The influence of polar interface on the conformation and degradation performance of calcium alginate gel units

Yu Li, Yongbin Shen, Pingyan Bian, Jianping Wang
2021 Polymer testing  
The degradation of the bio-scaffold directly affects its structure, function and survival rate of 6 the loaded cells. Sodium alginate as the raw material and calcium chloride as the cross-linking agent 7 were used to prepare calcium alginate hydrogel bio-scaffold; by changing the ratio of Iso-Propyl 8 Alcohol (IPA) to Deionized water (DW) in the crosslinking solvent, coaxial reaction flow interfaces 9 with different polarity conditions were obtained, which affected the aggregation morphology of
more » ... ation morphology of gel 10 units of calcium alginate gel. The regulation ability of interface polarity on the degradation process of 11 calcium alginate gel was investigated. The results show that the polarity index of the solvent changes 12 from 9 to 3.9 with the increase of the proportion of IPA in the crosslinking agent; as the polarity of the 13 interface decreases, the microscopic gel unit of the prepared fiber becomes more orderly; the 14 degradation rate of alginate fibers is slowed down by the ordered and dense morphology of gel units; 15 the mass-loss rate of DW-based fiber scaffold on day 5 is 91.16% while that of IPA-based fiber scaffold 16 is 73.86%; the denser the gel unit, the lower the swelling degree, and the swelling balance has a 17 retarding effect on the degradation process. 19 In tissue engineering applications, the environmental factors (temperature, pH, etc.) of the 31 alginate gel are basically unchanged. The main cause of degradation is that the chelated divalent 32 ions will exchange with other ions in the environment around the gel. resulting in the gel being 33 easier to dissolve in the physiological environment and losing the gel characteristics [7, 8] . In 34 particular, if the crosslinked divalent ions are eluted, the alginate hydrogel will quickly decompose. 35 At present, the main control strategies for the degradation rate of alginic acid gel are hydrophobic 36 modification [9][10][11] and changing the degree of gel network aggregation [12][13][14][15][16][17] . Since there is no 37 J o u r n a l P r e -p r o o f D. . . . Scaffold degradation rate 126 In order to simulate the environment of body fluid infiltration in the body, this study designed 127 a set of extracorporeal circulation degradation system, as shown in Fig.2 . Among them, the 128 magnetic stirrer created a turbulent environment for body fluids and maintains an ambient 129 temperature of 37°C.Phosphate Buffered Saline(PBS) phosphate buffer (Biosharp BL551A 10x) 130 needed to be changed regularly during the degradation process. In order to prevent the PBS from 131 being contaminated, the degradation process was carried out on a clean bench, and the buffer was 132 changed every two days. 133 J o u r n a l P r e -p r o o f 216 The swelling behavior and ion movement caused by infiltration make the fiber begin to 217 absorb more water and sodium and potassium ions from PBS solution, and replace calcium ions 218 from alginate, resulting in the disintegration of eggshell-like structure and the inclusion of more 219 water into the molecular chain, while the hydrogel structure begins to deform, which also leads to 220 the degradation of the fiber. The swelling degree of each polarity base fiber is consistent with the 221 density characteristic of the micro morphology, that is, the lower the polarity, the more compact 222 and ordered the fiber, the lower the swelling degree and the slower the degradation. 223 Considering that relevant studies (Dena [30] , He Shulan [31] ) showed that the mechanical 224 J o u r n a l P r e -p r o o f 273
doi:10.1016/j.polymertesting.2021.107188 fatcat:mm3ineslz5erde4rrqzq3saoae