Tunable hydrogels have gained significant attention in the bioengineering field due to their designer preparation approach. Towards this end, gelatine stands out as a promising candidate owing to its desirable attributes, such as biocompatibility, ability to support cell adhesion and proliferation, biodegradability, and cost-effectiveness. This study presents the preparation of a robust gelatine hydrogel employing sacran aldehyde (SDA) as a natural cross-linker. The resulting SDA-cross-linked gelatine hydrogels (GSDA) display an optimal compressive stress of 0.15 MPa at 50% strain, five times higher than pure gelatine hydrogel. As SDA cross-linking concentration is increased, the swelling capacity of GSDA declines. This decline in swelling capacity, from 80% to 40%, is a result of strong crosslinking of gelatin with SDA. Probing further with FT-IR spectroscopy and SEM at the micron scale unveiled a dual-cross-linking mechanism within the hydrogels. This mechanism encompasses both short- and long-range covalent cross-linking, along with thermo-induced physical cross-linking, resulting in a significant enhancement of the load-bearing capacity of the fabricated hydrogels.

PVA/Sacran and PVA/Q-sacran HMNs were created. The Q-sacran HMNs swelled more, while PVA/Sacran HMNs were stronger and penetrated the skin better. All were non-toxic, loaded/released DOX, and exhibited anticancer activity.

The molecular orientation of liquid crystalline (LC) hydrogels has the potential to induce a range of functionalities that can deliver great mechanical strength. Sacran is a supergiant LC polysaccharide isolated from the cyanobacterium Aphanothece sacrum with a high amount of anionic functional groups such as sulfates and carboxylates. In this article, ultra-strong sacran hydrogels and their dried fibers were produced by cross-linking under injection flow with trivalent metal ions such as Al³⁺, Cr³⁺, Fe³⁺, In³⁺, and rare-earth metal ions such Er³⁺ and Sr³⁺. Crossed-polarizing microscopy and X-ray diffraction imaging revealed a uniaxial molecular orientation in the LC gel fiber, resulting in outstanding mechanical characteristics.

Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural analyses of the sacran rods. A heterogeneous acid-hydrolysis method using a protonated cation-exchange resin was adopted to examine the short-time exposition of concentrated acid to sacran rods. From the supernatant, the oligomeric fraction that was soluble in water and methanol was isolated. The oligomeric fraction had a main sugar ratio of α-Glc:β-Glc:α-Xyl:β-Xyl:α-Rha of 2:5:1.5:1.5:4 (Glc:Xyl:Rha = 7 (=4 + 3):3:4), and it was speculated that the sacran structure includes rhamnoglucan and xyloglucan (4:3), which are generally rigid enough to exhibit LC. To make oriented microfibers of LC sacran, solubility testing was performed on sacran to find good new solvents of polyhydroxy alcohols such as ethylene glycol, 1,2-propanediol, and glycerol. The oriented film was prepared from a sacran aqueous solution where calcium compound particles deposited on the film are different from polyhydroxy alcohol solutions. Although sacran could not form microfibers by itself, polymer composite microfibers of sacran with poly(vinyl alcohol) were prepared by electrospinning. Cross-polarizing microscopy revealed the molecular orientation of the microfibers.

Tunable hydrogels have gained significant attention in the bioengineering field due to their designer preparation approach. Towards this end, gelatine stands out as a promising candidate owing to the desirable attributes, such as biocompatibility, ability to support cell adhesion and proliferation, biodegradability, along with being cost-effective. This study presents the preparation of a robust gelatine hydrogel employing sacran dialdehyde (SDA) as a natural crosslinker. The resulting SDA-crosslinked gelatine hydrogels (GSDA) display an optimal compressive stress of 0.15 MPa at 50% strain, five times higher as compared to pure gelatine hydrogel. As SDA crosslinking concentration is increased, swelling capacity of GSDA declines. Probing further with FTIR spectroscopy and SEM at the micron-scale unveiled a dual-crosslinking mechanism within the hydrogels. This mechanism encompasses both short- and long-range covalent crosslinking, along with thermo-reversible physical crosslinking, resulting in a significant enhancement of the load-bearing capacity of the fabricated hydrogels.