Development and Evaluation of Europium-Based Quantitative Lateral Flow Immunoassay for the Chronic Kidney Disease Marker Cystatin-C.

This study aimed to establish a Europium label time-resolved fluorescence immunoassay (TRFIA) to detect the chronic kidney disease (CKD) biomarker Cystatin-C. An Europium based Time resolved fluorescence immunoassay was developed to detect the concentration of Cystatin-C in a urine sample to increase the sensitivity with captured anti-Cystatin-C antibodies immobilized on nitrocellulose membrane and then bonded with detection anti-Cystatin-C labelled with CM-EU, followed by fluorescence measurement using time-resolved fluorometry in 15 min. The performance of this TRFIA was evaluated using the clinical urine serum and compared with the ELISA assays. The linear calibration range was 0.015-32 µg/ml, and the limit of detection (LOD) quantified was 0.0001 µg/ml. This current work has improved the LOD of our previous work from 0.013 µg/ml to 0.001 µg/ml. These results indicated that the CM-EU nanoparticle-based LFIA is rapid, more sensitive, reliable, and reproducible for point-of-care testing of Cys-C concentrations in urine.

State-of-the-art colloidal particles and unique interfaces-based SARS-CoV-2 detection methods and COVID-19 diagnosis.

In March 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-based infections were declared 'COVID-19 pandemic' by the World Health Organization. Pandemic raised the necessity to design and develop genuine and sensitive tests for precise specific SARS-CoV-2 infections detection. Nanotechnological methods offer new ways to fight COVID-19. Nanomaterials are ideal for unique sensor platforms because of their chemically versatile properties and they are easy to manufacture. In this context, selected examples for integrating nanomaterials and distinct biosensor platforms are given to detect SARS-CoV-2 biological materials and COVID-19 biomarkers, giving researchers and scientists more goals and a better forecast to design more relevant and novel sensor arrays for COVID-19 diagnosis.

The effect of nonsurgical periodontal treatment on gingival crevicular fluid stress hormone levels: A prospective study.

OBJECTIVES: The purpose of this prospective study was to investigate the effect of nonsurgical periodontal treatment (PT) on anxiety/depression scale scores and on gingival crevicular fluid (GCF) cortisol (COR) and dehydroepiandrosterone (DHEA) levels. METHODS: Fifty-five participants with generalized chronic periodontitis (GCP group, n: 21), with localized chronic periodontitis (LCP group, n: 19) and with gingivitis or healthy (control group, n: 15) subjects were treated and followed up for 6 months. Clinical periodontal parameters include plaque index, gingival index, bleeding on probing, probing depth and attachment level; psychosocial measurements include Beck Depression Inventory (BDI) and State-Trait Anxiety Inventory (STAI 1-2) psychometric instruments; hormone levels in GCF including COR and DHEA were evaluated. RESULTS: All clinical parameters were significantly decreased (except attachment loss) after PT (p < 0.05). No significant differences were observed between the two groups for STAI-1-2 and BDI scores, either at baseline or at 6 months (p > 0.05). COR levels were statistically lower following PT in GCP and LCP groups when compared to the baseline levels (p < 0.05). DHEA values at baseline and 6 months did not show significant differences. CONCLUSION: Within the limits of the study, decreased GCF COR and unchanged GCF DHEA levels were determined in nonsurgically treated patients regardless of the extent and severity of periodontitis.

Indirect, non-competitive amperometric immunoassay for accurate quantification of calpastatin, a meat tenderness marker, in bovine muscle.

A method is described for quantification of the beef tenderness marker, calpastatin, in meat samples by amperometric detection. Using a novel bovine recombinant partial calpastatin protein as standard antigen a low detection limit of 0.2 ng/mL was achieved. The influence of the complex matrix was minimised by heat pretreatment and dilution of the samples prior to detection of calpastatin. The relative error between the direct sample measurement and standard addition methods was 5.89%, confirming the accuracy of the developed amperometric immunoassay.

Label free capacitive immunosensor for detecting calpastatin--a meat tenderness biomarker.

An immunological capacitive biosensor for calpastatin was developed, optimized and applied for the analysis of meat extract samples. Anti-calpastatin antibody was immobilized on a gold electrode modified with a self-assembled monolayer of mercaptoundecanoic acid and Protein A from Staphylococcus aureus, and the obtained immunosensor was inserted as the working electrode in an electrochemical cell of a flow injection system. The dynamic range of the sensor was 20 to 160 ng/mL calpastatin. The electrode could be regenerated and re-used for more than 7 days with minimal reduction in sensitivity. For the analysis of real samples, the target analyte was extracted from the Longissimus dorsi muscle from beef carcasses directly after slaughtering. The extract was analyzed both with the developed immunosensor and microtiter plate ELISA, and a good correlation was obtained. However the immunosensor offers advantages of speed, simplicity, sensitivity and possibility for miniaturization over conventional assays for calpastatin quantification.