Development of a Sensitive Quantum Dot-Linked Immunoassay for the Multiplex Detection of Biochemical Markers in a Microvolumeric Format

Abstract Purpose: For the diagnosis of various diseases, simultaneous sensitive detection of multiple biomarkers using low sample volumes is needed. The purpose of the present research was to develop sensitive multiplex detection model of QD-based ELISA (QLISA), through the spectroscopic QD-analyte complex measurements in microvolume liquid droplets on a glass microslide. Methods: QLISA was used for the detection of cartilage oligomeric matrix protein (COMP) and human growth hormone (hGH) as model analytes. The QLISA detection method included the formation of complexes consisting of analyte antigens, biotinylated antibodies and streptavidin-coated QDs. A specific immune-complex disassembling solution was used to dissociate analyte-antibody complexes from the bottom of the 96-well plate. After dissociation, the samples were diluted with PBS, and 2 μL transferred to a reusable glass slide for fluorescence (FL) scan. Results: The alkaline immune-complex disassembling solution that most efficiently amplified QDs FL within a prolonged 17 h time was selected. Comparison of median fluorescence intensity (MFI) of 50 nM COMP, 25 nM COMP, and 5 nM COMP detection using QD655 with the dilution of the detached samples with PBS and without dilution resulted in significant MFI differences in all cases. The FL signal readouts from QD655 in the microvolume format were from 10 to 40 times stronger than those measured directly from a 96-well plate QLISAs. In duplex analysis, two analytes COMP and hGH were measured using different QD605 and QD525 in the same well. In the respectful 96-well plate QLISA format, two different analyte concentrations can be hardly distinguishable, but the transfer to micro-volumetric detection on the glass slide highly increased the signal strength according to green and red FL intensity of QDs. Conclusion: Our method significantly enhances detection sensitivity, as compared to measured in parallel QLISAs in a 96 well plate format, enables multiplexing and may prove very valuable for samples of limited volumes.Abstract Purpose: For the diagnosis of various diseases, simultaneous sensitive detection of multiple biomarkers using low sample volumes is needed. The purpose of the present research was to develop sensitive multiplex detection model of QD-based ELISA (QLISA), through the spectroscopic QD-analyte complex measurements in microvolume liquid droplets on a glass microslide. Methods: QLISA was used for the detection of cartilage oligomeric matrix protein (COMP) and human growth hormone (hGH) as model analytes. The QLISA detection method included the formation of complexes consisting of analyte antigens, biotinylated antibodies and streptavidin-coated QDs. A specific immune-complex disassembling solution was used to dissociate analyte-antibody complexes from the bottom of the 96-well plate. After dissociation, the samples were diluted with PBS, and 2 μL transferred to a reusable glass slide for fluorescence (FL) scan. Results: The alkaline immune-complex disassembling solution that most efficiently amplified QDs FL within a prolonged 17 h time was selected. Comparison of median fluorescence intensity (MFI) of 50 nM COMP, 25 nM COMP, and 5 nM COMP detection using QD655 with the dilution of the detached samples with PBS and without dilution resulted in significant MFI differences in all cases. The FL signal readouts from QD655 in the microvolume format were from 10 to 40 times stronger than those measured directly from a 96-well plate QLISAs. In duplex analysis, two analytes COMP and hGH were measured using different QD605 and QD525 in the same well. In the respectful 96-well plate QLISA format, two different analyte concentrations can be hardly distinguishable, but the transfer to micro-volumetric detection on the glass slide highly increased the signal strength according to green and red FL intensity of QDs. Conclusion: Our method significantly enhances detection sensitivity, as compared to measured in parallel QLISAs in a 96 well plate format, enables multiplexing and may prove very valuable for samples of limited volumes

Emerging Technologies and Platforms for the Immunodetection of Multiple Biochemical Markers in Osteoarthritis Research and Therapy

