Self-assembly of malto-oligosaccharide-block-solanesol in aqueous solutions: Investigating morphology and sugar-based physiological compatibility

Abstract

Starch-derived hydrophilic malto-oligosaccharides (Glc_n, where n = 1–7) conjugated to hydrophobic solanesol through click chemistry, i.e., Glc_n-b-Sol copolymers, have demonstrated significant promise in developing fully natural block co-oligomers for solid-state nanopatterning applications. This study explores in detail the solution self-assembly, lectin recognition, and pancreatic digestion of Glc₆- and Glc₇-b-Sol. Above a critical micelle concentration (CMC) of 0.3 g/L, both systems demonstrated self-assembly into diverse morphologies. Using the pyrene probe method, a polarity parameter of 1.2 was observed at 1 mM samples. Dynamic light scattering experiments, which measured autocorrelation functions and relaxation times at various angles, revealed the anisotropic and heterogeneous characteristics of the morphologies. Specifically, Glc₆-b-Sol predominantly exhibited spherical and elongated worm-like micelles with considerable heterogeneity across the entire range of concentrations studied. In contrast, Glc₇-b-Sol primarily formed stable, shorter, worm-like structures at lower concentrations, as observed by transmission electron microscopy. However, small-angle X-ray scattering showed that higher concentrations led to the formation of longer worm-like structures, with Glc₇-b-Sol forming thicker diameters. Notably, interaction with Concanavalin A above the CMC resulted in complete agglutination. Pancreatic digestion with hog pancreas α-amylase resulted in morphological alterations, with Glc₃- and Glc₄-b-Sol emerging as the primary digestion products for Glc₆- and Glc₇-b-Sol, respectively.