A novel salt-responsive hydrogel on the base of calixresorcinarene–mPEG amide conjugate

Carboxybetaine and Carboxybetaine Ester Derivatives of Tetra(dodecyloxyphenyl)-calix[4]resorcinarene: Synthesis, Self-Assembly and In Vitro Toxicity

Amphiphilic calix[4]resorcinarenes are a class of macrocyclic compounds with broad potential utility including nanomedicine. Here the synthesis of new carboxybetaine and carboxybetaine ester calix[4]resorcinarene bearing 4-(dodecyloxy)phenyl groups on the lower rim is presented. The compounds were characterized by 1H-NMR, 13C-NMR, 2D NMR, IR, ESI and elemental analysis. The critical association concentration values are 1.00 × 10−5 and 1.18 × 10−5 mol·L−1 for carboxybetain and ester, respectively. The hemolytic activity of the macrocycles and their cytotoxicity against normal (WI-38, Chang liver) and tumor cells (M-HeLa) are also estimated.

Calix[4]Resorcinarene Carboxybetaines and Carboxybetaine Esters: Synthesis, Investigation of In Vitro Toxicity, Anti-Platelet Effects, Anticoagulant Activity, and BSA Binding Affinities

As a result of bright complexation properties, easy functionalization and the ability to self-organize in an aqueous solution, amphiphilic supramolecular macrocycles are being actively studied for their application in nanomedicine (drug delivery systems, therapeutic and theranostic agents, and others). In this regard, it is important to study their potential toxic effects. Here, the synthesis of amphiphilic calix[4]resorcinarene carboxybetaines and their esters and the study of a number of their microbiological properties are presented: cytotoxic effect on normal and tumor cells and effect on cellular and non-cellular components of blood (hemotoxicity, anti-platelet effect, and anticoagulant activity). Additionally, the interaction of macrocycles with bovine serum albumin as a model plasma protein is estimated by various methods (fluorescence spectroscopy, synchronous fluorescence spectroscopy, circular dichroic spectroscopy, and dynamic light scattering). The results demonstrate the low toxicity of the macrocycles, their anti-platelet effects at the level of acetylsalicylic acid, and weak anticoagulant activity. The study of BSA-macrocycle interactions demonstrates the dependence on macrocycle hydrophilic/hydrophobic group structure; in the case of carboxybetaines, the formation of complexes prevents self-aggregation of BSA molecules in solution. The present study demonstrates new data on potential drug delivery nanosystems based on amphiphilic calix[4]resorcinarenes for their cytotoxicity and effects on blood components.

High-Strength and Injectable Supramolecular Hydrogel Self-Assembled by Monomeric Nucleoside for Tooth-Extraction Wound Healing

Hydrogels with high mechanical strength and injectability have attracted extensive attention in biomedical and tissue engineering. However, endowing a hydrogel with both properties is challenging because they are generally inversely related. In this work, by constructing a multi-hydrogen-bonding system, a high-strength and injectable supramolecular hydrogel is successfully fabricated. It is constructed by the self-assembly of a monomeric nucleoside molecular gelator (2-amino-2'-fluoro-2'-deoxyadenosine (2-FA)) with distilled water/phosphate buffered saline as solvent. Its storage modulus reaches 1 MPa at a concentration of 5.0 wt%, which is the strongest supramolecular hydrogel comprising an ultralow-molecular-weight (MW < 300) gelator. Furthermore, it exhibits excellent shear-thinning injectability, and completes the sol-gel transition in seconds after injection at 37 °C. The multi-hydrogen-bonding system is essentially based on the synergistic interactions between the double NH₂ groups, water molecules, and 2'-F atoms. Furthermore, the 2-FA hydrogel exhibits excellent biocompatibility and antibacterial activity. When applied to rat molar extraction sockets, compared to natural healing and the commercial hemorrhage agent gelatin sponge, the 2-FA hydrogel exhibits faster degradation and induces less osteoclastic activity and inflammatory infiltration, resulting in more complete bone healing. In summary, this study provides ideas for proposing a multifunctional, high-strength, and injectable supramolecular hydrogel for various biomedical engineering applications.