Anti-CCP biosensors in rheumatoid arthritis.

Biosensors are unique analytical tools for the detection of biomarkers. Of these, autoantibodies against citrullinated proteins (ACPA) are useful for the differential diagnosis of rheumatoid arthritis (RA). The autoantibodies may be detected by immunoassay technology using synthetic cyclic citrullinated peptides (CCP), ie, anti-CCP. Recently, several biosensors have been developed for anti-CCP using CCP and mutated citrullinated vimentin (MCV) as recognition elements. In this review we highlight all currently available ACPA biosensor technology including those based on fluorescence, chemiluminescence, electrochemiluminescence (ECL), surface-enhanced Raman scattering (SERS)-based, surface plasmon resonance (SPR), lateral flow immunoassays (LFIA), and electrochemical. We explore various peptides as recognition elements, electrode modifiers and signal amplification systems thus providing new opportunities for next-generation biosensor design in RA.

Surface plasmon resonance biosensors for early troponin detection.

Acute myocardial infarction (AMI) is one of the life-threatening causes that decrease blood flow to the heart, leading to increased mortality and related complications. Recently, the measure of blood concentration of cardiac biomarkers has been suggested to overcome the limitations of electrocardiography (ECG) analyses for early diagnosis of this disease. Troponins, especially cardiac troponin I and cardiac troponin T, with high sensitivity and specificity, are considered the gold standards in myocardial diagnosis. Recently, the use of new biosensors such as surface plasmon resonance (SPR) for early detection of these biomarkers has been greatly appreciated. Due to the rapid, sensitive, real-time, and label-free detection of SPR-based biosensors, they can be applied for selective and nonspecific absorption that is intended to be used as an in situ cardiac biosensor. Here, we exclusively discussed the updated developments of these valuable predictors for the possible occurrence of AMI detected by SPR.

Recent Advances in Chemistry, Mechanism, and Applications of Quantum Dots in Photodynamic and Photothermal Therapy.

Semiconductor quantum dots (QD) are a kind of nanoparticle with unique optical properties that have attracted a lot of attention in recent years. In this paper, the characteristics of these nanoparticles and their applications in nanophototherapy have been reviewed. Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has gained special importance because of its high accuracy and local treatment due to the activation of the drug at the tumor site. PDT is a new way of cancer treatment that is performed by activating light-sensitive compounds named photosensitizers (PS) by light. PSs cause the destruction of diseased tissue through the production of singlet oxygen. PTT is another non-invasive method that induces cell death through the conversion of near-infrared light (NIR) into heat in the tumor situation by the photothermal agent (PA). Through using energy transfer via the FRET (Förster resonance energy transfer) process, QDs provide light absorption wavelength for both methods and cover the optical weaknesses of phototherapy agents.

Astaxanthin Binding Affinity to DNA: Studied By Fluorescence, Surface Plasmon Resonance and Molecular Docking Methods.

Carotenoid astaxanthin (Ax), a pink-red pigment, with its anti-oxidative feature, is useful as a therapeutic element for numerous diseases. The purpose of this study is to investigate the binding affinity of Ax to double strand (ds) DNA evaluated by using the fluorescence spectroscopy, surface plasmon resonance (SPR) and docking approaches. The fluorescence results show that Ax can quench the intensity of DNA fluorescence via a static quenching way. In the SPR method, for affinity evaluation, DNA molecules were attached on a gold sensor surface. Using different amounts of ds DNA, the kinetic values KD, KA, and Ka were calculated. The Van't Hoff equation was used to estimate thermodynamic parameters including enthalpy (∆H), entropy (∆S) and Gibbs free energy (∆G) changes. The obtained results for KD in SPR (6.89×10-5 M) and fluorescence (KD=0.76×10-5 M) methods were in line with each other. Thermodynamic studies were carried out at four different temperatures, and the resulted negative data for ΔH and ΔS displayed that the main binding strength in the interaction of Ax with DNA was hydrogen bonding. ΔG value calculated by fluorescence method was near -38 kJ. mol-1 and using the docking method, estimated -9.95 kcal. mol-1 (-41.63 kJ. mol-1) which shows the binding behavior has an exothermic and spontaneous mechanism. Molecular docking results confirmed that the side chains of Ax interact specifically with base pairs and the DNA backbone.