AbstractBiomarkers, especially biochemical markers, are important in osteoarthritis (OA) research, clinical trials, and drug development and have potential for more extensive use in therapeutic monitoring. However, they have not yet had any significant impact on disease diagnosis and follow-up in a clinical context. Nevertheless, the development of immunoassays for the detection and measurement of biochemical markers in OA research and therapy is an active area of research and development. The evaluation of biochemical markers representing low-grade inflammation or extracellular matrix turnover may permit OA prognosis and expedite the development of personalized treatment tailored to fit particular disease severities. However, currently detection methods have failed to overcome specific hurdles such as low biochemical marker concentrations, patient-specific variation, and limited utility of single biochemical markers for definitive characterization of disease status. These challenges require new and innovative approaches for development of detection and quantification systems that incorporate clinically relevant biochemical marker panels. Emerging platforms and technologies that are already on the way to implementation in routine diagnostics and monitoring of other diseases could potentially serve as good technological and strategic examples for better assessment of OA. State-of-the-art technologies such as advanced multiplex assays, enhanced immunoassays, and biosensors ensure simultaneous screening of a range of biochemical marker targets, the expansion of detection limits, low costs, and rapid analysis. This paper explores the implementation of such technologies in OA research and therapy. Application of novel immunoassay-based technologies may shed light on poorly understood mechanisms in disease pathogenesis and lead to the development of clinically relevant biochemical marker panels. More sensitive and specific biochemical marker immunodetection will complement imaging biomarkers and ensure evidence-based comparisons of intervention efficacy. We discuss the challenges hindering the development, testing, and implementation of new OA biochemical marker assays utilizing emerging multiplexing technologies and biosensors.Abstract Biomarkers, especially biochemical markers, are important in osteoarthritis (OA) research, clinical trials, and drug development and have potential for more extensive use in therapeutic monitoring. However, they have not yet had any significant impact on disease diagnosis and follow-up in a clinical context. Nevertheless, the development of immunoassays for the detection and measurement of biochemical markers in OA research and therapy is an active area of research and development. The evaluation of biochemical markers representing low-grade inflammation or extracellular matrix turnover may permit OA prognosis and expedite the development of personalized treatment tailored to fit particular disease severities. However, currently detection methods have failed to overcome specific hurdles such as low biochemical marker concentrations, patient-specific variation, and limited utility of single biochemical markers for definitive characterization of disease status. These challenges require new and innovative approaches for development of detection and quantification systems that incorporate clinically relevant biochemical marker panels. Emerging platforms and technologies that are already on the way to implementation in routine diagnostics and monitoring of other diseases could potentially serve as good technological and strategic examples for better assessment of OA. State-of-the-art technologies such as advanced multiplex assays, enhanced immunoassays, and biosensors ensure simultaneous screening of a range of biochemical marker targets, the expansion of detection limits, low costs, and rapid analysis. This paper explores the implementation of such technologies in OA research and therapy. Application of novel immunoassay-based technologies may shed light on poorly understood mechanisms in disease pathogenesis and lead to the development of clinically relevant biochemical marker panels. More sensitive and specific biochemical marker immunodetection will complement imaging biomarkers and ensure evidence-based comparisons of intervention efficacy. We discuss the challenges hindering the development, testing, and implementation of new OA biochemical marker assays utilizing emerging multiplexing technologies and biosensors

The Challenges of Local Intra-Articular Therapy

Fibroblast-like synoviocytes (FLSs) are among the main disease-driving players in most cases of monoarthritis (MonoA), oligoarthritis, and polyarthritis. In this review, we look at the characteristics and therapeutic challenges at the onset of arthritis and during follow-up management. In some cases, these forms of arthritis develop into autoimmune polyarthritis, such as rheumatoid arthritis (RA), whereas local eradication of the RA synovium could still be combined with systemic treatment using immunosuppressive agents. Currently, the outcomes of local synovectomies are well studied; however, there is still a lack of a comprehensive analysis of current local intra-articular treatments highlighting their advantages and disadvantages. Therefore, the aim of this study is to review local intra-articular therapy strategies. According to publications from the last decade on clinical studies focused on intra-articular treatment with anti-inflammatory molecules, a range of novel slow-acting forms of steroidal drugs for the local treatment of synovitis have been investigated. As pain is an essential symptom, caused by both inflammation and cartilage damage, various molecules acting on pain receptors are being investigated in clinical trials as potential targets for local intra-articular treatment. We also overview the new targets for local treatment, including surface markers and intracellular proteins, non-coding ribonucleic acids (RNAs), etc

Evaluation of Cartilage Integrity Following Administration of Oral and Intraarticular Nifedipine in a Murine Model of Osteoarthritis

