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Zwitterionic Nanogels and Microgels: An Overview on Their Synthesis and Applications
2021, Saha, Pabitra, Ganguly, Ritabrata, Li, Xin, Das, Rohan, Singha, Nikhil K., Pich, Andrij
Zwitterionic polymers by virtue of their unique chemical and physical attributes have attracted researchers in recent years. The simultaneous presence of positive and negative charges in the same repeat unit renders them of various interesting properties such as superhydrophilicity, which has significantly broadened their scope for being used in different applications. Among polyzwitterions of different architectures, micro- and/or nano-gels have started receiving attention only until recently. These 3D cross-linked colloidal structures show peculiar characteristics in context to their solution properties, which are attributable either to the comonomers present or the presence of different electrolytes and biological specimens. In this review, a concise yet detailed account is provided of the different synthetic techniques and application domains of zwitterion-based micro- and/or nanogels that have been explored in recent years. Here, the focus is kept solely on the “polybetaines,” which have garnered maximum research interest and remain the extensively studied polyzwitterions in literature. While their vast application potential in the biomedical sector is being detailed here, some other areas of scope such as using them as microreactors for the synthesis of metal nanoparticles or making smart membranes for water-treatment are discussed in this minireview as well.
Bioactive Nanogels Mimicking the Antithrombogenic Nitric Oxide-Release Function of the Endothelium
2023, Hosseinnejad, Aisa, Ludwig, Nadine, Mersmann, Sina, Winnerbach, Patrick, Bleilevens, Christian, Rossaint, Rolf, Rossaint, Jan, Singh, Smriti
Nitric oxide (NO) plays a significant role in controlling the physiology and pathophysiology of the body, including the endothelial antiplatelet function and therefore, antithrombogenic property of the blood vessels. This property of NO can be exploited to prevent thrombus formation on artificial surfaces like extracorporeal membrane oxygenators, which when come into contact with blood lead to protein adsorption and thereby platelet activation causing thrombus formation. However, NO is extremely reactive and has a very short biological half-life in blood, so only endogenous generation of NO from the blood contacting material can result into a stable and kinetically controllable local delivery of NO. In this regards, highly hydrophilic bioactive nanogels are presented which can endogenously generate NO in blood plasma from endogenous NO-donors thereby maintaining a physiological NO flux. It is shown that NO releasing nanogels could initiate cGMP-dependent protein kinase signaling followed by phosphorylation of vasodilator-stimulated phosphoprotein in platelets. This prevents platelet activation and aggregation even in presence of highly potent platelet activators like thrombin, adenosine 5′-diphosphate, and U46619 (thromboxane A2 mimetic).