Glucose-isomerism effect on sugar-lectin interaction of glycopolymer

Based on the biological properties of saccharides, saccharide-protein interaction, self-assembling ability and high quantum yield of perylene bisimide derivatives, glucose functionalized water-soluble perylene bisimide derivatives were designed. Tri-block glycopolymers with different sugar units, 1-linked glucose (1-Glc) and 6-linked glucose (6-Glc), were synthesized by atom transfer radical polymerization (ATRP) and click reaction, using perylene bisimide (PBI) as the initiator. Dynamic light scattering (DLS), transmission electron microscopy (TEM) and ultraviolet-visible absorption spectra (UV-Vis) were used to characterize the morphology, size and optical property of the glycopolymers in aqueous solution. The results show that the polymers had high absorption in the near IR region. In addition, the photoacoustic property of the polymers was studied by photoacoustic imaging. The results showed that the glycopolymers had strong photoacoustic signals. Moreover, a variety of characterizations including UV-Vis and DLS were conducted to observe the interaction between the two glycopolymers and Con A in order to study glyco-regioisomerism effect on lectin-binding. It was found that the turbidity and particle size of PBI-1-Glc solution increased significantly with the addition of Con A lectin, while PBI-6-Glc solution showed little change. Further more, photoacoustic imaging was also applied to study the recognition of glycopolymers and lectin. The results indicated that Con A could increase the photoacoustic signal of PBI-1-Glc solution, and photoacoustic technology could also be used to identify the interaction between two polymers and lectins effectively. In conclusion, the experimental results showed that PBI-1-Glc had a strong interaction with lectin Con A, whereas PBI-6-Glc did not, confirming that the monosaccharide isomerization effect on their biological function of glycopolymers had universality in a certain degree.