Cellular interaction of polygycerol dendrimers and those derivatives

Abstract

Event Abstract Back to Event Cellular interaction of polygycerol dendrimers and those derivatives Tooru Ooya1 and Yuji Kawashima1 1 Kobe University, Department of Chemical Science and Engineering, Japan Introduction: Understanding of cellular events is crucial for the development of nanomedicine. Polyglycerol dendrimers (PGDs) and hyperbranched polyglycerol (HyPG) have been examined for various biomedical applications due to their positive biocompatibilities and unique physicochemical properties[1]. Although HyPG-based naogels were reported with showing a size-dependent cellular uptake[2], PGDs, which modulate the polarity of water[3]-[5], has not been subjected to cellular interaction. In this study, PGDs and glycerol dendrons (GDs)-modified liposomes were investigated to evaluate modulating cellular functions in terms of cellular uptake, death and activation. Materials and Methods: PGDs of generation 3 and 4 (Fig. 1) were prepared by our previous method. Cytotoxicity test was performed by MTT assay using HeLa cells. Fig. 1 Chemical Structure of PGDs of generations 3 and 4 Mono-stearyl PGD-G4 was mixed with Qdot655 organic quantum dots to obtain PGD-G4-coated Qdot655. Nitric oxide (NO) release from mouse macrophage-like cell line J774.1 stimulated by the addition of the PGD-G4-coated Qdot655 was evaluated by measuring emission intensity of the NO-reacted DAF-FM. GDylated liposomes were prepared and evaluated in terms of cellular uptake (Fig. 2). The obtained conjugates were introduced into bare liposomes, in which doxorubicin (DOX) was preliminarily encapsulated, by a post-insertion method. Cellular uptake amount of each liposomes was evaluated by flow cytometry. Fig. 2 Preparation of GD-modified liposome containing L-α-phosphatidylcholine, cholesterol, and DSPE-GD-G2. Results and Discussion: With increasing the generation of PGDs, T1 was significantly shorten at the same number of hydroxyl groups per one water molecule, whereas the T1 value of PGD-G4 was larger than that of PGD-G3. This result suggests that the amount of bound water located on PGD-G3 molecule was apparently larger than that on PGD-G4. PGD-G3 showed significant cytotoxicity comparing with PGD-G4, suggesting the amount of bound water state affected to the interaction with Hela cells. The results of NO release stimulated by the PGD-G4-coated Qdot655 suggest that the PGD-G4-coatedQdot655 might induce nitric oxide synthase activation. Cellular uptake behavior of DOX-loaded GDylated liposomes was significantly greater than that of PEGylated liposome. Particularly, GD-G2ylated liposomes were internalized into cells as well as PEGylated liposomes, but GD-G1ylated liposome was much greater than the other liposomes. Conclusion: Local density of hydoxy groups provided by PGDs induced possibly both cell death and cellular activation. GDylation of liposome is a valuable approach to modulating cellular uptake of the encapsulated biologically active compounds. This work was partially supported by Grant-in-Aid for Scientific Research on Innovative Areas (New Polymeric Materials Based on Element-Blocks) (No. 15H00748) from JSPS, Japan.