Zwitterionic Nanogels and Microgels: An Overview on Their Synthesis and Applications

Abstract

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.

Translating Therapeutic Microgels into Clinical Applications

“…Existing reviews about microgels focus on their mechanical and physicochemical properties. [24][25][26] There are also reviews about the potential applications of microgels [27][28][29][30][31][32][33][34][35][36] also in the biomedical field. [37][38][39][40][41][42][43][44][45][46][47] However, the community is lacking an instructive review that covers the requirements for microgels to be employed in the human body, while at the same time discussing which approaches have already translated into preclinical studies as well as clinical applications.…”

Recent advances of zwitterionic-based topological polymers for biomedical applications

“…The hydrogel sensor can accurately and reliably identify underwater motion signals. Moreover, based on the potential biomedical advantages of hydrogels, Saha et al 124 reviewed the synthesis and applications of zwitterionic microgels or nanogels developed in recent years. In the next section, we will focus on various biological applications of zwitterionic-based topological polymers.…”

“…In addition to the topological zwitterionic polymers mentioned above, there are other types of polymer, such as spherical brushes, granular polymers, nano-microspheres, block-combs and so on. [116][117][118][119] For example, Jiang and co-workers have done a lot of work on initiating the polymerization of zwitterions on a variety of planes and nanoparticle surfaces (Fig. 7a).…”

Nanogels as Novel Nanocarrier Systems for Efficient Delivery of CNS Therapeutics

“…The modulation of nanogels (e.g., ligands complementary to receptors) can direct them to the affected tissues with lesions, which differentially express the corresponding receptors, thereby facilitating the uptake and retention of the drugs at a target site ( Saha et al, 2021 ). Vinogradov et al synthesized a new system based on a nanogel network of crosslinked PEG and PEI, which is capable of efficiently delivery of ODNs to the brain across the BBB.…”