A sensitive diagnostic assay of rheumatoid arthritis using three-dimensional ZnO nanorod structure

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.

Mitochondrial-Targeted Ratiometric Near-Infrared Fluorescence Probe for Monitoring Nitric Oxide in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a destructive autoimmune disease, where nitric oxide (NO) is closely implicated in the inflammatory processes of RA. Therefore, direct visualization of NO is essential to assess the pathological changes in RA. Herein, a mitochondrial-targeted near-infrared ratiometric fluorescent probe (NFL-NH2), based on the intramolecular charge transfer effect, was synthesized and applied to monitor the changes of NO content in early RA. Specially, probe NFL-NH2 showed a 44-fold fluorescent intensity ratio (I705/I780) response toward NO with a detection limit of 0.536 nM, enabling qualitative and quantitative analysis of NO. Additionally, NFL-NH2 can accurately target mitochondria and sensitively detect exogenous and endogenous NO in RAW 264.7 cells. Notably, in vivo RA monitoring assays demonstrated that NFL-NH2 can rapidly detect NO levels associated with the inflammatory damage degree in RA mice models by ratiometric fluorescence imaging. These results validate that NFL-NH2 holds significant potential for diagnosing NO-mediated RA diseases.

Preparation and characterization of cyclic citrullinated peptide-immobilized latex beads for measurement of anti-citrillinated protein antibody through latex particle-enhanced turbidimetric immunoassay

The anti-citrillinated protein antibody (ACPA) plays an important role in early diagnosis of rheumatoid arthritis (RA), and is usually detected by using cyclic citrullinated peptide (CCP) as antigen. The ACPA against CCP test is usually performed utilizing enzyme-linked immunosorbent assay (ELISA), but the ELISA is expensive and time-consuming. Here, latex particle-enhanced turbidimetric immunoassay (LTIA) based on CCP-immobilized latex bead was proposed for fast measurements of ACPA of RA patients. CCP-immobilized latex bead was fabricated through three methods, including direct coupling, overall coupling and layer by layer coupling. According to the optimized experiments, layer-by-layer coupling was the best method with advantages of time-saving, simple operation and good repeatability. In addition, a spacer arm of appropriate length between latex beads and CCP could avoid stereoscopic obstacles and make ACPA closer to CCP. The CCP-immobilized latex bead based on layer by layer coupling (CCP-LB-LLC) was used for assembling the homemade kit, which was applied in fast measurements of ACPA through LTIA. The homemade kit possessed a low limit of detection (0.2 U/mL) and an acceptable the batch-to-batch reproducibility. In addition, the homemade kit can be stored at 4 °C for at least one month. When used to detect 20 clinical samples, the results of homemade kit were consistent with commercial ELISA. Furthermore, LTIA based on the homemade kit was simpler and cheaper than ELISA. These results demonstrated that the homemade kit could be useful for diagnosis of RA patients.

Biosensors for Detection of Biochemical Markers Relevant to Osteoarthritis

This systematic review aimed to assess the advantages of biosensors in detecting biomarkers for the early diagnosis of osteoarthritis (OA). OA is the most prevalent musculoskeletal disease and is a leading cause of disability and pain worldwide. The diagnosis of OA could be performed through clinical examinations and imaging only during the late stages of the disease. Biomarkers could be used for the diagnosis of the disease in the very early stages. Biosensors could detect biomarkers with high accuracy and low costs. This paper focuses on the biosensors mainly adopted to detect OA markers (electrochemical, optical, Quartz crystal microbalance, molecular and wearable biosensors). A comprehensive search on PubMed, Cochrane, CINAHL and Embase databases was conducted from the inception to November 2020. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used to improve the reporting of the review. The Methodological Index for Non-Randomized Studies (MINORS) was used for quality assessment. From a total amount of 1086 studies identified, only 19 articles were eligible for this study. The main advantages of the biosensors reported were accuracy, limited cost and ease of use, compared to traditional methods (ELISA). Otherwise, due to the lack of data and the low level of evidence of the papers included, it was impossible to find significant results. Therefore, further high-quality studies are required.

Recent Advances in Smart Biomaterials for the Detection and Treatment of Autoimmune Diseases

Autoimmune diseases are a group of debilitating illnesses that are often idiopathic in nature. The steady rise in the prevalence of these conditions warrants new approaches for diagnosis and treatment. Stimuli-responsive biomaterials also known as "smart", "intelligent" or "recognitive" biomaterials are widely studied for their applications in drug delivery, biosensing and tissue engineering due to their ability to produce thermal, optical, chemical, or structural changes upon interacting with the biological environment. This critical analysis highlights studies within the last decade that harness the recognitive capabilities of these biomaterials towards the development of novel detection and treatment options for autoimmune diseases.

Peptide-based electrochemical biosensor for juvenile idiopathic arthritis detection

Juvenile idiopathic arthritis (JIA) is a wide group of diseases, characterized by synovial inflammation and joint tissue damage. Due to the delay in the implementation of biomarkers into clinical practice and the association with severe sequels, there is an imperative need for new JIA diagnosis strategies. Electrochemical biosensors based on screen-printed electrodes and peptides are promising alternatives for molecular diagnosis. In this work, a novel biosensor for detecting juvenile idiopathic arthritis (JIA) was developed based on the immobilization of the PRF+1 mimetic peptide, as recognition biological element, on the surface of screen-printed carbon electrode. This biosensor was able to discriminate the JIA positive and negative serum samples from different individuals using differential pulse voltammetry, presenting limits of detection and quantification in diluted samples of 1:784 (v/v) and 1:235 (v/v), respectively. Evaluation by electrochemical impedance spectroscopy showed R_CT 3 times higher for JIA positive sample than for a pool of human serum samples from healthy individuals. Surface analysis of the biosensor by atomic force microscopy, after contact with JIA positive serum, presented great globular clusters irregularly distributed. The long-term stability of the biosensor was evaluated, remaining functional for over 40 days of storage (after storage at 8°C). Therefore, a simple, miniaturized and selective biosensor was developed, being the first one based on mimetic peptide and screen-printed carbon electrode, aiming at the diagnosis of the juvenile idiopathic arthritis in real serum samples.

