Abstract:Objective To investigate the feasibility, effectiveness and safety of a new type of nanocomposite gel of laponite and sodium glycerophosphate (GP). Methods The 0.3% GP powder was mixed with different volume of laponite powder before mixing with pure water to synthesize different concentrations （2％ to 5%） of hydrogel. The morphology of the hydrogel was observed and its degradation rate and rheological property were determined. And 2 ml of normal saline, 0.4% sodium hyaluronate and different concentrations of hydrogel were injected into the submucosa of freshly isolated pig stomach to observe the changes of gastric mucosal eminence height with time. After injection of the same area, electrosurgical dissection was performed by simulating endoscopic submucosal dissection (ESD), and the time of complete dissection was recorded. The effect of 5% hydrogel extract on the survival rate of GES-1 cells in gastric mucosa was detected by CCK8. Results The characterization experiments showed that the synthesized hydrogel had porous structure, stable property and shear thinning ability, and the gelation rate was faster with the increase of the concentration of laponite. In vitro submucosal eminence test, at 90 min, the eminence height maintenance rate was less than 50% in normal saline, about 55% in 0.4% sodium hyaluronate, and about 68%-91% in the 2%-5% hydrogel group, the difference was significant (P<0.05). The average time of simulated ESD stripping was also shorter than that of the control group without significant difference (P<0.05). In the cytotoxicity test, GES-1 activity in the 1-3 d after adding 5% hydrogel extract was not significantly different from that in the control group (P>0.05). Conclusion The nanocomposite gel of laponite and GP is simple, which has shear thinning property, and it can maintain ideal uplift height under the submucosal condition with good biocompatibility. It is expected to become a new submucosal injection.