Biomarkers and optical based biosensors in cardiac disease detection: early and accurate diagnosis.

Rapid and precise detection methods for the early-stage detection of cardiovascular irregularities are crucial to stopping and reducing their development. Cardiovascular diseases (CVDs) are the leading cause of death in the world. Hence, cardiac-related biomarkers are essential for monitoring and managing of process. The necessity for biomarker detection has significantly widened the field of biosensor development. Bio-sensing methods offer rapid detection, low cost, sensitivity, portability, and selectivity in the development of devices for biomarker detection. For the prediction of cardiovascular diseases, some biomarkers can be used, like C-reactive protein (CRP), troponin I or T, creatine kinase (CK-MB), B-type natriuretic peptide (BNP), myoglobin (Mb), suppression of tumorigenicity 2 protein (ST2) and galectin-3 (Gal3). In this review, recent research studies were covered for gaining insight into utilizing optical-based biosensors, including surface plasmon resonance (SPR), photonic crystals (PCs), fluorescence-based techniques, fiber optics, and also Raman spectroscopy biosensors for the ultrasensitive detection of cardiac biomarkers. The main goal of this review is to focus on the improvement of optical biosensors in the future for the diagnosis of heart diseases and to discuss how to enhance their properties for use in medicine. Some main data from each study reviewed are emphasized, including the CVD biomarkers and the response range of the optical-based devices and biosensors.

Major depressive disorder: Biomarkers and biosensors.

Depressive disorders belong to highly heterogeneous psychiatric diseases. Loss of in interest in previously enjoyed activities and a depressed mood are the main characteristics of major depressive disorder (MDD). Moreover, due to significant heterogeneity in clinical presentation and lack of applicable biomarkers, diagnosis and treatment remains challenging. Identification of relevant biomarkers would allow for improved disease classification and more personalized treatment strategies. Herein, we review the current state of these biomarkers and then discuss diagnostic techniques of aimed to specifically target these analytes using state of the art biosensor technology.

Toxoplasmosis diagnostic techniques: Current developed methods and biosensors.

Toxoplasma gondii infection is a usual worldwide issue since a broad range of vertebrate hosts are infected by this famous parasite. However fetuses and immuno-compromised patients infected by parasite is of specific concern. Developing the easy-to-use, accurate, real time and selective methods for detection of toxoplasma infection has a key role in the treatment and management of patients. In this regard, rapid detection methods with reproducible outcomes during short period are highly interested. In this review, we discussed the recent developed molecular-based laboratory methods for detecting of Toxoplasma infection and also rapid diagnostic methods, especially optic and electrochemical based biosensors with point-of-care features.

The role of statins in lung cancer.

Lung cancer is one of the most common causes of cancer-related mortality in the 21st century. Statins as inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase not only reduce the cholesterol levels in the blood and decrease the risk of cardiovascular disease but may also play an important role in the prevention and treatment of lung cancer. Statins have several antitumor properties including the ability to reduce cell proliferation and angiogenesis, decrease invasion and synergistic suppression of lung cancer progression. Statins induce tumor cell apoptosis by inhibition of downstream products such as small GTP-binding proteins, Rho, Ras and Rac, which are dependent on isoprenylation. Statins reduce angiogenesis in tumors by down-regulation of pro-angiogenic factors, such as vascular endothelial growth factor. In this review, the feasibility and efficacy of statins in the prevention and treatment of lung cancer are discussed.

Study of ß-lactam-based drug interaction with albumin protein using optical, sensing, and docking methods.