Osteoarthritis (OA) ranks as the prevailing type of arthritis on a global scale, for which no effective treatments are currently available. Arterial hypertension is a common comorbidity in OA patients, and antihypertensive drugs, such as nifedipine (NIF), may affect the course of OA progression. The aim of this preclinical study was to determine the effect of nifedipine on healthy and OA cartilage, depending on its route of administration. In this study, we used the destabilization of medial meniscus to develop a mouse model of OA. Nifedipine was applied per os or intraarticularly (i.a.) for 8 weeks to both mice with OA and healthy animals. Serum biomarker concentrations were evaluated using the Luminex platform and alterations in the knee cartilage were graded according to OARSI histological scores and investigated immunohistochemically. Nifedipine treatment per os and i.a. exerted protective effects, as assessed by the OARSI histological scores. However, long-term nifedipine i.a. injections induced the deterioration of healthy cartilage. Lubricin, cartilage intermediate layer matrix protein (CILP), collagen type VI (COLVI), CILP, and Ki67 were upregulated by the nifedipine treatment. Serum biomarkers MMP-3, thrombospondin-4, and leptin were upregulated in the healthy groups treated with nifedipine, while only the levels of MMP-3 were significantly higher in the OA group treated with nifedipine per os compared to the untreated group. In conclusion, this study highlights the differential effects of nifedipine on cartilage integrity, depending on the route of administration and cartilage condition

Magneto-Immunoassay for the Detection and Quantification of Human Growth Hormone

Physiological and endocrine maintenance of a normal human growth hormone (hGH) concentration is crucial for growth, development, and a number of essential biological processes. In this study, we describe the preparation and characterization of magnetic nanoparticles coated with a gold shell (MNPs-Au). The optimal surface concentration of monoclonal anti-hGH antibodies (m-anti-hGH) on magnetic nanoparticles, as well as conditions that decrease non-specific interactions during the magneto-immunoassay, were elaborated. After the selective recognition, separation, and pre-concentration of hGH by MNPs-Au/m-anti-hGH and the hGH interaction with specific polyclonal biotin-labeled antibodies (p-anti-hHG-B) and streptavidin modified horseradish peroxidase (S-HRP), the MNPs-Au/m-anti-hGH/hGH/p-anti-hGH-B/S-HRP immunoconjugate was formed. The concentration of hGH was determined after the addition of 3,3′,5,5′-tetramethylbenzidine and hydrogen peroxide substrate solution for HRP; the absorbance at 450 nm was registered after the addition of STOP solution. The developed sandwich-type colorimetric magneto-immunoassay is characterized by a clinically relevant linear range (from 0.1 to 5.0 nmol L−1, R2 0.9831), low limit of detection (0.082 nmol L−1), and negligible non-specific binding of other antibodies or S-HRP. The obtained results demonstrate the applicability of the developed magneto-immunoassay for the concentration and determination of hGH in the serum. Additionally, important technical solutions for the development of the sandwich-type colorimetric magneto-immunoassay are discussed.</jats:p

Magneto-Immunoassay for the Detection and Quantification of Human Growth Hormone

Physiological and endocrine maintenance of a normal human growth hormone (hGH) concentration is crucial for growth, development, and a number of essential biological processes. In this study, we describe the preparation and characterization of magnetic nanoparticles coated with a gold shell (MNPs-Au). The optimal surface concentration of monoclonal anti-hGH antibodies (m-anti-hGH) on magnetic nanoparticles, as well as conditions that decrease non-specific interactions during the magneto-immunoassay, were elaborated. After the selective recognition, separation, and pre-concentration of hGH by MNPs-Au/m-anti-hGH and the hGH interaction with specific polyclonal biotin-labeled antibodies (p-anti-hHG-B) and streptavidin modified horseradish peroxidase (S-HRP), the MNPs-Au/m-anti-hGH/hGH/p-anti-hGH-B/S-HRP immunoconjugate was formed. The concentration of hGH was determined after the addition of 3,3&prime;,5,5&prime;-tetramethylbenzidine and hydrogen peroxide substrate solution for HRP; the absorbance at 450 nm was registered after the addition of STOP solution. The developed sandwich-type colorimetric magneto-immunoassay is characterized by a clinically relevant linear range (from 0.1 to 5.0 nmol L&minus;1, R2 0.9831), low limit of detection (0.082 nmol L&minus;1), and negligible non-specific binding of other antibodies or S-HRP. The obtained results demonstrate the applicability of the developed magneto-immunoassay for the concentration and determination of hGH in the serum. Additionally, important technical solutions for the development of the sandwich-type colorimetric magneto-immunoassay are discussed