Fabrication of Flexible pH-Responsive Agarose/Succinoglycan Hydrogels for Controlled Drug Release

Abstract

Agarose/succinoglycan hydrogels were prepared as pH-responsive drug delivery systems with significantly improved flexibility, thermostability, and porosity compared to agarose gels alone. Agarose/succinoglycan hydrogels were made using agarose and succinoglycan, a polysaccharide directly isolated from Sinorhizobium meliloti. Mechanical and physical properties of agarose/succinoglycan hydrogels were investigated using various instrumental methods such as rheological measurements, attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopic analysis, X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM). The results showed that the agarose/succinoglycan hydrogels became flexible and stable network gels with an improved swelling pattern in basic solution compared to the hard and brittle agarose gel alone. In addition, these hydrogels showed a pH-responsive delivery of ciprofloxacin (CPFX), with a cumulative release of ~41% within 35 h at pH 1.2 and complete release at pH 7.4. Agarose/succinoglycan hydrogels also proved to be non-toxic as a result of the cell cytotoxicity test, suggesting that these hydrogels would be a potential natural biomaterial for biomedical applications such as various drug delivery system and cell culture scaffolds.

Gallic Acid-Loaded Sodium Alginate-Based (Polyvinyl Alcohol-Co-Acrylic Acid) Hydrogel Membranes for Cutaneous Wound Healing: Synthesis and Characterization

“…X-ray diffraction (TD-3500 X-ray diffractometer, Dandong, China) using Copper Kα examined crystallinity variations over the diffraction angle range of 10 to 60° [ 68 ]. Various samples were measured, including sodium alginate, PVA, gallic acid and hydrogel membrane.…”

Bacterial Succinoglycans: Structure, Physical Properties, and Applications

“…On the other hand, the succinoglycan from Sinorhizobium meliloti 1021 strain displayed a broad peak at 2θ = 18.7. Because of poor crystallinity, agarose/succinoglycan hydrogels (AG/SG) showed lower and shifted diffraction peaks at angles of 17.5, 17.4, and 18.0 on the 2θ scale compared to pure agarose [71]. In addition, succinoglycan metallohydrogel using trivalent chromium (Cr 3+ ) was verified via XRD measurements [72].…”

Smart Hydrogels for Advanced Drug Delivery Systems

“…PRHs are usually developed by the polyelectrolytes that contain weak acidic or basic function groups. Therefore, they can be classified into two major categories, namely, cationic and anionic hydrogels, which have alkaline groups (such as –NH 2 ) and acidic groups (such as –COOH) on their molecular chains, respectively [ 38 , 39 ]. The swelling of PRHs is affected by the pH value of the surrounding medium at the pKa and pKb values of the pendant acidic and basic groups [ 38 ].…”