The quality and strength of drug and albumin interaction affecting the drug-free concentration and physiological activity are important issues in pharmacokinetic research. In the present study, not only did we evaluate the binding strength of ceftriaxone and ceftizoxime to bovine serum albumin (BSA), but we also investigated the kinetic and thermodynamic parameters including KD, KA, ΔS, and ΔH. We applied in vitro optical fluorescence spectroscopy and surface plasmon resonance (SPR) sensing approaches as well as molecular docking analyses. The kinetic and thermodynamic investigations were done using different concentrations of drugs at three temperatures. Thermodynamic parameters visibly demonstrated that the binding was an exothermic and spontaneous process. The obtained negative values of both enthalpy change (ΔH) and entropy change (ΔS) in fluorescence and SPR and also molecular docking investigations showed that the major binding force involved in the complexation of drugs to BSA was hydrogen bonding. Static quenching was the foremost fluorescence quenching mechanism between them. Furthermore, the results of ΔG and KD values proved that the interaction of ceftriaxone-BSA was stronger than ceftizoxime-BSA. Finally, molecular docking confirmed that the preferable binding sites of ceftizoxime and ceftriaxone were site IIA and site IB of albumin, respectively.

Molecular mechanism and thermodynamic study of Rosuvastatin interaction with human serum albumin using a surface plasmon resonance method combined with a multi-spectroscopic, and molecular modeling approach.

Rosuvastatin (ROS) is an anti-cholesterol drug belonging to statin drugs. A multi-spectroscopic approach combined with a molecular modeling technique was used to assess ROS association with human serum albumin (HSA). Besides, an HSA immobilized surface plasmon resonance (SPR) chip was used to obtain kinetic parameters (ka, kd, and KD). Fluorescence quenching titrations revealed that ROS interacts with HSA via a dynamic, exothermic, enthalpy-driven mechanism. Hydrogen bonds and van der Waals interactions as the most prevalent bonding forces contribute to ROS-HSA complex formation. ROS binding to HSA alters HSA conformation. The SPR results indicated that ROS and HSA have a strong interaction possessing an equilibrium constant (KD) of 1.55 × 10-8 M at 298 K. A competitive analysis of site markers showed that ROS has a higher tendency to bind to the warfarin binding site (site IIA), which may explain why warfarin has a higher anticoagulant effect in ROS users. FRET analysis indicated that non-radiation energy transfer occurred between ROS and HSA. According to molecular docking studies, ROS prefers binding sites IB and IIA while the ROS-HSA complex stabilizes due to the hydrogen bond and π-π interaction. The presence of hydrogen-bond donors and acceptors, as well as aromatic ROS moieties, facilitates such interactions.

Resveratrol reduced the detrimental effects of malondialdehyde on human endothelial cells.

Introduction: According to the statistics, vascular injury occurs during the onset of diabetic changes after the production of several byproducts. Many authorities have focused to find an alternative therapy for diabetic patients. In this study, we investigated the therapeutic effects of natural polyphenol like resveratrol on human endothelial cells exposed to malondialdehyde for 48 hours. Methods: Human Umbilical Vein Endothelial Cells were randomly classified into four groups;control, malondialdehyde (2.5 mM), resveratrol (100 µM), and cells received the combined regime for 48 hours. Cell viability was determined by 3-(4, 5-dimethyl thiazol-2-yl) 2, 5-diphenyl-tetrazoliumbromide (MTT) assay. Griess reaction was performed to measure the content of Nitric oxide (NO).Apoptosis was studied by using real-time polymerase chain reaction (RT-PCR) and western blotting assays. Levels of receptor tyrosine kinases like VEGFR-1, -2, Tie-1, and -2 were analyzed by enzyme-linked immunosorbent assay(ELISA). The affinity of resveratrol and malondialdehyde to serum albumin was measured by Surface Plasmon Resonance Assay. Any changes in chromatin remodeling were detected by PCR array analysis. Results: Resveratrol reduced cytotoxicity and NO content inside cells induced by malondialdehyde(MDA) (P < 0.05). Endothelial cell apoptosis was decreased by the reduction of pro-apoptotic factor Bax and increase of Bcl-2 following the incubation with resveratrol (P < 0.05). MDA-induced receptor tyrosine kinases increase was inhibited by resveratrol and reached near-to-normal levels (P < 0.05).Surface Plasmon Resonance revealed a higher affinity of resveratrol to albumin compared to the malondialdehyde-albumin complex. Polymerase chain reaction (PCR) array revealed the potency of resveratrol in chromatin remodeling following the treatment with malondialdehyde (P < 0.05). Conclusion: Based on our findings, resveratrol has the potential to decrease diabetic vascular injury induced by lipid byproducts such as MDA.

