Recent Advances in Biosensors for Diagnosis of Autoimmune Diseases

Over the last decade, autoimmune diseases (ADs) have undergone a significant increase because of genetic and/or environmental factors; therefore, their simple and fast diagnosis is of high importance. The conventional diagnostic techniques for ADs require tedious sample preparation, sophisticated instruments, a dedicated laboratory, and qualified personnel. For these reasons, biosensors could represent a useful alternative to these methods. Biosensors are considered to be promising tools that can be used in clinical analysis for an early diagnosis due to their high sensitivity, simplicity, low cost, possible miniaturization (POCT), and potential ability for real-time analysis. In this review, recently developed biosensors for the detection of autoimmune disease biomarkers are discussed. In the first part, we focus on the main AD biomarkers and the current methods of their detection. Then, we discuss the principles and different types of biosensors. Finally, we overview the characteristics of biosensors based on different bioreceptors reported in the literature.

Immunosensors for Autoimmune-Disease-Related Biomarkers: A Literature Review

Immunosensors are a special class of biosensors that employ specific antibodies for biorecognition of the target analyte. Immunosensors that target disease biomarkers may be exploited as tools for disease diagnosis and/or follow-up, offering several advantages over conventional analytical techniques, such as rapid and easy analysis of patients' samples at the point-of-care. Autoimmune diseases have been increasingly prevalent worldwide in recent years, while the COVID-19 pandemic has also been associated with autoimmunity. Consequently, demand for tools enabling the early and reliable diagnosis of autoimmune diseases is expected to increase in the near future. To this end, interest in immunosensors targeting autoimmune disease biomarkers, mainly, various autoantibodies and specific pro-inflammatory proteins (e.g., specific cytokines), has been rekindled. This review article presents most of the immunosensors proposed to date as potential tools for the diagnosis of various autoimmune diseases, such as type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. The signal transduction and the immunoassay principles of each immunosensor have been suitably classified and are briefly presented along with certain sensor elements, e.g., special nano-sized materials used in the construction of the immunosensing surface. The main concluding remarks are presented and future perspectives of the field are also briefly discussed.

Electrochemical biosensors for monitoring of selected pregnancy hormones during the first trimester: A systematic review

The hormones human chorionic gonadotropin, progesterone, estrogen and four of its metabolites (estradiol, estrone, estriol, estetrol), as well as relaxin play an essential role in the development of the fetus during the first trimester. Imbalances in these hormones during the first trimester have been directly linked to miscarriages. However, frequent monitoring of the hormones is limited by the current conventional centralized analytical tools that do not allow a rapid response time. Electrochemical sensing is considered an ideal tool to detect hormones owing to its advantages such as quick response, user-friendliness, low economic costs, and possibility of use in point-of-care settings. Electrochemical detection of pregnancy hormones is an emerging field that has been demonstrated primarily at research level. Thus, it is timely with a comprehensive overview of the characteristics of the reported detection techniques. This is the first extensive review focusing on the advances related to electrochemical detection of hormones linked to the first trimester of pregnancy. Additionally, this review offers insights into the main challenges that must be addressed imminently to ensure progress from research to clinical applications.

Advances in the diagnosis of autoimmune diseases based on citrullinated peptides/proteins

Introduction: Autoimmune diseases are still one of the hard obstacles associated with humanity. There are many exogenous and endogenous etiological factors behind autoimmune diseases, which may be combined or dispersed to stimulate the autoimmune responses. Protein citrullination represents one of these factors. Harnessing specific citrullinated proteins/peptides could early predict and/or diagnose some of the autoimmune diseases. Many generations of diagnostic tools based on citrullinated peptides with comparable specificity/sensitivity are available worldwide.Areas covered: In this review, we discuss the deimination reaction behind the citrullination of most known autoantigens targeted, different generations of diagnostic tools based on citrullinated probes with specificity/sensitivity of each as well as newly developed assays. Furthermore, the most advanced molecular analytical tools to detect the citrullinated residues in the biological fluid and their performance are also evaluated, providing new avenues to early detect autoimmune diseases with high accuracy.Expert opinion: With the current specificity/sensitivity tools available for autoimmune disease detection, emphasis must be placed on developing more advance and effective, early, rapid, and simple diagnostic devices for autoimmune disease monitoring (similar to a portable device for sugar test at home). The molecular analytical devices with dual and/or multiplexe functions should be more simplified and invested in clinical laboratories.

Electrochemical Detection of dsDNA-Specific Antibodies

Electrochemical biosensors have shown great promise as useful point-of-care tests since they operate on electronic circuits which can be miniaturized and whose readout process can be easily automated. Here, we describe a method for the electrochemical sensing of antibodies directed against double-stranded DNA (α-dsDNA), which are often present at higher-than-normal levels in the sera of autoimmune disease patients. The method can be easily implemented in any lab and requires little investment in equipment, namely a potentiostat. An artificial reference serum sample containing known amounts of spiked-in α-dsDNA antibodies enables reporting results in absolute scale rather than titer. Once electrodes are modified with DNA and the calibration curves are made (i.e., after the biosensor construction phase), individual measurements in test samples can be obtained in as low as 35 min.

Rapid screening of anti-tumor metastasis drugs targeting integrin macrophage antigen-1 using immobilized cell capillary electrophoresis

In this research a method called immobilized cell capillary electrophoresis (ICCE) was established under approximately physiological conditions for rapid screening of anti-tumor metastasis drugs targeting integrin macrophage antigen-1 (MAC-1). In this method, separation and purification of the target receptors on cell membranes was unnecessary, thus, maintaining their natural conformation and bioactivity. MAC-1-, CD11b-, or CD18-overexpressing HEK293 cells (human embryonic kidney) were cultured and immobilized on the inner wall of capillaries as stationary phase, and their interactions with lactosyl derivative Gu-4 (positive control)/dimethylsulfoxide (DMSO; negative control) were studied using ICCE. Using this method, 29 phenylethanoid glycosides from Cistanches Herba were screened, and the binding kinetic parameters (K, ka, kd, and k') of active compounds were calculated, and the specific subunits of MAC-1 were determined. Then, molecular docking studies were performed to discover the direct interaction sites between active compounds and MAC-1, and the order of Glide-calculated Emodel value obtained from the molecular docking study is consistent with that of the binding constants obtained using ICCE. Finally, pharmaceutical efficacy assays in vitro and in vivo were carried out to show that the anti-tumor metastasis activity of the active compound had better pharmaceutical efficacy and lower toxic side effects. The method was verified to be valid and practical for further use, and it is expected that it will be transferred to capillary array electrophoresis for use in high-throughput drug screening.