Coagulation dynamics of a blood sample by multiple scattering analysis

Physico chemical characterisation of pectin incorporated gelatin sponge and its functional evaluation in modulating contact activation haemostasis

Even though it is a common occurrence in practice, maintaining haemostasis can sometimes become a challenging issue in case of trauma, perioperative period, coagulation disorders, cancers, etc. Hemostatic materials are extensively used to assist in the cessation of bleeding. However, the definition of efficiency of haemostasis varies between intended procedures. This paper explores the feasibility of incorporating agents to increase the efficiency of local haemostasis. Pectin or β -D galacto hexopyranuronic acid/β Gal A, a structural polysaccharide widely present in terrestrial plants having an intrinsic hemostatic potential, is blended with gelatin and is explored in modulating passive haemostasis. The sponges are physico chemically characterized, and their hemostatic efficiency is evaluated in vitro using various assays. Biocompatibility evaluation is done by in vitro cytotoxicity assay. The results suggest that this biopolymer combination is a promising candidate for hemostatic control.

Evolving Paradigm of Prothrombin Time Diagnostics with Its Growing Clinical Relevance towards Cardio-Compromised and COVID-19 Affected Population

Prothrombin time (PT) is a significant coagulation (hemostasis) biomarker used to diagnose several thromboembolic and hemorrhagic complications based on its direct correlation with the physiological blood clotting time. Among the entire set of PT dependents, candidates with cardiovascular ailments are the major set of the population requiring lifelong anticoagulation therapy and supervised PT administration. Additionally, the increasing incidence of COVID affected by complications in coagulation dynamics has been strikingly evident. Prolonged PT along with sepsis-induced coagulopathy (SIC score > 3) has been found to be very common in critical COVID or CAC-affected cases. Considering the growing significance of an efficient point-of-care PT assaying platform to counter the increasing fatalities associated with cardio-compromised and coagulation aberrations propping up from CAC cases, the following review discusses the evolution of lab-based PT to point of care (PoC) PT assays. Recent advances in the field of PoC PT devices utilizing optics, acoustics, and mechanical and electrochemical methods in microsensors to detect blood coagulation are further elaborated. Thus, the following review holistically aims to motivate the future PT assay designers/researchers by detailing the relevance of PT and associated protocols for cardio compromised and COVID affected along with the intricacies of previously engineered PoC PT diagnostics.

Development of an Optical Method for the Evaluation of Whole Blood Coagulation

Blood coagulation is a defense mechanism, which is activated in case of blood loss, due to vessel damage, or other injury. Pathological cases arise from malfunctions of the blood coagulation mechanism, and rapid growth of clots results in partially or even fully blocked blood vessel. The aim of this work is to characterize blood coagulation, by analyzing the time-dependent structural properties of whole blood, using an inexpensive design and robust processing approaches. The methods used in this work include brightfield microscopy and image processing techniques, applied on finger-prick blood samples. The blood samples were produced and directly utilized in custom-made glass microchannels. Color images were captured via a microscopy-camera setup for a period of 35 min, utilizing three different magnifications. Statistical information was extracted directly from the color components and the binary conversions of the images. The main advantage in the current work lies on a Boolean classification approach utilized on the binary data, which enabled to identify the interchange between specific structural elements of blood, namely the red blood cells, the plasma and the clotted regions, as a result of the clotting process. Coagulation indices produced included a bulk coagulation index, a plasma-reduction based index and a clot formation index. The results produced with the inexpensive design and the low computational complexity in the current approach, show good agreement with the literature, and a great potential for a robust characterization of blood coagulation.

Three-dimensional quantitative phase imaging of blood coagulation structures by optical projection tomography in flow cytometry using digital holographic microscopy

Blood coagulation is an important role in the hemostasis process. In the observation using microscopies, an aggregation structure of red blood cells indicates the degree of blood coagulation. Recently, it has been proposed that digital holographic microscopy (DHM) is a powerful tool for biomedical cell imaging on the basis of quantitative phase information. DHM has the advantage in that the real-time and three-dimensional (3-D) quantitative phase imaging can be realized in the wide field of view, which means that the 3-D morphological parameters of biological cells without a staining process are obtained in real time. We report the complete 3-D quantitative phase imaging of blood coagulation structures by optical projection tomography in a flow cytometry using DHM.

Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor

Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients. To measure PT/INR, conventional coagulation testing (CCT) is performed, which is time-consuming and requires the separation of cellular components from whole blood. Here, we report on a portable and battery-operated optical sensor that can rapidly quantify PT/INR within seconds by measuring alterations in the viscoelastic properties of a drop of whole blood following activation of coagulation with thromboplastin. In this study, PT/INR values were measured in 60 patients using the optical sensor and compared with the corresponding CCT values. Our results report a close correlation and high concordance between PT/INR measured using the two approaches. These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.

Assessing blood coagulation status with laser speckle rheology

We have developed and investigated a novel optical approach, Laser Speckle Rheology (LSR), to evaluate a patient's coagulation status by measuring the viscoelastic properties of blood during coagulation. In LSR, a blood sample is illuminated with laser light and temporal speckle intensity fluctuations are measured using a high-speed CMOS camera. During blood coagulation, changes in the viscoelastic properties of the clot restrict Brownian displacements of light scattering centers within the sample, altering the rate of speckle intensity fluctuations. As a result, blood coagulation status can be measured by relating the time scale of speckle intensity fluctuations with clinically relevant coagulation metrics including clotting time and fibrinogen content. Our results report a close correlation between coagulation metrics measured using LSR and conventional coagulation results of activated partial thromboplastin time, prothrombin time and functional fibrinogen levels, creating the unique opportunity to evaluate a patient's coagulation status in real-time at the point of care.

Evaluation of optical coherence tomography for the measurement of the effects of activators and anticoagulants on the blood coagulation in vitro

Optical properties of human blood during coagulation were studied using optical coherence tomography (OCT) and the parameter of clotting time derived from the 1/e light penetration depth (d(1/e)) versus time was developed in our previous work. In this study, in order to know if a new OCT test can characterize the blood-coagulation process under different treatments in vitro, the effects of two different activators (calcium ions and thrombin) and anticoagulants, i.e., acetylsalicylic acid (ASA, a well-known drug aspirin) and melagatran (a direct thrombin inhibitor), at various concentrations are evaluated. A swept-source OCT system with a 1300 nm center wavelength is used for detecting the blood-coagulation process in vitro under a static condition. A dynamic study of d1/e reveals a typical behavior due to coagulation induced by both calcium ions and thrombin, and the clotting time is concentration-dependent. Dose-dependent ASA and melagatran prolong the clotting times. ASA and melagatran have different effects on blood coagulation. As expected, melagatran is much more effective than ASA in anticoagulation by the OCT measurements. The OCT assay appears to be a simple method for the measurement of blood coagulation to assess the effects of activators and anticoagulants, which can be used for activator and anticoagulant screening.

Design and evaluation of a portable optical-based biosensor for testing whole blood prothrombin time

Point-of-care diagnostics (POCD) for blood coagulation benefit patients on-site, but available POCD devices are too expensive to be affordable in many countries. Optically based methodologies are cheap and reliable, and have been exploited in bench-top coagulometers to monitor coagulation with plasma, but not whole blood, which contains cellular components that cause massive interference. However, the POCD testing of whole blood gives a more accurate picture of physiological conditions than does testing plasma. In this study, a portable device for performing the prothrombin time (PT) test was designed, comprising an optical sensor, an electrical processing and control circuit to monitor the optical changes that occurred during the coagulation process in whole blood. The PT was when the slope of the first-order derivative of the coagulation curve, recorded from real-time light transmittance signals, was maximal. The POCD PT testing of 167 samples revealed that 153 (91.6%) were successfully detected and the results were highly consistent with the results of whole blood international normalized ratio (INR) (r=0.985, p<0.001) by the conventional manual method and those of plasma INR (r=0.948, p<0.001) with the ACL TOP 700 bench-top coagulometer (Beckman Colter). Hematological parameters were further analyzed, revealing that fibrinogen titers (p=0.036), red blood cell numbers (p=0.017) and distribution of red cell width (p=0.015) affected the effectiveness of the current POCD PT determination. Furthermore, a highly positive correlation was revealed between fibrinogen titers and the maximum speed of change in transmittance (v/t) (r=0.805, p<0.001), suggesting that fibrinogen might be evaluated simultaneously in this POCD testing. In conclusion, the proposed portable optical-based device performs the highly sensitive and accurate determination of whole blood PT and has commercial potential because of its small volume and low fabrication cost.