Improving Hemocompatibility: How Can Smart Surfaces Direct Blood To Fight against Thrombi

Abstract

Nature utilizes endothelium as a blood interface that perfectly controls hemostasis, preventing the uncontrolled formation of thrombi. The management of positive and negative feedback that finely tunes thrombosis and fibrinolysis is essential for human life, especially for patients who undergo extracorporeal circulation (ECC) after a severe respiratory or cardiac failure. The exposure of blood to a surface different from healthy endothelium inevitably initiates coagulation, drastically increasing the mortality rate by thromboembolic complications. In the present study, an ultrathin antifouling fibrinolytic coating capable of disintegrating thrombi in a self-regulated manner is reported. The coating system is composed of a polymer brush layer that can prevent any unspecific interaction with blood. The brushes are functionalized with a tissue plasminogen activator (tPA) to establish localized fibrinolysis that solely and exclusively is active when it is required. This interactive switching between the dormant and active state is realized through an amplification mechanism that increases (positive feedback) or restores (negative feedback) the activity of tPA depending on whether a thrombus is detected and captured or not. Thus, only a low surface density of tPA is necessary to lyse real thrombi. Our work demonstrates the first report of a coating that self-regulates its fibrinolytic activity depending on the conditions of blood.

Zwitterionic Conducting Polymers: From Molecular Design, Surface Modification, and Interfacial Phenomenon to Biomedical Applications

“…Moreover, the surface properties of CPs are vital for controlling their interactions with various biomolecules in natural environments, such as protein adsorption and cell attachment. To improve the specificity and sensitivity of bioanalytical procedures, a surface modification that resists nonspecific binding and reduces background interference is crucial. − Antifouling strategies have become essential to promoting the performance for long-term applications and implanted devices by reducing unwanted protein adsorption and the inflammatory response, which may cause electronic malfunction. − Various types of antifouling polymers have been designed, and their adequate performance has also been reported. , Generally, their powerful antifouling properties are attributed to the hydrated surface caused by hydrophilic functional groups or molecules. On this basis, antifouling polymers can be classified into three categories, i.e., polymers with (1) zwitterionic moieties, (2) poly­(ethylene glycol) (PEG)-based moieties, and (3) other kinds of hydrophilic coatings such as peptides, hydrogels, and hydrophilic natural biocides. , These antifouling moieties can be functionalized onto CPs and then immobilized onto electrode surfaces to resist the damage due to nonspecific adsorption.…”

An anticoagulant/hemostatic indwelling needle for oral glucose tolerance test

“…The interaction of different coatings with blood components was investigated using static blood experiments to evaluate their anticoagulant or hemostatic properties. 33 FEP, PDA/PEIcoated FEP, PDA/PEI-Hep-coated FEP and dry CMCS/HA-CHO were immersed in 500 μL of fresh heparinized blood and incubated at 37 °C for 1 h. Then, FEP, PDA/PEI-coated FEP, and PDA/PEI-Hep-coated FEP were carefully rinsed three times with PBS for 3 min to remove loosely bound blood cells. The CMCS/HA-CHO hydrogel swollen in blood was gently rinsed with PBS.…”

Brush‐Like Interface on Surface‐Attached Hydrogels Repels Proteins and Bacteria

“…[17,18] The best protection or even complete suppression of fouling has been achieved by brushes of carboxybetaine [19,20] and HPMA. [14,21] Leading to applications in biosensors, [22] coatings for implants and hemocompatible surfaces. [21,23] The synthesis of brushes has witnessed great progress with the advancement of new techniques for controlled radical polymerization that make grafting readily accessible under laboratory conditions.…”

“…[14,21] Leading to applications in biosensors, [22] coatings for implants and hemocompatible surfaces. [21,23] The synthesis of brushes has witnessed great progress with the advancement of new techniques for controlled radical polymerization that make grafting readily accessible under laboratory conditions. However, such conditions are still too complex for translation to medical devices.…”