Fibrinolysis and thrombosis of fibrinogen-modified gold nanoparticles for detection of fibrinolytic-related proteins

Application of Multiharmonic QCM-D for Detection of Plasmin at Hydrophobic Surfaces Modified by β-Casein

Plasmin protease plays an important role in many processes in living systems, including milk. Monitoring plasmin activity is important for control of the nutritional quality of milk and other dairy products. We designed a biosensor to detect the proteolytic activity of plasmin, using multiharmonic quartz crystal microbalance with dissipation (QCM-D). The β-casein immobilized on the hydrophobic surface of 1-dodecanethiol on the AT-cut quartz crystal was used to monitor plasmin activity. We demonstrated detection of plasmin in a concentration range of 0.1–20 nM, with the limit of detection about 0.13 ± 0.01 nM. The analysis of viscoelastic properties of the β-casein layer showed rapid changes of shear elasticity modulus, μ, and coefficient of viscosity, η, at plasmin sub-nanomolar concentrations, followed by modest changes at nanomolar concentrations, indicating multilayer architecture β-casein. A comparative analysis of viscoelastic properties of β-casein layers following plasmin and trypsin cleavage showed that the higher effect of trypsin was due to larger potential cleavage sites of β-casein.

Monitoring coagulation-fibrinolysis activation prompted timely diagnosis of hemophagocytic lymphohistiocytosis-related disseminated intravascular coagulation

Background

Timely diagnosis of disseminated intravascular coagulation (DIC) in hemophagocytic lymphohistiocytosis (HLH) patients is crucial but challenging, as HLH interferes with the results of the laboratory tests included in the DIC score system.

Case presentation

Here, we reported a case of lymphoma-associated HLH, in which coagulation-fibrinolysis activation /inhibition markers (TAT, tPAIC, and PIC), prompted timely diagnosis of early stage DIC (initial phase of microvascular thrombosis, yet non-overt), prior to the development of organ failures and/or bleedings.

Conclusions

This report highlights the importance of the implementation of new biomarkers (such as TAT, tPAIC, and PIC), into the diagnostic work-up for coagulation disorders. These biomarkers are directly suggestive of microthrombus formation, therefore they can be of paramount importance in diagnosing DIC with complicated etiologies, such as hematological diseases-related DIC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00338-y.

A red-shifted Bioluminescence Resonance Energy Transfer (BRET) biosensing system for rapid measurement of plasmin activity in human plasma

Proteases are key signalling molecules for many physiological processes and their dysregulation is implicated in the progression of a range of diseases. Sensitive methods to measure protease activities in complex biological samples are critical for rapid disease diagnoses. The proteolytic activity of plasmin reflects the fibrinolysis state of blood and its deregulation can indicate pathologies such as bleeding events. While Bioluminescence Resonance Energy Transfer (BRET) is a powerful and sensitive method for the detection of protease activity, the commonly applied blue-shifted BRET² system, consisting of the Renilla luciferase Rluc2 and the large-stokes shift fluorescent protein GFP², suffers from light absorption and light scattering in human plasma samples. To address this challenge, we developed a red-shifted BRET-based plasmin sensor by substituting BRET² with the BRET⁶ system. BRET⁶ is composed of the red-shifted RLuc8.6 luciferase linked to the red light emitting fluorescent protein TurboFP635. The BRET⁶ biosensor exhibited 3-fold less light absorption in plasma samples compared to the BRET² sensor leading to an up to a 5-fold increase in sensitivity for plasmin detection in plasma. The limits of detection for plasmin were determined to be 11.90 nM in 7.5% (v/v) plasma with a 10 min assay which enables biologically relevant plasmin activities of thrombolytic therapies to be detected. While a colorigenic plasmin activity assay achieved a similar detection limit of 10.91 nM in 7.5% (v/v) human plasma, it required a 2 h incubation period. The BRET⁶ sensor described here is faster and more specific than the colorigenic assay as it did not respond to unspiked human plasma samples.

Engineered nanoparticles: thrombotic events in cancer

Engineered nanoparticles are being increasingly produced for specific applications in medicine. Broad selections of nano-sized constructs have been developed for applications in diagnosis, imaging, and drug delivery. Nanoparticles as contrast agents enable conjugation with molecular markers which are essential for designing effective diagnostic and therapeutic strategies. Such investigations can also lead to a better understanding of disease mechanisms such as cancer-associated thrombosis which remains unpredictable with serious bleeding complications and high risk of death. Here we review the recent and current applications of engineered nanoparticles in diagnosis and therapeutic strategies, noting their toxicity in relation to specific markers as a target.