Fixation of biological tissues with a naturally occurring crosslinking agent: Fixation rate and effects of pH, temperature, and initial fixative concentration

Abstract

In an attempt to overcome the cytotoxicity problem of the glutaraldehyde-fixed tissues, a naturally occurring crosslinking agent (genipin) was used by our group to fix biological tissues. The study was intended to investigate the rate of tissue fixation by genipin. Glutaraldehyde was used as a control. In addition, the degrees of tissue fixation by genipin at different pHs (pH 4.0, pH 7. 4, pH 8.5, or pH 10.5), temperatures (4 degrees C, 25 degrees C, 37 degrees C, or 45 degrees C), and initial fixative concentrations (0.250%, 0.625%, or 1.000%) were examined. The results obtained revealed that the rate of tissue fixation by glutaraldehyde was significantly faster than that by genipin. The degree of tissue fixation by genipin may be controlled by adjusting its fixation duration or fixation conditions. The order in degree of tissue fixation by genipin at different pHs, from high to low, was: at nearly neutral pH (pH 7.4 or pH 8.5) > at basic pH (pH 10.5) > at acidic pH (pH 4.0). The degrees of tissue fixation by genipin at different temperatures were about the same, except for that at 4 degrees C. In contrast, the initial fixative concentration did not seem to affect the degree of tissue fixation by genipin, if only the amount of genipin in the fixation solution was sufficient to complete tissue fixation. The concentrations of genipin in the aqueous solutions at different pHs, temperatures, and initial fixative concentrations tended to decrease with time with or without the occurrence of tissue fixation. This indicated that genipin was not stable in the aqueous solution. The instability of aqueous genipin was more remarkable with increasing pH or temperature. The results obtained in this study may be used to optimize the fixation process for developing bioprostheses fixed by genipin.

Characterization of a Conjugate between Rose Bengal and Chitosan for Targeted Antibiofilm and Tissue Stabilization Effects as a Potential Treatment of Infected Dentin

“…The bacterial collagenase enzyme degraded collagen by hydrolyzing the peptide bond on the amino-terminal side of glycine (-X-Gly-Pro) (44). Use of a commercially available purified bacterial collagenase has been used previously to degrade collagenous tissues (25,40). Following cross-linking of collagen, the sites of collagenase attack may be hidden or modified, and this contributes to the significant difference in the release of amino acid residues following enzymatic degradation (21).…”

“…On the 8th day, the medium was removed from the wells, and the biofilm was carefully washed once with sterile deionized water to remove the dead cells. The biofilm was sensitized with 1 ml of RB (10 M) or CSRB (0.3 mg/ml) at 37°C for 15 min and irradiated at different doses (20,40, and 60 J/cm 2 ). Dark toxicity was evaluated after the sensitization period with the two photosensitizers.…”

Construction and Characterization of Three-Dimensional Silk Fibroin-Gelatin Scaffolds

“…Then join the gelatin, we fabricated the scaffolds cross-linked by genipin under different freeze-dried temperatures. Genipin can spontaneously react with the amine groups on amino acids or proteins to form dark blue pigments 19) . The change of color in SF-G scaffolds cross-linked with genipin indicates microstructure changes during crosslinking.…”

Albumin–genipin solder for laser tissue repair

“…Some researchers have reported that genipin reacts slowly in phosphate buffer solution with 98% of primary amines after 3 days, when the genipin concentration is 0.3% w/v and temperature $378C [13].…”

“…Genipin powder was stirred in deionized water at 58C for approximately 24 hours until a uniform suspension was obtained and subsequently heated at 378C for 30 minutes to partially dissolve the genipin without inactivating it [13]. The initial genipin concentration could not exceed 1% (w/v), due to the limited solubility of the crosslinker in aqueous solutions.…”