A molecularly imprinted photonic polymer based on an inverse opal structure for sensing D-dimer at the point-of-care

Simple and sensitive sandwich-like electrochemical immunosensing strategy for D-dimer based on cyclodextrin-carbon nanotube and nanogold-ferrocene

D-dimer is a very important biomarker about sepsis, pulmonary thromboembolism and atherosclerosis, thus designing effective and sensitive method for its detection is of great significance. Herein, by synthesizing β-cyclodextrin-carbon nanotube nanohybrid (CNTs-CD) as the carrier to assemble the initial antibody (Ab1) of D-dimer, immobilizing secondary antibody (Ab2) and sulfydryl ferrocene (Fc) on the nanogold (Au) particles surface as the signaling amplifier (Ab2-Au-Fc), a low cost, simple, sensitive and effective sandwich-like electrochemical immunosensing (SEI) platform of D-dimer was proposed in this work for the first time. Briefly, CNTs shows large specific area and superior electroconductivity, and CD provides high host guest recognition ability that could bound with Ab1; meanwhile, the Fc probe offers stable current response which are proportionable positively to the level of D-dimer. Under the best conditions, the designed SEI platform exhibits prominent analytical performances for D-dimer: low detection limit of 3.0 ng mL-1 and large linearity of 10.0-800.0 ng mL-1. In addition, the selectivity, stability and reproducibility as well as real applications of the proposed SEI assay were evaluated and the obtained results are satisfactory.

Advances in D-dimer testing: progress in harmonization of clinical assays and innovative detection methods

The D-dimer is a sensitive indicator of coagulation and fibrinolysis activation, especially valuable as a biomarker of intravascular thrombosis. Measurement of plasma D-dimer levels plays a crucial role in the diagnosis and monitoring of conditions such as deep vein thrombosis, pulmonary embolism, and disseminated intravascular coagulation. A variety of immunoassays, including enzyme-linked immunosorbent assays, latex-enhanced immunoturbidimetric assays, whole-blood aggregation analysis, and immunochromatography assays, are widely used in clinical settings to determine D-dimer levels. However, the results obtained from different D-dimer assays vary significantly. These assays exhibit intra-method coefficients of variation ranging from 6.4% to 17.7%, and the measurement discrepancies among different assays can be as high as 20-fold. The accuracy and reliability of D-dimer testing cannot be guaranteed due to the lack of an internationally endorsed reference measurement system (including reference materials and reference measurement procedures), which may lead to misdiagnosis and underdiagnosis, limiting its full clinical application. In this review, we present an in-depth analysis of clinical D-dimer testing, summarizing the existing challenges, the current state of metrology, and progress towards harmonization. We also review the latest advancements in D-dimer detection techniques, which include mass spectrometry and electrochemical and optical immunoassays. By comparing the basic principles, the definition of the measurand, and analytical performance of these methods, we provide an outlook on the potential improvements in D-dimer clinical testing.