Stereocomplexation of Poly(lactic acid) and Chemical Crosslinking of Ethylene Glycol Dimethacrylate (EGDMA) Double-Crosslinked Temperature/pH Dual Responsive Hydrogels

Abstract

Physical crosslinking and chemical crosslinking were used to further improve the mechanical properties and stability of the gel. A temperature/pH dual sensitive and double-crosslinked gel was prepared by the stereo-complex of HEMA-PLLA20 and HEMA-PDLA20 as a physical crosslinking agent, ethylene glycol dimethacrylate (EGDMA) as a chemical crosslinking agent, and azodiisobutyronitrile (AIBN) as an initiator for free radical polymerization. This paper focused on the performance comparison of chemical crosslinked gel, a physical crosslinked gel, and a dual crosslinked gel. The water absorption, temperature, and pH sensitivity of the three hydrogels were studied by a scanning electron microscope (SEM) and swelling performance research. We used a thermal analysis system (TGA) and dynamic viscoelastic spectrometer to study thermal properties and mechanical properties of these gels. Lastly, the in vitro drug release behavior of double-crosslinked hydrogel loaded with doxorubicin under different conditions was studied. The results show that the double-crosslinked and temperature/pH dual responsive hydrogels has great mechanical properties and good stability.

An Overview on Recent Progress of the Hydrogels: From Material Resources, Properties, to Functional Applications

“…polymer monomers through chemical bonds, [169] while the physical cross-linking forms the supramolecular structures through non-chemical bounds including the van der Waals force and hydrophobic interaction, ionic bond, and hydrogen bond. [170] These two main cross-linking forms are heterogeneous organizations with independent structure domains (Figure 3) therefore they are network structures with different molecule properties.…”

“…Reproduced under terms of the CC-BY license. [169] Copyright 2020, the Author(s). Published by MDPI.…”

“…Besides, the comprehensive properties of hydrogels are determined by several factors namely the polymerization method, the type and composition of monomers, and the structure and type of cross-linking agent. [184,186] For example, Wang et al mentioned the preparation of pH/temperature sensitive double crosslinking hydrogels using HEMa-PDLA20 and HEMa-PLLA20 as the physical cross-linking agents, ethylene glycol dimethacrylate as chemical cross-linking agent, and azodiisobutyronitrile as initiator, [169] as shown in Figure 5A. Among them, diethylaminoethyl methacrylate monomer makes the hydrogel sensitive to pH.…”

Nanoformulations of Ursolic Acid: A Modern Natural Anticancer Molecule

“…Polylactic acid (PLA), a product of a certain amount of lactic acid condensation reaction, is a biodegradable polymer material with good biocompatibility and is an ideal carrier for drug-carrying nanoparticles ( Wang Z et al, 2020d ). One study successfully prepared a UA polylactic acid nanoparticle with a high encapsulation rate of up to 96%, which meant that the loss of UA was greatly reduced during the preparation process ( Antônio et al, 2017 ).…”

Application of Bioactive Hydrogels for Functional Treatment of Intrauterine Adhesion

“…Compared with traditional hormone replacement therapy, this method may reduce the incidence of related risks like breast hyperplasia caused by oral estrogen in treating IUA. Several experiments that demonstrate that the effectiveness of a hydrogel-based drug delivery model in treating IUA have used animal models, and there has been limited evidence of clinical practice in human ( Wang et al, 2020b ). Whether hydrogels as in situ drug delivery systems are more beneficial than traditional drug delivery is still not clear in humans.…”