Denatured thiolated collagen

Injectable in situ Physically and Chemically Crosslinkable Gellan Hydrogel

“…It is known that thiolate anions are much more reactive to oxygen in air than their protonated counterparts. 27 In PBS, 0.2% thiolated gellan solution was able to form a physical gel at room temperature as discussed previously. The molecular mobility of thiolated gellan polymer chains was constrained and the thiol groups from different chain strands were brought closer together, favoring intermolecular crosslinking, or the thiol group oxidation.…”

“…The molecular mobility of thiolated gellan polymer chains was constrained and the thiol groups from different chain strands were brought closer together, favoring intermolecular crosslinking, or the thiol group oxidation. 27 This explains why the oxidation rate in PBS medium is much faster than that in water at the same conditions. In addition, the gelation was also observed in the water media when only approximately half of the thiol groups were oxidized, implying that a chemical network could be set up at a low crosslinking degree.…”

“…8 In addition, the change in molar ellipticity at 202 nm is proportional to the change in the population of the random coil. 27 Figure 8 exhibits the CD spectra of 0.5% thiolated gellan hydrogel obtained under the same conditions as those of unmodified gellan. It can be seen that all the spectra correspond to the double-helical structure, which strongly supports the rheology measurement results that the double-helical conformation was retained after gellan thiolation.…”

“…The chemical mechanism behind thiolated hydrogel reduction is based on exchange reactions between disulfide bonds from hydrogels and thiol groups from reducing reagents. 27 DTT is the most frequently used reducing agent. 27, 29 Basic condition favors the reducing process as only the negatively charged thiolate form is reactive.…”

“…27 DTT is the most frequently used reducing agent. 27, 29 Basic condition favors the reducing process as only the negatively charged thiolate form is reactive. 27 In our experiment, the thiolated gellan hydrogels were reduced by adding excessive DTT (5 equivalents of DTT per disulfide) at pH = 7.5–8.0 under ambient conditions.…”