Fundamental Properties of One-Dimensional Zinc Oxide Nanomaterials and Implementations in Various Detection Modes of Enhanced Biosensing

Recent bioapplications of one-dimensional (1D) zinc oxide (ZnO) nanomaterials, despite the short development period, have shown promising signs as new sensors and assay platforms offering exquisite biomolecular sensitivity and selectivity. The incorporation of 1D ZnO nanomaterials has proven beneficial to various modes of biodetection owing to their inherent properties. The more widely explored electrochemical and electrical approaches tend to capitalize on the reduced physical dimensionality, yielding a high surface-to-volume ratio, as well as on the electrical properties of ZnO. The newer development of the use of 1D ZnO nanomaterials in fluorescence-based biodetection exploits the innate optical property of their high anisotropy. This review considers stimulating research advances made to identify and understand fundamental properties of 1D ZnO nanomaterials, and examines various biosensing modes utilizing them, while focusing on the unique optical properties of individual and ensembles of 1D ZnO nanomaterials specifically pertaining to their bio-optical applications in simple and complex fluorescence assays.

Fundamental Properties of One-Dimensional Zinc Oxide Nanomaterials and Implementations in Various Detection Modes of Enhanced Biosensing

Recent bioapplications of one-dimensional (1D) zinc oxide (ZnO) nanomaterials, despite the short development period, have shown promising signs as new sensors and assay platforms offering exquisite biomolecular sensitivity and selectivity. The incorporation of 1D ZnO nanomaterials has proven beneficial to various modes of biodetection owing to their inherent properties. The more widely explored electrochemical and electrical approaches tend to capitalize on the reduced physical dimensionality, yielding a high surface-to-volume ratio, as well as on the electrical properties of ZnO. The newer development of the use of 1D ZnO nanomaterials in fluorescence-based biodetection exploits the innate optical property of their high anisotropy. This review considers stimulating research advances made to identify and understand fundamental properties of 1D ZnO nanomaterials, and examines various biosensing modes utilizing them, while focusing on the unique optical properties of individual and ensembles of 1D ZnO nanomaterials specifically pertaining to their bio-optical applications in simple and complex fluorescence assays.

Facile fabrication of microsphere-polymer brush hierarchically three-dimensional (3D) substrates for immunoassays

A facile strategy was developed to create a microsphere-polymer brush hierarchically three-dimensional substrate for high signal and low noise in immunoassays.

Redox-active gold nanoclusters immobilized ZnO nanorod electrodes for electrochemical sensing applications

Well-defined composite electrodes were fabricated by combining redox-active Au₂₅ nanoclusters with highly oriented ZnO nanorods.

A simple one-step assay platform based on fluorescence quenching of macroporous silicon

We synthesized 3D macroporous silicon through a simple electrochemical dissolution process and systematically estimated its protein adsorption and effect on fluorescence emission. Compared with conventional 2D polystyrene plate, the macroporous silicon showed a superior protein adsorption capacity and significant fluorescence quenching effect. We developed a 3D macroporous silicon-based adenosine assay system through the following fabrication process: streptavidin molecules that have been immobilized on the surface of macroporous silicon are attached with biotin-linked and adenosine-specific DNA aptamer, followed by hybridization between the attached aptamer and fluorescent chemical (carboxytetramethylrhodamine/CTMR) that is conjugated with a short complementary DNA sequence. In the absence of adenosine, the aptamer-CTMR complexes remain closely attached to the surface of porous silicon, hence fluorescence being significantly quenched. Upon binding to adenosine, the DNA aptamer is subject to structure switching that leads to dissociation of CTMR from DNA aptamer, and consequently the CTMR fluorescence is restored, indicating a simple one-step assay of adenosine. Compared to the conventional 2D PS and ZnO nanorods-based assays, adenosine at much lower (sub-micromolar) concentration was successfully detected through the 3D macroporous silicon-based assay. The three-dimensionally and densely immobilized aptamer probes and effective fluorescence quenching on the surface of macroporous silicon enables adenosine to be detected at lower levels. Although the adenosine detection is reported here as a proof-of-concept, the developed macroporous silicon-based simple one-step assay platform can be applied in general to fluorescence quenching -based detection of many other biomolecules.

Recent advances in ZnO nanostructures and thin films for biosensor applications: review

Biosensors have shown great potential for health care and environmental monitoring. The performance of biosensors depends on their components, among which the matrix material, i.e., the layer between the recognition layer of biomolecule and transducer, plays a crucial role in defining the stability, sensitivity and shelf-life of a biosensor. Recently, zinc oxide (ZnO) nanostructures and thin films have attracted much interest as materials for biosensors due to their biocompatibility, chemical stability, high isoelectric point, electrochemical activity, high electron mobility, ease of synthesis by diverse methods and high surface-to-volume ratio. ZnO nanostructures have shown the binding of biomolecules in desired orientations with improved conformation and high biological activity, resulting in enhanced sensing characteristics. Furthermore, compatibility with complementary metal oxide semiconductor technology for constructing integrated circuits makes ZnO nanostructures suitable candidate for future small integrated biosensor devices. This review highlights recent advances in various approaches towards synthesis of ZnO nanostructures and thin films and their applications in biosensor technology.