, such as abnormal heme metabolism and oxygen transport can be registered long before the acute phase of infection. This is a consequence of the observed binding activity to Hb which is much higher than the binding to the monoclonal antibodies, as reported in a recent paper of ours [ 23 ]. In support of this hypothesis, it is worth mentioning that the common viral loads for COVID-19-positive patients have been found to be in the range of 10 6 –10 11 RNA copies/mL [ 24 ], while we observed a pronounced binding at 10 4 RNA copies/ml.…”

Section: Discussionsupporting

confidence: 70%

“…The reported data demonstrate that SPR and DR LPG can detect proteins with a limit of detection reaching several tens of fM. This is in contrast to the 130 fM, achieved by the SPR detection based on antibody-antigen interaction, as reported in a recent paper of ours [ 23 ]. This comparison is admissible since constant concentrations of ligands and proteins were maintained in our experiments.…”

Section: Discussionmentioning

confidence: 48%

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Binding of SARS-CoV-2 Structural Proteins to Hemoglobin and Myoglobin Studied by SPR and DR LPG

Dyankov

Genova-Kalоu

Eftimov

et al. 2023

Sensors

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One of the first clinical observations related to COVID-19 identified hematological dysfunctions. These were explained by theoretical modeling, which predicted that motifs from SARS-CoV-2 structural proteins could bind to porphyrin. At present, there is very little experimental data that could provide reliable information about possible interactions. The surface plasmon resonance (SPR) method and double resonance long period grating (DR LPG) were used to identify the binding of S/N protein and the receptor bind domain (RBD) to hemoglobin (Hb) and myoglobin (Mb). SPR transducers were functionalized with Hb and Mb, while LPG transducers, were only with Hb. Ligands were deposited by the matrix-assisted laser evaporation (MAPLE) method, which guarantees maximum interaction specificity. The experiments carried out showed S/N protein binding to Hb and Mb and RBD binding to Hb. Apart from that, they demonstrated that chemically-inactivated virus-like particles (VLPs) interact with Hb. The binding activity of S/N- and RBD proteins was assessed. It was found that protein binding fully inhibited heme functionality. The registered N protein binding to Hb/Mb is the first experimental fact that supports theoretical predictions. This fact suggests another function of this protein, not only binding RNA. The lower RBD binding activity reveals that other functional groups of S protein participate in the interaction. The high-affinity binding of these proteins to Hb provides an excellent opportunity for assessing the effectiveness of inhibitors targeting S/N proteins.

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Section: Discussionsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 48%

Binding of SARS-CoV-2 Structural Proteins to Hemoglobin and Myoglobin Studied by SPR and DR LPG

Dyankov

Genova-Kalоu

Eftimov

et al. 2023

Sensors

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“…The method was successfully applied for SARS CoV-2 structural proteins detection [8,9]. The optical set-up used for amplitude SPR detection is shown in figure 1.…”

Section: Surface Plasmon Resonance Methodsmentioning

confidence: 99%

Biosensor-based serological assay for diagnosing Helicobacter pylori infection

Kolev,

Hikova,

Kisov

et al. 2024

IOP Conf. Ser.: Earth Environ. Sci.

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Helicobacter pylori causes the most common bacterial infection involving 50% of the global population. According to the World Health Organization H. pylori infection contributes to approximately 75% of the stomach cancer cases and 5.5% of all types of cancer. Therefore, timely diagnosis of the infection is highly desirable. Serological assays are widely performed for diagnosing H. pylori infection, the most frequently used one being ELISA. In the present study we showed that a serological assay can also be carried out using a biosensor based on Surface Plasmon Resonance (SPR). Unlike our previous studies where we used amplitude detection of the binding reactions, here we applied phase-sensitive detection. It was performed with a the channeled spectroscopic ellipsometer, which allowed fast measurement with high sensitivity. Thus, the detection limit achieved was more than two times lower than that of the amplitude detection. In terms of CFU, phase detection was sensitive even at 200 CFU, while amplitude detection was applicable at 3000 CFU.

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“…The SPR biochip is a grating covered with a biorecognition layer of blood antigen Lewis b of certain thickness, as shown in Figure 1. Details on our SPR measurement system based on spectrum readout can be fo [26]. The spectrometer accuracy measurement was 0.2 nm, while the overall accu the resonance shift measurement of the SPR system was appraised at about 2 n limit of detection (LOD) was evaluated by considering the accuracy of the spectro as well as the accuracy of the goniometer for setting up the angle of light incidence Details on our SPR measurement system based on spectrum readout can be found in [26].…”

Section: Spr Platformsmentioning

confidence: 99%

SPR and Double Resonance LPG Biosensors for Helicobacter pylori BabA Antigen Detection

Dyankov,

Eftimov,

Hikova

et al. 2024

Sensors

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Given the medical and social significance of Helicobacter pylori infection, timely and reliable diagnosis of the disease is required. The traditional invasive and non-invasive conventional diagnostic techniques have several limitations. Recently, opportunities for new diagnostic methods have appeared based on the recent advance in the study of H. pylori outer membrane proteins and their identified receptors. In the present study we assess the way in which outer membrane protein–cell receptor reactions are applicable in establishing a reliable diagnosis. Herein, as well as in other previous studies of ours, we explore the reliability of the binding reaction between the best characterized H. pylori adhesin BabA and its receptor, the blood antigen Leb. For the purpose we developed surface plasmon resonance (SPR) and double resonance long period grating (DR LPG) biosensors based on the BabA–Leb binding reaction for diagnosing H. pylori infection. In SPR detection, the sensitivity was estimated at 3000 CFU/mL—a much higher sensitivity than that of the RUT test. The DR LPG biosensor proved to be superior in terms of accuracy and sensitivity—concentrations as low as 102 CFU/mL were detected.

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Capabilities of Double-Resonance LPG and SPR Methods for Hypersensitive Detection of SARS-CoV-2 Structural Proteins: A Comparative Study

Cited by 8 publications

References 47 publications

Binding of SARS-CoV-2 Structural Proteins to Hemoglobin and Myoglobin Studied by SPR and DR LPG

Binding of SARS-CoV-2 Structural Proteins to Hemoglobin and Myoglobin Studied by SPR and DR LPG

Biosensor-based serological assay for diagnosing Helicobacter pylori infection

SPR and Double Resonance LPG Biosensors for Helicobacter pylori BabA Antigen Detection

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