Monitoring the Formation of Fibrin Clots as Part of the Coagulation Cascade Using Fluorescent Single-Walled Carbon Nanotubes

Abstract

Blood coagulation is a critical defense mechanism against bleeding that results in the conversion of liquid blood into a solid clot through a complicated cascade, which involves multiple clotting factors. One of the final steps in the coagulation pathway is the conversion of fibrinogen to insoluble fibrin mediated by thrombin. Because coagulation disorders can be life-threatening, the development of novel methods for monitoring the coagulation cascade dynamics is of high importance. Here, we use near-infrared (NIR)-fluorescent single-walled carbon nanotubes (SWCNTs) to image and monitor fibrin clotting in real time. Following the binding of fibrinogen to a tailored SWCNT platform, thrombin transforms the fibrinogen into fibrin monomers, which start to polymerize. The SWCNTs are incorporated within the clot and can be clearly visualized in the NIR-fluorescent channel, where the signal-to-noise ratio is improved compared to bright-field imaging in the visible range. Moreover, the diffusion of individual SWCNTs within the fibrin clot gradually slows down after the addition of thrombin, manifesting a coagulation rate that depends on both fibrinogen and thrombin concentrations. Our platform can open new opportunities for coagulation disorder diagnostics and allow for real-time monitoring of the coagulation cascade with a NIR optical signal output in the biological transparency window.

A nIR fluorescent single walled carbon nanotube sensor for broad-spectrum diagnostics

“…2b). 27 Fibrinogen undergoes polymerization and forms fibrin clots with thrombin exposure. The unique structural characteristics of dipalmitoylpho-sphatidylethanolamine (DPPE)–poly(ethylene glycol) (PEG) (5000) corona formed upon adsorption onto the SWCNT surface, along with the distinctive structure of fibrinogen, are hypothesized to play a crucial role in molecular recognition.…”

“…Furthermore, single bundle SWCNT tracking reveals a gradual slowdown of SWCNT diffusion during the fibrin polymerization process, with the rates being influenced by both fibrinogen and thrombin concentrations. 27 This strategy utilizing DPPE–PEG/SWCNT enables the evaluation of the coagulation process, offering real-time insights throughout the cascade. It can contribute to blood coagulation research and promote the development of innovative diagnostic tools of blood coagulation.…”

Carbon Nanomaterial Fluorescent Probes and Their Biological Applications

“…SWCNT emission wavelength-shift is not the only sensing modality of proteins, and intensiometric sensing of proteins has also been demonstrated. , In two studies, Bisker and colleagues used PEG-phospholipid functionalized SWCNTs for sensing the blood protein fibrinogen. In vitro , the sensor exhibited a dose-dependent fluorescence quenching in response to fibrinogen.…”

Nanoreporter Identifies Lysosomal Storage Disease Lipid Accumulation Intracranially

“…The NIR-II emission allows for deep optical penetration, reduced scattering, and low autofluorescence in biological tissues. Engineered SWCNTs, achieved through surface functionalization, − enable the detection of various biomolecules like protein biomarkers, , pH, microRNA, and lipids , in live cells.…”