Improved sample preparation method on the morphology observation of hydrophilic polysaccharides for atomic force microscopy (AFM)

With the deepening of polysaccharide research, whether the real polysaccharide structure can be clearly observed directly affects researchers' understanding of polysaccharide structure and function. Therefore, the establishment of a suitable method to study polysaccharide structure is urgent. Konjac glucomannan (KGM), agar, and curdlan were selected in this paper to investigate the effects of drying temperature, plasticizer type and dosage on the molecular structure of polysaccharides in the preparation of polysaccharide samples for AFM testing. The experimental results showed that the molecular morphology changes of different polysaccharides varied at different drying temperatures. Adding a certain dose of plasticizer could relieve the shrinkage of the hydrophilic polysaccharide molecular chain during the drying process. Compared with Tween 20 and Tween 80, glycerol showed a superior effect on relieving molecular chain shrinkage with the same addition amount. Finally, a new polysaccharide sample preparation method for AFM was proposed, and the feasibility of the method was confirmed, which provided a new idea for better use of AFM to observe the morphology of polysaccharides.