Exploring The Interactions of a Natural Gamma-Oryzanol with Human Serum Albumin: Surface Plasmon Resonance, Fluorescence, and Molecular Modeling Studies.

γ-oryzanol (ORY) is the vital bioactive compound, which is a mixture of ferulic acid ester and plant sterols. In the present work, the binding of ORY to human serum albumin (HSA) was investigated at the molecular level using fluorescence spectroscopy and surface plasmon resonance (SPR) as well as molecular modeling studies. Based on the fluorescence data analysis, ORY can form a non-fluorescent complex with HSA and induce static quenching of the emission intensity of HSA. Also, the high value of K SV (34.69 × 104 M-1) confirmed a high sensitivity of HSA toward ORY. The real-time monitoring of the binding of ORY to HSA was carried out using the SPR technique. The small K D value (1.23 × 10-6 M) calculated by SPR analysis indicated a high affinity of ORY toward HSA. The molecular modeling studies confirmed that ORY has only one binding site on HSA and binds HSA in a cavity between subdomain IIA and IIIA.

Photonic crystal based biosensors: Emerging inverse opals for biomarker detection.

Photonic crystal (PC)-based inverse opal (IO) arrays are one of the substrates for label-free sensing mechanism. IO-based materials with their advanced and ordered three-dimensional microporous structures have recently found attractive optical sensor and biological applications in the detection of biomolecules like proteins, DNA, viruses, etc. The unique optical and structural properties of IO materials can simplify the improvements in non-destructive optical study capabilities for point of care testing (POCT) used within a wide variety of biosensor research. In this review, which is an interdisciplinary investigation among nanotechnology, biology, chemistry and medical sciences, the recent fabrication methodologies and the main challenges regarding the application of (inverse opals) IOs in terms of their bio-sensing capability are summarized.

Recent advances in surface plasmon resonance biosensors for microRNAs detection.

miRNAs are a large family of non-coding RNAs which play important roles in translational and post-transcriptional regulation of gene expression and biological processes. Abnormal expression of miRNAs is related to the initiation and progression of different diseases which make them be promising candidates for early medical diagnostics. Thus, accurate detection of miRNAs has great significance for disorder diagnosis. Nevertheless, their intrinsic characteristics such as short sequence, low concentration and sequence homology challenge routine techniques. The detection assays need to be extremely sensitive and selective in small value of intricate RNA samples. Biosensor-based strategies have emerged as potential alternatives to conventional methods in miRNA quantification. The surface plasmon resonance (SPR), an optical biosensor, possessing various advantages including excellent reliability, selectivity and reproducibility represents a wide range of applications in real-time monitoring of biomolecular interactions and detection of biological and chemical analytes with label-based or label free form. Various signal amplification methods can overcome the limitation of SPR methods for detection of small molecules, making it suitable for clinical diagnosis. This review discusses main concepts and performance characteristics of SPR biosensor. Mainly, it focuses on newly emerged enhanced SPR biosensors towards high-throughput and ultrasensitive screening of miRNAs using labeling processes with focusing on the future application in biomedical research and clinical diagnosis. Actually, label-based signal amplification strategies of SPR platforms including nanoparticle enhancement, supersandwich assembly, streptavidin/biotin complex, antibody amplification, enzymatic reactions, triplex structure formation and catalytic hairpin assembly are discussed. Finally label free detection of miRNAs and advantages of SPR-based method was presented.

