Fabrication and Characterization of Polysaccharide Metallohydrogel Obtained from Succinoglycan and Trivalent Chromium

Abstract

In the present study, a polysaccharide metallohydrogel was successfully fabricated using succinoglycan and trivalent chromium and was verified via Fourier transform infrared spectroscopy, differential scanning calorimetry analysis, thermogravimetric analysis (TGA), field emission scanning electron microscopy, and rheological measurements. Thermal behavior analysis via TGA indicated that the final mass loss of pure succinoglycan was 87.8% although it was reduced to 65.8% by forming a hydrogel with trivalent chromium cations. Moreover, succinoglycan-based metallohydrogels exhibited improved mechanical properties based on the added concentration of Cr3+ and displayed a 10 times higher compressive stress and enhanced storage modulus (G′) of 230% at the same strain. In addition, the pore size of the obtained SCx could be adjusted by changing the concentration of Cr3+. Gelation can also be adjusted based on the initial pH of the metallohydrogel formulation. This was attributed to crosslinking between chromium trivalent ions and hydroxyl/carboxyl groups of succinoglycan, each of which exhibits a specific pH-dependent behavior in aqueous solutions. It could be used as a soft sensor to detect Cr3+ in certain biological systems, or as a soft matrix for bioseparation that allows control of pore size and mechanical strength by tuning the Cr3+ concentration.

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

“…The absorption peak at 1722 cm −1 was associated with C=O stretching of the acetyl ester [ 35 ]. The absorption peaks observed at 1608 cm −1 and 1372 cm −1 are assigned to asymmetric and symmetric COO − stretching vibration of the succinate and pyruvate acid groups [ 36 ]. However, in the case of agarose/succinoglycan hydrogels, as the ratio of succinoglycan increased, the −OH stretching vibration peak observed at 3351 cm −1 was shifted to 3358 cm −1 (AG8/SG2), 3349 cm −1 (AG6/SG4), and to 3333 cm −1 (AG4/SG6), respectively.…”

“…This confirmed the successful preparation of agarose/succinoglycan hydrogels. On the other hand, the decrease in peak intensities of 930 cm −1 and 892 cm −1 in the AG10 spectrum indicated that successful network formation was induced in agarose/succinoglycan hydrogels, probably due to the intermolecular interactions such as hydrogen bondings and van der Waals interactions [ 35 , 36 ].…”

pH-Responsive Succinoglycan-Carboxymethyl Cellulose Hydrogels with Highly Improved Mechanical Strength for Controlled Drug Delivery Systems

“…They have succinate, pyruvate, and acetate groups as non-carbohydrate substituents [ 16 ]. Due to the functional groups with a carboxyl group, it is easy to crosslink with metal cations such as Fe 3+ and Cr 3+ [ 17 ], and is very sensitive to pH [ 18 ]. In addition, succinoglycan can maintain the physical consistency of its physical properties even under extreme conditions such as high temperature, high shear rate, high salinity, or ionic concentration [ 19 , 20 ].…”

“…In addition, succinoglycan can maintain the physical consistency of its physical properties even under extreme conditions such as high temperature, high shear rate, high salinity, or ionic concentration [ 19 , 20 ]. In particular, the high heat stability of succinoglycan showed mass stability of about 60%, even at 600 °C, as measured using thermogravimetric analysis (TGA) [ 17 ].…”

“…To our knowledge, there have been no reports of non-beaded CMC-based hydrogels capable of pH-responsive drug delivery using succinoglycan, an unmodified bacterial polysaccharide to significantly improve the mechanical strength of hydrogels while maintaining characteristic superabsorbency. We hypothesized that bacterial succinoglycan could increase the mechanical strength of CMC-based hydrogels because succinoglycan can maintain a stable consistency of physical properties even in extreme environments [ 7 , 17 ].…”