The Influence of Bloom Index, Endotoxin Levels and Polyethylene Glycol Succinimidyl Glutarate Crosslinking on the Physicochemical and Biological Properties of Gelatin Biomaterials

Abstract

In the medical device sector, bloom index and residual endotoxins should be controlled, as they are crucial regulators of the device’s physicochemical and biological properties. It is also imperative to identify a suitable crosslinking method to increase mechanical integrity, without jeopardising cellular functions of gelatin-based devices. Herein, gelatin preparations with variable bloom index and endotoxin levels were used to fabricate non-crosslinked and polyethylene glycol succinimidyl glutarate crosslinked gelatin scaffolds, the physicochemical and biological properties of which were subsequently assessed. Gelatin preparations with low bloom index resulted in hydrogels with significantly (p < 0.05) lower compression stress, elastic modulus and resistance to enzymatic degradation, and significantly higher (p < 0.05) free amine content than gelatin preparations with high bloom index. Gelatin preparations with high endotoxin levels resulted in films that induced significantly (p < 0.05) higher macrophage clusters than gelatin preparations with low endotoxin level. Our data suggest that the bloom index modulates the physicochemical properties, and the endotoxin content regulates the biological response of gelatin biomaterials. Although polyethylene glycol succinimidyl glutarate crosslinking significantly (p < 0.05) increased compression stress, elastic modulus and resistance to enzymatic degradation, and significantly (p < 0.05) decreased free amine content, at the concentration used, it did not provide sufficient structural integrity to support cell culture. Therefore, the quest for the optimal gelatin crosslinker continues.

Dual drug delivery collagen vehicles for modulation of skin fibrosis in vitro

“…Starting with biomechanical analysis, the collagen hydrogels showed a typical stress-strain curve of semicrystalline polymers that experience both elastic and plastic deformation [76,77]. Crosslinking resulted in increased resistance to mechanical forces, as has been well-documented previously in the literature with PEG crosslinked collagen fibres [45,78], films [46,47,79], sponges [80,81] and hydrogels [44,82], as well as gelatin hydrogels [83] and scleral collagen [84]. Moving into molecular loading and release, crosslinking restrained the release of the encapsulated FITC-dextran, TSA and T122bt, which can be attributed to the resultant tight molecular structure that increases resistance to degradation and slows down the diffusion process [85][86][87][88][89][90].…”

Finding the sweet spot: a library of hydrogels with tunable degradation for tissue model development

“…24,54 Chemical crosslinking can also be toxic to cells, but the SG approach has been used extensively and show low toxicity. [55][56][57] In this work, we created a library of gels and looked at cell survival. The gels that showed maximum longterm survival, adhesion, migration, and capillary-like network formation (4 : 1 and 8 : 1-75% PLL gels) have a low concentration of PAA in the hydrogel and the lowest number of free amines in the system (Fig.…”

Effective Endotoxin Removal from Chitosan That Preserves Chemical Structure and Improves Compatibility with Immune Cells

“…Many studies employ natural sources of biomaterials, which are susceptible to endotoxin contamination [ 25 , 26 ]. Furthermore, synthetic biomaterials can also be contaminated with endotoxin due to contaminated laboratory equipment or reagents [ 15 , 17 ].…”