Surface plasmon resonance biosensors for detection of Alzheimer's biomarkers; an effective step in early and accurate diagnosis.

The rapid and direct detection of biomarkers in biofluids at clinically relevant concentrations faces serious limitations to develop diagnostic criteria for neurodegenerative diseases such as Alzheimer's disease (AD). In this regard, the early detection of biomarkers correlated with AD using novel modalities and instruments is at the center of attention. Recently, some newly invented optical-based biosensors namely Surface Plasmon Resonance (SPR) has been extensively investigated for the detection of biomarkers using a label-free method or by checking interaction between ligand and analyte. These approaches can sense a very small amount of target molecules in the blood and cerebrospinal fluids samples. In this review, the different hypothesis related to AD, and the structural properties of AD biomarkers was introduced. Also, we aim to highlight the specific role of available SPR-based sensing methods for early detection of AD biomarkers such as aggregated ß-amyloid and tau proteins. Efforts to better understand the accuracy and efficiency of optical-based biosensors in the field of neurodegenerative disease enable us to accelerate the advent of novel modalities in the clinical setting for therapeutic and diagnostic purposes.

Estradiol modulated colorectal cancer stem cells bioactivity and interaction with endothelial cells.

This study aimed to evaluate the modulatory role of sex-related hormone estradiol on cancer stem cells with the origin of colorectal adenocarcinoma in vitro. Cancer stem cells were incubated with 100 nM estradiol for 48 h. The cell survival rate was analyzed using the MTT assay. Immunocytochemistry staining of Ki-67 and Inhibin and Apoptosis PCR array were done to measure proliferation/apoptosis. Cell migration was monitored via the Transwell Migration assay. The expression of exosome biogenesis genes was measured using a real-time PCR assay. The fatty acid profile was monitored using gas chromatography. The level of FAK, SQSTM1, ER, and SIRT1 was examined using Western blotting. Cancer stem-endothelial cell interaction was investigated using Surface Plasmon Resonance assay. Data showed no significant differences in cancer stem cell viability and proliferation between control and estradiol-treated groups (p>0.05). PCR array highlighted the up-regulation of both pro- and anti-apoptosis effectors in the treatment group compared to the control cells (p<0.05). Cell migration capacity was increased after treatment with estradiol (p<0.001). Both exocytosis and exosome biogenesis were decreased in cancer stem cells exposed to estradiol (p<0.05). Data showed the reduction of palmitic acid, and increase of Palmitoleic and Linolenic acids in estradiol-treated cells. Estrogen induced estrogen receptor, SQSTM1 proteins and decreased SIRT1 factor after 48 h. Surface Plasmon Resonance revealed the suppression of cancer stem-endothelial cell interaction and affinity. Estradiol could change the migration, juxtacrine and paracrine activities of cancer stem cells, showing the importance of sex-related hormones in the dynamic of cancer development.

SPR enhanced DNA biosensor for sensitive detection of donkey meat adulteration.

Herein, a surface plasmon resonance (SPR) enhanced DNA biosensor has been developed for real-time detection of donkey meat marker using biotinylated reporter and streptavidin functionalized gold nanostars (Stre@GNSs). Compared to the direct detection assay, this sandwich format for the enhancement of the signal, resulted in 6-folds orders increase in the sensitivity. Target DNA could be detected with the lower limit of quantification (LLOQ) of 1.0 nM with a relative standard deviation (RSD, n = 3) of 0.85%. In addition, the fabricated SPR sensor showed good selectivity for the target analyte over full complementary, single-base mismatch, three base-mismatch and non-complementary oligonucleotides. Finally, the proposed sensor was successfully applied for detection of donkey meat adulteration with various percentages in homemade beef sausage, as a real sample. The results indicated that the proposed biosensor provides a high specificity, easy, good sensitivity and fast approach for identification of donkey meat adulteration in food samples.

Kinetic and thermodynamic study of c-Met interaction with single chain fragment variable (scFv) antibodies using phage based surface plasmon resonance.

Mesenchymal epithelial transition factor (c-Met) has been recently regarded as an attractive target for the treatment of cancer. Our previous study showed that c-Met-specific single chain fragment variables (scFvs) can be considered as a promising therapy for cancer, however, their molecular interaction with c-Met protein have not been assessed. Accordingly, in the current study we aim to evaluate the kinetic and thermodynamic properties of c-Met interaction with these scFvs as anticancer agents by means of surface plasmon resonance (SPR) technique. Phage-scFvs were immobilized on the 11-mercaptoundecanoic acid gold chips after carboxylic groups activation by N-ethyl-N-(3-diethylaminopropyl) carbodiimide/N-hydroxysuccinimide and, then the c-Met binding to each scFvs (ES1, ES2, and ES3) at different concentrations (ranging from 20 to 665 µM) was explored. Kinetic studies revealed that ES1 has the highest affinity (KD = 3.36 × 10-8) toward its target at 25°C. Calculation of thermodynamic parameters also showed positive values for enthalpy and entropy changes, which was representative of hydrophobic forces between c-Met and ES1. Furthermore, the positive value of Gibbs free energy indicated that c-Met binding to ES1 was enthalpy-driven. Taken together, we concluded that produced ES1 can be applied as promising scFv-based therapy for diagnosis or targeting of c-Met in various cancers.

Kinetic and thermodynamic study of beta-Boswellic acid interaction with Tau protein investigated by surface plasmon resonance and molecular modeling methods.

Introduction: Beta-Boswellic acid (BBA) is a pentacyclic terpene which has been obtained from frankincense and its beneficial effects on neurodegenerative disorders such as Alzheimer's disease (AD) have been addressed. Methods: In the present study, thermodynamic and kinetic aspects of BBA interaction with Tau protein as one of the important proteins involved in AD in the absence and presence of glucose has been investigated using surface plasmon resonance (SPR) method. Tau protein was immobilized onto the carboxy methyl dextran chip and its binding interactions with BBA were studied at physiological pH at various temperatures. Glucose interference with these interactions was also investigated. Results: Results showed that BBA forms a stable complex with Tau (KD=8.45×10-7 M) at 298 K. Molecular modeling analysis showed a hydrophobic interaction between BBA and HVPGGG segment of R2 and R4 repeated domains of Tau. Conclusion: The binding affinity increased by temperature enhancement, while it decreased significantly in the presence of glucose. Both association and dissociation of the BBA-Tau complex were accompanied with an entropic activation barrier; however, positive enthalpy and entropy changes revealed that hydrophobic bonding is the main force involved in the interaction.

SPR signals enhancement by gold nanorods for cell surface marker detection.

Introduction: The detection of micrometer-sized particles like cells is limited by surface plasmon resonance (SPR) biosensors because of having a depth of evanescent wave <500 nm. In this study, for the first time, we exhibited the use of streptavidin-functionalized gold nanorods (GNRs) as intensification labels for detection of cell surface markers in SPR-based biosensors. Methods: The GNRs (ʎ max: 735 nm) were modified with streptavidin using EDC/NHS coupling method and human umbilical vein endothelial cells (HUVECs) were selected as the cell model for detecting VE-cadherin on cell surface using real-time SPR device in the 785 nm wavelength of the laser source. Results: The investigations revealed that the plasmonic field extension produced from the gold layer and GNRs resulted in multiple enhancement of SPR signals when the wavelength of laser source in SPR instrument was matched with the wavelength of maximum absorbance in GNRs. Moreover, the results showed that the growth of ∆RU value in specific and non-specific bindings for various cell number injections were produced with increasing the cell number. Conclusion: The results displayed that cell detection can be performed in real- time form without any need to a time-consuming process used in conventional methods like immunocytochemistry, flow cytometry, and western blotting.